• DAY3SVR: Nws Storm Prediction Center Norman Ok

    From COD Weather Processor@1:2320/107 to [email protected] on Tue Apr 14 07:23:23 2026
    ACUS03 KWNS 140723
    SWODY3
    SPC AC 140722

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0222 AM CDT Tue Apr 14 2026

    Valid 161200Z - 171200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO
    VALLEY...

    ...SUMMARY...
    Isolated strong to severe thunderstorms are possible on Thursday
    across portions of the Ohio Valley.

    ...Lower Ohio Valley/Midwest vicinity...

    An upper shortwave trough will move from the MS Valley to the
    Appalachians on Thursday. Moderate southwesterly deep-layer flow
    will overspread the MO Bootheel toward Lake Erie ahead of this
    feature. At the surface, a corridor of upper 50s to low 60s F
    dewpoints will be in place ahead of a surface front. Some ongoing
    convection and cloudiness early in the day will limit stronger
    destabilization, but at least weak MLCAPE around 500-1000 J/kg is
    forecast. While low-level flow will be weak, around 30-40 kt
    west/southwesterly flow between 850-700 mb and 40+ kt effective
    shear magnitudes will aid in some storm organization. A mix of
    clusters and line segments will bring a risk of locally strong gusts
    where stronger heating results in steepened low-level lapse rates.

    ...Southern Plains vicinity...

    A conditionally favorable supercell environment will be in place
    across the southern Plains on Thursday ahead of a dryline. A weak
    shortwave impulse is forecast to move across the region early in the
    day, departing by early afternoon. Height rises/shortwave ridging is
    then forecast to build across the area. At this time, thunderstorm
    development is not forecast as weak capping in the absence of
    large-scale ascent should be maintained. However, trends will be
    monitored given the otherwise very favorable thermodynamic and
    kinematic environment. Otherwise, isolated elevated convection is
    possible late in the period in a warm advection regime across north
    TX into southern OK.

    ..Leitman.. 04/14/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Tue Apr 14 19:16:28 2026
    ACUS03 KWNS 141916
    SWODY3
    SPC AC 141915

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0215 PM CDT Tue Apr 14 2026

    Valid 161200Z - 171200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
    OHIO VALLEY REGION INTO PARTS OF NEW YORK...

    ...SUMMARY...
    Isolated strong to severe thunderstorms are possible on Thursday
    extending from southeast Missouri across the Ohio Valley and into
    parts of New York.

    ...Synopsis...
    A progressive pattern will persist on Thursday, with a leading
    shortwave trough moving quickly across OH valley into the Northeast.
    This wave will breakdown the ridge along the East Coast, and provide
    a focus for scattered strong storms. Low-level warm advection out of
    the west/southwest will help destabilize the region with storms most
    likely during the afternoon from the Lower Great Lake across much of
    upstate NY and northern PA. Instability will be sufficient to
    support a few fast-moving cells capable of marginal hail and locally
    damaging gusts.

    To the southeast, storm coverage is less certain, particularly from
    AR/MO into the lower OH Valley. Here, cool temperatures aloft will
    linger, aiding instability, though somewhat behind the upper trough
    affecting the northeastern states. Showers and storms are most
    likely in the morning in association with the main wave, but
    conditional severe probabilities will be higher during the afternoon
    when instability redevelops. Any storms that form will be capable of
    producing hail, from MO into AR, western TN/KY, IL and IN.

    ..Jewell.. 04/14/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Wed Apr 15 07:29:35 2026
    ACUS03 KWNS 150729
    SWODY3
    SPC AC 150728

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0228 AM CDT Wed Apr 15 2026

    Valid 171200Z - 181200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF NORTHERN OKLAHOMA AND EASTERN KANSAS...MISSOURI...IOWA...AND FAR
    NORTHWEST ILLINOIS...

    ...SUMMARY...
    Widespread severe thunderstorms are expected from parts of the
    southern Plains to the Middle and Upper Mississippi Valley vicinity
    on Friday and Friday night. All severe hazards will be possible.

