FOUS30 KWBC 271924
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
324 PM EDT Sat Sep 27 2025

Day 1
Valid 16Z Sat Sep 27 2025 - 12Z Sun Sep 28 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHWEST AND MID-ATLANTIC...

...Desert Southwest, Four Corners, and Southern Rockies...
An anomalous upper low (700-500mb heights falling beneath the 10th
percentile from the CFSR climatology) will slowly fill today as it
pivots slowly over the low deserts of CA/AZ. Downstream of this
feature, confluent low and mid level flow will push northward out
of the Baja region of Mexico, leading to a surge of PWs reaching as
high as 1.25 inches in southern CA/AZ, and as high as 0.75 inches
into UT, around the 90th percentile for the date according to the
SPC sounding climatology. Farther east, and somewhat displaced from
the upper low, a secondary surge in moisture will lift out of the
Rio Grande Valley, surging PWs to around the 90th percentile as
well into southern NM. This moisture will overlap with increasing
instability (MUCAPE 500-1000 J/kg) to result in widespread showers
and thunderstorms today, first beneath the upper low through late
morning, and then expanding across a much larger region during peak
heating this aftn/eve.

In general, convection that develops today will move steadily
north/northwest in the vicinity of the upper low, with 0-6km mean
winds progged to be 10-15kts. This suggests that storms should be
generally progressive outside of terrain influences during
development, but aligned propagation vectors in the cyclonic regime
will allow for repeating rounds of cells in some areas. With rain
rates progged by both the HREF neighborhood probabilities and the
UA HRRR-forced WRF to potentially reach 0.5-1.0"/hr, this could
result in stripes of 1 to as much as 3 inches of rainfall, leading
to scattered instances of flash flooding.

The inherited risk areas were still well supported by the latest
guidance suite, so only minor adjustments were made to the previous
outlook.


...Mid-Atlantic States and Coastal Southeast...
A mid-level longwave trough anchored just inland from the
Southeast Coast and aligned into the Ohio Valley will maintain
intensity today, shedding vorticity lobes and accompanying weak
impulses northeast through the region. At the surface, a wavy front
will meander in the vicinity, with multiple low-pressures rippling
along it in response to the mid-level shortwaves. The entire area
will embedded within favorable thermodynamics for convection (PWS
1.5-2.0 inches, locally above the 97th percentile according to
NAEFS, overlapped with MUCAPE around 750 J/kg), with freezing
levels of 13,000-14,000 ft supporting efficient warm rain processes
this aftn.

It is likely that thunderstorms will become widespread, especially
during the peak diurnal cycle, and the HREF neighborhood
probabilities for 2"/hr reach as high as 30-40%. While in general
FFG exceedance probabilities are modest at 10-20%, there are
pockets of much higher probabilities (up to 40%) across the
Tidewater region of VA where a wave of low pressure and enhanced
bulk shear will help organize thunderstorms a bit more
significantly (and some of this is already ongoing, please see WPC
Metwatch #1145 for more information). Here, FFG is also
compromised below most adjacent areas, and the CSU First Guess
Field suggests a higher- end SLGT risk today. So while in general
flash flood instances should be pretty widely scattered, some
locally more numerous impacts are possible in southeast VA through
this evening.


Weiss

Day 2
Valid 12Z Sun Sep 28 2025 - 12Z Mon Sep 29 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
FAR WEST TEXAS AND NEW MEXICO...

...Great Basin through the Southern Rockies...
The closed low over the Low Deserts on D1 will gradually open and
fill during Sunday while meandering slowly northeast such that the
primary trough axis is positioned over the Four Corners by 12Z
Monday. Despite this weakening, pronounced height falls and
periodic PVA from weak embedded impulses will maintain broad ascent
from the Great Basin through the Southern Rockies. At the same
time, downstream southerly flow ahead of the trough axis will
continue to manifest as a surge of elevated PWs, with widespread PW
anomalies from the NAEFS reaching the 97th to 99th percentiles.

This broad southerly flow combined with the lowering heights aloft
will also produce elevated MUCAPE of 500-750 J/kg across most of
this area, with locally enhanced instability above 1000 J/kg over
NM. This setup will support scattered to widespread convection as
suggested by available CAMs simulated reflectivity, with rain rates
potentially reaching 1"/hr at times. Mean 0-6km winds Sunday should
again be steady out of the south at 10-15 kts, although aligned
propagation vectors could result in some repeating/training,
especially across New Mexico. The inherited risk areas were
adjusted for new guidance, but changes were primarily cosmetic.


...Southeast Coast...
Concern on Sunday turns towards Tropical Depression Nine and its
evolution as it starts to lift slowly northward from the Bahamas
while strengthening. While there continues to be quite a bit of
model uncertainty, the general model trends have been for a slower
progression of this system, with very dry air likely positioned
just to its west as reflected by 750-500mb RH fields.=20

This suggests that precipitation may be a bit slower to move=20
onshore from the FL Peninsula into the Carolinas, but as Nine=20
deepens and the subsequent 850mb winds to the north intensify, the=20 accompanying strengthening cyclonic flow will transport impressive=20
tropical moisture westward and onshore, with PWs likely reaching=20
above 2" from Cape Fear southward through the Space Coast. As
tropical rain showers move onshore, they will be extremely
efficient, with rain rates likely reaching 2-3"/hr. These showers
will repeatedly generate offshore and then train onshore, so right
along the immediate coast where sufficient instability and
moistening can occur, total rainfall could exceed 3", especially
across Florida, as reflected by HREF probabilities exceeding 40%.
Of course, any additional trends west or slower in the track of
Nine could enhance this rainfall, and locally higher totals are
expected.

The inherited MRGL risk was trimmed closer to the coast, especially
across the Carolinas, with this update, with additional, but=20
minimal cosmetic adjustments over the Florida Peninsula also made
with this update.


Weiss

Day 3
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS THE COASTAL
PLAIN FROM NORTH CAROLINA THROUGH THE CENTRAL FLORIDA PENINSULA...

...Southeast and Mid-Atlantic...
All attention will be on Tropical Depression Nine, which is
forecast by NHC to be a strong Tropical Storm or Cat 1 Hurricane on
Monday as it lifts slowly northward from the Bahamas. While
guidance has been slowly converging on a solution that brings the
storm to a stall east of the GA/SC coast by the end of D3, there is
still considerable spread in the ensembles. Staying close to the
NHC track brings heavy rainfall D3 from the Space Coast of Florida
northward into Southeast North Carolina. The exact track and
intensity of Nine will determine where the greatest moisture
convergence will occur to create the heaviest rainfall amounts, but
anywhere along and north of the track will likely receive training
tropical showers with 2-3"/hr rain rates. The heaviest rain still
appears to be confined to the immediate coast due to dry air to the
west, but as the column slowly saturates in response to persistent
and increasing moist advection on strengthening onshore 850mb flow,
heavy rain will eventually spread inland, especially into SC and
NC. While the inherited SLGT risk was trimmed to the south a bit
over NC and expanded along the eastern coast of the FL Peninsula
with this update, in general, changes were minimal due to
continuing track uncertainty.


...Northern California/Southwest Oregon...
An impressive trough will push eastward across the Pacific Monday,
reaching the coast and angling onshore by 12Z Tuesday. This will
drive a frontal system onshore, and the resulting low-level
convergence overlapped by a modestly coupled jet structure will
provide plentiful ascent for heavy rainfall along the coast of
northern CA/southern OR D3. Moisture transport will become
impressive ahead of the front as reflected by high probabilities
(70-80%) for IVT exceeding 500 kg/m/s from both the ECENS and GEFS
ensembles, pushing PWs to above 1 inch on increasing southerly
850mb inflow. Where this moisture overlaps with sufficient
instability (progs suggest at least 250 J/kg MUCAPE) it will result
in periods of moderate to heavy rainfall with rates of
0.25-0.5"/hr which may be sufficient for at least localized impacts
in vulnerable terrain, especially where training or enhanced
convergence along terrain features can produce more than 1 inch of
rainfall.


Weiss


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5SAbkh4zNICpaHd6TpGKcYsey254oPT-WO4_kxPGpkCc= nxSOYBx9Nzlz29keLykPRIfXX_2W9snq7GcHwtsWFyCYFIc$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5SAbkh4zNICpaHd6TpGKcYsey254oPT-WO4_kxPGpkCc= nxSOYBx9Nzlz29keLykPRIfXX_2W9snq7GcHwtsWjZnSZyM$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5SAbkh4zNICpaHd6TpGKcYsey254oPT-WO4_kxPGpkCc= nxSOYBx9Nzlz29keLykPRIfXX_2W9snq7GcHwtsW1R4SeSw$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 280057
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
857 PM EDT Sat Sep 27 2025

Day 1
Valid 01Z Sun Sep 28 2025 - 12Z Sun Sep 28 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHWEST...

...Southwest...
A Slight risk was maintained across portions of southeast CA into
western AZ. Isolated to scattered instances of flash flooding
continue this evening. Still generally expect to see the coverage
and intensity of convection decrease overnight, although with
lingering instability and the mid level low overhead we could see
at least some localized areas of heavier convection continue.

The Slight risk was removed over NM with this update. Still expect
to see some convection overnight, and localized instances of flash
flooding are still possible. However, activity has generally=20
underperformed so far today, and with instability lower here=20
compared to farther west, generally think the flash flood risk is=20
isolated enough to warrant just the Marginal risk.

...East Coast...
A Marginal risk was maintained in the vicinity of the Delmarva
where low topped convection will support efficient warm rain
processes. Overall not expecting much in the way of a flood=20
threat, but heavy rates could result in a localized risk.

Slow moving convection near the mid/upper vort energy will
continue to support an isolated flash flood risk over portions of=20
southwest VA and central NC. Overall the expectation is for this=20
activity to decrease in coverage/intensity going forward...but=20
models have not had a great handle on this convection and thus=20
another instance or two of flash flooding can not be ruled out.

Increasing easterly flow well north of Tropical Depression Nine=20
may help locally enhance convergence along the east coast of FL=20
tonight into Sunday morning. Low confidence on these details, but=20
if heavier convection is able to develop then a localized urban=20
flash flood risk is a possibility.

Chenard


Day 2
Valid 12Z Sun Sep 28 2025 - 12Z Mon Sep 29 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
FAR WEST TEXAS AND NEW MEXICO...

...Great Basin through the Southern Rockies...
The closed low over the Low Deserts on D1 will gradually open and
fill during Sunday while meandering slowly northeast such that the
primary trough axis is positioned over the Four Corners by 12Z
Monday. Despite this weakening, pronounced height falls and
periodic PVA from weak embedded impulses will maintain broad ascent
from the Great Basin through the Southern Rockies. At the same
time, downstream southerly flow ahead of the trough axis will
continue to manifest as a surge of elevated PWs, with widespread PW
anomalies from the NAEFS reaching the 97th to 99th percentiles.

This broad southerly flow combined with the lowering heights aloft
will also produce elevated MUCAPE of 500-750 J/kg across most of
this area, with locally enhanced instability above 1000 J/kg over
NM. This setup will support scattered to widespread convection as
suggested by available CAMs simulated reflectivity, with rain rates
potentially reaching 1"/hr at times. Mean 0-6km winds Sunday should
again be steady out of the south at 10-15 kts, although aligned
propagation vectors could result in some repeating/training,
especially across New Mexico. The inherited risk areas were
adjusted for new guidance, but changes were primarily cosmetic.


...Southeast Coast...
Concern on Sunday turns towards Tropical Depression Nine and its
evolution as it starts to lift slowly northward from the Bahamas
while strengthening. While there continues to be quite a bit of
model uncertainty, the general model trends have been for a slower
progression of this system, with very dry air likely positioned
just to its west as reflected by 750-500mb RH fields.

This suggests that precipitation may be a bit slower to move
onshore from the FL Peninsula into the Carolinas, but as Nine
deepens and the subsequent 850mb winds to the north intensify, the
accompanying strengthening cyclonic flow will transport impressive
tropical moisture westward and onshore, with PWs likely reaching
above 2" from Cape Fear southward through the Space Coast. As
tropical rain showers move onshore, they will be extremely
efficient, with rain rates likely reaching 2-3"/hr. These showers
will repeatedly generate offshore and then train onshore, so right
along the immediate coast where sufficient instability and
moistening can occur, total rainfall could exceed 3", especially
across Florida, as reflected by HREF probabilities exceeding 40%.
Of course, any additional trends west or slower in the track of
Nine could enhance this rainfall, and locally higher totals are
expected.

The inherited MRGL risk was trimmed closer to the coast, especially
across the Carolinas, with this update, with additional, but
minimal cosmetic adjustments over the Florida Peninsula also made
with this update.


Weiss

Day 3
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS THE COASTAL
PLAIN FROM NORTH CAROLINA THROUGH THE CENTRAL FLORIDA PENINSULA...

...Southeast and Mid-Atlantic...
All attention will be on Tropical Depression Nine, which is
forecast by NHC to be a strong Tropical Storm or Cat 1 Hurricane on
Monday as it lifts slowly northward from the Bahamas. While
guidance has been slowly converging on a solution that brings the
storm to a stall east of the GA/SC coast by the end of D3, there is
still considerable spread in the ensembles. Staying close to the
NHC track brings heavy rainfall D3 from the Space Coast of Florida
northward into Southeast North Carolina. The exact track and
intensity of Nine will determine where the greatest moisture
convergence will occur to create the heaviest rainfall amounts, but
anywhere along and north of the track will likely receive training
tropical showers with 2-3"/hr rain rates. The heaviest rain still
appears to be confined to the immediate coast due to dry air to the
west, but as the column slowly saturates in response to persistent
and increasing moist advection on strengthening onshore 850mb flow,
heavy rain will eventually spread inland, especially into SC and
NC. While the inherited SLGT risk was trimmed to the south a bit
over NC and expanded along the eastern coast of the FL Peninsula
with this update, in general, changes were minimal due to
continuing track uncertainty.


...Northern California/Southwest Oregon...
An impressive trough will push eastward across the Pacific Monday,
reaching the coast and angling onshore by 12Z Tuesday. This will
drive a frontal system onshore, and the resulting low-level
convergence overlapped by a modestly coupled jet structure will
provide plentiful ascent for heavy rainfall along the coast of
northern CA/southern OR D3. Moisture transport will become
impressive ahead of the front as reflected by high probabilities
(70-80%) for IVT exceeding 500 kg/m/s from both the ECENS and GEFS
ensembles, pushing PWs to above 1 inch on increasing southerly
850mb inflow. Where this moisture overlaps with sufficient
instability (progs suggest at least 250 J/kg MUCAPE) it will result
in periods of moderate to heavy rainfall with rates of
0.25-0.5"/hr which may be sufficient for at least localized impacts
in vulnerable terrain, especially where training or enhanced
convergence along terrain features can produce more than 1 inch of
rainfall.


Weiss


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-6rocvidYNaM1uOSopYxalkmeDx6R8ZniWv4HMxaBGi0= UHiWneK-G6emfOSJa5NE-UMoQlkYTc4XHkMuVF1yUL4CsZQ$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-6rocvidYNaM1uOSopYxalkmeDx6R8ZniWv4HMxaBGi0= UHiWneK-G6emfOSJa5NE-UMoQlkYTc4XHkMuVF1yoj88jXE$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-6rocvidYNaM1uOSopYxalkmeDx6R8ZniWv4HMxaBGi0= UHiWneK-G6emfOSJa5NE-UMoQlkYTc4XHkMuVF1yu09dmxA$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 280829
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
429 AM EDT Sun Sep 28 2025

Day 1
Valid 01Z Sun Sep 28 2025 - 12Z Sun Sep 28 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS MUCH OF NEW
MEXICO AND PORTIONS OF FAR WESTERN TEXAS/SOUTHERN COLORADO...

...Four Corners/Southwest...
An upper trough centered over the Southwest will continue=20
directing mid-level vortices northward through the Four Corners=20
region today. Moisture from Tropical Cyclone Narda in the East=20
Pacific will continue surging north into the Four Corners, where=20
scattered showers and thunderstorms are likely to proliferate throughout
the day. PWATs between 1-1.5 inches within the right entrance=20
region of the upper jet and modest instability around 500-1000+=20
J/Kg (MLCAPE) could yield rain rates between 0.5-1 in./hr.,=20
especially where the slight risk is currently drawn. Burn scars,=20
scars slot canyons and upslope areas within the risk areas are=20
especially vulnerable to flash flooding.=20

HREF's neighborhood exceedance probabilities of 2 in. in 24 hours=20
are between 25-50% while EAS probabilities of exceeding 0.5 in.=20
hover around 20-40% within the depicted slight risk area.


...Southeast...
An upper trough will pivot eastward over the Southeast while=20
moisture from T.C. Nine continues surging northward toward the=20
Southeast Coast. Current guidance keeps the axis of heaviest QPF=20
offshore, but enough moisture may propagate far enough north and=20
west to interact with a surface front draped along the coast and=20
produce localized excessive rainfall. HREF EAS exceedance=20
probabilities of 1 inch in 24 hours are between 5-15% along much=20
of the Carolina Coast today, which supports the marginal risk area
depicted.

Kebede

Day 2
Valid 12Z Sun Sep 28 2025 - 12Z Mon Sep 29 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CAROLINA COAST...

...Southeast...
Guidance continue to depict T.C. Nine propagating north toward the
Southeast Coast on Monday, while a surface front draped along the=20
coast acts as the focus for heavy rainfall. QPF has trended=20
downward given slowing trends in the track of T.C. Nine on Monday.
The GFS suite in particular diverges most from the Canadian and=20
Euro suites when depicting the system's slower forward motion.=20
Despite this, enough moisture should work its way into the coast
and interact with the surface front to generate scattered thunderstorms. There'll be enough moisture (1.5-2.5in PWATs) and instability=20
(1000+ J/KG MUCAPE) present to support rainfall rates in excess of
1 in./hr..

...Northern California/Great Basin/Southern Cascades...
An upper low centered over the East Pacific will send mid-level=20
vortices into the West Coast on Monday. Pacific moisture may=20
collide with the remnant tropical moisture from Narda to produce=20
heavy rainfall from northern California into the Great Basin.=20
Synoptic forcing provided by a strong surface cold front should=20
focus PWATs in the range of 0.75-1.25 in. to produce quarter inch=20
rain rates along the immediate coast. More robust instability over=20
the Great Basin should yield higher rain rates between 0.5-1=20
in./hr. in some areas. Upslope enhancement may generate higher=20
totals in parts of the terrain.

Kebede

Day 3
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CAROLINA COAST...

...Southeast...
The inherited marginal and slight risk areas along the Southeast=20
Coast were downsized based on trends in the guidance suggesting=20
T.C. Nine's hard turn out to sea on Tuesday. Despite the resulting
smaller QPF footprint than previous cycles, the flash flood risk=20
remains. Instability will be negligible (less than 500 J/Kg=20
MUCAPE), which supports the possibility that the flood threat will be
due to runoff over saturated soils from Sunday and Monday's=20
rainfall. Exceedance probabilities of over 2 inches is over 10% in
the 00z ECENS/CMCE, while below 10% in the GEFS along the=20
immediate Carolina Coast.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9CYiVEneZMixDw3UL5rD9-gc3wknJ8S7ajYNrYVy8laI= -OdCwgYjk8PgU-OpCcCOUI1bgfGEhDQ4uNQSes0gJ8-bKFE$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9CYiVEneZMixDw3UL5rD9-gc3wknJ8S7ajYNrYVy8laI= -OdCwgYjk8PgU-OpCcCOUI1bgfGEhDQ4uNQSes0gDqUrKE0$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9CYiVEneZMixDw3UL5rD9-gc3wknJ8S7ajYNrYVy8laI= -OdCwgYjk8PgU-OpCcCOUI1bgfGEhDQ4uNQSes0g4as4coA$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 281556
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1156 AM EDT Sun Sep 28 2025

Day 1
Valid 12Z Sun Sep 28 2025 - 12Z Mon Sep 29 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS MUCH OF NEW
MEXICO AND PORTIONS OF FAR WESTERN TEXAS/SOUTHERN COLORADO, AS WELL
AS, PORTIONS OF NORTHWEST ARIZONA...

16z update:
New Mexico/West TX Panhandle: Mid-level sub-tropical moisture=20
continues to stream northward through the leading height-=20
falls/outer edge of deep-layer cyclone across Western TX Panhandle=20
through the Sacramento Mountains and points northward. Reinforcing=20
surface to boundary layer moisture return through up- slope process
will maintain 1-1.25" total PWats. Embedded mid-level impulses=20
through the large base of the cyclone will allow for multiple=20
rounds across S NM/W TX Panhandle to maintain the Slight Risk.=20

Southwest (N AZ): Near the northwest edge of the inner core of the
upper- low in NW AZ, there remains a slightly enhanced signal for=20
increased rainfall rates/totals per HREF probs and 12z Hi-Res CAMs.
Enough so to be highlighted with 20-40% of 2"+ through 12z . Given
slow cell motions and position relative to the deeper cyclone and=20
fairly saturated soils over the last few days is sufficient to=20
highlight a small separate Slight Risk area.=20

Further North (ID/WY): A subtle vorticity center is lifting north=20
through the northern Great Basin toward the Snake River Plain; Hi-
Res CAMs indicate slightly better instability from 250-500 J/kg may
allow for scattered mountain anchored convection through the
afternoon/evening trending northward toward Tetons and Ranges=20
across SE ID/far W WY. Enough so, to expand the Marginal Risk=20
northward to encompass the increase in potential.=20

Southeast: Forecast remains on track, solid onshore flow and
enhanced deep layer moisture values over 2-2.25 and some weak
500-1000 J/kg of CAPE should allow for scattered thunderstorm
activity capable of locally intense rates. Only minor adjustments
were made to the Marginal Risk line.=20

Gallina

~~~~Prior Discussion~~~~~

...Four Corners/Southwest...
An upper trough centered over the Southwest will continue
directing mid-level vortices northward through the Four Corners
region today. Moisture from Tropical Cyclone Narda in the East
Pacific will continue surging north into the Four Corners, where
scattered showers and thunderstorms are likely to proliferate throughout
the day. PWATs between 1-1.5 inches within the right entrance
region of the upper jet and modest instability around 500-1000+
J/Kg (MLCAPE) could yield rain rates between 0.5-1 in./hr.,
especially where the slight risk is currently drawn. Burn scars,
scars slot canyons and upslope areas within the risk areas are
especially vulnerable to flash flooding.

HREF's neighborhood exceedance probabilities of 2 in. in 24 hours
are between 25-50% while EAS probabilities of exceeding 0.5 in.
hover around 20-40% within the depicted slight risk area.


...Southeast...
An upper trough will pivot eastward over the Southeast while
moisture from T.C. Nine continues surging northward toward the
Southeast Coast. Current guidance keeps the axis of heaviest QPF
offshore, but enough moisture may propagate far enough north and
west to interact with a surface front draped along the coast and
produce localized excessive rainfall. HREF EAS exceedance
probabilities of 1 inch in 24 hours are between 5-15% along much
of the Carolina Coast today, which supports the marginal risk area
depicted.

Kebede

Day 2
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CAROLINA COAST...

...Southeast...
Guidance continue to depict T.C. Nine propagating north toward the
Southeast Coast on Monday, while a surface front draped along the
coast acts as the focus for heavy rainfall. QPF has trended
downward given slowing trends in the track of T.C. Nine on Monday.
The GFS suite in particular diverges most from the Canadian and
Euro suites when depicting the system's slower forward motion.
Despite this, enough moisture should work its way into the coast
and interact with the surface front to generate scattered thunderstorms. There'll be enough moisture (1.5-2.5in PWATs) and instability
(1000+ J/KG MUCAPE) present to support rainfall rates in excess of
1 in./hr..

...Northern California/Great Basin/Southern Cascades...
An upper low centered over the East Pacific will send mid-level
vortices into the West Coast on Monday. Pacific moisture may
collide with the remnant tropical moisture from Narda to produce
heavy rainfall from northern California into the Great Basin.
Synoptic forcing provided by a strong surface cold front should
focus PWATs in the range of 0.75-1.25 in. to produce quarter inch
rain rates along the immediate coast. More robust instability over
the Great Basin should yield higher rain rates between 0.5-1
in./hr. in some areas. Upslope enhancement may generate higher
totals in parts of the terrain.

Kebede

Day 3
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CAROLINA COAST...

...Southeast...
The inherited marginal and slight risk areas along the Southeast
Coast were downsized based on trends in the guidance suggesting
T.C. Nine's hard turn out to sea on Tuesday. Despite the resulting
smaller QPF footprint than previous cycles, the flash flood risk
remains. Instability will be negligible (less than 500 J/Kg
MUCAPE), which supports the possibility that the flood threat will be
due to runoff over saturated soils from Sunday and Monday's
rainfall. Exceedance probabilities of over 2 inches is over 10% in
the 00z ECENS/CMCE, while below 10% in the GEFS along the
immediate Carolina Coast.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!6uFAzqYdJ_L88XfT5_yzene3C0vAwFQe-dS9asUoHY2O= tb-02gXBFHsvM_b7AEC68SWxmlR637fniM7cMsFfXBYWidY$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6uFAzqYdJ_L88XfT5_yzene3C0vAwFQe-dS9asUoHY2O= tb-02gXBFHsvM_b7AEC68SWxmlR637fniM7cMsFfs82RwyM$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6uFAzqYdJ_L88XfT5_yzene3C0vAwFQe-dS9asUoHY2O= tb-02gXBFHsvM_b7AEC68SWxmlR637fniM7cMsFfIs1Rpx0$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 281927
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
327 PM EDT Sun Sep 28 2025

Day 1
Valid 16Z Sun Sep 28 2025 - 12Z Mon Sep 29 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS MUCH OF NEW
MEXICO AND PORTIONS OF FAR WESTERN TEXAS/SOUTHERN COLORADO, AS=20
WELL AS, PORTIONS OF NORTHWEST ARIZONA...

16z update:
New Mexico/West TX Panhandle: Mid-level sub-tropical moisture
continues to stream northward through the leading height-
falls/outer edge of deep-layer cyclone across Western TX Panhandle
through the Sacramento Mountains and points northward. Reinforcing
surface to boundary layer moisture return through up- slope process
will maintain 1-1.25" total PWats. Embedded mid-level impulses
through the large base of the cyclone will allow for multiple
rounds across S NM/W TX Panhandle to maintain the Slight Risk.

Southwest (N AZ): Near the northwest edge of the inner core of the
upper- low in NW AZ, there remains a slightly enhanced signal for
increased rainfall rates/totals per HREF probs and 12z Hi-Res CAMs.
Enough so to be highlighted with 20-40% of 2"+ through 12z . Given
slow cell motions and position relative to the deeper cyclone and
fairly saturated soils over the last few days is sufficient to
highlight a small separate Slight Risk area.

Further North (ID/WY): A subtle vorticity center is lifting north
through the northern Great Basin toward the Snake River Plain; Hi-
Res CAMs indicate slightly better instability from 250-500 J/kg may
allow for scattered mountain anchored convection through the
afternoon/evening trending northward toward Tetons and Ranges
across SE ID/far W WY. Enough so, to expand the Marginal Risk
northward to encompass the increase in potential.

Southeast: Forecast remains on track, solid onshore flow and
enhanced deep layer moisture values over 2-2.25 and some weak
500-1000 J/kg of CAPE should allow for scattered thunderstorm
activity capable of locally intense rates. Only minor adjustments
were made to the Marginal Risk line.

Gallina

~~~~Prior Discussion~~~~~

...Four Corners/Southwest...
An upper trough centered over the Southwest will continue
directing mid-level vortices northward through the Four Corners
region today. Moisture from Tropical Cyclone Narda in the East
Pacific will continue surging north into the Four Corners, where
scattered showers and thunderstorms are likely to proliferate throughout
the day. PWATs between 1-1.5 inches within the right entrance
region of the upper jet and modest instability around 500-1000+
J/Kg (MLCAPE) could yield rain rates between 0.5-1 in./hr.,
especially where the slight risk is currently drawn. Burn scars,
scars slot canyons and upslope areas within the risk areas are
especially vulnerable to flash flooding.

HREF's neighborhood exceedance probabilities of 2 in. in 24 hours
are between 25-50% while EAS probabilities of exceeding 0.5 in.
hover around 20-40% within the depicted slight risk area.


...Southeast...
An upper trough will pivot eastward over the Southeast while
moisture from T.C. Nine continues surging northward toward the
Southeast Coast. Current guidance keeps the axis of heaviest QPF
offshore, but enough moisture may propagate far enough north and
west to interact with a surface front draped along the coast and
produce localized excessive rainfall. HREF EAS exceedance
probabilities of 1 inch in 24 hours are between 5-15% along much
of the Carolina Coast today, which supports the marginal risk area
depicted.

Kebede

Day 2
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE IMMEDIATE=20
CAROLINA COASTLINE...

21z update:

...Central New Mexico...
Upper-level trough across the Southwest continues to march east-=20
northeast, filling fairly rapidly as it reaches the Four Corners in
the early forecast period. This has diminished overall wind field=20
and pushed the deeper warm conveyor/moisture plume into the Plains.
However, lingering sufficient moisture (.75"-1"), modest=20
divergence aloft at least initially,clearing for solid insolation=20
and solid lapse rates (500 J/kg) aloft will allow for potential for
stronger thunderstorms along the Sacramento Range. While the=20
overall intensity and potential for higher rates is reducing=20
relative to prior days, there is sufficient rainfall rate/total=20
signals with 12z HREF probability of 50% of 2"+ and even a small=20
15% or 3" totals across the Sacramento Range and ridge lines east=20
of the Rio Grande Valley. As such, will include a small Marginal=20
Risk area across the ridge of south-central to central New Mexico.

...Southeast...
Strong easterly onshore flow will continue and in proximity to the
coastal front, weak elevated showers and embedded convective=20
elements are expected along/downstream across the western Piedmont=20
into the foothills of the southern Appalachian Range, combined with
upslope enhancement localized 1-2" totals are possible and have=20
expanded the Marginal Risk slightly westward into the eastern=20
slopes of the Appalachians.

However, the trends for T.S. Imelda remain slow with a sharp=20
eastward turn, further shifting the QPF gradient southeastward and
offshore relative to prior cycles. However, strong confluent flow=20
in proximity to the coastal front and Gulf Stream may allow for=20
scattered thunderstorms to remain possible very close to the=20
beaches of southeast North Carolina and the South Carolina coast.=20
Higher probabilities suggest strongest rates/totals will remain=20
offshore. While there was some solid consideration for removing the
Slight Risk from this update; collaboration with the local=20
forecast offices and a few remaining solutions that bring the=20
surface rooted frontal convection further north to the coast have=20
maintained a narrow Slight Risk mainly for the coastal cities of=20
Northeast SC/Southeast NC.=20

...Northern California/Great Basin/Idaho,W Montana Rockies...
The sharp, elongated meridional trough axis has trended a bit
faster in the northern portion to allow for a slightly more evolved
wave along the frontal zone reaching far NW California Coast,
increasing duration of moderate onshore rainfall allowing for a
slight northward expansion of the Marginal Risk across SW OR.
Additionally, the upstream strong shortwave originating from
Kamchatka, rapidly advances and deepens the upstream wave and
further narrows the spacing between it and the leading wave. This
provides increased downstream divergence across the Great Basin
into the Idaho/Montana Rockies, while also strengthening the cross
Sierra Nevada flow to allow for a favorable back-building regime
across western Nevada (just east of the natural rain shadow of the
Sierra Nevada Range). Potential repeating convective elements=20
across N NV, SE OR and SW ID show an uptick in rainfall totals=20
with even some HREF probabilities of 1"/hr toward late evening,=20
early overnight period. Instability is a bit better along the
upwind edge reaching near 1000 J/kg across the Great Basin enough=20
that 2"/12hr probabilities are nearing 50% in central NV. At this=20
time, confidence is increasing, but not enough to delineate any=20
Slight Risk area at this time.=20

Gallina


~~~~Prior Discussion~~~~

...Southeast...
Guidance continue to depict T.C. Nine propagating north toward the
Southeast Coast on Monday, while a surface front draped along the
coast acts as the focus for heavy rainfall. QPF has trended
downward given slowing trends in the track of T.C. Nine on Monday.
The GFS suite in particular diverges most from the Canadian and
Euro suites when depicting the system's slower forward motion.
Despite this, enough moisture should work its way into the coast
and interact with the surface front to generate scattered thunderstorms. There'll be enough moisture (1.5-2.5in PWATs) and instability
(1000+ J/KG MUCAPE) present to support rainfall rates in excess of
1 in./hr..

...Northern California/Great Basin/Southern Cascades...
An upper low centered over the East Pacific will send mid-level
vortices into the West Coast on Monday. Pacific moisture may
collide with the remnant tropical moisture from Narda to produce
heavy rainfall from northern California into the Great Basin.
Synoptic forcing provided by a strong surface cold front should
focus PWATs in the range of 0.75-1.25 in. to produce quarter inch
rain rates along the immediate coast. More robust instability over
the Great Basin should yield higher rain rates between 0.5-1
in./hr. in some areas. Upslope enhancement may generate higher
totals in parts of the terrain.

Kebede

Day 3
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE GRAND
STRAND AND SOUTHEAST NORTH CAROLINA...

21z update:
...Southeast...
As noted above in Day 2, the trends for Day 3 QPF are even further
offshore as the sharp eastward turn of T.S. Imelda is expected. The
coastal front and general confluent flow along the Gulf Stream
north and northwest of the developing system will keep some risk of thunderstorm activity in the vicinity of the coastal cites. Much
like Day 2, there was a strong consideration for full removal of
the Slight Risk, however, in coordination with the local forecast
offices felt removal may be premature, with some scattered
thunderstorms in the area with potential for training/back-
building off the Gulf Stream instability gradient and now lies=20
along the urban centers of the Grand Strand through Wilmington, NC.

...Intermountain West...
At the start of the Day 3 period (30.12z), the end of the Hi-Res
CAM window, most show some organized showers and embedded
convective activity along and east of unseasonably strong Pacific
cold front. Initial meridional mid-level trough will be weakening,
but upstream stronger trough will be sharpening the flow and
maintaining favorable divergent flow aloft to provide larger scale
ascent. Highly anomalous moisture with 2.5-4 standard anomaly
values in the .75"+ range remain confluent on 15-25kts of=20
850-700mb southwesterly flow. The remaining Hi-Res CAMs (Nam-Nest=20
and GEM Regional), along with global guidance (GFS/ECMWF) suggest=20
some weak remaining instability/weak lapse rates to support some=20
continued convective activity through the early morning. Some=20
insolation could help recharge the upper reaches of the Snake River
Basin and combined with solid upslope flow may reinvigorate=20
convective activity across the terrain of SE ID into W WY.=20
Scattered spots of 1-2" are possible. This atypical moisture regime
and solid dynamic forcing suggest introduction (supported by=20
continuation from Day 2 period) of a Marginal Risk across the=20
northern Great Basin into the Snake River Basin for Day 3.

Gallina

~~~~Prior Discussion~~~~
...Southeast...
The inherited marginal and slight risk areas along the Southeast
Coast were downsized based on trends in the guidance suggesting
T.C. Nine's hard turn out to sea on Tuesday. Despite the resulting
smaller QPF footprint than previous cycles, the flash flood risk
remains. Instability will be negligible (less than 500 J/Kg
MUCAPE), which supports the possibility that the flood threat will be
due to runoff over saturated soils from Sunday and Monday's
rainfall. Exceedance probabilities of over 2 inches is over 10% in
the 00z ECENS/CMCE, while below 10% in the GEFS along the
immediate Carolina Coast.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!7Gi7bJL_28qHTZbLJ7t8gEZfIhBvOnWS1dGIwrpEhaWf= bh98BRF8eUlsoYd3fODOPIj2o0eXdDbahEmRZQlfksTb7vY$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7Gi7bJL_28qHTZbLJ7t8gEZfIhBvOnWS1dGIwrpEhaWf= bh98BRF8eUlsoYd3fODOPIj2o0eXdDbahEmRZQlfzQtim78$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7Gi7bJL_28qHTZbLJ7t8gEZfIhBvOnWS1dGIwrpEhaWf= bh98BRF8eUlsoYd3fODOPIj2o0eXdDbahEmRZQlfpRL4bNk$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 290035
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
835 PM EDT Sun Sep 28 2025

Day 1
Valid 01Z Mon Sep 29 2025 - 12Z Mon Sep 29 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS=20
OF THE SOUTHWEST AND COASTAL SOUTHEAST...