    ...Southern Plains to MS Valley...

    A robust upper trough will eject eastward from the northern High
    Plains and central Rockies to the Upper Midwest and central Plains
    on Friday. As this occurs, strong deep-layer southwesterly flow will
    overspread portions of the central/southern Plains to the Mid/Upper
    MS Valley and Great Lakes. Flow at 850-700 mb around 40-60 kt will
    be common. At the surface, a cold front will extend from northern MN
    to a low over eastern NE Friday morning. Meanwhile, a dryline will
    extend southwest from the NE low into central KS, northwest OK and
    western TX. A warm front initially arcing across central IA into
    south-central IL will lift northward through the period ahead of the eastward-advancing surface low tracking across northern IA/southern
    MN into WI. A warm sector characterized by mid/upper 60s F dewpoints
    will be in place across the southern Plains to the Mid-MS Valley by
    midday, with a narrow plume of low 60s F dewpoints extending north
    into portions of eastern MN and WI. Steep midlevel lapse rates (7-8
    C/km) will overspread this moist boundary layer, resulting in
    moderate to strong destabilization.

    As strong ascent overspreads the aforementioned surface boundaries
    by mid afternoon, widespread thunderstorm development is expected.
    While initial supercells are possible given a favorable
    thermodynamic environment and supercell vertical wind profiles,
    linear forcing along the front combined with strong deep-layer
    southwesterly flow parallel to the initiating boundary may result in
    rapid upscale development into a QLCS, particularly from northeast
    KS/northwest MO into IA. A well-organized line of convection will
    pose a damaging wind risk along with possible QLCS tornadoes as
    convection develops eastward through the afternoon/evening. If any
    discrete supercells develop, an all-hazards risk will also accompany
    that activity.

    Further south across southern KS into OK, supercell development may
    be more probable, at least initially. Convection will initially
    develop along the dryline prior to the cold front overtaking this
    boundary later in the evening. Any supercells that develop and can
    maintain discrete characteristics will pose a risk for very large
    hail, strong tornadoes, and damaging winds. With time, the cold
    front will overtake the dryline during the evening and move
    southeast overnight. Linear convection is expected along the front,
    posing a damaging wind and isolated tornado risk during the
    nighttime hours.

    Capping, weakening large-scale ascent and more modest vertical shear
    with southern extent may limit storm potential along the dryline in western/west-central TX.

    ..Leitman.. 04/15/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Wed Apr 15 19:33:27 2026
    ACUS03 KWNS 151933
    SWODY3
    SPC AC 151932

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0232 PM CDT Wed Apr 15 2026

    Valid 171200Z - 181200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM OKLAHOMA NORTHEASTWARD INTO IOWA AND ILLINOIS...

    ...SUMMARY...
    Widespread severe thunderstorms are expected from parts of the
    southern Plains to the Middle and Upper Mississippi Valley vicinity
    Friday into Friday night. A few tornadoes, possibly strong, very
    large hail, and damaging winds will be possible.

    ...Synopsis...
    An upper trough will move out of the Rockies and into the Plains on
    Friday, with primary midlevel speed max intensifying from the
    central Plains into the upper MS Valley. A southern stream system
    will also intensify the upper-wind pattern from northern Mexico into
    the southern Plains.

    At the surface, a cold front is forecast to extend from MN into KS
    Friday morning, progressing roughly to a WI to central MO to
    northern OK line by 00Z. Meanwhile, a warm front will push north
    into WI, extending southeastward near Chicago.

    Of particular note for this setup are model trends, which have
    consistently shown the cold front pushing farther east and south
    than the previous model runs. This results in a lower confidence
    forecast in terms of the precise area of greatest threat and degree
    of tornado potential.

    Despite these uncertainties, the environment ahead of the cold front
    will be quite favorable for supercells, with steep midlevel lapse
    rates, ample shear, and strong instability. These factors will
    clearly favor very large damaging hail, a risk of tornadoes, and
    eventually damaging winds. A broad 40-50 kt low-level jet will
    contribute to favorable low-level shear for tornadoes, and a couple
    strong tornadoes will be possible prior to the cold front and
    aggregate outflows undercutting the initial activity. Favored areas
    for tornadoes will be southern KS into western/northern OK in
    proximity to the dryline, and farther north into eastern IA and
    southern WI where SRH will be stronger near the low.

    Even if the cold front surges faster than currently indicated, a
    widespread damaging wind threat could occur. Trends will continue to
    be monitored as the event nears.

    ..Jewell.. 04/15/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Thu Apr 16 07:07:06 2026
    ACUS03 KWNS 160707
    SWODY3
    SPC AC 160705

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0205 AM CDT Thu Apr 16 2026

    Valid 181200Z - 191200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    THE OHIO VALLEY...

    ...SUMMARY...
    Isolated strong to severe thunderstorms capable of damaging winds
    and hail will be possible on Saturday across part of the Ohio
    Valley.

    ...Ohio Valley...

    A large-scale upper trough oriented over the Upper Midwest and
    Plains will shift east over the Great Lakes, Midwest and TN Valley
    on Saturday/Saturday night. Strong deep-layer southwesterly flow
    will overspread the Ohio Valley ahead of an eastward-advancing cold
    front. This front should be located from Lower MI into southeast MO
    Saturday morning, moving across the Ohio Valley through early
    evening. Modest boundary-layer moisture will be in place ahead of
    the front. Daytime heating into the 70s and modestly steep midlevel
    lapse rates will support weak destabilization (generally less than
    1000 J/kg MLCAPE). While instability will be modest, strong low and
    midlevel flow will support organized cells and/or line segments
    capable of strong gusts. Any discrete cellular activity also may
    produce marginally severe hail. These severe risk should gradually
    wane during the evening with eastward extent.

    ...TX to the Lower MS Valley...

    Thunderstorms are expected along a southeast-advancing cold front
    Saturday afternoon and evening. Deep-layer flow will be oriented
    parallel to the front, and convection may largely be anafrontal or
    quickly undercut by the front. While weak MUCAPE is noted in
    forecast soundings, severe potential is not expected at this time.

    ..Leitman.. 04/16/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Thu Apr 16 19:27:41 2026
    ACUS03 KWNS 161927
    SWODY3
    SPC AC 161926

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0226 PM CDT Thu Apr 16 2026

    Valid 181200Z - 191200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
    UPPER OHIO VALLEY...

    ...SUMMARY...
    Scattered strong to severe thunderstorms capable of damaging winds
    and hail will be possible on Saturday from the upper Ohio Valley.

    ...Synopsis...
    An upper trough will move toward the upper Great Lakes and OH Valley
    on Saturday, with a cold front moving quickly east and extending
    from western NY/PA into KY/TN by 00Z. A narrow plume of upper 50s F
    to near 60 F dewpoints will exist and contribute to up to 1000 J/kg
    MUCAPE.

    Storms will likely be ongoing early in the day along the front as it
    moves out of IN and into western OH/KY, and 40-50 kt southwest winds
    at 850 mb may support damaging gusts potential. Heating ahead of the
    front from OH/PA southward into WV/KY/TN may support new
    development, although lapse rates aloft over southern areas will be
    poor. Still, favorable deep-layer mean wind speeds and sufficient
    shear may support isolated severe gusts or marginal hail, especially
    into OH/western PA. Further, low-level shear will be strongest over
    northern areas, with some supercell potential.

    ..Jewell.. 04/16/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Fri Apr 17 06:55:16 2026
    ACUS03 KWNS 170655
    SWODY3
    SPC AC 170653

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0153 AM CDT Fri Apr 17 2026

    Valid 191200Z - 201200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Severe thunderstorms are not expected on Sunday.

    ...Synopsis...
    A strong mid-level trough will move from the Great Lakes to
    southeast Canada during the day on Sunday. A cold front is forecast
    to initially exist from southeast Virginia to the Florida Panhandle.
    The cold front will move into the Atlantic and Gulf as surface high
    pressure builds in its wake.