...Southwest...
We will maintain a Marginal risk area over NM into far west TX=20
with this update. A few more hours of locally intense convection=20
can be expected, with increasing low level easterly flow helping=20
support some continued development through the evening hours. The=20 expectation is that instability will erode overnight resulting in a
decrease in convective coverage and intensity. Generally think the
coverage of any additional flash flood risk has decreased enough=20
to remove the Slight and let the Marginal cover the threat.

...Southeast...
A Marginal risk was maintained from the east coast of FL into
eastern North Carolina. Across FL, onshore flow north of Imelda is
helping enhance coastal convergence and resulting in localized
areas of slow moving convection. This should continue through the
overnight hours, and isolated rainfall totals over 3" are possible.

Farther up the coast we have a stationary front just offshore, with
moisture well north of Imelda interacting with this front. We also
have the mid level trough and upper jet over the Southeast. As the
night progresses we will probably see some of this rain offshore=20
move inland across the Carolinas, with the aforementioned trough=20
and jet helping support this inland advancement. Most of this=20
activity will likely be lower rate rainfall given the low level=20 northeasterly flow and lack of instability. However we may be able=20
to get some higher rates into immediate coastal areas closer to=20
the stationary front. 18z/12z HREF and REFS runs had the higher 3"=20 probabilities along the SC coast, however more recent HRRR and RRFS
runs are shifting towards the NC coast. Recent radar trends also=20
seem to point towards far southeast NC as seeing the best chance of
some slow moving low topped convection getting onshore, which=20
could locally drop upwards of 3" of rainfall. Overall the flash=20
flood threat appears pretty localized along these coastal areas=20
from FL into NC, but the risk is non-zero and a Marginal risk will=20
be maintained.

Chenard

Day 2
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE IMMEDIATE
CAROLINA COASTLINE...

21z update:

...Central New Mexico...
Upper-level trough across the Southwest continues to march east-
northeast, filling fairly rapidly as it reaches the Four Corners in
the early forecast period. This has diminished overall wind field
and pushed the deeper warm conveyor/moisture plume into the Plains.
However, lingering sufficient moisture (.75"-1"), modest
divergence aloft at least initially,clearing for solid insolation
and solid lapse rates (500 J/kg) aloft will allow for potential for
stronger thunderstorms along the Sacramento Range. While the
overall intensity and potential for higher rates is reducing
relative to prior days, there is sufficient rainfall rate/total
signals with 12z HREF probability of 50% of 2"+ and even a small
15% or 3" totals across the Sacramento Range and ridge lines east
of the Rio Grande Valley. As such, will include a small Marginal
Risk area across the ridge of south-central to central New Mexico.

...Southeast...
Strong easterly onshore flow will continue and in proximity to the
coastal front, weak elevated showers and embedded convective
elements are expected along/downstream across the western Piedmont
into the foothills of the southern Appalachian Range, combined with
upslope enhancement localized 1-2" totals are possible and have
expanded the Marginal Risk slightly westward into the eastern
slopes of the Appalachians.

However, the trends for T.S. Imelda remain slow with a sharp
eastward turn, further shifting the QPF gradient southeastward and
offshore relative to prior cycles. However, strong confluent flow
in proximity to the coastal front and Gulf Stream may allow for
scattered thunderstorms to remain possible very close to the
beaches of southeast North Carolina and the South Carolina coast.
Higher probabilities suggest strongest rates/totals will remain
offshore. While there was some solid consideration for removing the
Slight Risk from this update; collaboration with the local
forecast offices and a few remaining solutions that bring the
surface rooted frontal convection further north to the coast have
maintained a narrow Slight Risk mainly for the coastal cities of
Northeast SC/Southeast NC.

...Northern California/Great Basin/Idaho,W Montana Rockies...
The sharp, elongated meridional trough axis has trended a bit
faster in the northern portion to allow for a slightly more evolved
wave along the frontal zone reaching far NW California Coast,
increasing duration of moderate onshore rainfall allowing for a
slight northward expansion of the Marginal Risk across SW OR.
Additionally, the upstream strong shortwave originating from
Kamchatka, rapidly advances and deepens the upstream wave and
further narrows the spacing between it and the leading wave. This
provides increased downstream divergence across the Great Basin
into the Idaho/Montana Rockies, while also strengthening the cross
Sierra Nevada flow to allow for a favorable back-building regime
across western Nevada (just east of the natural rain shadow of the
Sierra Nevada Range). Potential repeating convective elements
across N NV, SE OR and SW ID show an uptick in rainfall totals
with even some HREF probabilities of 1"/hr toward late evening,
early overnight period. Instability is a bit better along the
upwind edge reaching near 1000 J/kg across the Great Basin enough
that 2"/12hr probabilities are nearing 50% in central NV. At this
time, confidence is increasing, but not enough to delineate any
Slight Risk area at this time.

Gallina


~~~~Prior Discussion~~~~

...Southeast...
Guidance continue to depict T.C. Nine propagating north toward the
Southeast Coast on Monday, while a surface front draped along the
coast acts as the focus for heavy rainfall. QPF has trended
downward given slowing trends in the track of T.C. Nine on Monday.
The GFS suite in particular diverges most from the Canadian and
Euro suites when depicting the system's slower forward motion.
Despite this, enough moisture should work its way into the coast
and interact with the surface front to generate scattered thunderstorms. There'll be enough moisture (1.5-2.5in PWATs) and instability
(1000+ J/KG MUCAPE) present to support rainfall rates in excess of
1 in./hr..

...Northern California/Great Basin/Southern Cascades...
An upper low centered over the East Pacific will send mid-level
vortices into the West Coast on Monday. Pacific moisture may
collide with the remnant tropical moisture from Narda to produce
heavy rainfall from northern California into the Great Basin.
Synoptic forcing provided by a strong surface cold front should
focus PWATs in the range of 0.75-1.25 in. to produce quarter inch
rain rates along the immediate coast. More robust instability over
the Great Basin should yield higher rain rates between 0.5-1
in./hr. in some areas. Upslope enhancement may generate higher
totals in parts of the terrain.

Kebede

Day 3
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE GRAND
STRAND AND SOUTHEAST NORTH CAROLINA...

21z update:
...Southeast...
As noted above in Day 2, the trends for Day 3 QPF are even further
offshore as the sharp eastward turn of T.S. Imelda is expected. The
coastal front and general confluent flow along the Gulf Stream
north and northwest of the developing system will keep some risk of thunderstorm activity in the vicinity of the coastal cites. Much
like Day 2, there was a strong consideration for full removal of
the Slight Risk, however, in coordination with the local forecast
offices felt removal may be premature, with some scattered
thunderstorms in the area with potential for training/back-
building off the Gulf Stream instability gradient and now lies
along the urban centers of the Grand Strand through Wilmington, NC.

...Intermountain West...
At the start of the Day 3 period (30.12z), the end of the Hi-Res
CAM window, most show some organized showers and embedded
convective activity along and east of unseasonably strong Pacific
cold front. Initial meridional mid-level trough will be weakening,
but upstream stronger trough will be sharpening the flow and
maintaining favorable divergent flow aloft to provide larger scale
ascent. Highly anomalous moisture with 2.5-4 standard anomaly
values in the .75"+ range remain confluent on 15-25kts of
850-700mb southwesterly flow. The remaining Hi-Res CAMs (Nam-Nest
and GEM Regional), along with global guidance (GFS/ECMWF) suggest
some weak remaining instability/weak lapse rates to support some
continued convective activity through the early morning. Some
insolation could help recharge the upper reaches of the Snake River
Basin and combined with solid upslope flow may reinvigorate
convective activity across the terrain of SE ID into W WY.
Scattered spots of 1-2" are possible. This atypical moisture regime
and solid dynamic forcing suggest introduction (supported by
continuation from Day 2 period) of a Marginal Risk across the
northern Great Basin into the Snake River Basin for Day 3.

Gallina

~~~~Prior Discussion~~~~
...Southeast...
The inherited marginal and slight risk areas along the Southeast
Coast were downsized based on trends in the guidance suggesting
T.C. Nine's hard turn out to sea on Tuesday. Despite the resulting
smaller QPF footprint than previous cycles, the flash flood risk
remains. Instability will be negligible (less than 500 J/Kg
MUCAPE), which supports the possibility that the flood threat will be
due to runoff over saturated soils from Sunday and Monday's
rainfall. Exceedance probabilities of over 2 inches is over 10% in
the 00z ECENS/CMCE, while below 10% in the GEFS along the
immediate Carolina Coast.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9yPOzGL9oyHiBEtiIushDRM9R_t6bGNc0FUruPl0c_5X= vkxXC8CV9jQJNW7EiYKk3oUh7c0Zrl_OVAejQjbu7juiK_0$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9yPOzGL9oyHiBEtiIushDRM9R_t6bGNc0FUruPl0c_5X= vkxXC8CV9jQJNW7EiYKk3oUh7c0Zrl_OVAejQjbu5RVs0Eo$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9yPOzGL9oyHiBEtiIushDRM9R_t6bGNc0FUruPl0c_5X= vkxXC8CV9jQJNW7EiYKk3oUh7c0Zrl_OVAejQjbu8X3o1Wg$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 290830
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
430 AM EDT Mon Sep 29 2025

Day 1
Valid 01Z Mon Sep 29 2025 - 12Z Mon Sep 29 2025

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF=20
NORTHERN CALIFORNIA, SOUTHWESTERN OREGON, THE GREAT BASIN, SOUTH-
CENTRAL NEW MEXICO AND THE SOUTHEAST...

...Carolinas...
Moisture from tropical storm Imelda is expected to continue=20
streaming into the Southeast Coast today. A surface front draped=20
off the coast should provide forcing for thunderstorm development=20
beginning this morning. Convective bands may work their way into a=20
moisture rich environment in the Carolinas, where PWATs will be=20
between 1.5-2.25in.. MUCAPE between 250-500 J/Kg will spread=20
inland throughout the day, but the greatest convective potential=20
will be within the bands that propagate inland through North=20
Carolina this morning and afternoon. Neighborhood probabilities of=20
exceeding 2 inches of rainfall in 24 hours are between 15-30% over=20
parts of western and central North Carolina today.

Despite the presence of deep tropical moisture, much of the
convection and heaviest rainfall associated with Imelda should stay
offshore closer to Imelda and the draped front.

...Northern California/Great Basin...
A deep upper low centered over the Gulf of Alaska will send waves
of low pressure into the West Coast over the next couple of days.=20
A strong cold front may bring heavy rainfall to portions of=20
Northern California up into southern Oregon and the Great Basin=20
today. A weak instability gradient will develop ahead of the front=20
this afternoon and during peak heating. The 00z HREF suggest up to=20 0.25in./hr. rates across the coastal ranges, southern Cascades and=20
northern Sierra, with potential for upslope enhancement across=20
windward facing slopes.=20

EAS 24 hour 1 inch exceedance probabilities are over 45% along the
coast and southern Cascades, while a more modest 5-15% chance=20
remains over the Great Basin. There's a steep drop off in=20
probabilities once you get into the 2 inch exceedance range.

...South-central New Mexico...
There continues to be a signal for heavy rainfall over much of the
Sacramento Mountains, where instability (500-1000 J/Kg MLCAPE)
could support thunderstorm development and propagation into the
mountains early this evening. Much of the state has already
received over a half inch of rainfall in the past 24 hours with
pockets of 2 inch amounts present including within the Sacramento
Mountains. This may contribute to susceptibility of soils to runoff
from additional rain. Burn Scars such as the Ft. Stanton Piles
prescribed burn area are especially susceptible to flash flooding.


Kebede

Day 2
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND NORTHERN ROCKIES...

The marginal risk area inherited from the previous cycle was mostly
maintained with an expansion south into central Utah due to trends
in the guidance. The cold front responsible for heavy rainfall
potential in northern California on Monday will propagate through
the Great Basin and Northern Rockies on Tuesday, focusing
additional instability and moisture along its convergence zone.
Ensemble exceedance probabilities of 0.5 inches in 24 hours are=20
between 5-25% over parts of northeastern Nevada, northern Utah,
southeastern Idaho and western Wyoming. The progressive nature of
the front should mitigate flash flooding concerns.

Kebede

Day 3
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA...

A shortwave propagating through the southern periphery of the Gulf
of Alaska low will phase with it and move just off of the British
Columbia Coast by Wednesday. This new system will send a cold=20
front into the Pacific Northwest. The proximity of the upper low
and associated vorticity lobes should destabilize the environment=20
(100-300 J/Kg MUCAPE) enough to support isolated thunderstorm=20
activity. Favorable RER dynamics and mid-level moisture=20
advection should support efficient rain rates especially over the=20
Olympic Mountains. ECENS 24 hour exceedance probabilities of 2=20
inches is between 20-40% for much of the area.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!982xJkrpFgC71mUHP6iNhc8sD5AKYCZ6MNJsaAZUo7UN= 3yD6iSxI4FKSW_naOhtnUdVwHmS5qZf5nOsyJuDPIQqfngc$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!982xJkrpFgC71mUHP6iNhc8sD5AKYCZ6MNJsaAZUo7UN= 3yD6iSxI4FKSW_naOhtnUdVwHmS5qZf5nOsyJuDPxFFDGMY$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!982xJkrpFgC71mUHP6iNhc8sD5AKYCZ6MNJsaAZUo7UN= 3yD6iSxI4FKSW_naOhtnUdVwHmS5qZf5nOsyJuDPTRCoIrA$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 291543
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1143 AM EDT Mon Sep 29 2025

Day 1
Valid 12Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHERN CALIFORNIA, SOUTHWESTERN OREGON, THE GREAT BASIN, SOUTH-
CENTRAL NEW MEXICO AND THE SOUTHEAST...

16z update:
12z Hi-Res CAMs and HREF probabilities remain on track with only
small adjustments made for the West and Southeast.

CIRA LPW suite shows deeper layer (850-500 layers) show lingering=20
moisture remains across central NM than initially forecast over the
last few days, with some weak intrusion noted from the south. As
such, 12z Hi-Res solutions continue to show scattered thunderstorms
across along the ranges west of the Rio Grande in New Mexico. Given
recent rains, saturation and scattered flooding instances over the
past few days; the potential remains for similar if relatively
slightly reduced to have inclusion into the Marginal Risk already
in place over the Sacramento Range, further east.=20=20

Gallina


~~~~Prior Discussion~~~~
...Carolinas...
Moisture from tropical storm Imelda is expected to continue
streaming into the Southeast Coast today. A surface front draped
off the coast should provide forcing for thunderstorm development
beginning this morning. Convective bands may work their way into a
moisture rich environment in the Carolinas, where PWATs will be
between 1.5-2.25in.. MUCAPE between 250-500 J/Kg will spread
inland throughout the day, but the greatest convective potential
will be within the bands that propagate inland through North
Carolina this morning and afternoon. Neighborhood probabilities of
exceeding 2 inches of rainfall in 24 hours are between 15-30% over
parts of western and central North Carolina today.

Despite the presence of deep tropical moisture, much of the
convection and heaviest rainfall associated with Imelda should stay
offshore closer to Imelda and the draped front.

...Northern California/Great Basin...
A deep upper low centered over the Gulf of Alaska will send waves
of low pressure into the West Coast over the next couple of days.
A strong cold front may bring heavy rainfall to portions of
Northern California up into southern Oregon and the Great Basin
today. A weak instability gradient will develop ahead of the front
this afternoon and during peak heating. The 00z HREF suggest up to
0.25in./hr. rates across the coastal ranges, southern Cascades and
northern Sierra, with potential for upslope enhancement across
windward facing slopes.

EAS 24 hour 1 inch exceedance probabilities are over 45% along the
coast and southern Cascades, while a more modest 5-15% chance
remains over the Great Basin. There's a steep drop off in
probabilities once you get into the 2 inch exceedance range.

...South-central New Mexico...
There continues to be a signal for heavy rainfall over much of the
Sacramento Mountains, where instability (500-1000 J/Kg MLCAPE)
could support thunderstorm development and propagation into the
mountains early this evening. Much of the state has already
received over a half inch of rainfall in the past 24 hours with
pockets of 2 inch amounts present including within the Sacramento
Mountains. This may contribute to susceptibility of soils to runoff
from additional rain. Burn Scars such as the Ft. Stanton Piles
prescribed burn area are especially susceptible to flash flooding.


Kebede

Day 2
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND NORTHERN ROCKIES...

The marginal risk area inherited from the previous cycle was mostly
maintained with an expansion south into central Utah due to trends
in the guidance. The cold front responsible for heavy rainfall
potential in northern California on Monday will propagate through
the Great Basin and Northern Rockies on Tuesday, focusing
additional instability and moisture along its convergence zone.
Ensemble exceedance probabilities of 0.5 inches in 24 hours are
between 5-25% over parts of northeastern Nevada, northern Utah,
southeastern Idaho and western Wyoming. The progressive nature of
the front should mitigate flash flooding concerns.

Kebede

Day 3
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA...

A shortwave propagating through the southern periphery of the Gulf
of Alaska low will phase with it and move just off of the British
Columbia Coast by Wednesday. This new system will send a cold
front into the Pacific Northwest. The proximity of the upper low
and associated vorticity lobes should destabilize the environment
(100-300 J/Kg MUCAPE) enough to support isolated thunderstorm
activity. Favorable RER dynamics and mid-level moisture
advection should support efficient rain rates especially over the
Olympic Mountains. ECENS 24 hour exceedance probabilities of 2
inches is between 20-40% for much of the area.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!7R3QU7EDUpQtdR0ldkFCz08OwHtNfe08opkv3pj545bJ= y25nrhkJzxbavbWWvUtmkntXjSeKlNuKw3oXu1mzmzcbNhA$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7R3QU7EDUpQtdR0ldkFCz08OwHtNfe08opkv3pj545bJ= y25nrhkJzxbavbWWvUtmkntXjSeKlNuKw3oXu1mzZTHKTXc$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7R3QU7EDUpQtdR0ldkFCz08OwHtNfe08opkv3pj545bJ= y25nrhkJzxbavbWWvUtmkntXjSeKlNuKw3oXu1mzj0AV47M$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 291924
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
324 PM EDT Mon Sep 29 2025

Day 1
Valid 16Z Mon Sep 29 2025 - 12Z Tue Sep 30 2025

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHERN CALIFORNIA, SOUTHWESTERN OREGON, THE GREAT BASIN, SOUTH-
CENTRAL NEW MEXICO AND THE SOUTHEAST...

16z update:
12z Hi-Res CAMs and HREF probabilities remain on track with only
small adjustments made for the West and Southeast.

CIRA LPW suite shows deeper layer (850-500 layers) show lingering
moisture remains across central NM than initially forecast over the
last few days, with some weak intrusion noted from the south. As
such, 12z Hi-Res solutions continue to show scattered thunderstorms
across along the ranges west of the Rio Grande in New Mexico. Given
recent rains, saturation and scattered flooding instances over the
past few days; the potential remains for similar if relatively
slightly reduced to have inclusion into the Marginal Risk already
in place over the Sacramento Range, further east.

Gallina


~~~~Prior Discussion~~~~
...Carolinas...
Moisture from tropical storm Imelda is expected to continue
streaming into the Southeast Coast today. A surface front draped
off the coast should provide forcing for thunderstorm development
beginning this morning. Convective bands may work their way into a
moisture rich environment in the Carolinas, where PWATs will be
between 1.5-2.25in.. MUCAPE between 250-500 J/Kg will spread
inland throughout the day, but the greatest convective potential
will be within the bands that propagate inland through North
Carolina this morning and afternoon. Neighborhood probabilities of
exceeding 2 inches of rainfall in 24 hours are between 15-30% over
parts of western and central North Carolina today.

Despite the presence of deep tropical moisture, much of the
convection and heaviest rainfall associated with Imelda should stay
offshore closer to Imelda and the draped front.

...Northern California/Great Basin...
A deep upper low centered over the Gulf of Alaska will send waves
of low pressure into the West Coast over the next couple of days.
A strong cold front may bring heavy rainfall to portions of
Northern California up into southern Oregon and the Great Basin
today. A weak instability gradient will develop ahead of the front
this afternoon and during peak heating. The 00z HREF suggest up to
0.25in./hr. rates across the coastal ranges, southern Cascades and
northern Sierra, with potential for upslope enhancement across
windward facing slopes.

EAS 24 hour 1 inch exceedance probabilities are over 45% along the
coast and southern Cascades, while a more modest 5-15% chance
remains over the Great Basin. There's a steep drop off in
probabilities once you get into the 2 inch exceedance range.

...South-central New Mexico...
There continues to be a signal for heavy rainfall over much of the
Sacramento Mountains, where instability (500-1000 J/Kg MLCAPE)
could support thunderstorm development and propagation into the
mountains early this evening. Much of the state has already
received over a half inch of rainfall in the past 24 hours with
pockets of 2 inch amounts present including within the Sacramento
Mountains. This may contribute to susceptibility of soils to runoff
from additional rain. Burn Scars such as the Ft. Stanton Piles
prescribed burn area are especially susceptible to flash flooding.

Kebede

Day 2
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND NORTHERN ROCKIES & OLYMPIC PENINSULA...

21z update...

...Great Basin...
12z Hi-Res CAMs/HREF and global guidance continue a slightly more
progressive solutions with respect to the timing of the cold front
and therefore the moisture flux convergence through the Great Basin
resulting in a slight southeastward expansion of the Day 2 Marginal
Risk across east-central NV and portions of west-central UT. Narrow
streets of training convection within this anomalous moisture=20
stream with modest remaining instability may result in spots of=20
.5-1.25" in 1-3 hours, mainly early in the period. Naturally lower=20
FFG values would suggest scattered incident or two of localized=20
flash flooding may result, especially along the upwind edge of the=20
longer overall Marginal area, where backbuilding may be more=20
likely.=20

...Olympic Peninsula...
Second and slightly stronger warm conveyor belt increases moisture
flux out of the northeast Pacific. Deep moisture plume of greater
than 1" total PWat, but may tick up to 1.25" will be advected on
mainly southerly flow. Given the oblique nature to the Coastal
Range, mainly the upslope and highest IVT values (peaking around
600-700 kg/m/s) will intersect the SW facing topography of the
Olympic Range. A narrow drying period will likely exist after 00z
toward 06-09z, before the eastern edge of the strengthening core to
the closed low approaches toward the end of the forecast period,
01.12z. HREF probability over 50% of 3"/24hrs exists while a few=20
Hi- Res guidance members tickle the potential of 5"/24hrs (15-20%=20
for HREF) across the range. Combined with rain on Day 1, and
continuing into Day 3, felt it appropriate given totals to have a
low potential of exceedance worthy of a Marginal Risk, matching up
with the inherited Day 3 Marginal.=20

Gallina

~~~~Prior Discussion~~~~
The marginal risk area inherited from the previous cycle was=20
mostly maintained with an expansion south into central Utah due to=20
trends in the guidance. The cold front responsible for heavy=20
rainfall potential in northern California on Monday will propagate=20
through the Great Basin and Northern Rockies on Tuesday, focusing=20
additional instability and moisture along its convergence zone.=20
Ensemble exceedance probabilities of 0.5 inches in 24 hours are=20
between 5-25% over parts of northeastern Nevada, northern Utah,=20
southeastern Idaho and western Wyoming. The progressive nature of=20
the front should mitigate flash flooding concerns.

Kebede

Day 3
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA...

21z update...
No change to the placement of the Day 3 Marginal Risk area, though
12z global guidance is showing a slight uptick in strength of CAA
aloft allowing for 250-500 J/kg of elevated CAPE. The overall deep
layer moisture reduces toward .75" but with prolonged southerly
flow of 30-40kts, IVT values are persistent around 300-450 kg/m/s
nearly the entire 24hr period. So consistent light to moderate
upslope rains will have occasional, short duration bursts of=20
localized convective cores that will add to saturating soils over=20
the prolonged 3 day event. An additional 2-4" seems likely, but=20
given scattered convective nature, will be interesting to see any=20
localized enhanced totals as we move toward the full Hi-Res CAM=20
window, but end of 12z NAM-Nest and GEM Regional already hint at=20
slightly higher values...pretty good for an Atmospheric River=20
season "opener".

Gallina

~~~~Prior Discussion~~~~
A shortwave propagating through the southern periphery of the Gulf
of Alaska low will phase with it and move just off of the British=20
Columbia Coast by Wednesday. This new system will send a cold front
into the Pacific Northwest. The proximity of the upper low and=20
associated vorticity lobes should destabilize the environment=20
(100-300 J/Kg MUCAPE) enough to support isolated thunderstorm=20
activity. Favorable RER dynamics and mid- level moisture advection=20
should support efficient rain rates especially over the Olympic=20
Mountains. ECENS 24 hour exceedance probabilities of 2 inches is=20
between 20-40% for much of the area.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-sQU-92vlWcGu0LZO5wPQPp-uxEY55CuVqAppuYI7cRW= D5zaHHmTkJNZ5Xp4BL5p7vuQ526ZeMjbLH-7F64V6FXWu-A$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-sQU-92vlWcGu0LZO5wPQPp-uxEY55CuVqAppuYI7cRW= D5zaHHmTkJNZ5Xp4BL5p7vuQ526ZeMjbLH-7F64VS1Kq71o$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-sQU-92vlWcGu0LZO5wPQPp-uxEY55CuVqAppuYI7cRW= D5zaHHmTkJNZ5Xp4BL5p7vuQ526ZeMjbLH-7F64VTiK09is$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 300057
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
857 PM EDT Mon Sep 29 2025

Day 1
Valid 01Z Tue Sep 30 2025 - 12Z Tue Sep 30 2025

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHERN CALIFORNIA, SOUTHWESTERN OREGON, THE GREAT BASIN AND
COASTAL NORTH CAROLINA...

...West...
Showers and thunderstorms will continue to move across portions of
NV and ID tonight. Not a lot of instability to work with, and cells
are quick moving...thus it seems unlikely we will get high enough=20
rainfall rates to cause too much of a flash flood concern. However=20
looks like decent coverage of 0.5" to 1" rainfall, with amounts=20
locally exceeding 1". Thus we will maintain the Marginal risk as a=20
very localized flash flood risk can not be ruled out. Also will=20
need to keep an eye on the northern Sacramento Valley north of=20
Redding. Recent HRRR runs indicate the potential for slow moving=20
convection where low level flow locally enhances convergence in the
terrain.

...Southeast...
A Marginal risk was maintained for coastal areas of NC. Moisture=20
well to the north of Imelda will continue to interact with the=20
frontal boundary near the coast producing areas of showers and=20
locally embedded heavier convection. Still looks like most of the=20
higher rates will remain offshore overnight, but a few heavier=20
cells may continue to move into the immediate coast. Overall the=20
flash flood risk is low, but can not rule out a very localized=20
issue along areas of coastal NC, where upwards of 2-4" of rain has
fallen over the past 24 hours. Elsewhere over the Southeast the
higher rates are expected to stay offshore, with just some showery
conditions continuing which is unlikely to produce flash flooding.

Chenard


Day 2
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND NORTHERN ROCKIES & OLYMPIC PENINSULA...

21z update...

...Great Basin...
12z Hi-Res CAMs/HREF and global guidance continue a slightly more
progressive solutions with respect to the timing of the cold front
and therefore the moisture flux convergence through the Great Basin
resulting in a slight southeastward expansion of the Day 2 Marginal
Risk across east-central NV and portions of west-central UT. Narrow
streets of training convection within this anomalous moisture
stream with modest remaining instability may result in spots of
.5-1.25" in 1-3 hours, mainly early in the period. Naturally lower
FFG values would suggest scattered incident or two of localized
flash flooding may result, especially along the upwind edge of the
longer overall Marginal area, where backbuilding may be more
likely.

...Olympic Peninsula...
Second and slightly stronger warm conveyor belt increases moisture
flux out of the northeast Pacific. Deep moisture plume of greater
than 1" total PWat, but may tick up to 1.25" will be advected on
mainly southerly flow. Given the oblique nature to the Coastal
Range, mainly the upslope and highest IVT values (peaking around
600-700 kg/m/s) will intersect the SW facing topography of the
Olympic Range. A narrow drying period will likely exist after 00z
toward 06-09z, before the eastern edge of the strengthening core to
the closed low approaches toward the end of the forecast period,
01.12z. HREF probability over 50% of 3"/24hrs exists while a few
Hi- Res guidance members tickle the potential of 5"/24hrs (15-20%
for HREF) across the range. Combined with rain on Day 1, and
continuing into Day 3, felt it appropriate given totals to have a
low potential of exceedance worthy of a Marginal Risk, matching up
with the inherited Day 3 Marginal.

Gallina

~~~~Prior Discussion~~~~
The marginal risk area inherited from the previous cycle was
mostly maintained with an expansion south into central Utah due to
trends in the guidance. The cold front responsible for heavy
rainfall potential in northern California on Monday will propagate
through the Great Basin and Northern Rockies on Tuesday, focusing
additional instability and moisture along its convergence zone.
Ensemble exceedance probabilities of 0.5 inches in 24 hours are
between 5-25% over parts of northeastern Nevada, northern Utah,
southeastern Idaho and western Wyoming. The progressive nature of
the front should mitigate flash flooding concerns.

Kebede

Day 3
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA...

21z update...
No change to the placement of the Day 3 Marginal Risk area, though
12z global guidance is showing a slight uptick in strength of CAA
aloft allowing for 250-500 J/kg of elevated CAPE. The overall deep
layer moisture reduces toward .75" but with prolonged southerly
flow of 30-40kts, IVT values are persistent around 300-450 kg/m/s
nearly the entire 24hr period. So consistent light to moderate
upslope rains will have occasional, short duration bursts of
localized convective cores that will add to saturating soils over
the prolonged 3 day event. An additional 2-4" seems likely, but
given scattered convective nature, will be interesting to see any
localized enhanced totals as we move toward the full Hi-Res CAM
window, but end of 12z NAM-Nest and GEM Regional already hint at
slightly higher values...pretty good for an Atmospheric River
season "opener".

Gallina

~~~~Prior Discussion~~~~
A shortwave propagating through the southern periphery of the Gulf
of Alaska low will phase with it and move just off of the British
Columbia Coast by Wednesday. This new system will send a cold front
into the Pacific Northwest. The proximity of the upper low and
associated vorticity lobes should destabilize the environment
(100-300 J/Kg MUCAPE) enough to support isolated thunderstorm
activity. Favorable RER dynamics and mid- level moisture advection
should support efficient rain rates especially over the Olympic
Mountains. ECENS 24 hour exceedance probabilities of 2 inches is
between 20-40% for much of the area.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_eS4alwTQPGfJTYKCe9UlUvtB1Er220Iz0r5jfZhpnJ_= DNStGZglIJc3qHTsDLyjiachyN5L_CJcaWC7rAamV1fwndA$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_eS4alwTQPGfJTYKCe9UlUvtB1Er220Iz0r5jfZhpnJ_= DNStGZglIJc3qHTsDLyjiachyN5L_CJcaWC7rAamT4LxE7c$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_eS4alwTQPGfJTYKCe9UlUvtB1Er220Iz0r5jfZhpnJ_= DNStGZglIJc3qHTsDLyjiachyN5L_CJcaWC7rAam8J--Tes$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 300816
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
416 AM EDT Tue Sep 30 2025

Day 1
Valid 01Z Tue Sep 30 2025 - 12Z Tue Sep 30 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC MOUNTAINS, GREAT BASIN AND NORTHERN ROCKIES...

...Great Basin/Northern Rockies...
A deep upper low off the British Columbia Coast will send=20
shortwave energy through the Northwest today. A progressive cold=20
front will focus showers and thunderstorms over portions of the=20
Great Basin from northeast Nevada to western Montana/northern=20
Idaho. MUCAPE values between 100-500J/Kg and PWATs of 0.5-1in.=20
could produce excessive rainfall through this afternoon. This will=20
be especially true over portions of eastern Nevada into northern=20
Utah where 24 hour 1 inch exceedance probabilities are between=20
20-45%.

...Olympics...
The occluded parent low will direct anomalous Pacific moisture at=20
the Olympic coast beginning this afternoon. Some weak instability=20
(<200J/Kg MUCAPE) and PWAT's around 1 inch could produce some cells
capable of generating efficient rain rates, especially within the=20
windward side of the Olympics. IVT values between 500-700Kg/ms
support the excessive rainfall threat with isolated instances of
flash flooding.

Kebede

Day 2
Valid 12Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC MOUNTAINS...