    Some lingering moisture and weak instability will likely be present
    ahead of the front Sunday morning. By late morning, heating may be
    sufficient for some storms along and ahead of the front. However,
    given the weak instability, no severe weather is expected. This
    front will continue southeast into the Atlantic/Gulf by late
    afternoon and bring an end to any storm threat across the CONUS
    (except for the Florida Peninsula).

    ..Bentley.. 04/17/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Fri Apr 17 19:26:48 2026
    ACUS03 KWNS 171926
    SWODY3
    SPC AC 171925

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0225 PM CDT Fri Apr 17 2026

    Valid 191200Z - 201200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Severe thunderstorms are not expected on Sunday.

    ...Discussion...
    An amplified large-scale trough will move eastward from the Great
    Lakes to the Northeast on Sunday, while a related cold front moves
    off the Eastern Seaboard. Despite poor deep-layer lapse rates, a
    narrow corridor of diurnal heating amid lower/middle 60s dewpoints
    (higher over the FL Peninsula) ahead of the front should support
    isolated thunderstorms from the coastal Carolinas southward across
    parts of the FL Peninsula. Weak/narrow buoyancy profiles will limit thunderstorm intensity and the severe risk.

    ..Weinman.. 04/17/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Sat Apr 18 07:09:54 2026
    ACUS03 KWNS 180709
    SWODY3
    SPC AC 180708

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0208 AM CDT Sat Apr 18 2026

    Valid 201200Z - 211200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Severe storms are not expected on Monday.

    ...Discussion...
    High pressure and a dry airmass will limit thunderstorm potential
    across most of the CONUS on Monday. The only exceptions will be
    across South Florida and parts of the Southwest into West Texas.
    Across South Florida, mid 60s dewpoints are forecast to persist on
    Monday which may allow for sufficient instability for scattered
    storm development. Weak instability should limit any severe weather
    threat with this activity.

    Additional isolated storms are possible across parts of the
    Southwest into portions of West Texas as moisture return may lead to
    some weak instability. No severe storms are expected from this
    activity.

    ..Bentley.. 04/18/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Sat Apr 18 19:16:28 2026
    ACUS03 KWNS 181916
    SWODY3
    SPC AC 181915

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0215 PM CDT Sat Apr 18 2026

    Valid 201200Z - 211200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Severe storms are not expected on Monday.

    ...Discussion...
    A midlevel trough will move from the Northeast off the New England
    coast on Monday, while the tail end of a related cold front
    continues southward into the Caribbean Sea. North of the front in
    southern FL, diurnal heating amid a moist post-frontal air mass
    should support isolated to widely scattered thunderstorms, though
    weak buoyancy and limited large-scale forcing for ascent should
    limit the severe risk.

    Farther west, weak low-level warm advection and modest moisture
    return ahead of a low-amplitude midlevel impulse moving into south
    TX will support a couple rounds of isolated/elevated thunderstorms
    across southwest TX. Isolated thunderstorm potential could spread
    further north into central TX late in the period, though confidence
    in this scenario is currently low. Additional diurnal thunderstorms
    are possible across the Southwest as the midlevel moisture impinges
    on the region, with most of this activity expected over the higher
    terrain.

    ..Weinman.. 04/18/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Sun Apr 19 07:28:33 2026
    ACUS03 KWNS 190728
    SWODY3
    SPC AC 190727

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0227 AM CDT Sun Apr 19 2026

    Valid 211200Z - 221200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Thunderstorms will be possible across the western CONUS, the
    south-central CONUS, and the southern Great Lakes. No severe weather
    is anticipated.

    ... Synopsis ...

    A large-scale midlevel trough will move push inland across the
    western CONUS into the Great Basin on Wednesday, with downstream
    ridging building across the central CONUS in response. Across the
    Northeast, northwest flow aloft will prevail downstream of the
    central CONUS ridge. An embedded jet streak and associated vorticity
    maximum within the northwest flow will aid driving a weak surface
    low and attendant frontal boundary southeast across the Great Lakes
    through the forecast period. Meanwhile, the surface ridge across the
    Southeast will move east, just offshore of the Southeast Atlantic
    Coast, promoting return flow across the Plains. The return flow will
    be aided by the development of lee troughing across much of the High
    Plains.

    ... Western US ...

    Scattered showers are expected across portions of the West in
    association with the inland-moving large-scale trough. Seasonably
    cool midlevel temperatures will support enough instability for a few thunderstorms, although severe potential is very low.

    ... South-central US ...

    Showers and thunderstorms will be possible across the region within
    the return flow regime. Here, weak warm-air advection combined with
    between 500-1000 J/kg of MUCAPE will support convective development.
    Weak vertical shear and the lack of strong forcing for ascent should
    limit any severe potential.

    ... Southern Great Lakes ...

    Scattered showers a few thunderstorms will be possible within the
    surface frontal zone as it pushes south/southeast during the day.
    Instability around 500 J/kg MUCAPE and weak effective layer shear
    should preclude a more robust severe weather event, but a strong
    wind gust or two may be possible.

    ..Marsh.. 04/19/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Sun Apr 19 19:37:35 2026
    ACUS03 KWNS 191937
    SWODY3
    SPC AC 191936

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0236 PM CDT Sun Apr 19 2026

    Valid 211200Z - 221200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Thunderstorms will be possible across the western CONUS, the
    south-central CONUS, and the southern Great Lakes on Tuesday.
    Potential for severe weather appears low.

    ...Synopsis...
    Upper ridging will be the primary feature across much of the CONUS
    from the eastern Great Basin into Plains on Tuesday. Moderate
    northwesterly flow aloft will remain across the Upper Midwest and
    portions of the Ohio Valley in the wake of a stronger upper trough.
    Along the West Coast, an upper trough is expected to slowly move
    ashore in central California into the western Great Basin. At the
    surface, continued presence of high pressure in the Southeast and
    off the Atlantic coast will drive moisture return into a
    stalled/remnant cold front in central Plains and Lower Great Lakes
    vicinity.

    ...Lower Great Lakes...
    Modest moisture return ahead of the boundary is expected to promote
    isolated to widely scattered thunderstorms. This may not occur until
    early/mid evening, however. Temperatures will be quite cold aloft
    (perhaps near -20 C at 500 mb), but moisture could be quite limited (potentially in the 40s F). The NAM is again the most aggressive
    with moisture return as compared to other guidance. Should
    sufficient moisture return occur, shear will be sufficient for
    marginally organized convection capable of strong gusts and hail.
    Uncertainty is high given how dry the airmass is preceding this
    moisture return and convection near the Gulf Coast on preceding days
    will potentially slow northward progress.

    ...Central Valley California...
    Ahead of the upper low, southeasterly winds may develop within the
    Valley. While destabilization will not be overly strong, pockets of
    heating could lead to modest MLCAPE values by the afternoon. Shear
    will be a limiting factor for overall severe potential, but a
    stronger storm or two is possible.

    ...Central Texas...
    Convection will be ongoing early Tuesday morning. Modest deep-layer
    shear and elevated buoyancy could promote a couple stronger storms
    capable of small hail. However, storms should generally become less
    organized with time as upper-level ridging builds in through the
    day.

    ..Wendt.. 04/19/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Mon Apr 20 07:28:38 2026
    ACUS03 KWNS 200728
    SWODY3
    SPC AC 200727

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0227 AM CDT Mon Apr 20 2026

    Valid 221200Z - 231200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF THE HIGH PLAINS OF NEBRASKA SOUTH INTO THE TEXAS PANHANDLE...

    ...SUMMARY...
    Severe thunderstorms capable of hail and gusty winds may develop
    during the late afternoon and evening across portions of the High
    Plains. Elsewhere, thunderstorms will be possible across the
    northern Gulf Coast and portions of the Ohio Valley.