The excessive rainfall threat over the Olympics bleeds into
Wednesday as the upper low arrives off the coast of the Pacific
Northwest. A jetstreak aloft with MUCAPE around 150J/Kg Wednesday
morning could support some weak convection into the Olympics.
Unlike on day 1, maximum IVT values will remain offshore with 1=20
inch PWATs arriving early Thursday morning. Canadian and Euro
ensemble 2 inch exceedance probabilities are between 40-60% while=20
the GEFS 1 inch probabilities are around an inch.=20

Kebede

Day 3
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND EASTERN FLORIDA...

...Great Basin...
The upper low is expected to dig into the West Coast on Thursday
directing diffluent flow and left exit region jet dynamics into the
Great Basin. Weak instability (100-200J/Kg MUCAPE) along a
developing cold front could generate thunderstorms capable of=20
producing some isolated flash flooding, especially over parts of=20
the Great Basin that received rainfall on Tuesday.

...Eastern Florida...
An upper trough in the Southeast will direct embedded vorticity=20
into the Florida peninsula on Thursday. An upper ridge centered=20
over the West Atlantic will advect tropical moisture (PWATs=20
between 1.5-2in.) into eastern Florida, where it'll interact with=20
an inverted trough along the coast. Multiple rounds of short fused
convection will proliferate from the central Gulf across the=20
Florida Peninsula throughout the day with onshore flow into eastern
Florida producing isolated instances of flash flooding.=20
Probabilities of 24 hour qpf exceeding 1 inch is between 15-30%=20
across eastern Florida. Urban areas are especially susceptible to=20
flash flooding.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-7W00vFpJiSOKioLBq0E7XQg4GyhtrVCynVHNHK-jESU= GZHX7ffdnWMmniIt1HcA6kg8Ll8VnxlpAn-NAy5YOj_uWVw$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-7W00vFpJiSOKioLBq0E7XQg4GyhtrVCynVHNHK-jESU= GZHX7ffdnWMmniIt1HcA6kg8Ll8VnxlpAn-NAy5YLkFqa1Q$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-7W00vFpJiSOKioLBq0E7XQg4GyhtrVCynVHNHK-jESU= GZHX7ffdnWMmniIt1HcA6kg8Ll8VnxlpAn-NAy5YE8W9YH8$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 301552
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1152 AM EDT Tue Sep 30 2025

Day 1
Valid 16Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
TREAT BASIN AND NORTHERN ROCKIES...

...Great Basin/Northern Rockies...
...1600 UTC Update...
Cut back on the Marginal Risk area a bit, mainly on the western
side, based on the latest observational trends (radar and
satellite). Back edge of more concentrated area of heavier rain,=20 colder/higher cloud tops associated with ragged WCB, MUCAPEs of
250-500 J/Kg, and axis of higher TPWs (>0.75") along and east of=20
the mid-upper level vort lobe have now shifted east into northeast
NV. Expect the eastward trend to continue this afternoon, with only
a low-end marginal (localized) risk of flash flooding. 12Z HREF
probabilities of >=3D 0.50 in/hr rainfall rates peak between 30-4
over isolated areas, while maximum probabilities of 1hr QPF
exceeding current 1hr FFGs are between 15-20 percent.
3-3.5

...Olympics...
...1600 UTC Update...
We have removed the Marginal Risk area across the Olympics. Per=20
the latest (12Z) guidance, only the NAM CONUS Nest depicts 24hr=20
totals aoa 3.00". As a result, the 12Z HREF probabilities of 3+
inches in 24hrs is now only 30-35% over a small area, which is the
same probability of 0.50 in/hr rates for a brief time this evening
when the IVTs peak around 600 Kg/m/s.=20

Hurley

Day 2
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC MOUNTAINS...

The excessive rainfall threat over the Olympics bleeds into
Wednesday as the upper low arrives off the coast of the Pacific
Northwest. A jetstreak aloft with MUCAPE around 150J/Kg Wednesday
morning could support some weak convection into the Olympics.
Unlike on day 1, maximum IVT values will remain offshore with 1
inch PWATs arriving early Thursday morning. Canadian and Euro
ensemble 2 inch exceedance probabilities are between 40-60% while
the GEFS 1 inch probabilities are around an inch.

Kebede

Day 3
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND EASTERN FLORIDA...

...Great Basin...
The upper low is expected to dig into the West Coast on Thursday
directing diffluent flow and left exit region jet dynamics into the
Great Basin. Weak instability (100-200J/Kg MUCAPE) along a
developing cold front could generate thunderstorms capable of
producing some isolated flash flooding, especially over parts of
the Great Basin that received rainfall on Tuesday.

...Eastern Florida...
An upper trough in the Southeast will direct embedded vorticity
into the Florida peninsula on Thursday. An upper ridge centered
over the West Atlantic will advect tropical moisture (PWATs
between 1.5-2in.) into eastern Florida, where it'll interact with
an inverted trough along the coast. Multiple rounds of short fused
convection will proliferate from the central Gulf across the
Florida Peninsula throughout the day with onshore flow into eastern
Florida producing isolated instances of flash flooding.
Probabilities of 24 hour qpf exceeding 1 inch is between 15-30%
across eastern Florida. Urban areas are especially susceptible to
flash flooding.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5Fxlxr5W-_Qc-e8pJI8Fn0h_fYySDRGjp110wFDS3cCK= yqJZPiyRvbdP_vgRicht5Ss-sfFX72R3KQxu1KZ2tRqbIKM$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5Fxlxr5W-_Qc-e8pJI8Fn0h_fYySDRGjp110wFDS3cCK= yqJZPiyRvbdP_vgRicht5Ss-sfFX72R3KQxu1KZ2_F9NmIc$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5Fxlxr5W-_Qc-e8pJI8Fn0h_fYySDRGjp110wFDS3cCK= yqJZPiyRvbdP_vgRicht5Ss-sfFX72R3KQxu1KZ24g3kIUM$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 302028
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
428 PM EDT Tue Sep 30 2025

Day 1
Valid 16Z Tue Sep 30 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
TREAT BASIN AND NORTHERN ROCKIES...

...Great Basin/Northern Rockies...
...1600 UTC Update...
Cut back on the Marginal Risk area a bit, mainly on the western
side, based on the latest observational trends (radar and
satellite). Back edge of more concentrated area of heavier rain,
colder/higher cloud tops associated with ragged WCB, MUCAPEs of
250-500 J/Kg, and axis of higher TPWs (>0.75") along and east of
the mid-upper level vort lobe have now shifted east into northeast
NV. Expect the eastward trend to continue this afternoon, with only
a low-end marginal (localized) risk of flash flooding. 12Z HREF
probabilities of >=3D 0.50 in/hr rainfall rates peak between 30-4
over isolated areas, while maximum probabilities of 1hr QPF
exceeding current 1hr FFGs are between 15-20 percent.
3-3.5

...Olympics...
...1600 UTC Update...
We have removed the Marginal Risk area across the Olympics. Per
the latest (12Z) guidance, only the NAM CONUS Nest depicts 24hr
totals aoa 3.00". As a result, the 12Z HREF probabilities of 3+
inches in 24hrs is now only 30-35% over a small area, which is the
same probability of 0.50 in/hr rates for a brief time this evening
when the IVTs peak around 600 Kg/m/s.

Hurley


Day 2
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC MOUNTAINS AND THE EAST COAST OF FLORIDA...

...Olympics...

An anomalous mid-level closed low will be slow to=20
move off of the coast of the Pacific Northwest on Wednesday into=20
Thursday. Moisture anomalies along the coast are forecast to=20
remain neutral to weakly positive but onshore flow will keep the=20
region unsettled and left-exit region upper level jet induced=20
divergence may aid in rainfall intensities early on Wednesday. Low=20
level flow will be oriented from the SSW into the Olympics with a=20
high likelihood for showers (isolated thunder given weak=20
instability near the coast) throughout the 24 hour period with=20
occasional bursts of rain rates in excess of 0.5 in/hr. 12Z HREF=20 probabilities of QPF over the 24 hour period ending Thursday at 12Z
were 80-90 percent for 3+ inches, and 50-60 percent for 5+ inches.
Given forecast rainfall of 1 to 3 inches ending Wednesday morning,
and the additional rainfall on Wednesday into Thursday of 3 to 5=20
inches locally (with embedded high rates), localized runoff in and=20
around the Olympics may result.=20

...East Coast of Florida...

With the eastward departure of Imelda and Humberto from the western
Atlantic, a large surface ridge will build across the eastern U.S.,
with low level easterly flow setting up perpendicular ot the east
coast of the Florida Peninsula. 925-850 mb winds are forecast by
the 12Z GFS to peak in the 20-30 kt range and offshore instability
of at least 500-1000 J/kg is forecast by the latest model=20
consensus to set up just offshore and along the coast. Upper level
support for ascent will be aided by the right-entrance region of a
70-80 kt ahead of an upper level shortwave tracking east from the=20
central Gulf Coast.

While moisture parameters are forecast to be only near average for
early October, PW values are still forecast to range from 1.5 to=20
2.0 inches at times with low level convergence helping to focus=20
small but intense cores of heavy rain with hourly rainfall of 2 to=20
3 inches expected at times. The flash flood threat is expected to=20
remain rather localized, but given the presence of the highly=20
populated eastern Peninsula and potential for localized 4 to 5+=20
inch totals, a Marginal Risk was introduced for this update.

Otto


Day 3
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND EASTERN FLORIDA...

...Great Basin...
The upper low from Wednesday is expected to dig into the West=20
Coast on Thursday directing diffluent flow and left exit region jet
divergence into the Great Basin. Weak instability (less than 250
J/kg MUCAPE from most models) along a developing cold front could=20
generate repeating rounds of thunderstorms and short term training=20
capable of producing some isolated flash flooding. While PWATs are
forecast to be anomalous for early October (+2 to +3 standardized=20 anomalies), moisture and instability values will be relatively=20
modest in an absolute sense which may limit rain rates. However,
local sensitivities, including burn scars, could be at risk of
impactful rainfall rates.

...Eastern Florida...
As an upper level trough over the Southeast slowly edges eastward
on Thursday, a similar setup as seen on Wednesday will be in place
across the east coast of Florida. This includes instability of at
least 500-1000 J/kg, PWAT values of 1.5 to 2.0+ inches and low
level onshore flow of 20-30 kt at times. Slow cell motions could
allow for hourly rainfall of 2 to 3 inches in a couple of
locations with a focus along coastal/high population density=20
sections of eastern Florida. While hires model data is limited to
the 12Z RRFS for the day 3 time frame, the RRFS shows a spot of 6-7
inches in northern portions of the outlook area, indicative of the
potential for locally high rainfall totals.

Otto


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_xXrjf5FD_5yya27yWuF2sKaog7cu_i6pdFFHI89hcs_= BsLMMH4lco5i58j18PS4uShFO7J11I1_PptErJ8sb3UFPaI$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_xXrjf5FD_5yya27yWuF2sKaog7cu_i6pdFFHI89hcs_= BsLMMH4lco5i58j18PS4uShFO7J11I1_PptErJ8sdzmrFlo$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_xXrjf5FD_5yya27yWuF2sKaog7cu_i6pdFFHI89hcs_= BsLMMH4lco5i58j18PS4uShFO7J11I1_PptErJ8sZQGaB4g$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 010029
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
829 PM EDT Tue Sep 30 2025

Day 1
Valid 01Z Wed Oct 01 2025 - 12Z Wed Oct 01 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Bann


Day 2
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC MOUNTAINS AND THE EAST COAST OF FLORIDA...

...Olympics...

An anomalous mid-level closed low will be slow to
move off of the coast of the Pacific Northwest on Wednesday into
Thursday. Moisture anomalies along the coast are forecast to
remain neutral to weakly positive but onshore flow will keep the
region unsettled and left-exit region upper level jet induced
divergence may aid in rainfall intensities early on Wednesday. Low
level flow will be oriented from the SSW into the Olympics with a
high likelihood for showers (isolated thunder given weak
instability near the coast) throughout the 24 hour period with
occasional bursts of rain rates in excess of 0.5 in/hr. 12Z HREF
probabilities of QPF over the 24 hour period ending Thursday at 12Z
were 80-90 percent for 3+ inches, and 50-60 percent for 5+ inches.
Given forecast rainfall of 1 to 3 inches ending Wednesday morning,
and the additional rainfall on Wednesday into Thursday of 3 to 5
inches locally (with embedded high rates), localized runoff in and
around the Olympics may result.

...East Coast of Florida...

With the eastward departure of Imelda and Humberto from the western
Atlantic, a large surface ridge will build across the eastern U.S.,
with low level easterly flow setting up perpendicular ot the east
coast of the Florida Peninsula. 925-850 mb winds are forecast by
the 12Z GFS to peak in the 20-30 kt range and offshore instability
of at least 500-1000 J/kg is forecast by the latest model
consensus to set up just offshore and along the coast. Upper level
support for ascent will be aided by the right-entrance region of a
70-80 kt ahead of an upper level shortwave tracking east from the
central Gulf Coast.

While moisture parameters are forecast to be only near average for
early October, PW values are still forecast to range from 1.5 to
2.0 inches at times with low level convergence helping to focus
small but intense cores of heavy rain with hourly rainfall of 2 to
3 inches expected at times. The flash flood threat is expected to
remain rather localized, but given the presence of the highly
populated eastern Peninsula and potential for localized 4 to 5+
inch totals, a Marginal Risk was introduced for this update.

Otto


Day 3
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE GREAT BASIN AND EASTERN FLORIDA...

...Great Basin...
The upper low from Wednesday is expected to dig into the West
Coast on Thursday directing diffluent flow and left exit region jet
divergence into the Great Basin. Weak instability (less than 250
J/kg MUCAPE from most models) along a developing cold front could
generate repeating rounds of thunderstorms and short term training
capable of producing some isolated flash flooding. While PWATs are
forecast to be anomalous for early October (+2 to +3 standardized
anomalies), moisture and instability values will be relatively
modest in an absolute sense which may limit rain rates. However,
local sensitivities, including burn scars, could be at risk of
impactful rainfall rates.

...Eastern Florida...
As an upper level trough over the Southeast slowly edges eastward
on Thursday, a similar setup as seen on Wednesday will be in place
across the east coast of Florida. This includes instability of at
least 500-1000 J/kg, PWAT values of 1.5 to 2.0+ inches and low
level onshore flow of 20-30 kt at times. Slow cell motions could
allow for hourly rainfall of 2 to 3 inches in a couple of
locations with a focus along coastal/high population density
sections of eastern Florida. While hires model data is limited to
the 12Z RRFS for the day 3 time frame, the RRFS shows a spot of 6-7
inches in northern portions of the outlook area, indicative of the
potential for locally high rainfall totals.

Otto


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!--vzlDqCKAME7aiKq4Jdwed_ujN-XNs14mrnuXUUpEc5= ZUmK_p9kuVQ-1lZS3_VG3iQ8bkt5sWiwLmAc8k1lXf45ZBo$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!--vzlDqCKAME7aiKq4Jdwed_ujN-XNs14mrnuXUUpEc5= ZUmK_p9kuVQ-1lZS3_VG3iQ8bkt5sWiwLmAc8k1lK0gAEaY$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!--vzlDqCKAME7aiKq4Jdwed_ujN-XNs14mrnuXUUpEc5= ZUmK_p9kuVQ-1lZS3_VG3iQ8bkt5sWiwLmAc8k1l9TZNecA$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 010830
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
430 AM EDT Wed Oct 1 2025

Day 1
Valid 01Z Wed Oct 01 2025 - 12Z Wed Oct 01 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA AND EASTERN FLORIDA...

...Olympic Peninsula...
A deep upper low centered off of the British Columbia Coast will=20
direct embedded ripples of vorticity into the Pacific Northwest=20
today. A strong 60-100 kts RER jet with associated 100-200 J/Kg=20
MUCAPE and 200-400 Kg/ms IVT out of the southwest should be enough
to generate scattered thunderstorm activity across the region=20
today. These favorable dynamics paired with PWATs between 0.65-0.90
should produce efficient rain rates throughout the day, especially
along the windward side of the Olympics, where upslope enhancement
may occur.

...Eastern Florida...
A positively tilted trough will swing through the Southeast today.
CAA over warm Gulf/Atlantic waters should generate convection along
a surface convergence zone over the Florida Coast today. MUCAPE=20
between 500-1000 J/Kg within a moist environment (1.75-2.25 in.=20
PWATs) should produce scattered thunderstorms with efficient rain=20
rates. Moist easterly flow over the inverted coastal surface trough
may generate some backbuilding storms this afternoon/evening. HREF
5" neighborhood exceedance probabilities are between 20-30% across
the entire risk area, so there's potential for overperformance of
rainfall. Urban areas are of particular concern to flash flooding.


Kebede

Day 2
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA, THE SIERRA, THE GREAT BASIN AND EASTERN=20
FLORIDA...

...Olympic Mountains...
The excessive rainfall threat spills over into Thursday across the
Olympics as the upper low begins to dig down into the West Coast.=20
100-200 J/Kg MUCAPE and 0.75-1" PWATs should sustain the potential=20
for excessive rainfall, particularly earlier on in the period=20
(12-18z) before the trough pushes farther east into the interior
and high pressure builds over the Olympic Peninsula. CMCE 1"=20
exceedance probabilities are around 15-35% within the marginal risk
area.

...Great Basin/Sierra...
Strong diffluence associated with the digging upper trough will=20
spread throughout the interior West on Thursday. An 80-100 kts RER=20
jet with a 100 J/Kg MUCAPE should support convection with PWATs=20
between 0.75-1", which will be 3-4 stndv above average. This will
provide enough moisture to produce high enough rain rates to=20
overtake flash flood guidance, which is below 1".=20

...Eastern Florida...
Shortwave vortices within a mean upper trough will propagate south
through the Florida Peninsula on Thursday. Sufficient instability
(500-1000 J/Kg MUCAPE) and moisture (2"+ PWATs) associated with=20
Imelda may produce excessive rainfall along the immediate coast
early on in the day. The latest qpf trend is decreasing, partly
because the heavy rainfall threat is split between two days (00z
Wednesday--15z Thursday), but urban areas continue to be
susceptible to runoff.


Kebede

Day 3
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA...

...Eastern Florida... Continued troughing in the Southeast will=20
promote more unsettled weather across Florida on Friday. Easterly=20
flow will continue advecting rich tropical moisture (2-2.25" PWATs)
from Imelda into the Peninsula with plenty of instability=20
(500-1000 J/Kg MUCAPE) to generate scattered thunderstorms. 2"=20
ensemble exceedance probabilities are between 5-15%, which supports
the inherited marginal risk area. Again, the greatest threat for=20
flash flooding is in urbanized areas.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-9Vg9wXg0GFxnT-3E6UqhDAGmivk1Vp-OjBY4_RQCJBk= 3VSq6fkjXgJd0BmHjrXUW2ewaRqpaOWiyPow1W0l_VUE0ao$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-9Vg9wXg0GFxnT-3E6UqhDAGmivk1Vp-OjBY4_RQCJBk= 3VSq6fkjXgJd0BmHjrXUW2ewaRqpaOWiyPow1W0lxiXrC_c$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-9Vg9wXg0GFxnT-3E6UqhDAGmivk1Vp-OjBY4_RQCJBk= 3VSq6fkjXgJd0BmHjrXUW2ewaRqpaOWiyPow1W0lruMQrU0$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 010833
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
433 AM EDT Wed Oct 1 2025

Day 1
Valid 12Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA AND EASTERN FLORIDA...

...Olympic Peninsula...
A deep upper low centered off of the British Columbia Coast will
direct embedded ripples of vorticity into the Pacific Northwest
today. A strong 60-100 kts RER jet with associated 100-200 J/Kg
MUCAPE and 200-400 Kg/ms IVT out of the southwest should be enough
to generate scattered thunderstorm activity across the region
today. These favorable dynamics paired with PWATs between 0.65-0.90
should produce efficient rain rates throughout the day, especially
along the windward side of the Olympics, where upslope enhancement
may occur.

...Eastern Florida...
A positively tilted trough will swing through the Southeast today.
CAA over warm Gulf/Atlantic waters should generate convection along
a surface convergence zone over the Florida Coast today. MUCAPE
between 500-1000 J/Kg within a moist environment (1.75-2.25 in.
PWATs) should produce scattered thunderstorms with efficient rain
rates. Moist easterly flow over the inverted coastal surface trough
may generate some backbuilding storms this afternoon/evening. HREF
5" neighborhood exceedance probabilities are between 20-30% across
the entire risk area, so there's potential for overperformance of
rainfall. Urban areas are of particular concern to flash flooding.


Kebede

Day 2
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA, THE SIERRA, THE GREAT BASIN AND EASTERN
FLORIDA...

...Olympic Mountains...
The excessive rainfall threat spills over into Thursday across the
Olympics as the upper low begins to dig down into the West Coast.
100-200 J/Kg MUCAPE and 0.75-1" PWATs should sustain the potential
for excessive rainfall, particularly earlier on in the period
(12-18z) before the trough pushes farther east into the interior
and high pressure builds over the Olympic Peninsula. CMCE 1"
exceedance probabilities are around 15-35% within the marginal risk
area.

...Great Basin/Sierra...
Strong diffluence associated with the digging upper trough will
spread throughout the interior West on Thursday. An 80-100 kts RER
jet with a 100 J/Kg MUCAPE should support convection with PWATs
between 0.75-1", which will be 3-4 stndv above average. This will
provide enough moisture to produce high enough rain rates to
overtake flash flood guidance, which is below 1".

...Eastern Florida...
Shortwave vortices within a mean upper trough will propagate south
through the Florida Peninsula on Thursday. Sufficient instability
(500-1000 J/Kg MUCAPE) and moisture (2"+ PWATs) associated with
Imelda may produce excessive rainfall along the immediate coast
early on in the day. The latest qpf trend is decreasing, partly
because the heavy rainfall threat is split between two days (00z
Wednesday--15z Thursday), but urban areas continue to be
susceptible to runoff.


Kebede

Day 3
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA...

...Eastern Florida...=20
Continued troughing in the Southeast will promote more unsettled=20
weather across Florida on Friday. Easterly flow will continue=20
advecting rich tropical moisture (2-2.25" PWATs) from Imelda into=20
the Peninsula with plenty of instability (500-1000 J/Kg MUCAPE) to=20
generate scattered thunderstorms. 2" ensemble exceedance=20
probabilities are between 5-15%, which supports the inherited=20
marginal risk area. Again, the greatest threat for flash flooding=20
is in urbanized areas.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4UnSa_wq00OZYj86Y4W7Lf7iHP_LJPflziHRmW0TYTq4= ajC-j_04GbTTCQJOR5oc8Qo_4FU0J3sT8pO1avACpQyCou8$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4UnSa_wq00OZYj86Y4W7Lf7iHP_LJPflziHRmW0TYTq4= ajC-j_04GbTTCQJOR5oc8Qo_4FU0J3sT8pO1avACOGRgcI8$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4UnSa_wq00OZYj86Y4W7Lf7iHP_LJPflziHRmW0TYTq4= ajC-j_04GbTTCQJOR5oc8Qo_4FU0J3sT8pO1avACk2skvVQ$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 011529
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1129 AM EDT Wed Oct 1 2025

Day 1
Valid 16Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE=20=20
EASTERN FLORIDA PENINSULA...

16Z Update: After coordination with local Seattle WFO and
observational/short term trends in guidance, have opted to remove
the MRGL risk in place across the Olympic's for the period. Locally
heavy rainfall will be expected with the current pattern, however
low probs for >2"/6-hrs and generally sub <1"/hr rainfall rates
expected outside a few elevated convective signals later in the
period over the highest terrain warrant a non-zero, but sub-MRGL
risk forecast for flash flood prospects.=20

Across eastern FL, the threat for locally heavy rainfall continues
for the afternoon and evening with a favoring setup closer to the
end of the forecast when surface trough alignment along the eastern
peninsula generates a stronger low-lvl convergence signature in
proximity to the trough. HREF blended mean QPF still distributes
between 1-1.5" in the mean for spots along the eastern coast,
however HREF neighborhood probs for >5" are between 15-35% along
the same area of the QPF mean. This is grounds for maintaining a
forecast of locally enhanced rainfall rates that could overperform
the mean quite easily if they setup in a given area. For this
alone, the risk area was relatively maintained with the biggest
change being the addition of all of the Miami metro included in the
latest update.=20

Kleebauer

..Previous Discussion..

...Eastern Florida...

A positively tilted trough will swing through the Southeast today.
CAA over warm Gulf/Atlantic waters should generate convection along
a surface convergence zone over the Florida Coast today. MUCAPE
between 500-1000 J/Kg within a moist environment (1.75-2.25 in.
PWATs) should produce scattered thunderstorms with efficient rain
rates. Moist easterly flow over the inverted coastal surface trough
may generate some backbuilding storms this afternoon/evening. HREF
5" neighborhood exceedance probabilities are between 20-30% across
the entire risk area, so there's potential for overperformance of
rainfall. Urban areas are of particular concern to flash flooding.

Kebede


Day 2
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OLYMPIC PENINSULA, THE SIERRA, THE GREAT BASIN AND EASTERN
FLORIDA...

...Olympic Mountains...
The excessive rainfall threat spills over into Thursday across the
Olympics as the upper low begins to dig down into the West Coast.
100-200 J/Kg MUCAPE and 0.75-1" PWATs should sustain the potential
for excessive rainfall, particularly earlier on in the period
(12-18z) before the trough pushes farther east into the interior
and high pressure builds over the Olympic Peninsula. CMCE 1"
exceedance probabilities are around 15-35% within the marginal risk
area.

...Great Basin/Sierra...
Strong diffluence associated with the digging upper trough will
spread throughout the interior West on Thursday. An 80-100 kts RER
jet with a 100 J/Kg MUCAPE should support convection with PWATs
between 0.75-1", which will be 3-4 standard deviations above=20
average. This will provide enough moisture to produce high enough=20
rain rates to overtake flash flood guidance, which is below 1".

...Eastern Florida...
Shortwave vortices within a mean upper trough will propagate south
through the Florida Peninsula on Thursday. Sufficient instability
(500-1000 J/Kg MUCAPE) and moisture (2"+ PWATs) associated with
Imelda may produce excessive rainfall along the immediate coast
early on in the day. The latest qpf trend is decreasing, partly
because the heavy rainfall threat is split between two days (00z
Wednesday--15z Thursday), but urban areas continue to be
susceptible to runoff.


Kebede

Day 3
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA...

...Eastern Florida...
Continued troughing in the Southeast will promote more unsettled
weather across Florida on Friday. Easterly flow will continue
advecting rich tropical moisture (2-2.25" PWATs) from Imelda into
the Peninsula with plenty of instability (500-1000 J/Kg MUCAPE) to
generate scattered thunderstorms. 2" ensemble exceedance
probabilities are between 5-15%, which supports the inherited
marginal risk area. Again, the greatest threat for flash flooding
is in urbanized areas.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!6avUEPTz7w5KE2suAXqsVP1dVLAbmfdPmxgnZEtLOWFq= zArm3NgCYckK9c96cz_B9_Kd_Zo1KG9KS1hlKIMbFB9gD5g$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6avUEPTz7w5KE2suAXqsVP1dVLAbmfdPmxgnZEtLOWFq= zArm3NgCYckK9c96cz_B9_Kd_Zo1KG9KS1hlKIMby97pyUw$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6avUEPTz7w5KE2suAXqsVP1dVLAbmfdPmxgnZEtLOWFq= zArm3NgCYckK9c96cz_B9_Kd_Zo1KG9KS1hlKIMbgHk9OV4$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 011939
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
339 PM EDT Wed Oct 1 2025

Day 1
Valid 16Z Wed Oct 01 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE
EASTERN FLORIDA PENINSULA...

16Z Update: After coordination with local Seattle WFO and
observational/short term trends in guidance, have opted to remove
the MRGL risk in place across the Olympic's for the period. Locally
heavy rainfall will be expected with the current pattern, however
low probs for >2"/6-hrs and generally sub <1"/hr rainfall rates
expected outside a few elevated convective signals later in the
period over the highest terrain warrant a non-zero, but sub-MRGL
risk forecast for flash flood prospects.

Across eastern FL, the threat for locally heavy rainfall continues
for the afternoon and evening with a favoring setup closer to the
end of the forecast when surface trough alignment along the eastern
peninsula generates a stronger low-lvl convergence signature in
proximity to the trough. HREF blended mean QPF still distributes
between 1-1.5" in the mean for spots along the eastern coast,
however HREF neighborhood probs for >5" are between 15-35% along
the same area of the QPF mean. This is grounds for maintaining a
forecast of locally enhanced rainfall rates that could overperform
the mean quite easily if they setup in a given area. For this
alone, the risk area was relatively maintained with the biggest
change being the addition of all of the Miami metro included in the
latest update.

Kleebauer

..Previous Discussion..

...Eastern Florida...

A positively tilted trough will swing through the Southeast today.
CAA over warm Gulf/Atlantic waters should generate convection along
a surface convergence zone over the Florida Coast today. MUCAPE
between 500-1000 J/Kg within a moist environment (1.75-2.25 in.
PWATs) should produce scattered thunderstorms with efficient rain
rates. Moist easterly flow over the inverted coastal surface trough
may generate some backbuilding storms this afternoon/evening. HREF
5" neighborhood exceedance probabilities are between 20-30% across
the entire risk area, so there's potential for overperformance of
rainfall. Urban areas are of particular concern to flash flooding.

Kebede


Day 2
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR EASTERN
FLORIDA, THE OLYMPIC PENINSULA, AND FROM THE SIERRA THROUGH THE
GREAT BASIN...

...Eastern Florida...
An inverted surface trough lingering near the Atlantic coast of
Florida will continue to provide a focus for ascent, aided by a
subtly deepening impulse aloft drifting westward through D2.
Together, these will result in widespread showers and thunderstorms
moving steadily westward through the day around the periphery of an
anomalous high pressure wedge centered near the Mid-Atlantic. With
PWs likely exceeding 2" overlapped with MUCAPE above 1000 J/kg,
convection that trains across the area may contain rain rates of
2-3"/hr (30-40% chance from the HREF). While the greatest potential
for impactful rain appears to be along the immediate coast due to
frictional convergence and a longer period of elevated instability,
with 850mb winds exceeding the mean flow, and Corfidi vectors
aligned anti-parallel to the mean wind, training cells with heavy
rain may push well inland during Thursday evening as well. For this
reason the MRGL risk was expanded slightly westward from previous. Additionally, a small SLGT risk was considered for the Treasure=20
Coast and Gold Coast of SE Florida where both HREF and REFS=20
probabilities feature an elevated risk (40-60%) for rainfall=20
exceeding 5"/24 hrs, but after coordination with WFOs MLB and MFL,
the MRGL risk was maintained at this time due to recent dryness.


...Olympic Mountains...
A closed mid-level low pivoting just west of Washington State will
merge with secondary vorticity energy to manifest as an elongated
closed feature digging into Northern California by Friday morning.
Downstream of this evolution, S/SW low-to-mid level flow will
channel moisture onshore into the Olympic Peninsula, with high
probabilities (>80%) of IVT exceeding 250 kg/m/s continuing the
first part of D2. Where this moisture effectively intersects the
higher terrain of the Olympics to force upslope and enhanced
ascent, primarily within a narrow ribbon of MUCAPE > 250 J/kg, this
will drive some embedded heavier rain rates locally exceeding
0.5"/hr. While the resultant flash flood risk appears generally
isolated, some isolated impacts are possible where heavier showers
and isolated thunderstorms can repeat across the Olympics, so the
MRGL risk was maintained.


...Great Basin/Sierra...
Digging mid-level low will amplify and drop into Northern
California by Friday morning, placing impressive but channeled
downstream ascent from the Sierra through the Great Basin. This
will be enhanced by an impressive poleward arcing jet streak
developing downstream of the primary trough axis, leaving the
favorable RRQ atop the axis of greatest mid-level lift to produce
deep layer ascent. At the surface, this evolution will result in a
wavering stationary front draped from central CA through the Great
Basin and into the Northern High Plains, leading to additional
convergence, and this should manifest as a narrow corridor of
showers and isolated thunderstorms where thermodynamics (PWs above
0.75 inches and MUCAPE 250-500 J/kg) are supportive. Mean 0-6km
winds of 30 kts indicate showers will be progressive, but also
aligned to the front to support at least short duration training.
This could result in isolated instances of flash flooding, with the
greatest potential appearing to be in the Sierra where upslope flow
and regenerating cells supports a higher probability (60-90%) of
more than 1 inch of rainfall.


Weiss

Day 3
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20
EASTERN FLORIDA AND THE GREAT BASIN/INTERMOUNTAIN WEST...

...Eastern Florida...
Another day of onshore flow around the periphery of a wedge of high
pressure to the north will maintain moist convergence across the
Florida Peninsula. A mid-level trough persisting overhead will help
enhance instability as well, so Friday will again feature westward
moving showers and thunderstorms with efficient rainfall rates of
2-3"/hr supported by impressive thermodynamics (PWs 2-2.25" and
MUCAPE above 1000 J/kg). With showers and thunderstorms repeatedly
moving onshore, this training could produce rainfall accumulating
to 1-3" on Friday, and this is on top of what could be heavy rain
D1 and D2 as well. The MRGL risk was maintained and cosmetically
adjusted, with the greatest risk for impacts likely within urban
areas.


...Great Basin into the Northern Rockies...
An amplifying mid-level trough will swing east across the Great
Basin Friday, with heights falling below -1 sigma at 500mb by 00Z
Saturday. A potent shortwave and accompanying vorticity impulse
swinging through the base of this trough will reach the western
Four Corners states late D3, and as it sheds northeast within
downstream confluent flow, provide enhanced ascent through PVA atop
the accompanying height falls. At the same time, a jet streak
pivoting around the base of this trough will also amplify, leading
to pronounced deep layer lift from Nevada into Montana, generally
just upstream from an elongated frontal structure across the
Rockies (suggesting at least modest frontogenesis within this
region as well).

Within this corridor of enhanced ascent, PWs will be as high as
0.75" coincident with MUCAPE above 500 J/kg. This will support
scattered to widespread showers with embedded thunderstorms, and in
the deeper convection, rain rates could exceed 0.5"/hr. Mean 0-6km
winds aligned with propagation vectors will support training to
offset generally fast storm motions, and locally this could result
in 1-2" of rain with isolated flash flooding. A MRGL risk was added
after coordination with WFOs BOI/MSO/LKN/TFX.


Weiss


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!780aRhsm2qrXtyOe_M_L6tkx4ayLzuDjU1WJWOaqE42X= Byl7N1PLv8dIe6Ett4AvagG6rQomd6tbFs_dLhmGxtRjw-c$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!780aRhsm2qrXtyOe_M_L6tkx4ayLzuDjU1WJWOaqE42X= Byl7N1PLv8dIe6Ett4AvagG6rQomd6tbFs_dLhmGdZkgDJE$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!780aRhsm2qrXtyOe_M_L6tkx4ayLzuDjU1WJWOaqE42X= Byl7N1PLv8dIe6Ett4AvagG6rQomd6tbFs_dLhmG07iSnjw$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 020048
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
848 PM EDT Wed Oct 1 2025

Day 1
Valid 01Z Thu Oct 02 2025 - 12Z Thu Oct 02 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE
EASTERN FLORIDA PENINSULA...

Maintained the Marginal Risk area across eastern FL given
persistent deep-layer easterly flow and the expectation that a
trough along the eastern peninsula aligns in a way which favors
better low level convergence along/near the coast later tonight.=20
Latest HREF blended mean QPF still depicts spotty rainfall amounts=20
between 1-1.5" in the mean along the eastern coast. HREF neighborhood probabilities for >5" remained in the 15-35 percent range along=20
the same area of the QPF mean. This is grounds for maintaining a=20
forecast of locally enhanced rainfall rates which could result in
localized flooding from the Miami metro northward...similar in
placement with the previous Marginal Risk area. 00Z radiosondes=20
and ACARS data showed an overall moistening of the atmosphere given
the moisture transport tied to flow off the Atlantic which further
supports the model idea of increasing coverage of showers and=20
thunderstorms and of an atmosphere that could support local=20
downpours.

Bann

Day 2
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR EASTERN
FLORIDA, THE OLYMPIC PENINSULA, AND FROM THE SIERRA THROUGH THE
GREAT BASIN...

...Eastern Florida...
An inverted surface trough lingering near the Atlantic coast of
Florida will continue to provide a focus for ascent, aided by a
subtly deepening impulse aloft drifting westward through D2.
Together, these will result in widespread showers and thunderstorms
moving steadily westward through the day around the periphery of an
anomalous high pressure wedge centered near the Mid-Atlantic. With
PWs likely exceeding 2" overlapped with MUCAPE above 1000 J/kg,
convection that trains across the area may contain rain rates of
2-3"/hr (30-40% chance from the HREF). While the greatest potential
for impactful rain appears to be along the immediate coast due to
frictional convergence and a longer period of elevated instability,
with 850mb winds exceeding the mean flow, and Corfidi vectors
aligned anti-parallel to the mean wind, training cells with heavy
rain may push well inland during Thursday evening as well. For this
reason the MRGL risk was expanded slightly westward from previous. Additionally, a small SLGT risk was considered for the Treasure
Coast and Gold Coast of SE Florida where both HREF and REFS
probabilities feature an elevated risk (40-60%) for rainfall
exceeding 5"/24 hrs, but after coordination with WFOs MLB and MFL,
the MRGL risk was maintained at this time due to recent dryness.


...Olympic Mountains...
A closed mid-level low pivoting just west of Washington State will
merge with secondary vorticity energy to manifest as an elongated
closed feature digging into Northern California by Friday morning.
Downstream of this evolution, S/SW low-to-mid level flow will
channel moisture onshore into the Olympic Peninsula, with high
probabilities (>80%) of IVT exceeding 250 kg/m/s continuing the
first part of D2. Where this moisture effectively intersects the
higher terrain of the Olympics to force upslope and enhanced
ascent, primarily within a narrow ribbon of MUCAPE > 250 J/kg, this
will drive some embedded heavier rain rates locally exceeding
0.5"/hr. While the resultant flash flood risk appears generally
isolated, some isolated impacts are possible where heavier showers
and isolated thunderstorms can repeat across the Olympics, so the
MRGL risk was maintained.


...Great Basin/Sierra...
Digging mid-level low will amplify and drop into Northern
California by Friday morning, placing impressive but channeled
downstream ascent from the Sierra through the Great Basin. This
will be enhanced by an impressive poleward arcing jet streak
developing downstream of the primary trough axis, leaving the
favorable RRQ atop the axis of greatest mid-level lift to produce
deep layer ascent. At the surface, this evolution will result in a
wavering stationary front draped from central CA through the Great
Basin and into the Northern High Plains, leading to additional
convergence, and this should manifest as a narrow corridor of
showers and isolated thunderstorms where thermodynamics (PWs above
0.75 inches and MUCAPE 250-500 J/kg) are supportive. Mean 0-6km
winds of 30 kts indicate showers will be progressive, but also
aligned to the front to support at least short duration training.
This could result in isolated instances of flash flooding, with the
greatest potential appearing to be in the Sierra where upslope flow
and regenerating cells supports a higher probability (60-90%) of
more than 1 inch of rainfall.


Weiss

Day 3
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA AND THE GREAT BASIN/INTERMOUNTAIN WEST...

...Eastern Florida...
Another day of onshore flow around the periphery of a wedge of high
pressure to the north will maintain moist convergence across the
Florida Peninsula. A mid-level trough persisting overhead will help
enhance instability as well, so Friday will again feature westward
moving showers and thunderstorms with efficient rainfall rates of
2-3"/hr supported by impressive thermodynamics (PWs 2-2.25" and
MUCAPE above 1000 J/kg). With showers and thunderstorms repeatedly
moving onshore, this training could produce rainfall accumulating
to 1-3" on Friday, and this is on top of what could be heavy rain
D1 and D2 as well. The MRGL risk was maintained and cosmetically
adjusted, with the greatest risk for impacts likely within urban
areas.


...Great Basin into the Northern Rockies...
An amplifying mid-level trough will swing east across the Great
Basin Friday, with heights falling below -1 sigma at 500mb by 00Z
Saturday. A potent shortwave and accompanying vorticity impulse
swinging through the base of this trough will reach the western
Four Corners states late D3, and as it sheds northeast within
downstream confluent flow, provide enhanced ascent through PVA atop
the accompanying height falls. At the same time, a jet streak
pivoting around the base of this trough will also amplify, leading
to pronounced deep layer lift from Nevada into Montana, generally
just upstream from an elongated frontal structure across the
Rockies (suggesting at least modest frontogenesis within this
region as well).

Within this corridor of enhanced ascent, PWs will be as high as
0.75" coincident with MUCAPE above 500 J/kg. This will support
scattered to widespread showers with embedded thunderstorms, and in
the deeper convection, rain rates could exceed 0.5"/hr. Mean 0-6km
winds aligned with propagation vectors will support training to
offset generally fast storm motions, and locally this could result
in 1-2" of rain with isolated flash flooding. A MRGL risk was added
after coordination with WFOs BOI/MSO/LKN/TFX.


Weiss


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5-1DtE1QDhW5To79d3pWkPa6yeBHXukS-h93drZ4EU-B= wxxjYvAhPsTA3c_xpm-CWEU9FRQLDyUKKnjJNRcO5jOu_ko$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5-1DtE1QDhW5To79d3pWkPa6yeBHXukS-h93drZ4EU-B= wxxjYvAhPsTA3c_xpm-CWEU9FRQLDyUKKnjJNRcO2ykwwoM$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5-1DtE1QDhW5To79d3pWkPa6yeBHXukS-h93drZ4EU-B= wxxjYvAhPsTA3c_xpm-CWEU9FRQLDyUKKnjJNRcOeAUe72c$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 020828
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
428 AM EDT Thu Oct 2 2025

Day 1
Valid 12Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SIERRA, GREAT BASIN AND EASTERN FLORIDA...

...Sierra/Great Basin...
An upper low will dig into the West Coast while sending streams of
vorticity into the Sierra Nevada, Great Basin and Northern=20
Rockies. Diffluence will spread across the aforementioned areas=20
throughout the day on Friday. At the surface, a low pressure system
will propagate across the interior West, while anomalous moisture=20
(3-4 stndv PWATs) streams in behind the preceding cold front.=20
Scattered to isolated thunderstorms may develop and produce=20
isolated instances of excessive rainfall and flash flooding.=20

Upslope enhancement across the Sierra could produce heavier=20
rainfall totals than what are currently forecast. EAS probabilities
of 24 hour qpf exceeding 1 inch are over 40% in the Sierra and=20
between 15-40% in the Great Basin. Therefore, burn scars over=20
central and southern Idaho are at risk of flash flooding today.

...Eastern Florida...
Moist easterly flow into a surface front oriented north-south will
produce scattered convection across Florida today. The surface=20
boundary draped along the eastern coast will focus PWATs of around=20
2" in that area where MUCAPE between 500-1000 J/Kg will also likely
produce high rain rates. Neighborhood probabilities of exceeding=20
5" in 24 hours are between 40-90% from near Miami metro up through=20
Melbourne and Orlando.


Kebede

Day 2
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE'S A MARGINAL RISK FOR PORTIONS OF THE GREAT BASIN AND
EASTERN FLORIDA...

...Great Basin...
The upper trough propagates through the Great Basin and begins=20
lifting north on Friday. The excessive rainfall threat bleeds into
Friday from Thursday as thunderstorms weaken and spread from the=20
Great Basin into the Northern Rockies by Friday afternoon. Instability
and moisture will be relatively modest (100-200 J/Kg MUCAPE)=20
(0.5-0.9"). Ensemble exceedance probabilities of 1" are between=20
10-20% over northern Nevada with 2 day totals potentially eclipsing
2" in some places.

...Eastern Florida...
Moisture advection into Florida increases on Friday as a mid-level
circulation embedded within a broader upper ridge continues to
direct moisture and instability into the state's east coast.=20
Another inverted surface trough may develop along the state's east
coast and focus convection along the convergence zone. Ensemble=20
exceedance probabilities of 2" are between 5-15% along the=20
immediate coast, while first guess fields support the marginal with
5% flash flood probabilities.


Kebede

Day 3
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE'S A MARGINAL RISK FOR PORTIONS OF SOUTHEAST LOUISIANA AND
EASTERN FLORIDA INTO FAR SOUTHEASTERN GEORGIA...

...Central Gulf Coast...
Mid-level vorticity swirling over the Central Gulf Coast will
generate instability and pull an increasing amount of Gulf=20
moisture into the region on Saturday. Convection should fire along=20
a coastal convergence zone that develops and diurnal heating should
enhance afternoon/evening storms along that boundary. PWATs will
likely be over 2" with MUCAPE between 500-750 J/Kg. Ensemble exceedance probabilities of 2" are between 15-30% for much of southeast=20
Louisiana.

...Eastern Florida/Southeastern Georgia...
Tropical moisture associated with Imelda will continue flowing into
Florida due to and upper ridge over the East Coast and embedded
troughing over Florida and the Gulf. A modest instability plume=20
should flow up the Florida Peninsula into far southeastern Georgia=20
where PWAT's of over 2" and an inverted surface trough could
combine to produce thunderstorms capable of generating 0.75-1"/hr=20
rain rates. Ensemble exceedance probabilities of 2" are between=20
5-15% along Florida's east coast into southeastern Georgia.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5QMibcjbv8UIoTFzL7jA06j0OeJ8rgJX3NQrBodnUdto= 0N3yKv--zID7olPZgjbAEjsDg2dbjEODBS5D83_TzDyC4E0$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5QMibcjbv8UIoTFzL7jA06j0OeJ8rgJX3NQrBodnUdto= 0N3yKv--zID7olPZgjbAEjsDg2dbjEODBS5D83_T_tNI8og$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5QMibcjbv8UIoTFzL7jA06j0OeJ8rgJX3NQrBodnUdto= 0N3yKv--zID7olPZgjbAEjsDg2dbjEODBS5D83_TBlxoeD8$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 021544
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1144 AM EDT Thu Oct 2 2025

Day 1
Valid 16Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SIERRA, GREAT BASIN AND EASTERN FLORIDA...

16Z Update: The previous forecast has not changed much in the
overall synoptic and mesoscale expectations over the two risk areas outlined.=20

Across FL, locally heavy rainfall within the confines of
a surface trough axis aligned parallel, just inland from the
coastal plain will be the threat through the period with urban
flash flooding the most likely case of any potential. Highest 5"
probs via 12z HREF neighborhood output are still in that 40-90%
range, however the highest probs are centered between Melbourne to
West Palm Beach with a centroid near Port St Lucie. This is hi-res
indications of where they anticipate the strongest low-level
convergence regime with relevant moisture flux situated just off
the Atlantic coast at similar latitude to the elevated probs.
Considering some error in convective placement, it's still
reasonable to consider areas from Miami up to Daytona within the
proxy for locally enhanced rainfall rates with hourly rates ~3"/hr
at peak intensity when you factor PWATs hovering between 1.75-2"=20
as of the 10/12z RAOB soundings from Cape Canaveral. This signal=20
in the means and individual deterministic is more than sufficient=20
for a maintenance of the MRGL risk in place with only a minor=20
northward expansion in the area to cover for the current radar
trends.=20

Across the west, the setup remains consistent among all the CAMs
and global deterministic with a relative max situated over the
northern Sierra along and near I-80 where modest instability and
sufficient large scale ascent should initiate a period of moderate
to heavy rain for multiple hours that could enhance a localized
flood prospect. As we move further inland into the Great Basin, the
setup shifts to more scattered/widespread convective schemes that
are better suited for those highly localized flash flood concerns
within topography that historically favors flashier output due to
the soil composition and prevalence of dry washes and arroyos
littered over the high desert. This threat expands into the Snake
River basin of ID and adjacent zones later this evening. Totals
between 1-2" (Locally higher in the northern Sierra) will be most=20
common in the MRGL risk in place from the Central Valley of=20
California up into Sawtooth and Salmon River Ranges of Idaho.=20

Kleebauer

..Previous Discussions..

...Sierra/Great Basin...

An upper low will dig into the West Coast while sending streams of
vorticity into the Sierra Nevada, Great Basin and Northern=20
Rockies. Diffluence will spread across the aforementioned areas=20
throughout the day on Friday. At the surface, a low pressure system
will propagate across the interior West, while anomalous moisture=20
(3-4 stndv PWATs) streams in behind the preceding cold front.=20
Scattered to isolated thunderstorms may develop and produce=20
isolated instances of excessive rainfall and flash flooding.

Upslope enhancement across the Sierra could produce heavier
rainfall totals than what are currently forecast. EAS probabilities
of 24 hour qpf exceeding 1 inch are over 40% in the Sierra and
between 15-40% in the Great Basin. Therefore, burn scars over
central and southern Idaho are at risk of flash flooding today.

...Eastern Florida...

Moist easterly flow into a surface front oriented north-south will
produce scattered convection across Florida today. The surface
boundary draped along the eastern coast will focus PWATs of around
2" in that area where MUCAPE between 500-1000 J/Kg will also likely
produce high rain rates. Neighborhood probabilities of exceeding
5" in 24 hours are between 40-90% from near Miami metro up through
Melbourne and Orlando.

Kebede


Day 2
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE'S A MARGINAL RISK FOR PORTIONS OF THE GREAT BASIN AND
EASTERN FLORIDA...

...Great Basin...
The upper trough propagates through the Great Basin and begins
lifting north on Friday. The excessive rainfall threat bleeds into
Friday from Thursday as thunderstorms weaken and spread from the
Great Basin into the Northern Rockies by Friday afternoon. Instability
and moisture will be relatively modest (100-200 J/Kg MUCAPE)
(0.5-0.9"). Ensemble exceedance probabilities of 1" are between
10-20% over northern Nevada with 2 day totals potentially eclipsing
2" in some places.

...Eastern Florida...
Moisture advection into Florida increases on Friday as a mid-level
circulation embedded within a broader upper ridge continues to
direct moisture and instability into the state's east coast.
Another inverted surface trough may develop along the state's east
coast and focus convection along the convergence zone. Ensemble
exceedance probabilities of 2" are between 5-15% along the
immediate coast, while first guess fields support the marginal with
5% flash flood probabilities.


Kebede

Day 3
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE'S A MARGINAL RISK FOR PORTIONS OF SOUTHEAST LOUISIANA AND
EASTERN FLORIDA INTO FAR SOUTHEASTERN GEORGIA...

...Central Gulf Coast...
Mid-level vorticity swirling over the Central Gulf Coast will
generate instability and pull an increasing amount of Gulf
moisture into the region on Saturday. Convection should fire along
a coastal convergence zone that develops and diurnal heating should
enhance afternoon/evening storms along that boundary. PWATs will
likely be over 2" with MUCAPE between 500-750 J/Kg. Ensemble exceedance probabilities of 2" are between 15-30% for much of southeast
Louisiana.

...Eastern Florida/Southeastern Georgia...
Tropical moisture associated with Imelda will continue flowing into
Florida due to and upper ridge over the East Coast and embedded
troughing over Florida and the Gulf. A modest instability plume
should flow up the Florida Peninsula into far southeastern Georgia
where PWAT's of over 2" and an inverted surface trough could
combine to produce thunderstorms capable of generating 0.75-1"/hr
rain rates. Ensemble exceedance probabilities of 2" are between
5-15% along Florida's east coast into southeastern Georgia.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-TXaeIF6zJASOo8o2ZPRpSFXhdz9pbtfYb8Itozk9Wpn= YeHxPDMCzMp2yhoxlB8WXE2lf0pHGWzQUj--paKEvEq-Ky4$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-TXaeIF6zJASOo8o2ZPRpSFXhdz9pbtfYb8Itozk9Wpn= YeHxPDMCzMp2yhoxlB8WXE2lf0pHGWzQUj--paKEeqNXeZE$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-TXaeIF6zJASOo8o2ZPRpSFXhdz9pbtfYb8Itozk9Wpn= YeHxPDMCzMp2yhoxlB8WXE2lf0pHGWzQUj--paKEnyhorn4$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 021939
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
339 PM EDT Thu Oct 2 2025

Day 1
Valid 16Z Thu Oct 02 2025 - 12Z Fri Oct 03 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20
THE SIERRA, GREAT BASIN AND EASTERN FLORIDA...

16Z Update: The previous forecast has not changed much in the
overall synoptic and mesoscale expectations over the two risk areas
outlined.

Across FL, locally heavy rainfall within the confines of
a surface trough axis aligned parallel, just inland from the
coastal plain will be the threat through the period with urban
flash flooding the most likely case of any potential. Highest 5"
probs via 12z HREF neighborhood output are still in that 40-90%
range, however the highest probs are centered between Melbourne to
West Palm Beach with a centroid near Port St Lucie. This is hi-res
indications of where they anticipate the strongest low-level
convergence regime with relevant moisture flux situated just off
the Atlantic coast at similar latitude to the elevated probs.
Considering some error in convective placement, it's still
reasonable to consider areas from Miami up to Daytona within the
proxy for locally enhanced rainfall rates with hourly rates ~3"/hr
at peak intensity when you factor PWATs hovering between 1.75-2"
as of the 10/12z RAOB soundings from Cape Canaveral. This signal
in the means and individual deterministic is more than sufficient
for a maintenance of the MRGL risk in place with only a minor
northward expansion in the area to cover for the current radar
trends.

Across the west, the setup remains consistent among all the CAMs
and global deterministic with a relative max situated over the
northern Sierra along and near I-80 where modest instability and
sufficient large scale ascent should initiate a period of moderate
to heavy rain for multiple hours that could enhance a localized
flood prospect. As we move further inland into the Great Basin, the
setup shifts to more scattered/widespread convective schemes that
are better suited for those highly localized flash flood concerns
within topography that historically favors flashier output due to
the soil composition and prevalence of dry washes and arroyos
littered over the high desert. This threat expands into the Snake
River basin of ID and adjacent zones later this evening. Totals
between 1-2" (Locally higher in the northern Sierra) will be most
common in the MRGL risk in place from the Central Valley of
California up into Sawtooth and Salmon River Ranges of Idaho.

Kleebauer

..Previous Discussions..

...Sierra/Great Basin...

An upper low will dig into the West Coast while sending streams of
vorticity into the Sierra Nevada, Great Basin and Northern
Rockies. Diffluence will spread across the aforementioned areas
throughout the day on Friday. At the surface, a low pressure system
will propagate across the interior West, while anomalous moisture
(3-4 stndv PWATs) streams in behind the preceding cold front.
Scattered to isolated thunderstorms may develop and produce
isolated instances of excessive rainfall and flash flooding.

Upslope enhancement across the Sierra could produce heavier
rainfall totals than what are currently forecast. EAS probabilities
of 24 hour qpf exceeding 1 inch are over 40% in the Sierra and
between 15-40% in the Great Basin. Therefore, burn scars over
central and southern Idaho are at risk of flash flooding today.

...Eastern Florida...

Moist easterly flow into a surface front oriented north-south will
produce scattered convection across Florida today. The surface
boundary draped along the eastern coast will focus PWATs of around
2" in that area where MUCAPE between 500-1000 J/Kg will also likely
produce high rain rates. Neighborhood probabilities of exceeding
5" in 24 hours are between 40-90% from near Miami metro up through
Melbourne and Orlando.

Kebede


Day 2
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE EAST-=20
CENTRAL FLORIDA COAST...

...Eastern Florida...

20z Update: In coordination with the Melbourne WFO, a SLGT risk was
added to the east-central Florida coast south of Melbourne. A
remnant moisture flux tied to the trailing low-level shear axis
from Imelda will slowly propagate westward out of the Bahamas with
embedded mid-level vorticity trying to develop into a more
concentric circulation as we step into Saturday AM. The pattern is
a ongoing evolution that begins in D1 and just moves forward in
time with frictional convergence regime aligned along the eastern=20
FL coast, mainly in line with a surface trough forecast parallel to
the coastal plain for the foreseeable future. Sufficient low-level
buoyancy aided by a thin axis of 1500-2000 J/kg of MUCAPE along the
coast with PWATs between 1.8-2.2" situated within the same zone
should allow for a heightened threat of locally heavy rainfall
within the east-central FL coastal plain, noted by several CAMs and
ensemble members of both the GEFS/ECENS. Considering the high
neighborhood probs for >5" (45-80%) focused near and just south of
the Space Coast, a SLGT risk was added for the elevated threat of
flash flooding within the urban zones that align the immediate
coast to just inland around the I-95 corridor. Some adjustments in
future updates are plausible pending near term convective
evolutions, so this is a period to monitor closely as we move into
tomorrow morning and beyond.=20

...Great Basin...

20Z Update: Previous forecast remains steadfast with only minor
changes made to the MRGL risk forecast across the Great Basin into
portions of the interior Northwest. Heaviest precip axis will be
focused over central NV into southern ID as the upper trough begins
to close off as it migrates inland from the Pacific leading to
enhanced large scale forcing and steeper lapse rates Friday
afternoon and evening in these locations. Anticipating rates to
remain <1"/hr for the threat, however some of these locations are
susceptible to even 0.5"/hr rates due to high run and complex
topography that promotes funneling. As a result, there wasn't much
of a reason to deviate from the last forecast issuance, so only
minor adjustments based on updated probs and mean QPF distribution
were generated in this forecast cycle.=20

Kleebauer

..Previous Discussion..

The upper trough propagates through the Great Basin and begins
lifting north on Friday. The excessive rainfall threat bleeds into
Friday from Thursday as thunderstorms weaken and spread from the
Great Basin into the Northern Rockies by Friday afternoon. Instability
and moisture will be relatively modest (100-200 J/Kg MUCAPE)
(0.5-0.9"). Ensemble exceedance probabilities of 1" are between
10-20% over northern Nevada with 2 day totals potentially eclipsing
2" in some places.

Kebede


Day 3
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA
SPACE COAST...

...Eastern Florida...

20Z Update: Surface evolution of a weak surface low off the=20
eastern FL coast will be key in determining the extent of the heavy
rainfall persistence in-of the FL coast by Saturday. As of now,=20
the ensemble means suggest a weak surface reflection will form and=20
migrate slowly inland of the peninsula by Saturday afternoon=20
leading to a larger area of the FL coast being subject to enhanced=20 convergence and northern push of elevated PWATs/instability capable
of flash flood prospects. Ensemble means are more generous than=20
most deterministic, however the the scheme is certainly favorable=20
for the threat of a repeated heavy rain scenario in-of the FL Space
Coast. In coordination with the Melbourne WFO, another SLGT risk=20
was added for much of the CWA as ensemble mean QPF of >2" aligns=20
best within the zone that extends from Daytona Beach down to Port=20
St Lucie. If the D2 materializes, this will end up being a case=20
where wet antecedent conditions would exacerbate the potential=20
leading to a greater case for scattered flash flood signals as the=20
pattern evolves. With a better low-level convergence regime=20
generating from the surface reflection nearby, the chance for=20
heavier precip expanding north of the previous period would be be=20
higher, thus the SLGT risk having a larger areal footprint compared
to the previous D2. This remains a period to watch as small shifts
in the synoptic scheme could shift heavy rain proxy and subsequent magnitudes.=20

...Central Gulf Coast...

20Z Update: This setup remains on the lower end of the MRGL risk
threshold due to the differences in placement of the heaviest
precip aligned with the coastal convergence regime formulating over
the northern Gulf waters. The latitudinal push of the convergent
axis will likely dictate where the risk is even necessary as the
southern Parishes are more than capable to absorb the heavy rain
prospects promoted by some guidance. However, the urban corridor of
New Orleans and nearby suburbs are more susceptible to flash flood
prospects and were close enough to the highest mean QPF forecast
that the main shift was to include the metro and shrink the overall
risk footprint to align with areas that would see the heaviest
precip potential and have the ability to entice flash flood
prospects.=20

Kleebauer

..Previous Discussion..

Mid- level vorticity swirling over the Central Gulf=20
Coast will generate instability and pull an increasing amount of=20
Gulf moisture into the region on Saturday. Convection should fire=20
along a coastal convergence zone that develops and diurnal heating=20
should enhance afternoon/evening storms along that boundary. PWATs=20
will likely be over 2" with MUCAPE between 500-750 J/Kg. Ensemble=20
exceedance probabilities of 2" are between 15-30% for much of=20
southeast Louisiana.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-i4D47WCxDbxalBPmxU8kkMJUuLqC3vXbdJhglfFydnf= afXFExUEu1o9NNbpFBJWEtm1HpwPnLqKuVF-k_QOskagyg4$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-i4D47WCxDbxalBPmxU8kkMJUuLqC3vXbdJhglfFydnf= afXFExUEu1o9NNbpFBJWEtm1HpwPnLqKuVF-k_QOKCsvUaI$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-i4D47WCxDbxalBPmxU8kkMJUuLqC3vXbdJhglfFydnf= afXFExUEu1o9NNbpFBJWEtm1HpwPnLqKuVF-k_QOY2bKtH8$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 030042
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
842 PM EDT Thu Oct 2 2025

Day 1
Valid 01Z Fri Oct 03 2025 - 12Z Fri Oct 03 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SIERRA, GREAT BASIN AND EASTERN FLORIDA...

01Z Update: The overall picture has changed little and the mesoscale expectations over the two risk areas outlined largely remained on
track from the earlier outlook.

Across FL, localized but high rainfall rates are expected across
portions of the eastern Florida peninsula an southeast Florida
this evening and into the overnight hours. Hourly rainfall rates of
2 to 3 inches are expected which could result in localized flash
flooding with urbanized areas and regions of poor drainage being
the most vulnerable. With precipitable water values close to 2
inches across this portion of Florida...and easterly flow of 20 to
25 knots largely aligned perpendicular to the coastline which
maximizes convergence combined with subtle cyclonic rotations
evident on satellite imagery...the environment should be able to
support and sustain upwards of 3 inch per hour rates within any
slow moving axis of rainfall. Refer to Mesoscale Convective
Discussion 1155 for additional details.

Across portions of the Sierra and adjacent areas...training and
repeating of showers and thunderstorms this evening may result in
localized flash flooding due to hourly rainfall rates of 0.5 to
1.0 inches that could result in rainfall totals of 1 to 2 inches.
Even though instability is modest...the environment is
characterized by precipitable water values of 1.0 to 1.4 inches (on
the order of +2 to +4 standardized anomalies above climatology for
early October) which at least suggests locally intense but brief
downpours could be supported. Higher rainfall intensities falling
on sensitive burn scars or urban areas would be most at risk for
localized flash flooding into the late evening.

Bann


Day 2
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE EAST-
CENTRAL FLORIDA COAST...

...Eastern Florida...

20z Update: In coordination with the Melbourne WFO, a SLGT risk was
added to the east-central Florida coast south of Melbourne. A
remnant moisture flux tied to the trailing low-level shear axis
from Imelda will slowly propagate westward out of the Bahamas with
embedded mid-level vorticity trying to develop into a more
concentric circulation as we step into Saturday AM. The pattern is
a ongoing evolution that begins in D1 and just moves forward in
time with frictional convergence regime aligned along the eastern
FL coast, mainly in line with a surface trough forecast parallel to
the coastal plain for the foreseeable future. Sufficient low-level
buoyancy aided by a thin axis of 1500-2000 J/kg of MUCAPE along the
coast with PWATs between 1.8-2.2" situated within the same zone
should allow for a heightened threat of locally heavy rainfall
within the east-central FL coastal plain, noted by several CAMs and
ensemble members of both the GEFS/ECENS. Considering the high
neighborhood probs for >5" (45-80%) focused near and just south of
the Space Coast, a SLGT risk was added for the elevated threat of
flash flooding within the urban zones that align the immediate
coast to just inland around the I-95 corridor. Some adjustments in
future updates are plausible pending near term convective
evolutions, so this is a period to monitor closely as we move into
tomorrow morning and beyond.

...Great Basin...

20Z Update: Previous forecast remains steadfast with only minor
changes made to the MRGL risk forecast across the Great Basin into
portions of the interior Northwest. Heaviest precip axis will be
focused over central NV into southern ID as the upper trough begins
to close off as it migrates inland from the Pacific leading to
enhanced large scale forcing and steeper lapse rates Friday
afternoon and evening in these locations. Anticipating rates to
remain <1"/hr for the threat, however some of these locations are
susceptible to even 0.5"/hr rates due to high run and complex
topography that promotes funneling. As a result, there wasn't much
of a reason to deviate from the last forecast issuance, so only
minor adjustments based on updated probs and mean QPF distribution
were generated in this forecast cycle.

Kleebauer

..Previous Discussion..

The upper trough propagates through the Great Basin and begins
lifting north on Friday. The excessive rainfall threat bleeds into
Friday from Thursday as thunderstorms weaken and spread from the
Great Basin into the Northern Rockies by Friday afternoon. Instability
and moisture will be relatively modest (100-200 J/Kg MUCAPE)
(0.5-0.9"). Ensemble exceedance probabilities of 1" are between
10-20% over northern Nevada with 2 day totals potentially eclipsing
2" in some places.

Kebede


Day 3
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE FLORIDA
SPACE COAST...

...Eastern Florida...

20Z Update: Surface evolution of a weak surface low off the
eastern FL coast will be key in determining the extent of the heavy
rainfall persistence in-of the FL coast by Saturday. As of now,
the ensemble means suggest a weak surface reflection will form and
migrate slowly inland of the peninsula by Saturday afternoon
leading to a larger area of the FL coast being subject to enhanced
convergence and northern push of elevated PWATs/instability capable
of flash flood prospects. Ensemble means are more generous than
most deterministic, however the the scheme is certainly favorable
for the threat of a repeated heavy rain scenario in-of the FL Space
Coast. In coordination with the Melbourne WFO, another SLGT risk
was added for much of the CWA as ensemble mean QPF of >2" aligns
best within the zone that extends from Daytona Beach down to Port
St Lucie. If the D2 materializes, this will end up being a case
where wet antecedent conditions would exacerbate the potential
leading to a greater case for scattered flash flood signals as the
pattern evolves. With a better low-level convergence regime
generating from the surface reflection nearby, the chance for
heavier precip expanding north of the previous period would be be
higher, thus the SLGT risk having a larger areal footprint compared
to the previous D2. This remains a period to watch as small shifts
in the synoptic scheme could shift heavy rain proxy and subsequent
magnitudes.

...Central Gulf Coast...

20Z Update: This setup remains on the lower end of the MRGL risk
threshold due to the differences in placement of the heaviest
precip aligned with the coastal convergence regime formulating over
the northern Gulf waters. The latitudinal push of the convergent
axis will likely dictate where the risk is even necessary as the
southern Parishes are more than capable to absorb the heavy rain
prospects promoted by some guidance. However, the urban corridor of
New Orleans and nearby suburbs are more susceptible to flash flood
prospects and were close enough to the highest mean QPF forecast
that the main shift was to include the metro and shrink the overall
risk footprint to align with areas that would see the heaviest
precip potential and have the ability to entice flash flood
prospects.

Kleebauer

..Previous Discussion..

Mid- level vorticity swirling over the Central Gulf
Coast will generate instability and pull an increasing amount of
Gulf moisture into the region on Saturday. Convection should fire
along a coastal convergence zone that develops and diurnal heating
should enhance afternoon/evening storms along that boundary. PWATs
will likely be over 2" with MUCAPE between 500-750 J/Kg. Ensemble
exceedance probabilities of 2" are between 15-30% for much of
southeast Louisiana.

Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!7Sbq-SYohzwmL9S-WvAt0M62oMC6f3hAE52FREc2ydzh= pcqHMxBUUVNO5YAerMjNapHAPspy73jPMACLRhpeKMBuGys$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7Sbq-SYohzwmL9S-WvAt0M62oMC6f3hAE52FREc2ydzh= pcqHMxBUUVNO5YAerMjNapHAPspy73jPMACLRhpeOxUkboA$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7Sbq-SYohzwmL9S-WvAt0M62oMC6f3hAE52FREc2ydzh= pcqHMxBUUVNO5YAerMjNapHAPspy73jPMACLRhpeLXPSaA4$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 030743
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
343 AM EDT Fri Oct 3 2025

Day 1
Valid 12Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
FLORIDA'S EAST COAST...

...Florida's East Coast...

A closed mid-level disturbance will drift westward across the=20
Florida Peninsula and into the Gulf of Mexico today. This system
will bring tropical moisture from Imelda and Humberto with it. An=20
inverted trough oriented along the Florida coast will interact with
the moisture advecting into the region and force scattered=20
thunderstorm activity throughout the day. Modest instability=20
between 500-1000 J/Kg MUCAPE could produce quarter to half inch=20
rates over the slight risk area. Parts of central and southern=20
Florida that have received between 2-4 (isolated 5) inches of rain
in the past 24 hours will be especially susceptible to runoff from
today's storms. Neighborhood exceedance probabilities of 5 inches=20
are between 20-40% across Florida's east coast today.

...Great Basin...