    ... Synopsis ...

    A shortwave trough will eject northeast out of the basal region of
    the western CONUS trough and into the northern Plains on Wednesday.
    As this happens, strengthening southerly/southwesterly midlevel flow
    will overspread much of the High Plains. A surface cyclone over
    eastern Montana will gradually deepen as it slowly moves east.

    ... Central High Plains south into the southern High Plains ...

    As the Montana surface cyclone gradually deepens on Wednesday, Gulf
    moisture will be drawn northward into the central and northern
    Plains. As the upper trough approaches the region during the late afternoon/evening, modest height falls are expected to overspread a
    sharpening dryline across far eastern Colorado or western Nebraska
    south into the Texas Panhandle. Kinematic profiles up and down the
    dryline show ample vertical shear for supercells capable of
    producing hail and gusty winds. However, considerable uncertainty
    remains regarding thunderstorm coverage owing to the significant
    differences in the depth and quality of the boundary layer moisture
    return noted in the 20260420/00Z guidance suite. For example, the
    NAM is nearly 5F more moist along the dryline across portions of
    Nebraska than global models.

    That said, pattern recognition and 00Z RRFS suggest that at least a
    couple of storms should develop along the dryline from Nebraska
    south into the eastern Texas Panhandle. Deep-layer flow will largely
    parallel the dryline during the afternoon which should preclude much
    eastward advancement. A 5% unconditional risk area has been added to
    account for this potential.

    ... Elsewhere Across the CONUS ...

    Thunderstorms may be ongoing at the start of the forecast period and
    persist into the early afternoon across portions of the northern
    Gulf Coast. The thunderstorm potential should wane with time as
    increasing midlevel heights suppress large-scale ascent.

    Additionally, modest low-level moisture and weak instability may
    support a few lightning strikes within a weak surface boundary
    across the Ohio Valley.

    ..Marsh.. 04/20/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Mon Apr 20 19:31:42 2026
    ACUS03 KWNS 201931
    SWODY3
    SPC AC 201930

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 PM CDT Mon Apr 20 2026

    Valid 221200Z - 231200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
    HIGH PLAINS...

    ...SUMMARY...
    Severe thunderstorms capable of hail and gusty winds may develop
    during the late afternoon and evening across portions of the High
    Plains.

    ...Synopsis...
    A broad trough will begin to move into the Rockies and adjacent High
    Plains. A shortwave trough will eject into the northern Plains in
    association with the broader trough. At the surface, a deep surface
    low will develop in eastern Montana with a lee trough/dryline
    extending into the southern High Plains.

    ...High Plains...
    As the upper-trough approaches the Rockies, the lee trough and
    dryline are expected to sharpen. Forcing for ascent will be
    strongest in the Nebraska Panhandle/western South Dakota vicinity.
    This area is also has the largest variability in terms of moisture
    return (the NAM being much more bullish than the ECMWF). Farther
    south, moisture will generally be greater. Guidance is in agreement
    that 60s F dewpoints are probable in the Texas South Plains and
    perhaps parts of the Panhandle. The issue farther south will be the
    lack of synoptic ascent. Temperatures behind the dryline will be in
    the upper 80s F to perhaps low 90s F. The depth of the circulation
    may be enough to initiate an isolated storm or two, but confidence
    is still not overly high. Environmentally, deep-layer shear will be
    oriented roughly perpendicular to the dryline, especially from
    western Kansas southward. Supercells would be favored if storms
    develop. MLCAPE of 1000 J/kg in South Dakota to 1500-2500 J/kg
    farther south is expected by the afternoon. Large hail and severe
    wind gusts would be possible.

    ...Central/Easter Montana...
    With the surface low deepening through the day, at least modest
    moisture return northwestward is anticipated into central/eastern
    Montana. However, moisture will still be quite scant across the
    region. Dewpoints may not reach the 40s F. Given the forcing for
    ascent, high-based convection is possible. The very dry sub-cloud
    layers could lead to gusty outflow winds. At present, confidence in
    severe gusts is too low to warrant wind probabilities.