Additional rainfall is forecast to occur beneath the upper low,
which will continue propagating through the interior West today.=20
Recent heavy rainfall over portions of the Great Basin will likely
prime surfaces for runoff from additional precipitation. Burn=20
scars in central and southern Idaho continue to be of concern from=20
today's storms, the bulk of which should occur this morning into=20
afternoon before the upper low moves directly over the Great Basin=20
and instability weakens. HREF EAS exceedance probabilities of over=20
1 inch are between 15-35% over northern/central Nevada where PWATs=20
will be between 2-3 standard deviations above normal.


Kebede

Day 2
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
FLORIDA'S EAST COAST...

...Florida's East Coast...

Thunderstorms are expected to continue to develop along the=20
inverted trough axis oriented north-south along Florida's east=20
coast on Saturday. Moisture will lift north along with the mid-
level disturbance. The inherited slight and marginal risk areas=20
were maintained due to a mostly consistent signal for excessive=20
rainfall over the east central coast. Ensemble exceedance
probabilities of 2 inches are between 5-10% across the marginal
risk area. 48 hour totals between 3-5 inches (local 6") will likely
make overcoming flash flood guidance a bit easier.

...Central Gulf Coast...

The same moisture regime impacting the Florida peninsula will focus
over the central Gulf Coast this weekend. Mid-level vorticity will
lift into the area on Saturday, providing forcing for convection=20
along the immediate Louisiana/Mississippi coast. Anywhere between=20
4-6 inches of rain may occur over far southeastern Louisiana=20
through Saturday night. Despite 2" ensemble exceedance=20
probabilities being relatively low (5-10%), the multi day nature=20
of the rainfall could still produce isolated instances of flash=20
flooding.


Kebede

Day 3
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE CENTRAL GULF COAST AND THE SOUTHEAST COAST...

...Central Gulf Coast...

The mid-level disturbance continues propagating westward toward the
positively tilted upper trough centered over the West on Sunday.
Thus, the heavy rainfall threat will likely bleed over from=20
Saturday evening into Sunday morning for portions of the Central=20
Gulf Coast, before dissipating beneath diminished support aloft.
PWATs of 2-2.5" and instability between 500-1000 J/Kg MUCAPE could
churn out rain rates between 1-1.5"/hr Saturday morning into
afternoon. Ensemble exceedance probabilities of 2 inches are=20
between 5-15% along the far southeastern Louisiana to Florida=20
panhandle corridor, which supports the marginal risk area in=20
place.=20

...Southeast Coast...

Inverted troughing continues along the Florida/Southeast Coast
through the latter part of this weekend. Anomalous moisture (2-3=20
stndv) will continue interacting with the surface boundary to=20
generate scattered to isolated thunderstorms across the=20
Florida/Georgia coast. Rainfall totals of 1-3" are likely along=20
the Florida/Georgia/South Carolina coast on Saturday. The latest=20
guidance has trended away from tropical moisture making its way=20
inland, therefore a marginal risk was maintained for much of the=20
Southeast Coast.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8lou75ZfJWo2XtaYp7O5H36FbT1XQ0rdJuOpCqww5bLk= W6qQh2J7MWsvbtYwrLDOhkHS6lLKjThVbWuFloWTkAaU93w$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8lou75ZfJWo2XtaYp7O5H36FbT1XQ0rdJuOpCqww5bLk= W6qQh2J7MWsvbtYwrLDOhkHS6lLKjThVbWuFloWTugsQsDQ$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8lou75ZfJWo2XtaYp7O5H36FbT1XQ0rdJuOpCqww5bLk= W6qQh2J7MWsvbtYwrLDOhkHS6lLKjThVbWuFloWT2N5mr7I$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 031602
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1202 PM EDT Fri Oct 3 2025

Day 1
Valid 16Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA AND THE INTERMOUNTAIN WEST...

...Florida's East Coast...

For the 16Z Update, the Slight Risk centered along Florida's
Treasure Coast was removed. While easterly flow is still expected
to support showers and storms, with isolated heavy amounts possible=20
along Florida's East Coast, the consensus of the HREF/RRFS has=20
trended down along the Treasure Coast -- showing the focus for=20
deeper moisture and heavier amounts further south. Probabilities=20
from the HREF/RRFS now indicate the greatest chance for heavy=20
amounts through the remainder of Day 1 is across Southeast Florida,
which may result in runoff concerns, especially if they set up=20
over the urbanized areas. However, confidence in the details is=20
limited, with some indication that the heaviest amounts may set up
west of the urbanized areas over the Everglades. Therefore,=20
maintained just a Marginal Risk for now.

...Great Basin...

Additional rainfall is forecast to occur beneath the upper low,
which will continue propagating through the interior West today.
Recent heavy rainfall over portions of the Great Basin will likely
prime surfaces for runoff from additional precipitation. Burn
scars in central and southern Idaho continue to be of concern from
today's storms, the bulk of which should occur this morning into
afternoon before the upper low moves directly over the Great Basin
and instability weakens. HREF EAS exceedance probabilities of over
1 inch are between 15-35% over northern/central Nevada where PWATs
will be between 2-3 standard deviations above normal.


Pereira/Kebede

Day 2
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE'S A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
FLORIDA'S EAST COAST...

...Florida's East Coast...

Thunderstorms are expected to continue to develop along the
inverted trough axis oriented north-south along Florida's east
coast on Saturday. Moisture will lift north along with the mid-
level disturbance. The inherited slight and marginal risk areas
were maintained due to a mostly consistent signal for excessive
rainfall over the east central coast. Ensemble exceedance
probabilities of 2 inches are between 5-10% across the marginal
risk area. 48 hour totals between 3-5 inches (local 6") will likely
make overcoming flash flood guidance a bit easier.

...Central Gulf Coast...

The same moisture regime impacting the Florida peninsula will focus
over the central Gulf Coast this weekend. Mid-level vorticity will
lift into the area on Saturday, providing forcing for convection
along the immediate Louisiana/Mississippi coast. Anywhere between
4-6 inches of rain may occur over far southeastern Louisiana
through Saturday night. Despite 2" ensemble exceedance
probabilities being relatively low (5-10%), the multi day nature
of the rainfall could still produce isolated instances of flash
flooding.


Kebede

Day 3
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE'S A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE CENTRAL GULF COAST AND THE SOUTHEAST COAST...

...Central Gulf Coast...

The mid-level disturbance continues propagating westward toward the
positively tilted upper trough centered over the West on Sunday.
Thus, the heavy rainfall threat will likely bleed over from
Saturday evening into Sunday morning for portions of the Central
Gulf Coast, before dissipating beneath diminished support aloft.
PWATs of 2-2.5" and instability between 500-1000 J/Kg MUCAPE could
churn out rain rates between 1-1.5"/hr Saturday morning into
afternoon. Ensemble exceedance probabilities of 2 inches are
between 5-15% along the far southeastern Louisiana to Florida
panhandle corridor, which supports the marginal risk area in
place.

...Southeast Coast...

Inverted troughing continues along the Florida/Southeast Coast
through the latter part of this weekend. Anomalous moisture (2-3
stndv) will continue interacting with the surface boundary to
generate scattered to isolated thunderstorms across the
Florida/Georgia coast. Rainfall totals of 1-3" are likely along
the Florida/Georgia/South Carolina coast on Saturday. The latest
guidance has trended away from tropical moisture making its way
inland, therefore a marginal risk was maintained for much of the
Southeast Coast.


Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4W0WTOsZBXy7bIn50nQYOd9hE61R1hNw9pyfn6wACvrt= kINYEAYL_efBcfQO7vY3575CIscAmdX-SnGA4ejP47iUn1A$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4W0WTOsZBXy7bIn50nQYOd9hE61R1hNw9pyfn6wACvrt= kINYEAYL_efBcfQO7vY3575CIscAmdX-SnGA4ejPL2Jz_AY$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4W0WTOsZBXy7bIn50nQYOd9hE61R1hNw9pyfn6wACvrt= kINYEAYL_efBcfQO7vY3575CIscAmdX-SnGA4ejPfgJlpzM$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 031952
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
352 PM EDT Fri Oct 3 2025

Day 1
Valid 16Z Fri Oct 03 2025 - 12Z Sat Oct 04 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA AND THE INTERMOUNTAIN WEST...

...Florida's East Coast...

For the 16Z Update, the Slight Risk centered along Florida's
Treasure Coast was removed. While easterly flow is still expected
to support showers and storms, with isolated heavy amounts possible
along Florida's East Coast, the consensus of the HREF/RRFS has
trended down along the Treasure Coast -- showing the focus for
deeper moisture and heavier amounts further south. Probabilities
from the HREF/RRFS now indicate the greatest chance for heavy
amounts through the remainder of Day 1 is across Southeast Florida,
which may result in runoff concerns, especially if they set up
over the urbanized areas. However, confidence in the details is
limited, with some indication that the heaviest amounts may set up
west of the urbanized areas over the Everglades. Therefore,
maintained just a Marginal Risk for now.

...Great Basin...

Additional rainfall is forecast to occur beneath the upper low,
which will continue propagating through the interior West today.
Recent heavy rainfall over portions of the Great Basin will likely
prime surfaces for runoff from additional precipitation. Burn
scars in central and southern Idaho continue to be of concern from
today's storms, the bulk of which should occur this morning into
afternoon before the upper low moves directly over the Great Basin
and instability weakens. HREF EAS exceedance probabilities of over
1 inch are between 15-35% over northern/central Nevada where PWATs
will be between 2-3 standard deviations above normal.


Pereira/Kebede

Day 2
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20
FLORIDA'S EAST COAST...

20Z Update...
The Marginal Risk was removed from southeastern Louisiana.
Consensus of the 12Z HREF and 06Z RRFS showed their higher
probabilities for onshore heavy amounts that are associated with a
slow-moving wave remaining confined to the immediate coast and=20
away from the more vulnerable I-10 corridor. Should the models=20
trend back to the north, a Marginal Risk may be reintroduced, but=20
for now the area has been removed from the outlook.

For the Florida East Coast, the signal for widespread showers and
storms, with locally heavy amounts remain. Models have been
generally trending lighter with their QPF. However, with the HREF
still showing some higher probabilities for amounts over 3 inches,
left the Slight Risk centered along the Space/Treasure coasts in
place for now. Also extended the Marginal Risk further south into
the Miami metro, where the hi-res ensembles also show some higher
for amounts over 3 inches.

Previous Discussion...
...Florida's East Coast...

Thunderstorms are expected to continue to develop along the
inverted trough axis oriented north-south along Florida's east
coast on Saturday. Moisture will lift north along with the mid-
level disturbance. The inherited slight and marginal risk areas
were maintained due to a mostly consistent signal for excessive
rainfall over the east central coast. Ensemble exceedance
probabilities of 2 inches are between 5-10% across the marginal
risk area. 48 hour totals between 3-5 inches (local 6") will likely
make overcoming flash flood guidance a bit easier.


Pereira/Kebede

Day 3
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20
THE CENTRAL GULF COAST AND THE SOUTHEAST COAST...

20Z Update...

No significant changes were made to the previous outlook.

Previous Discussion...
...Central Gulf Coast...

The mid-level disturbance continues propagating westward toward the
positively tilted upper trough centered over the West on Sunday.
Thus, the heavy rainfall threat will likely bleed over from
Saturday evening into Sunday morning for portions of the Central
Gulf Coast, before dissipating beneath diminished support aloft.
PWATs of 2-2.5" and instability between 500-1000 J/Kg MUCAPE could
churn out rain rates between 1-1.5"/hr Saturday morning into
afternoon. Ensemble exceedance probabilities of 2 inches are
between 5-15% along the far southeastern Louisiana to Florida
panhandle corridor, which supports the marginal risk area in
place.

...Southeast Coast...

Inverted troughing continues along the Florida/Southeast Coast
through the latter part of this weekend. Anomalous moisture (2-3
stndv) will continue interacting with the surface boundary to
generate scattered to isolated thunderstorms across the
Florida/Georgia coast. Rainfall totals of 1-3" are likely along
the Florida/Georgia/South Carolina coast on Saturday. The latest
guidance has trended away from tropical moisture making its way
inland, therefore a marginal risk was maintained for much of the
Southeast Coast.


Pereira/Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-kSHFf9FGbEElz7CDUL0IWF94vaj4ZL2TdCZqDLSWmRw= 5cKYQ1bnLI8KZVYDgCgvfzkmuuOyFzpTu9I6x-oMNsNcmEY$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-kSHFf9FGbEElz7CDUL0IWF94vaj4ZL2TdCZqDLSWmRw= 5cKYQ1bnLI8KZVYDgCgvfzkmuuOyFzpTu9I6x-oMv40Y12o$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-kSHFf9FGbEElz7CDUL0IWF94vaj4ZL2TdCZqDLSWmRw= 5cKYQ1bnLI8KZVYDgCgvfzkmuuOyFzpTu9I6x-oMWwWDWsE$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 040056
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
856 PM EDT Fri Oct 3 2025

Day 1
Valid 01Z Sat Oct 04 2025 - 12Z Sat Oct 04 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN FLORIDA AND THE INTERMOUNTAIN WEST...

...Florida's East Coast...

For the 03/01Z Update, made few changes to either Marginal Risk
area. The northern portion of the Marginal Risk area in Florida was
removed for the duration of the overnight hours as drier air
filtered in from the north during the day. The respite should be
short-lived. Farther south...maintained the Marginal Risk area
where the moisture was deeper and radar still showed some showers
and thunderstorms poised to move inland with some potential to
bring brief heavy rainfall to highly urbanized areas in the short=20
term.


Across the West...Late afternoon/early evening water vapor
satellite imagery showed a shortwave trough making its was across
the southern portion of the Marginal risk area. That was helping
focus some generally light showers. Maintained the Marginal risk
area given recent heavy rainfall over portions of the Great Basin=20
will likely have primed surfaces for runoff from additional=20
precipitation. Burn scars continue to be of concern this evening.
Also noted that the 18Z HREF EAS exceedance probabilities continued
to show a low-end risk of 1- and 3-hourly flash flood guidance
being exceeded into the overnight hours over northern/central=20
Nevada where PWATs will be between 2-3 standard deviations above=20
normal.

Bann

Day 2
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
FLORIDA'S EAST COAST...

20Z Update...
The Marginal Risk was removed from southeastern Louisiana.
Consensus of the 12Z HREF and 06Z RRFS showed their higher
probabilities for onshore heavy amounts that are associated with a
slow-moving wave remaining confined to the immediate coast and
away from the more vulnerable I-10 corridor. Should the models
trend back to the north, a Marginal Risk may be reintroduced, but
for now the area has been removed from the outlook.

For the Florida East Coast, the signal for widespread showers and
storms, with locally heavy amounts remain. Models have been
generally trending lighter with their QPF. However, with the HREF
still showing some higher probabilities for amounts over 3 inches,
left the Slight Risk centered along the Space/Treasure coasts in
place for now. Also extended the Marginal Risk further south into
the Miami metro, where the hi-res ensembles also show some higher
for amounts over 3 inches.

Previous Discussion...
...Florida's East Coast...

Thunderstorms are expected to continue to develop along the
inverted trough axis oriented north-south along Florida's east
coast on Saturday. Moisture will lift north along with the mid-
level disturbance. The inherited slight and marginal risk areas
were maintained due to a mostly consistent signal for excessive
rainfall over the east central coast. Ensemble exceedance
probabilities of 2 inches are between 5-10% across the marginal
risk area. 48 hour totals between 3-5 inches (local 6") will likely
make overcoming flash flood guidance a bit easier.


Pereira/Kebede

Day 3
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE CENTRAL GULF COAST AND THE SOUTHEAST COAST...

20Z Update...

No significant changes were made to the previous outlook.

Previous Discussion...
...Central Gulf Coast...

The mid-level disturbance continues propagating westward toward the
positively tilted upper trough centered over the West on Sunday.
Thus, the heavy rainfall threat will likely bleed over from
Saturday evening into Sunday morning for portions of the Central
Gulf Coast, before dissipating beneath diminished support aloft.
PWATs of 2-2.5" and instability between 500-1000 J/Kg MUCAPE could
churn out rain rates between 1-1.5"/hr Saturday morning into
afternoon. Ensemble exceedance probabilities of 2 inches are
between 5-15% along the far southeastern Louisiana to Florida
panhandle corridor, which supports the marginal risk area in
place.

...Southeast Coast...

Inverted troughing continues along the Florida/Southeast Coast
through the latter part of this weekend. Anomalous moisture (2-3
stndv) will continue interacting with the surface boundary to
generate scattered to isolated thunderstorms across the
Florida/Georgia coast. Rainfall totals of 1-3" are likely along
the Florida/Georgia/South Carolina coast on Saturday. The latest
guidance has trended away from tropical moisture making its way
inland, therefore a marginal risk was maintained for much of the
Southeast Coast.


Pereira/Kebede


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!7q1YusVS2TQk_bBeEGA09DfUHFZVKq_Jy_wy8qjwKM0C= z4NJoGOVcYBasMjuB09LIxQl-P64D7tOb09edAZNsIPvlCM$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7q1YusVS2TQk_bBeEGA09DfUHFZVKq_Jy_wy8qjwKM0C= z4NJoGOVcYBasMjuB09LIxQl-P64D7tOb09edAZNPekqucc$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7q1YusVS2TQk_bBeEGA09DfUHFZVKq_Jy_wy8qjwKM0C= z4NJoGOVcYBasMjuB09LIxQl-P64D7tOb09edAZNI9JBRVY$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 040814
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
414 AM EDT Sat Oct 4 2025

Day 1
Valid 12Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE EASTERN GREAT BASIN ALONG WITH THE CENTRAL GULF COAST AND
COASTAL GEORGIA DOWN THROUGH THE FLORIDA EAST COAST...

...Eastern Great Basin...

An amplifying upper-level trough advancing through the Great Basin
will be driving multiple waves of low pressure northeastward along
a frontal zone draped across the Intermountain Region. The latest=20
forecast guidance supports a strengthening mid to upper-level=20
closed low circulation pivoting across northern UT early this=20
morning before ejecting through western WY this afternoon. Strong
dynamics/DPVA will ride up across northern UT along with far
southeast ID and western WY which will be interacting with the
front and the pooling of modest instability (MLCAPE ~500 J/kg)
along it for an axis of locally heavy showers and thunderstorms.
Much of this threat will be this morning (notably in the 12Z to 18Z
time frame) as the height falls pivot across the region. The 00Z
HREF guidance suggests some organized convection that will be
capable of producing 1 to 2+ inches of rain which may include some
brief cell-training concerns for areas near and west of the=20
Wasatch front including around the Great Salt Lake. Can't rule out
there being at least some isolated runoff/flash flooding concerns
from these stronger clusters of convection that evolve this
morning. Therefore, a Marginal Risk of excessive rainfall has been
introduced, but this again is mainly for early in the period today.

...Central Gulf Coast...

A low to mid-level vort center/disturbance over the northern Gulf
of America is forecast to slowly advance westward today which will
help to bring stronger low-level southeast flow and moisture into
southeast LA and coastal MS. Sufficient low-level forcing associated
with the vort energy coupled with at least modest instability with
MLCAPE values of 1000 to 1500 J/kg will support there being at
least scattered bands of convection that will develop and advance
inland across the central Gulf Coast. Some of the 00Z HREF guidance
and recent RRFS solutions suggest some linearly oriented convective
bands potentially setting up that would support some locally
enhanced rainfall totals. Given the improving PW environment with
values of 1.75 to 2+ inches, and a convergent southeast low-level=20
jet of 30+ kts, some of the rainfall rates may reach or exceed 2
inches/hour. The potential banded nature of the activity may
support some localized rainfall totals going into early Sunday
morning of 2 to 4+ inches. These rains will pose at least an=20
isolated threat for flash flooding, and especially if any of these=20
heavier rains were to make into the New Orleans metropolitan area.=20
As such, a Marginal Risk of excessive rainfall has been introduced=20
for this period for the central Gulf Coast.

...Coastal Georgia and the Florida East Coast...

Low-level easterly flow will persist today and tonight across the=20
FL East Coast given the placement of a well-established area of=20
surface high pressure farther north over the Mid-Atlantic states.=20
However, the surface ridging is forecast by the models to shift
offshore by later today which will allow for some veering and=20
strengthening of the Atlantic fetch a bit farther north up into=20
coastal areas of eastern GA. The latest hires model guidance=20
suggests a stronger axis of low-level moisture convergence along=20
with pooling of instability into coastal areas of eastern GA and=20
near the SC border. Some locally focused bands of relatively=20 shallow/warm-topped convection may attempt impact the coastal=20
areas here, with some guidance suggesting locally a couple inches=20
of rain being possible. Farther south, the FL East Coast should=20
continue to see scattered to broken areas of showers and=20
potentially a few thunderstorms. However, the activity should=20
remain disorganized given a lack of deeper layer forcing and only=20
modest low-level convergence along the coast. The Slight Risk area=20
that was inherited for the FL Space Coast vicinity has been removed
in favor of a Marginal Risk which will include the north/south=20
length of the FL East Coast, but extending northward now to the=20
SC/GA border. Any runoff concerns from heavy rainfall will tend to=20
be highly isolated and primarily focused over the more urbanized=20
areas.

Orrison


Day 2
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF=20
THE CENTRAL GULF COAST, THE SOUTHEAST COAST, AND THE CENTRAL=20
PLAINS...

...Central Gulf Coast...=20

A weak disturbance in the western Gulf will likely continue to focus=20 enhanced convergence and convection along portions of the central=20
Gulf Coast into Sunday. Heaviest rainfall totals may tend to stay=20
just offshore where the better instability will reside...although=20
coastal convergence and instability into the immediate coastline=20
should allow for some heavier cells to make it onshore. Even our=20 deterministic QPF, which is a multi model blend, brings two day=20
rainfall totals as high as 3-5" over far southeast LA and right=20
around 3" along coastal MS and AL. Given the convective nature of=20
rainfall and PWs over 2" would expect totals to locally exceed these=20 amounts, and isolated instances of flash flooding are possible. The=20
00z REFS probabilities of 8" is over 90% across coastal MS/AL. This=20
is seemingly an under dispersed ensemble in this case, but=20
interesting nonetheless, and possibly indicative of a lower=20
probability worst case scenario. Either way, will need to continue=20
to monitor trends, as can not rule out the need for a Slight risk=20
along portions of the immediate coast.

...Southeast Coast...=20

The model QPF signal continues to trend down across the Southeast=20
coast, although onshore easterly flow, coastal convergence and PWs=20
around 2" will support localized instances of heavy rainfall.=20
Overall the flash flood risk appears pretty low, but an isolated=20
threat can not be ruled out.

...Central Plains...

Convection will likely expand in coverage Sunday evening across=20
portions of northeast KS, southeast NE and southwest IA. A stalling=20
frontal boundary will allow for persistent moisture convergence in=20
the lower levels coupled with a divergence signature aloft. Thus it=20
seems probable that rainfall will persist through much of the night,=20
not moving all that much over that time. Whether we see any flash=20
flood risk evolve will likely come down to the degree of instability=20 present. It seems likely that we will initially have enough=20
instability for deeper convection and 1"+ an hour rainfall. However=20
most indications are that this instability axis will be rather=20
narrow and under 1000 j/kg. Thus would expect that instability to=20
get eroded fairly quickly, resulting in decreasing rainfall rates=20
overnight. Nonetheless, our latest deterministic QPF has 1-2" of=20
rain, with 2-3" if you include the rain that continues into Monday.=20
When accounting for convection resulting in locally heavier amounts,=20
and the possibility that instability ends up greater than forecast=20
(which a couple models show) then a low end flash flood risk can not=20
be ruled out.

Chenard


Day 3
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS EASTERN=20
FLORIDA AND THE CENTRAL PLAINS...

...Eastern FL...

The 00z ECMWF, AIFS and GEFS mean all suggest an increase in=20
convective coverage over eastern FL on Monday compared to Sunday.=20
The approach of a subtle mid level wave may help increase low level=20
easterly moisture transport while also providing a bit more in the=20
way of upper divergence. Isolated urban flash flooding should thus=20
remain a threat into Monday, although would anticipate the risk to=20
stay quite localized. There has been a clear model trend away from=20
bringing heavier rainfall into SC/GA and thus the northern extent of=20
the Marginal risk was cut back.

...Central Plains...

Some convection will likely be ongoing Monday morning across=20
portions of northeast KS, southeast NE, southwest IA and northwest=20
MO. The stalled front will remain in the area through the day likely=20
helping focus additional convection that should only slowly drift=20
southward. Instability should increase Monday along this front,=20
however this will coincide with a decrease in moisture transport and=20 convergence along the front. Thus not really anticipating anything=20
more than a very localized flash flood risk. The threat is likely a=20
lower end Marginal risk, but given the slow front and two day=20
rainfall totals of 2", to perhaps as high as 3-4", across this=20
corridor, localized flooding can not be ruled out. We will maintain=20
the inherited Marginal risk, but shrink to to better coincide with=20
the axis of highest two day rainfall totals.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!6B8zGnJotp6gy6Qp8HU2z8sabs-sIlBTh94Ul5vNaZo_= WgKrSOghCRdI2FqM_l-PHgqcavOaCjxcF0aMZVMwSelqNV8$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6B8zGnJotp6gy6Qp8HU2z8sabs-sIlBTh94Ul5vNaZo_= WgKrSOghCRdI2FqM_l-PHgqcavOaCjxcF0aMZVMwIdTvY4Q$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6B8zGnJotp6gy6Qp8HU2z8sabs-sIlBTh94Ul5vNaZo_= WgKrSOghCRdI2FqM_l-PHgqcavOaCjxcF0aMZVMwNTMmku8$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 041538
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1138 AM EDT Sat Oct 4 2025

Day 1
Valid 16Z Sat Oct 4 2025 - 12Z Sun Oct 5 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE EASTERN GREAT BASIN ALONG WITH THE CENTRAL GULF COAST AND
COASTAL GEORGIA DOWN THROUGH THE FLORIDA EAST COAST...

...Eastern Great Basin...

16Z Update: Upon examination of current radar trends in northern
Utah, it appears the mesoscale convective vortex associated with
the mid-level upper low is still producing widespread moderate to
heavy rainfall from the greater Salt Lake City area to near the
Idaho border. Movement of the vortex is slowly towards the NNE, and
recent CAM guidance suggests this will persist through about 18-20Z
before lifting out of the region and weakening. Therefore, the
existing Marginal Risk area will remain valid for now.

Previous discussion...

An amplifying upper-level trough advancing through the Great Basin
will be driving multiple waves of low pressure northeastward along
a frontal zone draped across the Intermountain Region. The latest
forecast guidance supports a strengthening mid to upper-level
closed low circulation pivoting across northern UT early this
morning before ejecting through western WY this afternoon. Strong
dynamics/DPVA will ride up across northern UT along with far
southeast ID and western WY which will be interacting with the
front and the pooling of modest instability (MLCAPE ~500 J/kg)
along it for an axis of locally heavy showers and thunderstorms.
Much of this threat will be this morning (notably in the 12Z to 18Z
time frame) as the height falls pivot across the region. The 00Z
HREF guidance suggests some organized convection that will be
capable of producing 1 to 2+ inches of rain which may include some
brief cell-training concerns for areas near and west of the
Wasatch front including around the Great Salt Lake. Can't rule out
there being at least some isolated runoff/flash flooding concerns
from these stronger clusters of convection that evolve this
morning. Therefore, a Marginal Risk of excessive rainfall has been
introduced, but this again is mainly for early in the period today.

...Central Gulf Coast...

A low to mid-level vort center/disturbance over the northern Gulf
is forecast to slowly advance westward today which will help to=20
bring stronger low-level southeast flow and moisture into southeast
LA and coastal MS. Sufficient low-level forcing associated with=20
the vort energy coupled with at least modest instability with=20
MLCAPE values of 1000 to 1500 J/kg will support there being at=20
least scattered bands of convection that will develop and advance=20
inland across the central Gulf Coast. Some of the 00Z HREF guidance
and recent RRFS solutions suggest some linearly oriented=20
convective bands potentially setting up that would support some=20
locally enhanced rainfall totals. Given the improving PW=20
environment with values of 1.75 to 2+ inches, and a convergent=20
southeast low-level jet of 30+ kts, some of the rainfall rates may=20
reach or exceed 2 inches/hour. The potential banded nature of the=20
activity may support some localized rainfall totals going into=20
early Sunday morning of 2 to 4+ inches. These rains will pose at=20
least an isolated threat for flash flooding, and especially if any=20
of these heavier rains were to make into the New Orleans=20
metropolitan area.=20

The existing Marginal Risk of excessive rainfall has been=20
maintained for this period for the central Gulf Coast, but trimmed=20
back to southeastern Louisiana south of Lake Pontchartrain where=20
the highest rainfall coverage is likely to reside.

...Coastal Georgia and the Florida East Coast...

Low-level easterly flow will persist today and tonight across the
FL East Coast given the placement of a well-established area of
surface high pressure farther north over the Mid-Atlantic states.
However, the surface ridging is forecast by the models to shift
offshore by later today which will allow for some veering and
strengthening of the Atlantic fetch a bit farther north up into
coastal areas of eastern GA. The latest hires model guidance
suggests a stronger axis of low-level moisture convergence along
with pooling of instability into coastal areas of eastern GA and
near the SC border. Some locally focused bands of relatively shallow/warm-topped convection may attempt impact the coastal
areas here, with some guidance suggesting locally a couple inches
of rain being possible. Farther south, the FL East Coast should
continue to see scattered to broken areas of showers and
potentially a few thunderstorms. However, the activity should
remain disorganized given a lack of deeper layer forcing and only
modest low-level convergence along the coast. Any runoff concerns=20
from heavy rainfall will tend to be highly isolated and primarily=20
focused over the more urbanized areas. No changes were necessary to
the ongoing Marginal Risk area for this region.

Hamrick/Orrison


Day 2
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL GULF COAST, THE SOUTHEAST COAST, AND THE CENTRAL
PLAINS...

...Central Gulf Coast...

A weak disturbance in the western Gulf will likely continue to focus
enhanced convergence and convection along portions of the central
Gulf Coast into Sunday. Heaviest rainfall totals may tend to stay
just offshore where the better instability will reside...although
coastal convergence and instability into the immediate coastline
should allow for some heavier cells to make it onshore. Even our
deterministic QPF, which is a multi model blend, brings two day
rainfall totals as high as 3-5" over far southeast LA and right
around 3" along coastal MS and AL. Given the convective nature of
rainfall and PWs over 2" would expect totals to locally exceed these
amounts, and isolated instances of flash flooding are possible. The
00z REFS probabilities of 8" is over 90% across coastal MS/AL. This
is seemingly an under dispersed ensemble in this case, but
interesting nonetheless, and possibly indicative of a lower
probability worst case scenario. Either way, will need to continue
to monitor trends, as can not rule out the need for a Slight risk
along portions of the immediate coast.

...Southeast Coast...

The model QPF signal continues to trend down across the Southeast
coast, although onshore easterly flow, coastal convergence and PWs
around 2" will support localized instances of heavy rainfall.
Overall the flash flood risk appears pretty low, but an isolated
threat can not be ruled out.

...Central Plains...

Convection will likely expand in coverage Sunday evening across
portions of northeast KS, southeast NE and southwest IA. A stalling
frontal boundary will allow for persistent moisture convergence in
the lower levels coupled with a divergence signature aloft. Thus it
seems probable that rainfall will persist through much of the night,
not moving all that much over that time. Whether we see any flash
flood risk evolve will likely come down to the degree of instability
present. It seems likely that we will initially have enough
instability for deeper convection and 1"+ an hour rainfall. However
most indications are that this instability axis will be rather
narrow and under 1000 j/kg. Thus would expect that instability to
get eroded fairly quickly, resulting in decreasing rainfall rates
overnight. Nonetheless, our latest deterministic QPF has 1-2" of
rain, with 2-3" if you include the rain that continues into Monday.
When accounting for convection resulting in locally heavier amounts,
and the possibility that instability ends up greater than forecast
(which a couple models show) then a low end flash flood risk can not
be ruled out.

Chenard


Day 3
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS EASTERN
FLORIDA AND THE CENTRAL PLAINS...

...Eastern FL...

The 00z ECMWF, AIFS and GEFS mean all suggest an increase in
convective coverage over eastern FL on Monday compared to Sunday.
The approach of a subtle mid level wave may help increase low level
easterly moisture transport while also providing a bit more in the
way of upper divergence. Isolated urban flash flooding should thus
remain a threat into Monday, although would anticipate the risk to
stay quite localized. There has been a clear model trend away from
bringing heavier rainfall into SC/GA and thus the northern extent of
the Marginal risk was cut back.

...Central Plains...

Some convection will likely be ongoing Monday morning across
portions of northeast KS, southeast NE, southwest IA and northwest
MO. The stalled front will remain in the area through the day likely
helping focus additional convection that should only slowly drift
southward. Instability should increase Monday along this front,
however this will coincide with a decrease in moisture transport and convergence along the front. Thus not really anticipating anything
more than a very localized flash flood risk. The threat is likely a
lower end Marginal risk, but given the slow front and two day
rainfall totals of 2", to perhaps as high as 3-4", across this
corridor, localized flooding can not be ruled out. We will maintain
the inherited Marginal risk, but shrink to to better coincide with
the axis of highest two day rainfall totals.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4axyas_ABHT28kL5L2Qt_blvD6pLxYxGQRpIpXeCQHlk= I5mP0nIqG9NOrCcc0rXSkgtwPt-HX-5XHO8pItnQ5KVnKUI$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4axyas_ABHT28kL5L2Qt_blvD6pLxYxGQRpIpXeCQHlk= I5mP0nIqG9NOrCcc0rXSkgtwPt-HX-5XHO8pItnQA094Ens$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4axyas_ABHT28kL5L2Qt_blvD6pLxYxGQRpIpXeCQHlk= I5mP0nIqG9NOrCcc0rXSkgtwPt-HX-5XHO8pItnQukx3IW4$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 041955
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
355 PM EDT Sat Oct 4 2025

Day 1
Valid 16Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE EASTERN GREAT BASIN ALONG WITH THE CENTRAL GULF COAST AND
COASTAL GEORGIA DOWN THROUGH THE FLORIDA EAST COAST...

...Eastern Great Basin...

16Z Update: Upon examination of current radar trends in northern
Utah, it appears the mesoscale convective vortex associated with
the mid-level upper low is still producing widespread moderate to
heavy rainfall from the greater Salt Lake City area to near the
Idaho border. Movement of the vortex is slowly towards the NNE, and
recent CAM guidance suggests this will persist through about 18-20Z
before lifting out of the region and weakening. Therefore, the
existing Marginal Risk area will remain valid for now.

Previous discussion...

An amplifying upper-level trough advancing through the Great Basin
will be driving multiple waves of low pressure northeastward along
a frontal zone draped across the Intermountain Region. The latest
forecast guidance supports a strengthening mid to upper-level
closed low circulation pivoting across northern UT early this
morning before ejecting through western WY this afternoon. Strong
dynamics/DPVA will ride up across northern UT along with far
southeast ID and western WY which will be interacting with the
front and the pooling of modest instability (MLCAPE ~500 J/kg)
along it for an axis of locally heavy showers and thunderstorms.
Much of this threat will be this morning (notably in the 12Z to 18Z
time frame) as the height falls pivot across the region. The 00Z
HREF guidance suggests some organized convection that will be
capable of producing 1 to 2+ inches of rain which may include some
brief cell-training concerns for areas near and west of the
Wasatch front including around the Great Salt Lake. Can't rule out
there being at least some isolated runoff/flash flooding concerns
from these stronger clusters of convection that evolve this
morning. Therefore, a Marginal Risk of excessive rainfall has been
introduced, but this again is mainly for early in the period today.

...Central Gulf Coast...

A low to mid-level vort center/disturbance over the northern Gulf
is forecast to slowly advance westward today which will help to
bring stronger low-level southeast flow and moisture into southeast
LA and coastal MS. Sufficient low-level forcing associated with
the vort energy coupled with at least modest instability with
MLCAPE values of 1000 to 1500 J/kg will support there being at
least scattered bands of convection that will develop and advance
inland across the central Gulf Coast. Some of the 00Z HREF guidance
and recent RRFS solutions suggest some linearly oriented
convective bands potentially setting up that would support some
locally enhanced rainfall totals. Given the improving PW
environment with values of 1.75 to 2+ inches, and a convergent
southeast low-level jet of 30+ kts, some of the rainfall rates may
reach or exceed 2 inches/hour. The potential banded nature of the
activity may support some localized rainfall totals going into
early Sunday morning of 2 to 4+ inches. These rains will pose at
least an isolated threat for flash flooding, and especially if any
of these heavier rains were to make into the New Orleans
metropolitan area.

The existing Marginal Risk of excessive rainfall has been
maintained for this period for the central Gulf Coast, but trimmed
back to southeastern Louisiana south of Lake Pontchartrain where
the highest rainfall coverage is likely to reside.

...Coastal Georgia and the Florida East Coast...

Low-level easterly flow will persist today and tonight across the
FL East Coast given the placement of a well-established area of
surface high pressure farther north over the Mid-Atlantic states.
However, the surface ridging is forecast by the models to shift
offshore by later today which will allow for some veering and
strengthening of the Atlantic fetch a bit farther north up into
coastal areas of eastern GA. The latest hires model guidance
suggests a stronger axis of low-level moisture convergence along
with pooling of instability into coastal areas of eastern GA and
near the SC border. Some locally focused bands of relatively shallow/warm-topped convection may attempt impact the coastal
areas here, with some guidance suggesting locally a couple inches
of rain being possible. Farther south, the FL East Coast should
continue to see scattered to broken areas of showers and
potentially a few thunderstorms. However, the activity should
remain disorganized given a lack of deeper layer forcing and only
modest low-level convergence along the coast. Any runoff concerns
from heavy rainfall will tend to be highly isolated and primarily
focused over the more urbanized areas. No changes were necessary to
the ongoing Marginal Risk area for this region.

Hamrick/Orrison


Day 2
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL GULF COAST, THE SOUTHEAST COAST, AND THE CENTRAL
PLAINS...

20Z Update: There has been an additional lighter trend in the
guidance for the coastal portions of Georgia, and the majority of
heavier showers in onshore flow is expected to be across eastern
Florida, so the new Marginal Risk area is trimmed back to=20
Jacksonville. For the Midwest, the Marginal Risk is extended a
little more to the northeast to include northeastern Iowa where a
relatively narrow band of higher QPF ahead of a slow moving cold
front is likely to be, with the potential for some convective
training that may result in a few instances of flooding where cells
persist the longest. All seems on track with the Marginal Risk area
for the central Gulf Coast. /Hamrick

Previous discussion...

...Central Gulf Coast...

A weak disturbance in the western Gulf will likely continue to focus
enhanced convergence and convection along portions of the central
Gulf Coast into Sunday. Heaviest rainfall totals may tend to stay
just offshore where the better instability will reside...although
coastal convergence and instability into the immediate coastline
should allow for some heavier cells to make it onshore. Even our
deterministic QPF, which is a multi model blend, brings two day
rainfall totals as high as 3-5" over far southeast LA and right
around 3" along coastal MS and AL. Given the convective nature of
rainfall and PWs over 2" would expect totals to locally exceed these
amounts, and isolated instances of flash flooding are possible. The
00z REFS probabilities of 8" is over 90% across coastal MS/AL. This
is seemingly an under dispersed ensemble in this case, but
interesting nonetheless, and possibly indicative of a lower
probability worst case scenario. Either way, will need to continue
to monitor trends, as can not rule out the need for a Slight risk
along portions of the immediate coast.

...Southeast Coast...

The model QPF signal continues to trend down across the Southeast
coast, although onshore easterly flow, coastal convergence and PWs
around 2" will support localized instances of heavy rainfall.
Overall the flash flood risk appears pretty low, but an isolated
threat can not be ruled out.

...Central Plains...

Convection will likely expand in coverage Sunday evening across
portions of northeast KS, southeast NE and southwest IA. A stalling
frontal boundary will allow for persistent moisture convergence in
the lower levels coupled with a divergence signature aloft. Thus it
seems probable that rainfall will persist through much of the night,
not moving all that much over that time. Whether we see any flash
flood risk evolve will likely come down to the degree of instability
present. It seems likely that we will initially have enough
instability for deeper convection and 1"+ an hour rainfall. However
most indications are that this instability axis will be rather
narrow and under 1000 j/kg. Thus would expect that instability to
get eroded fairly quickly, resulting in decreasing rainfall rates
overnight. Nonetheless, our latest deterministic QPF has 1-2" of
rain, with 2-3" if you include the rain that continues into Monday.
When accounting for convection resulting in locally heavier amounts,
and the possibility that instability ends up greater than forecast
(which a couple models show) then a low end flash flood risk can not
be ruled out.

Chenard


Day 3
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS EASTERN
FLORIDA AND THE CENTRAL PLAINS...

...Eastern FL...

The 00z ECMWF, AIFS and GEFS mean all suggest an increase in
convective coverage over eastern FL on Monday compared to Sunday.
The approach of a subtle mid level wave may help increase low level
easterly moisture transport while also providing a bit more in the
way of upper divergence. Isolated urban flash flooding should thus
remain a threat into Monday, although would anticipate the risk to
stay quite localized. There has been a clear model trend away from
bringing heavier rainfall into SC/GA and thus the northern extent of
the Marginal risk was cut back.

...Central Plains...

Some convection will likely be ongoing Monday morning across
portions of northeast KS, southeast NE, southwest IA and northwest
MO. The stalled front will remain in the area through the day likely
helping focus additional convection that should only slowly drift
southward. Instability should increase Monday along this front,
however this will coincide with a decrease in moisture transport and convergence along the front. Thus not really anticipating anything
more than a very localized flash flood risk. The threat is likely a
lower end Marginal risk, but given the slow front and two day
rainfall totals of 2", to perhaps as high as 3-4", across this
corridor, localized flooding can not be ruled out. We will maintain
the inherited Marginal risk, but shrink to to better coincide with
the axis of highest two day rainfall totals.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4jDMHgQqwOWYbpAZJWTukHWDK4WEZME1PLDEja4-eUeB= dpWUnEbmT9vsC5CxqJKUcx6Q0sDi7yzewgj6cczlOXdBUVM$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4jDMHgQqwOWYbpAZJWTukHWDK4WEZME1PLDEja4-eUeB= dpWUnEbmT9vsC5CxqJKUcx6Q0sDi7yzewgj6cczln7YBLZ4$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4jDMHgQqwOWYbpAZJWTukHWDK4WEZME1PLDEja4-eUeB= dpWUnEbmT9vsC5CxqJKUcx6Q0sDi7yzewgj6cczl7xxEeDo$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 042013
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
413 PM EDT Sat Oct 4 2025

Day 1
Valid 16Z Sat Oct 04 2025 - 12Z Sun Oct 05 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE EASTERN GREAT BASIN ALONG WITH THE CENTRAL GULF COAST AND
COASTAL GEORGIA DOWN THROUGH THE FLORIDA EAST COAST...

...Eastern Great Basin...

16Z Update: Upon examination of current radar trends in northern
Utah, it appears the mesoscale convective vortex associated with
the mid-level upper low is still producing widespread moderate to
heavy rainfall from the greater Salt Lake City area to near the
Idaho border. Movement of the vortex is slowly towards the NNE, and
recent CAM guidance suggests this will persist through about 18-20Z
before lifting out of the region and weakening. Therefore, the
existing Marginal Risk area will remain valid for now.

Previous discussion...

An amplifying upper-level trough advancing through the Great Basin
will be driving multiple waves of low pressure northeastward along
a frontal zone draped across the Intermountain Region. The latest
forecast guidance supports a strengthening mid to upper-level
closed low circulation pivoting across northern UT early this
morning before ejecting through western WY this afternoon. Strong
dynamics/DPVA will ride up across northern UT along with far
southeast ID and western WY which will be interacting with the
front and the pooling of modest instability (MLCAPE ~500 J/kg)
along it for an axis of locally heavy showers and thunderstorms.
Much of this threat will be this morning (notably in the 12Z to 18Z
time frame) as the height falls pivot across the region. The 00Z
HREF guidance suggests some organized convection that will be
capable of producing 1 to 2+ inches of rain which may include some
brief cell-training concerns for areas near and west of the
Wasatch front including around the Great Salt Lake. Can't rule out
there being at least some isolated runoff/flash flooding concerns
from these stronger clusters of convection that evolve this
morning. Therefore, a Marginal Risk of excessive rainfall has been
introduced, but this again is mainly for early in the period today.

...Central Gulf Coast...

A low to mid-level vort center/disturbance over the northern Gulf
is forecast to slowly advance westward today which will help to
bring stronger low-level southeast flow and moisture into southeast
LA and coastal MS. Sufficient low-level forcing associated with
the vort energy coupled with at least modest instability with
MLCAPE values of 1000 to 1500 J/kg will support there being at
least scattered bands of convection that will develop and advance
inland across the central Gulf Coast. Some of the 00Z HREF guidance
and recent RRFS solutions suggest some linearly oriented
convective bands potentially setting up that would support some
locally enhanced rainfall totals. Given the improving PW
environment with values of 1.75 to 2+ inches, and a convergent
southeast low-level jet of 30+ kts, some of the rainfall rates may
reach or exceed 2 inches/hour. The potential banded nature of the
activity may support some localized rainfall totals going into
early Sunday morning of 2 to 4+ inches. These rains will pose at
least an isolated threat for flash flooding, and especially if any
of these heavier rains were to make into the New Orleans
metropolitan area.

The existing Marginal Risk of excessive rainfall has been
maintained for this period for the central Gulf Coast, but trimmed
back to southeastern Louisiana south of Lake Pontchartrain where
the highest rainfall coverage is likely to reside.

...Coastal Georgia and the Florida East Coast...

Low-level easterly flow will persist today and tonight across the
FL East Coast given the placement of a well-established area of
surface high pressure farther north over the Mid-Atlantic states.
However, the surface ridging is forecast by the models to shift
offshore by later today which will allow for some veering and
strengthening of the Atlantic fetch a bit farther north up into
coastal areas of eastern GA. The latest hires model guidance
suggests a stronger axis of low-level moisture convergence along
with pooling of instability into coastal areas of eastern GA and
near the SC border. Some locally focused bands of relatively shallow/warm-topped convection may attempt impact the coastal
areas here, with some guidance suggesting locally a couple inches
of rain being possible. Farther south, the FL East Coast should
continue to see scattered to broken areas of showers and
potentially a few thunderstorms. However, the activity should
remain disorganized given a lack of deeper layer forcing and only
modest low-level convergence along the coast. Any runoff concerns
from heavy rainfall will tend to be highly isolated and primarily
focused over the more urbanized areas. No changes were necessary to
the ongoing Marginal Risk area for this region.

Hamrick/Orrison


Day 2
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL GULF COAST, THE SOUTHEAST COAST, AND THE CENTRAL
PLAINS...

20Z Update: There has been an additional lighter trend in the
guidance for the coastal portions of Georgia, and the majority of
heavier showers in onshore flow is expected to be across eastern
Florida, so the new Marginal Risk area is trimmed back to
Jacksonville. For the Midwest, the Marginal Risk is extended a
little more to the northeast to include northeastern Iowa where a
relatively narrow band of higher QPF ahead of a slow moving cold
front is likely to be, with the potential for some convective
training that may result in a few instances of flooding where cells
persist the longest. All seems on track with the Marginal Risk area
for the central Gulf Coast. /Hamrick

Previous discussion...

...Central Gulf Coast...

A weak disturbance in the western Gulf will likely continue to focus
enhanced convergence and convection along portions of the central
Gulf Coast into Sunday. Heaviest rainfall totals may tend to stay
just offshore where the better instability will reside...although
coastal convergence and instability into the immediate coastline
should allow for some heavier cells to make it onshore. Even our
deterministic QPF, which is a multi model blend, brings two day
rainfall totals as high as 3-5" over far southeast LA and right
around 3" along coastal MS and AL. Given the convective nature of
rainfall and PWs over 2" would expect totals to locally exceed these
amounts, and isolated instances of flash flooding are possible. The
00z REFS probabilities of 8" is over 90% across coastal MS/AL. This
is seemingly an under dispersed ensemble in this case, but
interesting nonetheless, and possibly indicative of a lower
probability worst case scenario. Either way, will need to continue
to monitor trends, as can not rule out the need for a Slight risk
along portions of the immediate coast.

...Southeast Coast...

The model QPF signal continues to trend down across the Southeast
coast, although onshore easterly flow, coastal convergence and PWs
around 2" will support localized instances of heavy rainfall.
Overall the flash flood risk appears pretty low, but an isolated
threat can not be ruled out.

...Central Plains...

Convection will likely expand in coverage Sunday evening across
portions of northeast KS, southeast NE and southwest IA. A stalling
frontal boundary will allow for persistent moisture convergence in
the lower levels coupled with a divergence signature aloft. Thus it
seems probable that rainfall will persist through much of the night,
not moving all that much over that time. Whether we see any flash
flood risk evolve will likely come down to the degree of instability
present. It seems likely that we will initially have enough
instability for deeper convection and 1"+ an hour rainfall. However
most indications are that this instability axis will be rather
narrow and under 1000 j/kg. Thus would expect that instability to
get eroded fairly quickly, resulting in decreasing rainfall rates
overnight. Nonetheless, our latest deterministic QPF has 1-2" of
rain, with 2-3" if you include the rain that continues into Monday.
When accounting for convection resulting in locally heavier amounts,
and the possibility that instability ends up greater than forecast
(which a couple models show) then a low end flash flood risk can not
be ruled out.

Chenard


Day 3
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS EASTERN
FLORIDA AND THE CENTRAL PLAINS...

...Eastern Florida...

The 00z ECMWF, AIFS and GEFS mean all suggest an increase in
convective coverage over eastern FL on Monday compared to Sunday.
The approach of a subtle mid level wave may help increase low level
easterly moisture transport while also providing a bit more in the
way of upper divergence. Isolated urban flash flooding should thus
remain a threat into Monday, although would anticipate the risk to
stay quite localized.=20

...Central Plains...

Some convection will likely be ongoing Monday morning across
portions of northeast KS, southeast NE, southwest IA and northwest
MO. The stalled front will remain in the area through the day likely
helping focus additional convection that should only slowly drift
southward. Instability should increase Monday along this front,
however this will coincide with a decrease in moisture transport and convergence along the front. Thus not really anticipating anything
more than a very localized flash flood risk. The threat is likely a
lower end Marginal risk, but given the slow front and two day
rainfall totals of 2", to perhaps as high as 3-4", across this
corridor, localized flooding is possible. The existing Marginal=20
Risk has been maintained with this update.

...Ohio Valley...

A Marginal Risk area has been introduced from eastern Arkansas to
southern Indiana. Moist return flow around a surface high off the
East Coast, in tandem with a frontal boundary slowly approaching
from the northwest, will result in a corridor of warm air advection
with scattered to numerous showers and thunderstorms developing.
Dewpoints rising into the upper 60s to lower 70s, in combination
with increasing mixed layer CAPE, will provide enough instability
for higher rainfall rates that may result in some instances of
flooding, mainly in the 18Z Monday-6Z Tuesday time period.=20

Hamrick/Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!7IHVf6B_SGqMHFW0BGr0Ud5FmWMltOyiVTywylngYn9Q= UwXkYnhIimhBcGU9MGJhw6xGn7bIYxHn9z0RbPZkfNeeSFM$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7IHVf6B_SGqMHFW0BGr0Ud5FmWMltOyiVTywylngYn9Q= UwXkYnhIimhBcGU9MGJhw6xGn7bIYxHn9z0RbPZkQ5ewxms$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7IHVf6B_SGqMHFW0BGr0Ud5FmWMltOyiVTywylngYn9Q= UwXkYnhIimhBcGU9MGJhw6xGn7bIYxHn9z0RbPZkBSHh0fo$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 050050
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
850 PM EDT Sat Oct 4 2025

Day 1
Valid 01Z Sun Oct 05 2025 - 12Z Sun Oct 05 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20
THE CENTRAL GULF COAST...

Maintained a small Marginal Risk area covering far southeastern
Louisiana and coastal Mississippi. While much of the heavier activity associated with a slow-moving wave has remained offshore into this
evening, guidance indicates that veering flow will be enough to=20
nudge both deeper moisture (PWs over 2 inches) and greater=20
instability further north, raising the threat for increasing rain=20
rates and accumulations along the coastal regions overnight. Recent
runs of the HRRR have been consistent in showing a signal for=20
localized heavy amounts moving onshore, while both the 18Z HREF and
the 12Z RRFS indicate that isolated totals over 3 inches are=20
possible.

Pereira

Day 2
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL GULF COAST, THE SOUTHEAST COAST, AND THE CENTRAL
PLAINS...

20Z Update: There has been an additional lighter trend in the
guidance for the coastal portions of Georgia, and the majority of
heavier showers in onshore flow is expected to be across eastern
Florida, so the new Marginal Risk area is trimmed back to
Jacksonville. For the Midwest, the Marginal Risk is extended a
little more to the northeast to include northeastern Iowa where a
relatively narrow band of higher QPF ahead of a slow moving cold
front is likely to be, with the potential for some convective
training that may result in a few instances of flooding where cells
persist the longest. All seems on track with the Marginal Risk area
for the central Gulf Coast. /Hamrick

Previous discussion...

...Central Gulf Coast...

A weak disturbance in the western Gulf will likely continue to focus
enhanced convergence and convection along portions of the central
Gulf Coast into Sunday. Heaviest rainfall totals may tend to stay
just offshore where the better instability will reside...although
coastal convergence and instability into the immediate coastline
should allow for some heavier cells to make it onshore. Even our
deterministic QPF, which is a multi model blend, brings two day
rainfall totals as high as 3-5" over far southeast LA and right
around 3" along coastal MS and AL. Given the convective nature of
rainfall and PWs over 2" would expect totals to locally exceed these
amounts, and isolated instances of flash flooding are possible. The
00z REFS probabilities of 8" is over 90% across coastal MS/AL. This
is seemingly an under dispersed ensemble in this case, but
interesting nonetheless, and possibly indicative of a lower
probability worst case scenario. Either way, will need to continue
to monitor trends, as can not rule out the need for a Slight risk
along portions of the immediate coast.

...Southeast Coast...

The model QPF signal continues to trend down across the Southeast
coast, although onshore easterly flow, coastal convergence and PWs
around 2" will support localized instances of heavy rainfall.
Overall the flash flood risk appears pretty low, but an isolated
threat can not be ruled out.

...Central Plains...

Convection will likely expand in coverage Sunday evening across
portions of northeast KS, southeast NE and southwest IA. A stalling
frontal boundary will allow for persistent moisture convergence in
the lower levels coupled with a divergence signature aloft. Thus it
seems probable that rainfall will persist through much of the night,
not moving all that much over that time. Whether we see any flash
flood risk evolve will likely come down to the degree of instability
present. It seems likely that we will initially have enough
instability for deeper convection and 1"+ an hour rainfall. However
most indications are that this instability axis will be rather
narrow and under 1000 j/kg. Thus would expect that instability to
get eroded fairly quickly, resulting in decreasing rainfall rates
overnight. Nonetheless, our latest deterministic QPF has 1-2" of
rain, with 2-3" if you include the rain that continues into Monday.
When accounting for convection resulting in locally heavier amounts,
and the possibility that instability ends up greater than forecast
(which a couple models show) then a low end flash flood risk can not
be ruled out.

Chenard


Day 3
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS EASTERN
FLORIDA AND THE CENTRAL PLAINS...

...Eastern Florida...

The 00z ECMWF, AIFS and GEFS mean all suggest an increase in
convective coverage over eastern FL on Monday compared to Sunday.
The approach of a subtle mid level wave may help increase low level
easterly moisture transport while also providing a bit more in the
way of upper divergence. Isolated urban flash flooding should thus
remain a threat into Monday, although would anticipate the risk to
stay quite localized.

...Central Plains...

Some convection will likely be ongoing Monday morning across
portions of northeast KS, southeast NE, southwest IA and northwest
MO. The stalled front will remain in the area through the day likely
helping focus additional convection that should only slowly drift
southward. Instability should increase Monday along this front,
however this will coincide with a decrease in moisture transport and convergence along the front. Thus not really anticipating anything
more than a very localized flash flood risk. The threat is likely a
lower end Marginal risk, but given the slow front and two day
rainfall totals of 2", to perhaps as high as 3-4", across this
corridor, localized flooding is possible. The existing Marginal
Risk has been maintained with this update.

...Ohio Valley...

A Marginal Risk area has been introduced from eastern Arkansas to
southern Indiana. Moist return flow around a surface high off the
East Coast, in tandem with a frontal boundary slowly approaching
from the northwest, will result in a corridor of warm air advection
with scattered to numerous showers and thunderstorms developing.
Dewpoints rising into the upper 60s to lower 70s, in combination
with increasing mixed layer CAPE, will provide enough instability
for higher rainfall rates that may result in some instances of
flooding, mainly in the 18Z Monday-6Z Tuesday time period.

Hamrick/Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8oPy0UYpPNvPJ6vH3Hqklmg11eP5HNEh2yww0dSR3rib= aKxxd5GgHvC9WnKRkBmmj0uySXYUwtRElPD8doK8lsGzmbE$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8oPy0UYpPNvPJ6vH3Hqklmg11eP5HNEh2yww0dSR3rib= aKxxd5GgHvC9WnKRkBmmj0uySXYUwtRElPD8doK8Tw0inpw$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8oPy0UYpPNvPJ6vH3Hqklmg11eP5HNEh2yww0dSR3rib= aKxxd5GgHvC9WnKRkBmmj0uySXYUwtRElPD8doK83O3et8I$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 050819
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
419 AM EDT Sun Oct 5 2025

Day 1
Valid 12Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL PLAINS AND MIDWEST ALONG WITH THE CENTRAL GULF COAST=20
AND EASTERN FLORIDA...

...Central Plains/Midwest...

In the wake of an upper-level trough and surface low transiting
portions of the northern Plains, a cold front will be gradually
settling southeastward today and tonight across the central Plains
and Midwest. Showers and thunderstorms are expected to develop
along the front by this evening across areas of central and
northern KS up through southeast NE and through central IA. MLCAPE
values as high as 1000 to 1500 J/kg are forecast to pool along the
boundary along with a seasonably moist airmass characterized by PWs
of 1.25 to 1.5+ inches. Moisture transport along the front will be
aided by a southwest low-level jet of 30 to 40+ kts going through=20
00Z this evening which coupled with the instability should help=20
drive some heavier rainfall rates capable of reaching 1 to 1.5=20
inches/hour. Going through Sunday night, the convection is expected
to linger as at least modest right-entrance region upper jet=20
dynamics overhead continue to interact with the front. Some post-=20
frontal shower and thunderstorm activity is expected as a pool of=20
elevated instability and frontogenesis lingers over the region. A=20
consensus of the 00Z HREF guidance supports some spotty 2 to 3+=20
inch rainfall totals in a narrow axis along the front. Antecedent=20
conditions are quite dry, but with some localized cell-training=20
concerns and heavier rainfall totals, there may be some isolated=20
and mainly urbanized runoff concerns. A Marginal Risk of excessive=20
rainfall will be maintained across the region.

...Central Gulf Coast...

An elongated low to mid-level low center/trough over the northwest
Gulf of America is expected to focus a corridor of stronger
convergence and moisture transport across the central Gulf Coast
region, with potential for multiple bands of very heavy showers and thunderstorms to evolve. The convection will be embedded within a=20
deep tropical environment characterized by PWs of 2 to 2.25=20
inches. This coupled with MLCAPE values of locally near 1500 J/kg=20
will help favor high rainfall rates that may easily reach 2 to 3=20
inches/hour with the stronger and more organized convective bands.=20
The 00Z HREF guidance generally supports the heaviest rainfall=20
totals remaining confined to the immediate Gulf Coast, however some
localized bands of convection that will be capable of cell-
training may be able to spread a bit farther inland including areas
of south-central to southeast LA through far southern MS and far=20
southern AL. Some urbanized Gulf Coast locations including New=20
Orleans and Mobile may be impacted going through Sunday night by=20
bands of heavy showers and thunderstorms. The latest REFS/RRFS=20
guidance is more aggressive with the rainfall potential, but a=20
HREF-led consensus of guidance would suggest some 2 to 4 inch=20
rainfall totals with spotty 5+ inch amounts not out of the question
where any cell-training occurs. The Marginal Risk area will be=20
maintained for the time being, with isolated areas of flash=20
flooding possible, and especially for the aforementioned urban=20
corridors. However, should the guidance trend any wetter, a Slight=20
Risk upgrade may be warranted for portions of the central Gulf=20
Coast.

...Eastern FL...

Moist and locally convergent low-level easterly Atlantic flow will
continue along the FL East Coast today. There are some locally
heavier rainfall signals showing up along the Space and Treasure
Coasts and stretching inland somewhat as the potential once again
for some broken bands of locally heavy showers and thunderstorms
sets up. Where any cell-training occurs within these bands, some
spotty rainfall totals of 2 to 4+ inches will be possible. This=20
may result in there being a highly localized concern for some
runoff problems. A Marginal Risk of excessive rainfall will be
maintained at this time.

Orrison


Day 2
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF=20
EASTERN ARKANSAS INTO THE OHIO VALLEY AND OVER EASTERN FLORIDA...

...TN and OH Valley...

A Marginal risk was maintained from portions of eastern AR=20
northeastward into southern IN. 850mb vorticity fields indicate the=20
tropical disturbance in the Gulf is likely to lift northward on=20
Monday brining increased PWs and the potential for areas of slow=20
moving convection. Scattered convection is expected during the day,=20
although the better focus for high rainfall amounts should come=20
Monday night as the approaching cold front from the west helps=20
increase convergence. The environment appears to favor efficient=20
warm rain processes...with the presence of the low level vorticity=20
from the Gulf and PWs around or above 2" (over the climatological=20
90th percentile). Only weak instability is forecast, which could end=20
up being a limiting factor for flash flooding. However, given the=20
expected efficient warm rain, there should still be enough=20
instability to get hourly rainfall rates into the 1-2" range in=20
spots. The latest WPC deterministic QPF is 1-2" across the area,=20
although several models indicate locally higher amounts. Given the=20 environment in place amounts locally getting into the 2-4" range=20
seems reasonable within the Marginal risk area.=20

Expect at least localized instances of flash flooding to be=20
possible, especially by Monday night. There is a bit of uncertainty=20 regarding the exact rainfall axis, with the new 00z ECMWF shifting=20
farther east into more of TN and KY. The eastern extent of the=20
Marginal risk was extended in this direction to account for this=20 potential...although the broader model consensus still favors a=20
slightly farther west axis, in line with the WPC QPF.

...Eastern FL...

Easterly low level flow will continue to support scattered=20
convection over eastern FL Monday into Monday night. Model guidance=20 continues to depict a modest uptick in rainfall coverage and=20
magnitudes on Monday compared to Sunday. Localized urban flash flood=20
impacts will remain possible.

...Central Plains...

We opted to remove the Marginal risk that stretched from northeast=20
KS into southern IA with this update. A localized flash flood risk=20
still exists on day 1, but by Monday the areas hit hardest on day 1=20
will be well north of the surface front. Thus most of the=20
instability will be gone, and rainfall rates should be much lower.=20
Thus the additional rainfall is not expected to be enough to result=20
in flash flooding. A bit more instability may reside over MO, but=20
this is south of the forecast rainfall axis on Sunday, and thus the=20
rainfall Monday is not expected to be enough to overcome the drier=20 antecedent conditions here.

Chenard


Day 3
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF=20
THE TENNESSEE AND OHIO VALLEY, OVER SOUTHEAST FLORIDA, AND PORTIONS=20
OF NEW MEXICO...

...TN and OH Valley...

A Marginal risk was maintained from TN northward into portions of OH=20
and southwest PA. Increasing moisture ahead of an approaching cold=20
front will likely lead to greater convective coverage and areas of=20
heavy rainfall. The forcing and moisture will be enhanced by the=20
same low level vorticity feature that was upstream on Monday and=20
over the Gulf on Sunday. With PWs forecast over the climatological=20
90th percentile do expect some warm rain processes, which should=20
help overcome marginal instability and help produce heavy rainfall=20
rates. Also note a well defined upper divergence signature centered=20
over this region within the right entrance region of an upper jet.=20
Thus the ingredients are there for widespread rainfall and at least=20
some pockets of heavy rates.=20

The main question for flash flood potential will be the duration of=20
these higher rates. Overall the front looks pretty progressive,=20
which should limit this duration. However, guidance does indicate=20
that some training could occur for a period Tuesday before the front=20
clears through, with the favored axis somewhere in the vicinity of=20
central to eastern KY. While differing on location, most 00z=20
deterministic models indicates a swath of 2-3" of rainfall, which=20
seems reasonable given the environment in place. In fact would not=20
be surprised if totals locally exceed 3". Overall this seems like a=20
solid Marginal risk with localized areas of flash flooding probable.=20
Can not rule out an embedded Slight risk upgrade on future updates=20
pending model trends.

The northern extent of the Marginal risk was cut out of the=20
Northeast with this update. Instability really drops off with=20
northern extent which will impact rainfall rate potential. These=20
lower rates combined with the drought conditions suggest flash=20
flooding is unlikely. We would probably need higher rates to overcome=20
the dry soil conditions, and this seems unlikely given the currently=20 forecast instability. So it is looking more like a beneficial=20
rainfall, with most areas around 0.75" but locally as high as 1.25"=20
or so.

...Southeast FL...

Expecting another day of scattered convection within the easterly low=20
level flow Tuesday. Compared to previous days the threat should=20
mostly be focused over southeast FL by this time, and a localized=20
urban flash flood risk is possible.

...NM...

A Marginal risk was maintained for portions of central and eastern=20
NM on Tuesday. Easterly low level post frontal flow will help=20
locally enhance convergence and upslope and scattered convection is=20
likely to develop. With PWs around 1" and CAPE only forecast between=20 500-1000 j/kg this is likely a lower end threat. Nonetheless,=20
locally heavier convection with high rates could result in isolated=20
flash flooding, particularly over any more sensitive burn scars or=20
basins.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8GvKwZltCeq5dZISEPQgVenkSTOu5CSAgX3QmqpZvOjM= pDD1Jx0V9vb00eCMAPZazLpfiAgE73imvZzj3Iq1QkH4KYQ$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8GvKwZltCeq5dZISEPQgVenkSTOu5CSAgX3QmqpZvOjM= pDD1Jx0V9vb00eCMAPZazLpfiAgE73imvZzj3Iq1qbyCR_Q$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8GvKwZltCeq5dZISEPQgVenkSTOu5CSAgX3QmqpZvOjM= pDD1Jx0V9vb00eCMAPZazLpfiAgE73imvZzj3Iq1hRWOTDE$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 051538
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1138 AM EDT Sun Oct 5 2025

Day 1
Valid 16Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL PLAINS AND MIDWEST ALONG WITH THE CENTRAL GULF COAST
AND EASTERN FLORIDA...

...16Z Outlook Update...
The ongoing ERO is on track with only minimal changes needed to
current risk areas. Impressive QPF/totals are beginning to show on
high-res models along a focused axis from north-central KS into
west-central IA. However, dry antecedent conditions and lack of
urban flash flood potential/hydrophobic ground surfaces suggests=20
that any flash flood potential should remain isolated. Isolated 4-6
inch rainfall totals are possible especially along the KS/NE=20
border region and points between just north of Salina, KS to west
of Des Moines, IA.

Localized/marginal flash flood potential should exist for a
couple more hours near the Savannah, GA vicinity this morning,
although the temporal window for deep convection (and 2-3 inch/hr
rain rates) is relatively brief and should close early this
afternoon. Excessive runoff is possible, but coverage should=20
remain below 5% there.

Lastly, isolated flash flood potential exists from southeastern
Louisiana eastward across the north-central Gulf Coast today
through early evening. A weak low is drifting northward toward
southern Louisiana and loosely organized, banded convection should
develop toward the Marginal Risk area in an abundantly moist
environment (2+ inch PW values). Storms should be slow-moving
enough for local rain rates of 2 inches/hr to occur on an
isolated/sporadic basis. This scenario should result in at least
isolated instances of excessive runoff through the afternoon and
evening.

See the previous discussion below for more information.

Cook

...Previous Discussion...

...Central Plains/Midwest...

In the wake of an upper-level trough and surface low transiting
portions of the northern Plains, a cold front will be gradually
settling southeastward today and tonight across the central Plains
and Midwest. Showers and thunderstorms are expected to develop
along the front by this evening across areas of central and
northern KS up through southeast NE and through central IA. MLCAPE
values as high as 1000 to 1500 J/kg are forecast to pool along the
boundary along with a seasonably moist airmass characterized by PWs
of 1.25 to 1.5+ inches. Moisture transport along the front will be
aided by a southwest low-level jet of 30 to 40+ kts going through
00Z this evening which coupled with the instability should help
drive some heavier rainfall rates capable of reaching 1 to 1.5
inches/hour. Going through Sunday night, the convection is expected
to linger as at least modest right-entrance region upper jet
dynamics overhead continue to interact with the front. Some post-
frontal shower and thunderstorm activity is expected as a pool of
elevated instability and frontogenesis lingers over the region. A
consensus of the 00Z HREF guidance supports some spotty 2 to 3+
inch rainfall totals in a narrow axis along the front. Antecedent
conditions are quite dry, but with some localized cell-training
concerns and heavier rainfall totals, there may be some isolated
and mainly urbanized runoff concerns. A Marginal Risk of excessive
rainfall will be maintained across the region.

...Central Gulf Coast...

An elongated low to mid-level low center/trough over the northwest
Gulf of America is expected to focus a corridor of stronger
convergence and moisture transport across the central Gulf Coast
region, with potential for multiple bands of very heavy showers and thunderstorms to evolve. The convection will be embedded within a
deep tropical environment characterized by PWs of 2 to 2.25
inches. This coupled with MLCAPE values of locally near 1500 J/kg
will help favor high rainfall rates that may easily reach 2 to 3
inches/hour with the stronger and more organized convective bands.
The 00Z HREF guidance generally supports the heaviest rainfall
totals remaining confined to the immediate Gulf Coast, however some
localized bands of convection that will be capable of cell-
training may be able to spread a bit farther inland including areas
of south-central to southeast LA through far southern MS and far
southern AL. Some urbanized Gulf Coast locations including New
Orleans and Mobile may be impacted going through Sunday night by
bands of heavy showers and thunderstorms. The latest REFS/RRFS
guidance is more aggressive with the rainfall potential, but a
HREF-led consensus of guidance would suggest some 2 to 4 inch
rainfall totals with spotty 5+ inch amounts not out of the question
where any cell-training occurs. The Marginal Risk area will be
maintained for the time being, with isolated areas of flash
flooding possible, and especially for the aforementioned urban
corridors. However, should the guidance trend any wetter, a Slight
Risk upgrade may be warranted for portions of the central Gulf
Coast.

...Eastern FL...

Moist and locally convergent low-level easterly Atlantic flow will
continue along the FL East Coast today. There are some locally
heavier rainfall signals showing up along the Space and Treasure
Coasts and stretching inland somewhat as the potential once again
for some broken bands of locally heavy showers and thunderstorms
sets up. Where any cell-training occurs within these bands, some
spotty rainfall totals of 2 to 4+ inches will be possible. This
may result in there being a highly localized concern for some
runoff problems. A Marginal Risk of excessive rainfall will be
maintained at this time.

Orrison


Day 2
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
EASTERN ARKANSAS INTO THE OHIO VALLEY AND OVER EASTERN FLORIDA...

...TN and OH Valley...

A Marginal risk was maintained from portions of eastern AR
northeastward into southern IN. 850mb vorticity fields indicate the
tropical disturbance in the Gulf is likely to lift northward on
Monday brining increased PWs and the potential for areas of slow
moving convection. Scattered convection is expected during the day,
although the better focus for high rainfall amounts should come
Monday night as the approaching cold front from the west helps
increase convergence. The environment appears to favor efficient
warm rain processes...with the presence of the low level vorticity
from the Gulf and PWs around or above 2" (over the climatological
90th percentile). Only weak instability is forecast, which could end
up being a limiting factor for flash flooding. However, given the
expected efficient warm rain, there should still be enough
instability to get hourly rainfall rates into the 1-2" range in
spots. The latest WPC deterministic QPF is 1-2" across the area,
although several models indicate locally higher amounts. Given the
environment in place amounts locally getting into the 2-4" range
seems reasonable within the Marginal risk area.

Expect at least localized instances of flash flooding to be
possible, especially by Monday night. There is a bit of uncertainty
regarding the exact rainfall axis, with the new 00z ECMWF shifting
farther east into more of TN and KY. The eastern extent of the
Marginal risk was extended in this direction to account for this potential...although the broader model consensus still favors a
slightly farther west axis, in line with the WPC QPF.

...Eastern FL...

Easterly low level flow will continue to support scattered
convection over eastern FL Monday into Monday night. Model guidance
continues to depict a modest uptick in rainfall coverage and
magnitudes on Monday compared to Sunday. Localized urban flash flood
impacts will remain possible.

...Central Plains...

We opted to remove the Marginal risk that stretched from northeast
KS into southern IA with this update. A localized flash flood risk
still exists on day 1, but by Monday the areas hit hardest on day 1
will be well north of the surface front. Thus most of the
instability will be gone, and rainfall rates should be much lower.
Thus the additional rainfall is not expected to be enough to result
in flash flooding. A bit more instability may reside over MO, but
this is south of the forecast rainfall axis on Sunday, and thus the
rainfall Monday is not expected to be enough to overcome the drier
antecedent conditions here.

Chenard


Day 3
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE TENNESSEE AND OHIO VALLEY, OVER SOUTHEAST FLORIDA, AND PORTIONS
OF NEW MEXICO...

...TN and OH Valley...

A Marginal risk was maintained from TN northward into portions of OH
and southwest PA. Increasing moisture ahead of an approaching cold
front will likely lead to greater convective coverage and areas of
heavy rainfall. The forcing and moisture will be enhanced by the
same low level vorticity feature that was upstream on Monday and
over the Gulf on Sunday. With PWs forecast over the climatological
90th percentile do expect some warm rain processes, which should
help overcome marginal instability and help produce heavy rainfall
rates. Also note a well defined upper divergence signature centered
over this region within the right entrance region of an upper jet.
Thus the ingredients are there for widespread rainfall and at least
some pockets of heavy rates.

The main question for flash flood potential will be the duration of
these higher rates. Overall the front looks pretty progressive,
which should limit this duration. However, guidance does indicate
that some training could occur for a period Tuesday before the front
clears through, with the favored axis somewhere in the vicinity of
central to eastern KY. While differing on location, most 00z
deterministic models indicates a swath of 2-3" of rainfall, which
seems reasonable given the environment in place. In fact would not
be surprised if totals locally exceed 3". Overall this seems like a
solid Marginal risk with localized areas of flash flooding probable.
Can not rule out an embedded Slight risk upgrade on future updates
pending model trends.

The northern extent of the Marginal risk was cut out of the
Northeast with this update. Instability really drops off with
northern extent which will impact rainfall rate potential. These
lower rates combined with the drought conditions suggest flash
flooding is unlikely. We would probably need higher rates to overcome
the dry soil conditions, and this seems unlikely given the currently
forecast instability. So it is looking more like a beneficial
rainfall, with most areas around 0.75" but locally as high as 1.25"
or so.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

A Marginal risk was maintained for portions of central and eastern
NM on Tuesday. Easterly low level post frontal flow will help
locally enhance convergence and upslope and scattered convection is
likely to develop. With PWs around 1" and CAPE only forecast between
500-1000 j/kg this is likely a lower end threat. Nonetheless,
locally heavier convection with high rates could result in isolated
flash flooding, particularly over any more sensitive burn scars or
basins.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_9lhZdipesCCQRyq3tylsHawmDLtgay6msNrhgkNYJmJ= UR9jI3e1mKUCyaqdl1S9ulbqa5b15iZ7RHduvw996Wb7xqk$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_9lhZdipesCCQRyq3tylsHawmDLtgay6msNrhgkNYJmJ= UR9jI3e1mKUCyaqdl1S9ulbqa5b15iZ7RHduvw99f3jfreQ$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_9lhZdipesCCQRyq3tylsHawmDLtgay6msNrhgkNYJmJ= UR9jI3e1mKUCyaqdl1S9ulbqa5b15iZ7RHduvw99eo3L4ss$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 051933
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
333 PM EDT Sun Oct 5 2025

Day 1
Valid 16Z Sun Oct 05 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL PLAINS AND MIDWEST ALONG WITH THE CENTRAL GULF COAST
AND EASTERN FLORIDA...

...16Z Outlook Update...
The ongoing ERO is on track with only minimal changes needed to
current risk areas. Impressive QPF/totals are beginning to show on
high-res models along a focused axis from north-central KS into
west-central IA. However, dry antecedent conditions and lack of
urban flash flood potential/hydrophobic ground surfaces suggests
that any flash flood potential should remain isolated. Isolated 4-6
inch rainfall totals are possible especially along the KS/NE
border region and points between just north of Salina, KS to west
of Des Moines, IA.

Localized/marginal flash flood potential should exist for a
couple more hours near the Savannah, GA vicinity this morning,
although the temporal window for deep convection (and 2-3 inch/hr
rain rates) is relatively brief and should close early this
afternoon. Excessive runoff is possible, but coverage should
remain below 5% there.

Lastly, isolated flash flood potential exists from southeastern
Louisiana eastward across the north-central Gulf Coast today
through early evening. A weak low is drifting northward toward
southern Louisiana and loosely organized, banded convection should
develop toward the Marginal Risk area in an abundantly moist
environment (2+ inch PW values). Storms should be slow-moving
enough for local rain rates of 2 inches/hr to occur on an
isolated/sporadic basis. This scenario should result in at least
isolated instances of excessive runoff through the afternoon and
evening.

See the previous discussion below for more information.

Cook

...Previous Discussion...

...Central Plains/Midwest...

In the wake of an upper-level trough and surface low transiting
portions of the northern Plains, a cold front will be gradually
settling southeastward today and tonight across the central Plains
and Midwest. Showers and thunderstorms are expected to develop
along the front by this evening across areas of central and
northern KS up through southeast NE and through central IA. MLCAPE
values as high as 1000 to 1500 J/kg are forecast to pool along the
boundary along with a seasonably moist airmass characterized by PWs
of 1.25 to 1.5+ inches. Moisture transport along the front will be
aided by a southwest low-level jet of 30 to 40+ kts going through
00Z this evening which coupled with the instability should help
drive some heavier rainfall rates capable of reaching 1 to 1.5
inches/hour. Going through Sunday night, the convection is expected
to linger as at least modest right-entrance region upper jet
dynamics overhead continue to interact with the front. Some post-
frontal shower and thunderstorm activity is expected as a pool of
elevated instability and frontogenesis lingers over the region. A
consensus of the 00Z HREF guidance supports some spotty 2 to 3+
inch rainfall totals in a narrow axis along the front. Antecedent
conditions are quite dry, but with some localized cell-training
concerns and heavier rainfall totals, there may be some isolated
and mainly urbanized runoff concerns. A Marginal Risk of excessive
rainfall will be maintained across the region.

...Central Gulf Coast...

An elongated low to mid-level low center/trough over the northwest
Gulf of America is expected to focus a corridor of stronger
convergence and moisture transport across the central Gulf Coast
region, with potential for multiple bands of very heavy showers and thunderstorms to evolve. The convection will be embedded within a
deep tropical environment characterized by PWs of 2 to 2.25
inches. This coupled with MLCAPE values of locally near 1500 J/kg
will help favor high rainfall rates that may easily reach 2 to 3
inches/hour with the stronger and more organized convective bands.
The 00Z HREF guidance generally supports the heaviest rainfall
totals remaining confined to the immediate Gulf Coast, however some
localized bands of convection that will be capable of cell-
training may be able to spread a bit farther inland including areas
of south-central to southeast LA through far southern MS and far
southern AL. Some urbanized Gulf Coast locations including New
Orleans and Mobile may be impacted going through Sunday night by
bands of heavy showers and thunderstorms. The latest REFS/RRFS
guidance is more aggressive with the rainfall potential, but a
HREF-led consensus of guidance would suggest some 2 to 4 inch
rainfall totals with spotty 5+ inch amounts not out of the question
where any cell-training occurs. The Marginal Risk area will be
maintained for the time being, with isolated areas of flash
flooding possible, and especially for the aforementioned urban
corridors. However, should the guidance trend any wetter, a Slight
Risk upgrade may be warranted for portions of the central Gulf
Coast.

...Eastern FL...

Moist and locally convergent low-level easterly Atlantic flow will
continue along the FL East Coast today. There are some locally
heavier rainfall signals showing up along the Space and Treasure
Coasts and stretching inland somewhat as the potential once again
for some broken bands of locally heavy showers and thunderstorms
sets up. Where any cell-training occurs within these bands, some
spotty rainfall totals of 2 to 4+ inches will be possible. This
may result in there being a highly localized concern for some
runoff problems. A Marginal Risk of excessive rainfall will be
maintained at this time.

Orrison


Day 2
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF=20
THE MID-SOUTH AND WESTERN OHIO VALLEY...

...TN and OH Valley...

...1900 UTC Update...

Based on the latest (12Z) CAM guidance, including the full HREF
probabilistic suite, per collaboration with the WFOs have hoisted a
Slight Risk area across far northeast AR, southeast MO, western
TN-KY, southern IL, and southwest IN (essentially the confluence=20
of the OH and MS River basins). As noted from the previous=20
discussion (below), warm-rain processes will be fairly optimal=20
given the abundant low-mid layer moisture associated with the=20
subtropical shortwave (TPWs approaching 2.00", or 2 standard=20
deviations above the norm, along with WBZ levels aoa 13.5kft).=20
Therefore despite not much deep-layer instability (MUCAPEs 500-1000
J/Kg), rainfall rates will nevertheless be highly efficient. HREF=20 neighborhood probabilities of 24hr rainfall amounts exceeding 3 and
5 inches are highest within this Slight Risk area (60-70% and=20
40-50% respectively).=20

Hurley

...Previous Discussion...

850mb vorticity fields indicate the tropical disturbance in the=20
Gulf is likely to lift northward on Monday brining increased PWs=20
and the potential for areas of slow moving convection. Scattered=20
convection is expected during the day, although the better focus=20
for high rainfall amounts should come Monday night as the=20
approaching cold front from the west helps increase convergence.=20
The environment appears to favor efficient warm rain=20
processes...with the presence of the low level vorticity from the=20
Gulf and PWs around or above 2" (over the climatological 90th=20
percentile). Only weak instability is forecast, which could end up=20
being a limiting factor for flash flooding. However, given the=20
expected efficient warm rain, there should still be enough=20
instability to get hourly rainfall rates into the 1-2" range in=20
spots. The latest WPC deterministic QPF is 1-2" across the area,=20
although several models indicate locally higher amounts. Given the=20 environment in place amounts locally getting into the 2-4" range=20
seems reasonable within the Marginal risk area.

Expect at least localized instances of flash flooding to be
possible, especially by Monday night. There is a bit of uncertainty
regarding the exact rainfall axis, with the new 00z ECMWF shifting
farther east into more of TN and KY. The eastern extent of the
Marginal risk was extended in this direction to account for this potential...although the broader model consensus still favors a
slightly farther west axis, in line with the WPC QPF.

...Eastern FL...

Easterly low level flow will continue to support scattered
convection over eastern FL Monday into Monday night. Model guidance
continues to depict a modest uptick in rainfall coverage and
magnitudes on Monday compared to Sunday. Localized urban flash flood
impacts will remain possible.

...Central Plains...

We opted to remove the Marginal risk that stretched from northeast
KS into southern IA with this update. A localized flash flood risk
still exists on day 1, but by Monday the areas hit hardest on day 1
will be well north of the surface front. Thus most of the
instability will be gone, and rainfall rates should be much lower.
Thus the additional rainfall is not expected to be enough to result
in flash flooding. A bit more instability may reside over MO, but
this is south of the forecast rainfall axis on Sunday, and thus the
rainfall Monday is not expected to be enough to overcome the drier
antecedent conditions here.

Chenard


Day 3
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS NORTHERN
TENNESSEE AND MUCH OF KENTUCKY INTO WESTERN PORTIONS OF WEST
VIRGINIA...

...TN and OH Valley...

...1900 UTC Update...

Only minor tweaks were made to the Marginal Risk area, however as
with the Day 2 ERO, we've added a low-end Slight Risk area on Day 3
from portions of northern TN and much of KY east-northeast into
western WV. This again follows along with the subtropical wave and
TPW plume that will be absorbed by the longwave (synoptic scale)=20
trough and associated surface front. Just as with Day 2, the deep-=20
layer instability isn't overly robust (MUCAPEs 500-1000 J/Kg tops),
while at the same time the flattening mid-upper trough across the=20
area (increasing deep-layer westerly flow) should allow for more a=20
faster W to E progression of the shortwave and surface front later=20
in the period (late Tue-Tue night). Still, anomalous deep-layer=20
moisture (warm rain processes as WBZ levels remain over 12KFT) will
allow for rather efficient short-term rainfall rates.=20

Hurley

...Previous Discussion...

Increasing moisture ahead of an approaching cold front
will likely lead to greater convective coverage and areas of heavy
rainfall. The forcing and moisture will be enhanced by the same=20
low level vorticity feature that was upstream on Monday and over=20
the Gulf on Sunday. With PWs forecast over the climatological 90th=20 percentile do expect some warm rain processes, which should help=20
overcome marginal instability and help produce heavy rainfall=20
rates. Also note a well defined upper divergence signature centered
over this region within the right entrance region of an upper jet.
Thus the ingredients are there for widespread rainfall and at=20
least some pockets of heavy rates.

The main question for flash flood potential will be the duration of
these higher rates. Overall the front looks pretty progressive,
which should limit this duration. However, guidance does indicate
that some training could occur for a period Tuesday before the front
clears through, with the favored axis somewhere in the vicinity of
central to eastern KY. While differing on location, most 00z
deterministic models indicates a swath of 2-3" of rainfall, which
seems reasonable given the environment in place. In fact would not
be surprised if totals locally exceed 3". Overall this seems like a
solid Marginal risk with localized areas of flash flooding probable.
Can not rule out an embedded Slight risk upgrade on future updates
pending model trends.

The northern extent of the Marginal risk was cut out of the
Northeast with this update. Instability really drops off with
northern extent which will impact rainfall rate potential. These
lower rates combined with the drought conditions suggest flash
flooding is unlikely. We would probably need higher rates to overcome
the dry soil conditions, and this seems unlikely given the currently
forecast instability. So it is looking more like a beneficial
rainfall, with most areas around 0.75" but locally as high as 1.25"
or so.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

A Marginal risk was maintained for portions of central and eastern
NM on Tuesday. Easterly low level post frontal flow will help
locally enhance convergence and upslope and scattered convection is
likely to develop. With PWs around 1" and CAPE only forecast between
500-1000 j/kg this is likely a lower end threat. Nonetheless,
locally heavier convection with high rates could result in isolated
flash flooding, particularly over any more sensitive burn scars or
basins.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-4jOVPqDRtzQd4mGBuzL64YLpmeMmCOg1791tFPDn_Ar= xddDi9fcanDksSoayd2lLkUNX1k6SCa472Zu3VehwHNTzl4$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-4jOVPqDRtzQd4mGBuzL64YLpmeMmCOg1791tFPDn_Ar= xddDi9fcanDksSoayd2lLkUNX1k6SCa472Zu3VehZh7iAFA$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-4jOVPqDRtzQd4mGBuzL64YLpmeMmCOg1791tFPDn_Ar= xddDi9fcanDksSoayd2lLkUNX1k6SCa472Zu3VehmN1VoIc$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 060050
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
850 PM EDT Sun Oct 5 2025

Day 1
Valid 01Z Mon Oct 06 2025 - 12Z Mon Oct 06 2025

...THERE IS MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL PLAINS AND MIDWEST ALONG WITH THE CENTRAL GULF COAST
AND EASTERN FLORIDA...

01Z Update...
Latest guidance indicates that at least a localized threat for
additional heavy rainfall will persist tonight within each of the=20
outlook areas, which may lead to isolated runoff concerns.=20
Therefore, each area was maintained, with minor adjustments.=20

The broken line of showers and storms that has developed along the
cold front from western Kansas northeastward into the upper=20
Mississippi Valley shows the greatest potential for scattered heavy
amounts. PWs of 1.25-1.5 inches. along with MUCAPEs above 1000=20
J/kg have been supporting spotty rainfall rates up to ~1 inch/hr=20
from western Kansas though southeastern Nebraska into southwestern=20
Iowa. Recent runs of the HRRR along with the HREF and RRFS indicate
some isolated totals of 2-3 inches are possible along this=20
corridor tonight.

Pereira


Previous Discussion...
...Central Plains/Midwest...

In the wake of an upper-level trough and surface low transiting
portions of the northern Plains, a cold front will be gradually
settling southeastward today and tonight across the central Plains
and Midwest. Showers and thunderstorms are expected to develop
along the front by this evening across areas of central and
northern KS up through southeast NE and through central IA. MLCAPE
values as high as 1000 to 1500 J/kg are forecast to pool along the
boundary along with a seasonably moist airmass characterized by PWs
of 1.25 to 1.5+ inches. Moisture transport along the front will be
aided by a southwest low-level jet of 30 to 40+ kts going through
00Z this evening which coupled with the instability should help
drive some heavier rainfall rates capable of reaching 1 to 1.5
inches/hour. Going through Sunday night, the convection is expected
to linger as at least modest right-entrance region upper jet
dynamics overhead continue to interact with the front. Some post-
frontal shower and thunderstorm activity is expected as a pool of
elevated instability and frontogenesis lingers over the region. A
consensus of the 00Z HREF guidance supports some spotty 2 to 3+
inch rainfall totals in a narrow axis along the front. Antecedent
conditions are quite dry, but with some localized cell-training
concerns and heavier rainfall totals, there may be some isolated
and mainly urbanized runoff concerns. A Marginal Risk of excessive
rainfall will be maintained across the region.

...Central Gulf Coast...

An elongated low to mid-level low center/trough over the northwest
Gulf of America is expected to focus a corridor of stronger
convergence and moisture transport across the central Gulf Coast
region, with potential for multiple bands of very heavy showers and thunderstorms to evolve. The convection will be embedded within a
deep tropical environment characterized by PWs of 2 to 2.25
inches. This coupled with MLCAPE values of locally near 1500 J/kg
will help favor high rainfall rates that may easily reach 2 to 3
inches/hour with the stronger and more organized convective bands.
The 00Z HREF guidance generally supports the heaviest rainfall
totals remaining confined to the immediate Gulf Coast, however some
localized bands of convection that will be capable of cell-
training may be able to spread a bit farther inland including areas
of south-central to southeast LA through far southern MS and far
southern AL. Some urbanized Gulf Coast locations including New
Orleans and Mobile may be impacted going through Sunday night by
bands of heavy showers and thunderstorms. The latest REFS/RRFS
guidance is more aggressive with the rainfall potential, but a
HREF-led consensus of guidance would suggest some 2 to 4 inch
rainfall totals with spotty 5+ inch amounts not out of the question
where any cell-training occurs. The Marginal Risk area will be
maintained for the time being, with isolated areas of flash
flooding possible, and especially for the aforementioned urban
corridors. However, should the guidance trend any wetter, a Slight
Risk upgrade may be warranted for portions of the central Gulf
Coast.

...Eastern FL...

Moist and locally convergent low-level easterly Atlantic flow will
continue along the FL East Coast today. There are some locally
heavier rainfall signals showing up along the Space and Treasure
Coasts and stretching inland somewhat as the potential once again
for some broken bands of locally heavy showers and thunderstorms
sets up. Where any cell-training occurs within these bands, some
spotty rainfall totals of 2 to 4+ inches will be possible. This
may result in there being a highly localized concern for some
runoff problems. A Marginal Risk of excessive rainfall will be
maintained at this time.

Orrison


Day 2
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE MID-SOUTH AND WESTERN OHIO VALLEY...

...TN and OH Valley...

...1900 UTC Update...

Based on the latest (12Z) CAM guidance, including the full HREF
probabilistic suite, per collaboration with the WFOs have hoisted a
Slight Risk area across far northeast AR, southeast MO, western
TN-KY, southern IL, and southwest IN (essentially the confluence
of the OH and MS River basins). As noted from the previous
discussion (below), warm-rain processes will be fairly optimal
given the abundant low-mid layer moisture associated with the
subtropical shortwave (TPWs approaching 2.00", or 2 standard
deviations above the norm, along with WBZ levels aoa 13.5kft).
Therefore despite not much deep-layer instability (MUCAPEs 500-1000
J/Kg), rainfall rates will nevertheless be highly efficient. HREF
neighborhood probabilities of 24hr rainfall amounts exceeding 3 and
5 inches are highest within this Slight Risk area (60-70% and
40-50% respectively).

Hurley

...Previous Discussion...

850mb vorticity fields indicate the tropical disturbance in the
Gulf is likely to lift northward on Monday brining increased PWs
and the potential for areas of slow moving convection. Scattered
convection is expected during the day, although the better focus
for high rainfall amounts should come Monday night as the
approaching cold front from the west helps increase convergence.
The environment appears to favor efficient warm rain
processes...with the presence of the low level vorticity from the
Gulf and PWs around or above 2" (over the climatological 90th
percentile). Only weak instability is forecast, which could end up
being a limiting factor for flash flooding. However, given the
expected efficient warm rain, there should still be enough
instability to get hourly rainfall rates into the 1-2" range in
spots. The latest WPC deterministic QPF is 1-2" across the area,
although several models indicate locally higher amounts. Given the
environment in place amounts locally getting into the 2-4" range
seems reasonable within the Marginal risk area.

Expect at least localized instances of flash flooding to be
possible, especially by Monday night. There is a bit of uncertainty
regarding the exact rainfall axis, with the new 00z ECMWF shifting
farther east into more of TN and KY. The eastern extent of the
Marginal risk was extended in this direction to account for this potential...although the broader model consensus still favors a
slightly farther west axis, in line with the WPC QPF.

...Eastern FL...

Easterly low level flow will continue to support scattered
convection over eastern FL Monday into Monday night. Model guidance
continues to depict a modest uptick in rainfall coverage and
magnitudes on Monday compared to Sunday. Localized urban flash flood
impacts will remain possible.

...Central Plains...

We opted to remove the Marginal risk that stretched from northeast
KS into southern IA with this update. A localized flash flood risk
still exists on day 1, but by Monday the areas hit hardest on day 1
will be well north of the surface front. Thus most of the
instability will be gone, and rainfall rates should be much lower.
Thus the additional rainfall is not expected to be enough to result
in flash flooding. A bit more instability may reside over MO, but
this is south of the forecast rainfall axis on Sunday, and thus the
rainfall Monday is not expected to be enough to overcome the drier
antecedent conditions here.

Chenard


Day 3
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS NORTHERN
TENNESSEE AND MUCH OF KENTUCKY INTO WESTERN PORTIONS OF WEST
VIRGINIA...

...TN and OH Valley...

...1900 UTC Update...

Only minor tweaks were made to the Marginal Risk area, however as
with the Day 2 ERO, we've added a low-end Slight Risk area on Day 3
from portions of northern TN and much of KY east-northeast into
western WV. This again follows along with the subtropical wave and
TPW plume that will be absorbed by the longwave (synoptic scale)
trough and associated surface front. Just as with Day 2, the deep-
layer instability isn't overly robust (MUCAPEs 500-1000 J/Kg tops),
while at the same time the flattening mid-upper trough across the
area (increasing deep-layer westerly flow) should allow for more a
faster W to E progression of the shortwave and surface front later
in the period (late Tue-Tue night). Still, anomalous deep-layer
moisture (warm rain processes as WBZ levels remain over 12KFT) will
allow for rather efficient short-term rainfall rates.

Hurley

...Previous Discussion...

Increasing moisture ahead of an approaching cold front
will likely lead to greater convective coverage and areas of heavy
rainfall. The forcing and moisture will be enhanced by the same
low level vorticity feature that was upstream on Monday and over
the Gulf on Sunday. With PWs forecast over the climatological 90th
percentile do expect some warm rain processes, which should help
overcome marginal instability and help produce heavy rainfall
rates. Also note a well defined upper divergence signature centered
over this region within the right entrance region of an upper jet.
Thus the ingredients are there for widespread rainfall and at
least some pockets of heavy rates.

The main question for flash flood potential will be the duration of
these higher rates. Overall the front looks pretty progressive,
which should limit this duration. However, guidance does indicate
that some training could occur for a period Tuesday before the front
clears through, with the favored axis somewhere in the vicinity of
central to eastern KY. While differing on location, most 00z
deterministic models indicates a swath of 2-3" of rainfall, which
seems reasonable given the environment in place. In fact would not
be surprised if totals locally exceed 3". Overall this seems like a
solid Marginal risk with localized areas of flash flooding probable.
Can not rule out an embedded Slight risk upgrade on future updates
pending model trends.

The northern extent of the Marginal risk was cut out of the
Northeast with this update. Instability really drops off with
northern extent which will impact rainfall rate potential. These
lower rates combined with the drought conditions suggest flash
flooding is unlikely. We would probably need higher rates to overcome
the dry soil conditions, and this seems unlikely given the currently
forecast instability. So it is looking more like a beneficial
rainfall, with most areas around 0.75" but locally as high as 1.25"
or so.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

A Marginal risk was maintained for portions of central and eastern
NM on Tuesday. Easterly low level post frontal flow will help
locally enhance convergence and upslope and scattered convection is
likely to develop. With PWs around 1" and CAPE only forecast between
500-1000 j/kg this is likely a lower end threat. Nonetheless,
locally heavier convection with high rates could result in isolated
flash flooding, particularly over any more sensitive burn scars or
basins.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4rTPxeEY5RSMIzcXvzHW9OgJjW5UEDtyiwHbULsJ2PR1= dN9shQI0O2IUoQ8ZcfqnPNorSPu1iXIq3HXibU01ATRPeT0$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4rTPxeEY5RSMIzcXvzHW9OgJjW5UEDtyiwHbULsJ2PR1= dN9shQI0O2IUoQ8ZcfqnPNorSPu1iXIq3HXibU011NgFZP4$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4rTPxeEY5RSMIzcXvzHW9OgJjW5UEDtyiwHbULsJ2PR1= dN9shQI0O2IUoQ8ZcfqnPNorSPu1iXIq3HXibU01Um6lnc8$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 060819
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
419 AM EDT Mon Oct 6 2025

Day 1
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE MID-SOUTH AND LOWER OHIO VALLEY...

...Mid-South/Lower Ohio Valley and the Central Gulf Coast...

An elongated low to mid-level vort center near the central Gulf
Coast will lift northward into the Mid-South today and gradually
stretch northeastward into portions of the Lower OH Valley by later tonight through early Tuesday morning. Increasingly convergent flow around
the eastern flank of the vort energy and an associated weak surface
low/trough axis coupled with enhancing moisture transport aided by
a 30 to 40 kt low-level jet will support broken bands of heavy
showers and thunderstorms. Modest instability with MLCAPE values of
500 to 1000 J/kg will be in place with the aid of diurnal heating,
but the vertical column will be quite moist with CIRA-ALPW data
showing the aforementioned vort energy embedded within a rather
deep tropical environment characterized by PWs of 2 to 2.25 inches.

Relatively warm-topped convection with high WBZ levels will support
very efficient rainfall processes for high rainfall rates as this
energy lifts north over the next 12 to 24 hours. The latest 00Z
HREF guidance supports broken convection with rainfall rates as
high as 1.5 to 2.5 inches/hour, and some concerns for some cell-=20
training that may foster some localized totals of 3 to 5 inches.=20
The more concentrated areas of convection are most likely to focus=20
across areas of eastern AR/western TN northeastward up into western
KY and southern IN going through Monday night and Tuesday morning
where the axis of stronger low-level convergence in conjunction
with some modest upper-level jet forcing/divergence is forecast to
become aligned. A Slight Risk of excessive rainfall will be=20
maintained for this period, with some southward expansion of it=20
depicted down across eastern AR compared to continuity given the
latest multi-model hires consensus. The setup will be conducive=20
for there being isolated to scattered areas of flash flooding which
will include urbanized flooding concerns.

Meanwhile, very moist and convergent low-level southerly flow off=20
the Gulf coupled with a moderately unstable boundary layer will=20
favor a threat for additional small-scale bands of convection to=20
impact parts of eastern LA along with coastal areas of southern=20
MS, southwest AL and into the western FL Panhandle. PWs running=20
close to or above 2 inches coupled with the instability will yield=20
high rainfall rates, with some localized additional rainfall totals
for this period of 2 to 4+ inches possible. This is supported by=20
the 00Z HREF guidance, and the setup will support isolated concerns
for runoff problems/flash flooding. As a result, a Marginal Risk=20
of excessive rainfall has been expanding to encompass these areas.

...Eastern FL...

Moist easterly low-level flow will continue to support scattered
areas of convection over eastern FL today through tonight. The
activity again should tend to be rather disorganized, but there=20
will be some potential for small-scale east/west oriented bands to=20
set up that may result in some isolated 2 to 4+ inch rainfall
totals. This may drive at least some isolated runoff concerns. As a
result, the Marginal Risk of excessive rainfall is maintained for
this period.

Orrison


Day 2
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE OHIO VALLEY...

...Ohio Valley into the Central Appalachians...

A Slight risk was maintained from portions of northern TN into much=20
of KY, southern IN and OH, and western WV where isolated to=20
scattered flash flooding is likely. Increasing southerly flow ahead=20
of an approaching cold front will advect moisture northward while=20
also enhancing lower level convergence. Also of note is a sfc-850mb=20
low that is over AR today and was over the northern Gulf on Sunday.=20
This feature will get more elongated in nature by Tuesday, but=20
should still act to locally increase moisture transport and=20
convergence over KY and surrounding areas. PWs are forecast around=20
2", which is well over the 90th percentile for this time of year.=20 Instability is expected to only be modest, generally in the 500-1000=20
j/kg range, however the strong synoptic forcing provided by the=20
approaching front and good upper level divergence should compensate=20
for this and still allow for organized convection.

Both the 00z HREF and REFS show moderate to high probabilities of=20
hourly rainfall exceeding 1", but only low probabilities of=20
exceeding 2". The limited instability is likely responsible for=20
the lack of 2"+ per hour rainfall rates. However the deep saturated=20
layer and low topped convection supports highly efficient warm rain=20 collision-coalascence processes, leading to the likelihood of at=20
least 1" per hour rainfall.=20=20

The main question for flash flood potential will be the duration of=20
these higher rates, as it seems unlikely that 1hr FFG will be=20
exceeded. While the front will be progressive, it does look like we=20
will have enough convective coverage to support some training, and=20
at least a few hours of heavy rainfall rates. Thus while 1hr FFG may=20
be difficult to overcome, it does look like there will be an=20
opportunity for some exceedance of the 3hr FFG...with both the 00z=20
HREF and REFS showing exceedance probabilities upwards of 25-50%.=20
The latest WPC QPF indicates event total rainfall of 2-4" over most=20
of the Slight risk area, which is supported by high HREF and REFS=20 neighborhood probabilities of exceeding 3". Also will note that=20
there are even moderate probabilities of locally exceeding 5" with=20
this event.

There is a bit of model spread on the most favored axis for heaviest=20 rainfall and flash flooding. Both the HREF and REFS supports a=20
slightly farther southwest axis across KY and northern TN, with the=20
global guidance generally more over eastern KY into WV. The Slight=20
risk was made big enough to support a compromise of these two camps,=20
and will need to continue to monitor trends going forward. Generally=20
think the highest risk is over KY, but can no rule out that shifting=20
into northern TN or portions of WV.

While the rainfall does look a bit more convective now over the=20
Northeast, 1" per hour probabilities are still low...with most=20
guidance peaking rainfall rates in the 0.5"-0.75" range. Given the=20
ongoing drought conditions it still seems unlikely that these rates=20
will be high enough to overcome the dry soil conditions. Thus even=20
with rainfall totals approaching 1.5" we will continue with no risk=20
area depicted.

...Southeast FL...

Expecting another day of scattered convection within the easterly low=20
level flow Tuesday. Compared to previous days the threat should=20
mostly be focused over southeast FL by this time, and a localized=20
urban flash flood risk is possible.

...NM...

The convective threat looks a bit better than it did this time last=20
night with models trending a bit more robust with development.=20
Easterly low level post frontal flow will help locally enhance=20
convergence and upslope and scattered convection is likely to=20
develop. Instability is forecast to be modest, but may get towards=20
1000 j/kg, which would be enough for heavy rainfall rates given the=20 anomalous PWs in place. The high res guidance is starting to show a=20
threat of 1"+ per hour rainfall, which would be enough for isolated=20
flash flooding.

Chenard


Day 3
Valid 12Z Wed Oct 08 2025 - 12Z Thu Oct 09 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF=20
NEW MEXICO...

Looking at a continuation of the localized heavy rainfall threat over=20
NM into Wednesday. The moisture plume and instability axis will=20
expand westward which should expand the isolated flash flood risk in=20
that direction as well. The environmental ingredients look pretty=20
similar to Tuesday, as do model QPF forecasts. So would generally=20
expect similar convective coverage and intensity with isolated flash=20 flooding again a concern.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!6yywByMHDqxIE-C_e9UglUOh9fXn5ctbW8VdFlrCDdDG= UoTrXjpadRuZY4V3xQ1ovUIW0W6z2vZ6wyW8gIUYL7spXRE$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6yywByMHDqxIE-C_e9UglUOh9fXn5ctbW8VdFlrCDdDG= UoTrXjpadRuZY4V3xQ1ovUIW0W6z2vZ6wyW8gIUYSzDxhYE$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6yywByMHDqxIE-C_e9UglUOh9fXn5ctbW8VdFlrCDdDG= UoTrXjpadRuZY4V3xQ1ovUIW0W6z2vZ6wyW8gIUYCK84gFs$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 061603
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1203 PM EDT Mon Oct 6 2025

Day 1
Valid 16Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE MID-SOUTH AND LOWER OHIO VALLEY...

...16z update...

Minor changes were made to the Day 1 ERO for the Mid-South/Lower
Ohio Valley and the Central Gulf Coast. The slight risk area was
expanded a little bit farther into southern Indiana/Illinois based
on hires trends and 12z HREF neighborhood exceedance probabilities
of 5 inches between 10-20%. A separate band of convection may=20
develop and lift north through those areas this afternoon/evening.
By contrast, the deterministic GFS and Euro keep the highest QPf=20
out of southern IN/IL.

The marginal risk area over eastern Florida remains unchanged due
to no significant changes in the guidance.

Kebede

...Previous Discussion...

...Mid-South/Lower Ohio Valley and the Central Gulf Coast...

An elongated low to mid-level vort center near the central Gulf
Coast will lift northward into the Mid-South today and gradually
stretch northeastward into portions of the Lower OH Valley by later tonight through early Tuesday morning. Increasingly convergent flow around
the eastern flank of the vort energy and an associated weak surface
low/trough axis coupled with enhancing moisture transport aided by
a 30 to 40 kt low-level jet will support broken bands of heavy
showers and thunderstorms. Modest instability with MLCAPE values of
500 to 1000 J/kg will be in place with the aid of diurnal heating,
but the vertical column will be quite moist with CIRA-ALPW data
showing the aforementioned vort energy embedded within a rather
deep tropical environment characterized by PWs of 2 to 2.25 inches.

Relatively warm-topped convection with high WBZ levels will support
very efficient rainfall processes for high rainfall rates as this
energy lifts north over the next 12 to 24 hours. The latest 00Z
HREF guidance supports broken convection with rainfall rates as
high as 1.5 to 2.5 inches/hour, and some concerns for some cell-
training that may foster some localized totals of 3 to 5 inches.
The more concentrated areas of convection are most likely to focus
across areas of eastern AR/western TN northeastward up into western
KY and southern IN going through Monday night and Tuesday morning
where the axis of stronger low-level convergence in conjunction
with some modest upper-level jet forcing/divergence is forecast to
become aligned. A Slight Risk of excessive rainfall will be
maintained for this period, with some southward expansion of it
depicted down across eastern AR compared to continuity given the
latest multi-model hires consensus. The setup will be conducive
for there being isolated to scattered areas of flash flooding which
will include urbanized flooding concerns.

Meanwhile, very moist and convergent low-level southerly flow off
the Gulf coupled with a moderately unstable boundary layer will
favor a threat for additional small-scale bands of convection to
impact parts of eastern LA along with coastal areas of southern
MS, southwest AL and into the western FL Panhandle. PWs running
close to or above 2 inches coupled with the instability will yield
high rainfall rates, with some localized additional rainfall totals
for this period of 2 to 4+ inches possible. This is supported by
the 00Z HREF guidance, and the setup will support isolated concerns
for runoff problems/flash flooding. As a result, a Marginal Risk
of excessive rainfall has been expanding to encompass these areas.

...Eastern FL...

Moist easterly low-level flow will continue to support scattered
areas of convection over eastern FL today through tonight. The
activity again should tend to be rather disorganized, but there
will be some potential for small-scale east/west oriented bands to
set up that may result in some isolated 2 to 4+ inch rainfall
totals. This may drive at least some isolated runoff concerns. As a
result, the Marginal Risk of excessive rainfall is maintained for
this period.

Orrison


Day 2
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE OHIO VALLEY...

...Ohio Valley into the Central Appalachians...

A Slight risk was maintained from portions of northern TN into much
of KY, southern IN and OH, and western WV where isolated to
scattered flash flooding is likely. Increasing southerly flow ahead
of an approaching cold front will advect moisture northward while
also enhancing lower level convergence. Also of note is a sfc-850mb
low that is over AR today and was over the northern Gulf on Sunday.
This feature will get more elongated in nature by Tuesday, but
should still act to locally increase moisture transport and
convergence over KY and surrounding areas. PWs are forecast around
2", which is well over the 90th percentile for this time of year.
Instability is expected to only be modest, generally in the 500-1000
j/kg range, however the strong synoptic forcing provided by the
approaching front and good upper level divergence should compensate
for this and still allow for organized convection.

Both the 00z HREF and REFS show moderate to high probabilities of
hourly rainfall exceeding 1", but only low probabilities of
exceeding 2". The limited instability is likely responsible for
the lack of 2"+ per hour rainfall rates. However the deep saturated
layer and low topped convection supports highly efficient warm rain collision-coalascence processes, leading to the likelihood of at
least 1" per hour rainfall.

The main question for flash flood potential will be the duration of
these higher rates, as it seems unlikely that 1hr FFG will be
exceeded. While the front will be progressive, it does look like we
will have enough convective coverage to support some training, and
at least a few hours of heavy rainfall rates. Thus while 1hr FFG may
be difficult to overcome, it does look like there will be an
opportunity for some exceedance of the 3hr FFG...with both the 00z
HREF and REFS showing exceedance probabilities upwards of 25-50%.
The latest WPC QPF indicates event total rainfall of 2-4" over most
of the Slight risk area, which is supported by high HREF and REFS
neighborhood probabilities of exceeding 3". Also will note that
there are even moderate probabilities of locally exceeding 5" with
this event.

There is a bit of model spread on the most favored axis for heaviest
rainfall and flash flooding. Both the HREF and REFS supports a
slightly farther southwest axis across KY and northern TN, with the
global guidance generally more over eastern KY into WV. The Slight
risk was made big enough to support a compromise of these two camps,
and will need to continue to monitor trends going forward. Generally
think the highest risk is over KY, but can no rule out that shifting
into northern TN or portions of WV.

While the rainfall does look a bit more convective now over the
Northeast, 1" per hour probabilities are still low...with most
guidance peaking rainfall rates in the 0.5"-0.75" range. Given the
ongoing drought conditions it still seems unlikely that these rates
will be high enough to overcome the dry soil conditions. Thus even
with rainfall totals approaching 1.5" we will continue with no risk
area depicted.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

The convective threat looks a bit better than it did this time last
night with models trending a bit more robust with development.
Easterly low level post frontal flow will help locally enhance
convergence and upslope and scattered convection is likely to
develop. Instability is forecast to be modest, but may get towards
1000 j/kg, which would be enough for heavy rainfall rates given the
anomalous PWs in place. The high res guidance is starting to show a
threat of 1"+ per hour rainfall, which would be enough for isolated
flash flooding.

Chenard


Day 3
Valid 12Z Wed Oct 08 2025 - 12Z Thu Oct 09 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
NEW MEXICO...

Looking at a continuation of the localized heavy rainfall threat over
NM into Wednesday. The moisture plume and instability axis will
expand westward which should expand the isolated flash flood risk in
that direction as well. The environmental ingredients look pretty
similar to Tuesday, as do model QPF forecasts. So would generally
expect similar convective coverage and intensity with isolated flash
flooding again a concern.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!6PFuZxcyxTQriYK4iOtRDfHlBxU-_U2BKIInbtKETfET= Hc_pDuqjUH-it79R6tq1gDYlx_MiQ2wfvPryEzKVzPwgiEo$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6PFuZxcyxTQriYK4iOtRDfHlBxU-_U2BKIInbtKETfET= Hc_pDuqjUH-it79R6tq1gDYlx_MiQ2wfvPryEzKVtw0nfAs$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6PFuZxcyxTQriYK4iOtRDfHlBxU-_U2BKIInbtKETfET= Hc_pDuqjUH-it79R6tq1gDYlx_MiQ2wfvPryEzKVoGkEOaY$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 061600
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1200 PM EDT Mon Oct 6 2025

Day 1
Valid 12Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE MID-SOUTH AND LOWER OHIO VALLEY...

...16z update...

Minor changes were made to the Day 1 ERO for the Mid-South/Lower
Ohio Valley and the Central Gulf Coast. The slight risk area was=20
expanded a little bit farther into southern Indiana/Illinois based=20
on hires trends and 12z HREF neighborhood exceedance probabilities=20
of 5 inches between 10-20%. A secondary band of convection may
occur over those areas this afternoon/evening. By contrast, the=20 deterministic GFS and Euro keep the highest QPf out of southern=20
IN/IL.=20

The marginal risk area over eastern Florida remains unchanged due=20
to no significant changes in the guidance.

Kebede

...Previous Discussion...

...Mid-South/Lower Ohio Valley and the Central Gulf Coast...

An elongated low to mid-level vort center near the central Gulf
Coast will lift northward into the Mid-South today and gradually
stretch northeastward into portions of the Lower OH Valley by later tonight through early Tuesday morning. Increasingly convergent flow around
the eastern flank of the vort energy and an associated weak surface
low/trough axis coupled with enhancing moisture transport aided by
a 30 to 40 kt low-level jet will support broken bands of heavy
showers and thunderstorms. Modest instability with MLCAPE values of
500 to 1000 J/kg will be in place with the aid of diurnal heating,
but the vertical column will be quite moist with CIRA-ALPW data
showing the aforementioned vort energy embedded within a rather
deep tropical environment characterized by PWs of 2 to 2.25 inches.

Relatively warm-topped convection with high WBZ levels will support
very efficient rainfall processes for high rainfall rates as this
energy lifts north over the next 12 to 24 hours. The latest 00Z
HREF guidance supports broken convection with rainfall rates as
high as 1.5 to 2.5 inches/hour, and some concerns for some cell-
training that may foster some localized totals of 3 to 5 inches.
The more concentrated areas of convection are most likely to focus
across areas of eastern AR/western TN northeastward up into western
KY and southern IN going through Monday night and Tuesday morning
where the axis of stronger low-level convergence in conjunction
with some modest upper-level jet forcing/divergence is forecast to
become aligned. A Slight Risk of excessive rainfall will be
maintained for this period, with some southward expansion of it
depicted down across eastern AR compared to continuity given the
latest multi-model hires consensus. The setup will be conducive
for there being isolated to scattered areas of flash flooding which
will include urbanized flooding concerns.

Meanwhile, very moist and convergent low-level southerly flow off
the Gulf coupled with a moderately unstable boundary layer will
favor a threat for additional small-scale bands of convection to
impact parts of eastern LA along with coastal areas of southern
MS, southwest AL and into the western FL Panhandle. PWs running
close to or above 2 inches coupled with the instability will yield
high rainfall rates, with some localized additional rainfall totals
for this period of 2 to 4+ inches possible. This is supported by
the 00Z HREF guidance, and the setup will support isolated concerns
for runoff problems/flash flooding. As a result, a Marginal Risk
of excessive rainfall has been expanding to encompass these areas.

...Eastern FL...

Moist easterly low-level flow will continue to support scattered
areas of convection over eastern FL today through tonight. The
activity again should tend to be rather disorganized, but there
will be some potential for small-scale east/west oriented bands to
set up that may result in some isolated 2 to 4+ inch rainfall
totals. This may drive at least some isolated runoff concerns. As a
result, the Marginal Risk of excessive rainfall is maintained for
this period.

Orrison


Day 2
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE OHIO VALLEY...

...Ohio Valley into the Central Appalachians...

A Slight risk was maintained from portions of northern TN into much
of KY, southern IN and OH, and western WV where isolated to
scattered flash flooding is likely. Increasing southerly flow ahead
of an approaching cold front will advect moisture northward while
also enhancing lower level convergence. Also of note is a sfc-850mb
low that is over AR today and was over the northern Gulf on Sunday.
This feature will get more elongated in nature by Tuesday, but
should still act to locally increase moisture transport and
convergence over KY and surrounding areas. PWs are forecast around
2", which is well over the 90th percentile for this time of year.
Instability is expected to only be modest, generally in the 500-1000
j/kg range, however the strong synoptic forcing provided by the
approaching front and good upper level divergence should compensate
for this and still allow for organized convection.

Both the 00z HREF and REFS show moderate to high probabilities of
hourly rainfall exceeding 1", but only low probabilities of
exceeding 2". The limited instability is likely responsible for
the lack of 2"+ per hour rainfall rates. However the deep saturated
layer and low topped convection supports highly efficient warm rain collision-coalascence processes, leading to the likelihood of at
least 1" per hour rainfall.

The main question for flash flood potential will be the duration of
these higher rates, as it seems unlikely that 1hr FFG will be
exceeded. While the front will be progressive, it does look like we
will have enough convective coverage to support some training, and
at least a few hours of heavy rainfall rates. Thus while 1hr FFG may
be difficult to overcome, it does look like there will be an
opportunity for some exceedance of the 3hr FFG...with both the 00z
HREF and REFS showing exceedance probabilities upwards of 25-50%.
The latest WPC QPF indicates event total rainfall of 2-4" over most
of the Slight risk area, which is supported by high HREF and REFS
neighborhood probabilities of exceeding 3". Also will note that
there are even moderate probabilities of locally exceeding 5" with
this event.

There is a bit of model spread on the most favored axis for heaviest
rainfall and flash flooding. Both the HREF and REFS supports a
slightly farther southwest axis across KY and northern TN, with the
global guidance generally more over eastern KY into WV. The Slight
risk was made big enough to support a compromise of these two camps,
and will need to continue to monitor trends going forward. Generally
think the highest risk is over KY, but can no rule out that shifting
into northern TN or portions of WV.

While the rainfall does look a bit more convective now over the
Northeast, 1" per hour probabilities are still low...with most
guidance peaking rainfall rates in the 0.5"-0.75" range. Given the
ongoing drought conditions it still seems unlikely that these rates
will be high enough to overcome the dry soil conditions. Thus even
with rainfall totals approaching 1.5" we will continue with no risk
area depicted.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

The convective threat looks a bit better than it did this time last
night with models trending a bit more robust with development.
Easterly low level post frontal flow will help locally enhance
convergence and upslope and scattered convection is likely to
develop. Instability is forecast to be modest, but may get towards
1000 j/kg, which would be enough for heavy rainfall rates given the
anomalous PWs in place. The high res guidance is starting to show a
threat of 1"+ per hour rainfall, which would be enough for isolated
flash flooding.

Chenard


Day 3
Valid 12Z Wed Oct 08 2025 - 12Z Thu Oct 09 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
NEW MEXICO...

Looking at a continuation of the localized heavy rainfall threat over
NM into Wednesday. The moisture plume and instability axis will
expand westward which should expand the isolated flash flood risk in
that direction as well. The environmental ingredients look pretty
similar to Tuesday, as do model QPF forecasts. So would generally
expect similar convective coverage and intensity with isolated flash
flooding again a concern.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8clLCxSuOFZ3lDOqRtmk7MUdUBvTdrcZB9P3v5upJyVH= 42B0CTUQvX6HWo2UiPf989XY3E-8nGjRvhHwmeN4ToDEMk0$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8clLCxSuOFZ3lDOqRtmk7MUdUBvTdrcZB9P3v5upJyVH= 42B0CTUQvX6HWo2UiPf989XY3E-8nGjRvhHwmeN4Z391juU$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8clLCxSuOFZ3lDOqRtmk7MUdUBvTdrcZB9P3v5upJyVH= 42B0CTUQvX6HWo2UiPf989XY3E-8nGjRvhHwmeN4-KCyowo$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 061942
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
342 PM EDT Mon Oct 6 2025

Day 1
Valid 16Z Mon Oct 06 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE MID-SOUTH AND LOWER OHIO VALLEY...

...16z update...

Minor changes were made to the Day 1 ERO for the Mid-South/Lower
Ohio Valley and the Central Gulf Coast. The slight risk area was
expanded a little bit farther into southern Indiana/Illinois based
on hires trends and 12z HREF neighborhood exceedance probabilities
of 5 inches between 10-20%. A separate band of convection may
develop and lift north through those areas this afternoon/evening.
By contrast, the deterministic GFS and Euro keep the highest QPf
out of southern IN/IL.

The marginal risk area over eastern Florida remains unchanged due
to no significant changes in the guidance.

Kebede

...Previous Discussion...

...Mid-South/Lower Ohio Valley and the Central Gulf Coast...

An elongated low to mid-level vort center near the central Gulf
Coast will lift northward into the Mid-South today and gradually
stretch northeastward into portions of the Lower OH Valley by later tonight through early Tuesday morning. Increasingly convergent flow around
the eastern flank of the vort energy and an associated weak surface
low/trough axis coupled with enhancing moisture transport aided by
a 30 to 40 kt low-level jet will support broken bands of heavy
showers and thunderstorms. Modest instability with MLCAPE values of
500 to 1000 J/kg will be in place with the aid of diurnal heating,
but the vertical column will be quite moist with CIRA-ALPW data
showing the aforementioned vort energy embedded within a rather
deep tropical environment characterized by PWs of 2 to 2.25 inches.

Relatively warm-topped convection with high WBZ levels will support
very efficient rainfall processes for high rainfall rates as this
energy lifts north over the next 12 to 24 hours. The latest 00Z
HREF guidance supports broken convection with rainfall rates as
high as 1.5 to 2.5 inches/hour, and some concerns for some cell-
training that may foster some localized totals of 3 to 5 inches.
The more concentrated areas of convection are most likely to focus
across areas of eastern AR/western TN northeastward up into western
KY and southern IN going through Monday night and Tuesday morning
where the axis of stronger low-level convergence in conjunction
with some modest upper-level jet forcing/divergence is forecast to
become aligned. A Slight Risk of excessive rainfall will be
maintained for this period, with some southward expansion of it
depicted down across eastern AR compared to continuity given the
latest multi-model hires consensus. The setup will be conducive
for there being isolated to scattered areas of flash flooding which
will include urbanized flooding concerns.

Meanwhile, very moist and convergent low-level southerly flow off
the Gulf coupled with a moderately unstable boundary layer will
favor a threat for additional small-scale bands of convection to
impact parts of eastern LA along with coastal areas of southern
MS, southwest AL and into the western FL Panhandle. PWs running
close to or above 2 inches coupled with the instability will yield
high rainfall rates, with some localized additional rainfall totals
for this period of 2 to 4+ inches possible. This is supported by
the 00Z HREF guidance, and the setup will support isolated concerns
for runoff problems/flash flooding. As a result, a Marginal Risk
of excessive rainfall has been expanding to encompass these areas.

...Eastern FL...

Moist easterly low-level flow will continue to support scattered
areas of convection over eastern FL today through tonight. The
activity again should tend to be rather disorganized, but there
will be some potential for small-scale east/west oriented bands to
set up that may result in some isolated 2 to 4+ inch rainfall
totals. This may drive at least some isolated runoff concerns. As a
result, the Marginal Risk of excessive rainfall is maintained for
this period.

Orrison


Day 2
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE OHIO VALLEY...

...2030z update...

Minor edits were made to New Mexico and Ohio Valley/Central
Appalachian risk areas on day 2. The slight and marginal risk=20
areas were expanded south and west into northern Tennessee and=20
southwestern Kentucky, where convection is forecast to continue
into Tuesday morning along a slow moving cold front. PWs are over=20
the 99th percentile across much of Kentucky and western Tennessee=20
through Tuesday afternoon.

Kebede

...Previous Discussion...

...Ohio Valley into the Central Appalachians...

A Slight risk was maintained from portions of northern TN into much
of KY, southern IN and OH, and western WV where isolated to
scattered flash flooding is likely. Increasing southerly flow ahead
of an approaching cold front will advect moisture northward while
also enhancing lower level convergence. Also of note is a sfc-850mb
low that is over AR today and was over the northern Gulf on Sunday.
This feature will get more elongated in nature by Tuesday, but
should still act to locally increase moisture transport and
convergence over KY and surrounding areas. PWs are forecast around
2", which is well over the 90th percentile for this time of year.
Instability is expected to only be modest, generally in the 500-1000
j/kg range, however the strong synoptic forcing provided by the
approaching front and good upper level divergence should compensate
for this and still allow for organized convection.

Both the 00z HREF and REFS show moderate to high probabilities of
hourly rainfall exceeding 1", but only low probabilities of
exceeding 2". The limited instability is likely responsible for
the lack of 2"+ per hour rainfall rates. However the deep saturated
layer and low topped convection supports highly efficient warm rain collision-coalascence processes, leading to the likelihood of at
least 1" per hour rainfall.

The main question for flash flood potential will be the duration of
these higher rates, as it seems unlikely that 1hr FFG will be
exceeded. While the front will be progressive, it does look like we
will have enough convective coverage to support some training, and
at least a few hours of heavy rainfall rates. Thus while 1hr FFG may
be difficult to overcome, it does look like there will be an
opportunity for some exceedance of the 3hr FFG...with both the 00z
HREF and REFS showing exceedance probabilities upwards of 25-50%.
The latest WPC QPF indicates event total rainfall of 2-4" over most
of the Slight risk area, which is supported by high HREF and REFS
neighborhood probabilities of exceeding 3". Also will note that
there are even moderate probabilities of locally exceeding 5" with
this event.

There is a bit of model spread on the most favored axis for heaviest
rainfall and flash flooding. Both the HREF and REFS supports a
slightly farther southwest axis across KY and northern TN, with the
global guidance generally more over eastern KY into WV. The Slight
risk was made big enough to support a compromise of these two camps,
and will need to continue to monitor trends going forward. Generally
think the highest risk is over KY, but can no rule out that shifting
into northern TN or portions of WV.

While the rainfall does look a bit more convective now over the
Northeast, 1" per hour probabilities are still low...with most
guidance peaking rainfall rates in the 0.5"-0.75" range. Given the
ongoing drought conditions it still seems unlikely that these rates
will be high enough to overcome the dry soil conditions. Thus even
with rainfall totals approaching 1.5" we will continue with no risk
area depicted.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

The convective threat looks a bit better than it did this time last
night with models trending a bit more robust with development.
Easterly low level post frontal flow will help locally enhance
convergence and upslope and scattered convection is likely to
develop. Instability is forecast to be modest, but may get towards
1000 j/kg, which would be enough for heavy rainfall rates given the
anomalous PWs in place. The high res guidance is starting to show a
threat of 1"+ per hour rainfall, which would be enough for isolated
flash flooding.

Chenard


Day 3
Valid 12Z Wed Oct 08 2025 - 12Z Thu Oct 09 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
NEW MEXICO...

...2030z update...

The marginal risk over New Mexico was expanded a little bit based=20
on qpf trends. The environmental setup remains very similar to the=20
day prior and the GEFS first guess fields continue to signal at
least a 5% chance of excessive rainfall, which supports the current
marginal risk area.

Kebede

...Previous Discussion...

Looking at a continuation of the localized heavy rainfall threat over
NM into Wednesday. The moisture plume and instability axis will
expand westward which should expand the isolated flash flood risk in
that direction as well. The environmental ingredients look pretty
similar to Tuesday, as do model QPF forecasts. So would generally
expect similar convective coverage and intensity with isolated flash
flooding again a concern.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8flRF7lFc_bTPYLISV3924Ux6lNK3oHqfsAaMW7F4_mg= vfX6XkaEVZpZ7P6Zi69ArRmcJefH5OdTkx2QW21AQeymvj4$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8flRF7lFc_bTPYLISV3924Ux6lNK3oHqfsAaMW7F4_mg= vfX6XkaEVZpZ7P6Zi69ArRmcJefH5OdTkx2QW21AtCzJO_I$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8flRF7lFc_bTPYLISV3924Ux6lNK3oHqfsAaMW7F4_mg= vfX6XkaEVZpZ7P6Zi69ArRmcJefH5OdTkx2QW21AD39cycc$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

FOUS30 KWBC 070054
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
854 PM EDT Mon Oct 6 2025

Day 1
Valid 01Z Tue Oct 07 2025 - 12Z Tue Oct 07 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE MID-SOUTH AND LOWER OHIO VALLEY...

...01Z Update...

For the Gulf Coast up through the Mid-South into the Ohio Valley,=20
made mostly minor adjustments based on observation trends, recent=20
runs of the HRRR, the 18Z HREF, and the 12Z RRFS.

Across eastern Florida, with showers and storms waning and with no
notable signal in the hi-res guidance for significant=20
redevelopment overnight, the Marginal Risk was dropped.

Pereira

...16z update...

Minor changes were made to the Day 1 ERO for the Mid-South/Lower
Ohio Valley and the Central Gulf Coast. The slight risk area was
expanded a little bit farther into southern Indiana/Illinois based
on hires trends and 12z HREF neighborhood exceedance probabilities
of 5 inches between 10-20%. A separate band of convection may
develop and lift north through those areas this afternoon/evening.
By contrast, the deterministic GFS and Euro keep the highest QPf
out of southern IN/IL.

The marginal risk area over eastern Florida remains unchanged due
to no significant changes in the guidance.

Kebede

...Previous Discussion...

...Mid-South/Lower Ohio Valley and the Central Gulf Coast...

An elongated low to mid-level vort center near the central Gulf
Coast will lift northward into the Mid-South today and gradually
stretch northeastward into portions of the Lower OH Valley by later tonight through early Tuesday morning. Increasingly convergent flow around
the eastern flank of the vort energy and an associated weak surface
low/trough axis coupled with enhancing moisture transport aided by
a 30 to 40 kt low-level jet will support broken bands of heavy
showers and thunderstorms. Modest instability with MLCAPE values of
500 to 1000 J/kg will be in place with the aid of diurnal heating,
but the vertical column will be quite moist with CIRA-ALPW data
showing the aforementioned vort energy embedded within a rather
deep tropical environment characterized by PWs of 2 to 2.25 inches.

Relatively warm-topped convection with high WBZ levels will support
very efficient rainfall processes for high rainfall rates as this
energy lifts north over the next 12 to 24 hours. The latest 00Z
HREF guidance supports broken convection with rainfall rates as
high as 1.5 to 2.5 inches/hour, and some concerns for some cell-
training that may foster some localized totals of 3 to 5 inches.
The more concentrated areas of convection are most likely to focus
across areas of eastern AR/western TN northeastward up into western
KY and southern IN going through Monday night and Tuesday morning
where the axis of stronger low-level convergence in conjunction
with some modest upper-level jet forcing/divergence is forecast to
become aligned. A Slight Risk of excessive rainfall will be
maintained for this period, with some southward expansion of it
depicted down across eastern AR compared to continuity given the
latest multi-model hires consensus. The setup will be conducive
for there being isolated to scattered areas of flash flooding which
will include urbanized flooding concerns.

Meanwhile, very moist and convergent low-level southerly flow off
the Gulf coupled with a moderately unstable boundary layer will
favor a threat for additional small-scale bands of convection to
impact parts of eastern LA along with coastal areas of southern
MS, southwest AL and into the western FL Panhandle. PWs running
close to or above 2 inches coupled with the instability will yield
high rainfall rates, with some localized additional rainfall totals
for this period of 2 to 4+ inches possible. This is supported by
the 00Z HREF guidance, and the setup will support isolated concerns
for runoff problems/flash flooding. As a result, a Marginal Risk
of excessive rainfall has been expanding to encompass these areas.


Orrison


Day 2
Valid 12Z Tue Oct 07 2025 - 12Z Wed Oct 08 2025

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE OHIO VALLEY...

...2030z update...

Minor edits were made to New Mexico and Ohio Valley/Central
Appalachian risk areas on day 2. The slight and marginal risk
areas were expanded south and west into northern Tennessee and
southwestern Kentucky, where convection is forecast to continue
into Tuesday morning along a slow moving cold front. PWs are over
the 99th percentile across much of Kentucky and western Tennessee
through Tuesday afternoon.

Kebede

...Previous Discussion...

...Ohio Valley into the Central Appalachians...

A Slight risk was maintained from portions of northern TN into much
of KY, southern IN and OH, and western WV where isolated to
scattered flash flooding is likely. Increasing southerly flow ahead
of an approaching cold front will advect moisture northward while
also enhancing lower level convergence. Also of note is a sfc-850mb
low that is over AR today and was over the northern Gulf on Sunday.
This feature will get more elongated in nature by Tuesday, but
should still act to locally increase moisture transport and
convergence over KY and surrounding areas. PWs are forecast around
2", which is well over the 90th percentile for this time of year.
Instability is expected to only be modest, generally in the 500-1000
j/kg range, however the strong synoptic forcing provided by the
approaching front and good upper level divergence should compensate
for this and still allow for organized convection.

Both the 00z HREF and REFS show moderate to high probabilities of
hourly rainfall exceeding 1", but only low probabilities of
exceeding 2". The limited instability is likely responsible for
the lack of 2"+ per hour rainfall rates. However the deep saturated
layer and low topped convection supports highly efficient warm rain collision-coalascence processes, leading to the likelihood of at
least 1" per hour rainfall.

The main question for flash flood potential will be the duration of
these higher rates, as it seems unlikely that 1hr FFG will be
exceeded. While the front will be progressive, it does look like we
will have enough convective coverage to support some training, and
at least a few hours of heavy rainfall rates. Thus while 1hr FFG may
be difficult to overcome, it does look like there will be an
opportunity for some exceedance of the 3hr FFG...with both the 00z
HREF and REFS showing exceedance probabilities upwards of 25-50%.
The latest WPC QPF indicates event total rainfall of 2-4" over most
of the Slight risk area, which is supported by high HREF and REFS
neighborhood probabilities of exceeding 3". Also will note that
there are even moderate probabilities of locally exceeding 5" with
this event.

There is a bit of model spread on the most favored axis for heaviest
rainfall and flash flooding. Both the HREF and REFS supports a
slightly farther southwest axis across KY and northern TN, with the
global guidance generally more over eastern KY into WV. The Slight
risk was made big enough to support a compromise of these two camps,
and will need to continue to monitor trends going forward. Generally
think the highest risk is over KY, but can no rule out that shifting
into northern TN or portions of WV.

While the rainfall does look a bit more convective now over the
Northeast, 1" per hour probabilities are still low...with most
guidance peaking rainfall rates in the 0.5"-0.75" range. Given the
ongoing drought conditions it still seems unlikely that these rates
will be high enough to overcome the dry soil conditions. Thus even
with rainfall totals approaching 1.5" we will continue with no risk
area depicted.

...Southeast FL...

Expecting another day of scattered convection within the easterly low
level flow Tuesday. Compared to previous days the threat should
mostly be focused over southeast FL by this time, and a localized
urban flash flood risk is possible.

...NM...

The convective threat looks a bit better than it did this time last
night with models trending a bit more robust with development.
Easterly low level post frontal flow will help locally enhance
convergence and upslope and scattered convection is likely to
develop. Instability is forecast to be modest, but may get towards
1000 j/kg, which would be enough for heavy rainfall rates given the
anomalous PWs in place. The high res guidance is starting to show a
threat of 1"+ per hour rainfall, which would be enough for isolated
flash flooding.

Chenard


Day 3
Valid 12Z Wed Oct 08 2025 - 12Z Thu Oct 09 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
NEW MEXICO...

...2030z update...

The marginal risk over New Mexico was expanded a little bit based
on qpf trends. The environmental setup remains very similar to the
day prior and the GEFS first guess fields continue to signal at
least a 5% chance of excessive rainfall, which supports the current
marginal risk area.

Kebede

...Previous Discussion...

Looking at a continuation of the localized heavy rainfall threat over
NM into Wednesday. The moisture plume and instability axis will
expand westward which should expand the isolated flash flood risk in
that direction as well. The environmental ingredients look pretty
similar to Tuesday, as do model QPF forecasts. So would generally
expect similar convective coverage and intensity with isolated flash
flooding again a concern.

Chenard


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8aHc7BMTwGdDDlwgBd5LFHYCd_LJRCJWX50qMo6_5awM= Vqh_vXGtZ7RY1CDpbmRVgbWiNdMH7K4w-myDYECkvzZvNwE$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8aHc7BMTwGdDDlwgBd5LFHYCd_LJRCJWX50qMo6_5awM= Vqh_vXGtZ7RY1CDpbmRVgbWiNdMH7K4w-myDYECk9RkDTP4$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8aHc7BMTwGdDDlwgBd5LFHYCd_LJRCJWX50qMo6_5awM= Vqh_vXGtZ7RY1CDpbmRVgbWiNdMH7K4w-myDYECkh7fjthE$=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at [email protected] and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)