    ..Wendt.. 04/20/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Tue Apr 21 07:31:45 2026
    ACUS03 KWNS 210731
    SWODY3
    SPC AC 210730

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 AM CDT Tue Apr 21 2026

    Valid 231200Z - 241200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    SOUTHERN MINNESOTA SOUTHWARD INTO NORTHERN OKLAHOMA...

    ...SUMMARY...
    Severe thunderstorms will be possible from northern Oklahoma into
    southern Minnesota on Thursday. Large hail to very large hail,
    damaging winds, and a few tornadoes are possible.

    ... Synopsis ...

    A complex convective setup is expected on Thursday as a broad,
    long-wave trough remains anchored across the Western US. While the initial/primary shortwave will be lifting northward into Canada, a
    secondary, lower amplitude wave is progged to approach the Southern
    Plains overnight Thursday into Friday.

    At the surface, a Pacific cold front and dryline will push eastward
    into the Central Plains. A secondary surface low is forecast to
    develop near the triple point in northwest Oklahoma/southwest
    Kansas. This feature will serve as the southern extent of the more
    organized severe threat, with a conditional threat southward along
    the dryline.

    ... Central Plains ...

    Thunderstorms are expected to develop an advancing cold
    front/dryline across portions eastern Nebraska into western Iowa,
    before expanding both north and south from here. MUCAPE values
    between 1500-2500 J/kg and deep-layer shear on the order of 30-40
    knots will support supercellular structures initially. However,
    unidirectional profiles will support splitting supercells and favor
    an upscale growth into one or more linear segments. While a few
    tornadoes may be possible early in the convective evolution, large
    hail and damaging winds may become the dominant threat with time.

    ... Southern Plains ...

    Convective initiation along the dryline south of the triple point
    remains uncertain due to stronger capping. However, any discrete
    cells that manage to initiate will do so in an environment
    characterized by MUCAPE values between 2000-3000 J/kg with 30-40
    knots of vertical shear. This will be more than sufficient to
    support supercells capable of very large hail.

    A secondary wave should approach the region overnight Thursday into
    Friday morning. Forecast soundings indicate a steepening of midlevel
    lapse rates associated with this feature and a subsequent increase
    in CAPE values. Depending on the evolution of thunderstorms during
    the afternoon and evening, additional thunderstorms may develop
    overnight. The severe potential of these storms is uncertain given
    the overnight timing of the wave and increasing convective
    inhibition. However, strong vertical shear would seem to support an
    ongoing hail and wind threat.

    ... Northern Plains/Upper Mississippi Valley ...

    As the cold front pushes into the more modest moisture and buoyancy
    profiles across northern Minnesota, the severe threat should be
    lesser than areas to the south. Still, proximity to the upper wave
    should support at least some threat for wind with any thunderstorms
    that develop.

    ..Marsh.. 04/21/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Tue Apr 21 07:39:45 2026
    ACUS03 KWNS 210739
    SWODY3
    SPC AC 210738

    Day 3 Convective Outlook CORR 1
    NWS Storm Prediction Center Norman OK
    0238 AM CDT Tue Apr 21 2026

    Valid 231200Z - 241200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    SOUTHERN MINNESOTA SOUTHWARD INTO NORTHERN OKLAHOMA...

    CORRECTED FOR TEXTUAL CLARITY

    ...SUMMARY...
    Severe thunderstorms will be possible from northern Oklahoma into
    southern Minnesota on Thursday. Large hail to very large hail,
    damaging winds, and a few tornadoes are possible.

    ... Synopsis ...

    A complex convective setup is expected on Thursday as a broad,
    long-wave trough remains anchored across the Western US. While the initial/primary shortwave will be lifting northward into Canada, a
    secondary, lower amplitude wave is progged to approach the Southern
    Plains overnight Thursday into Friday.

    At the surface, a Pacific cold front and dryline will push eastward
    into the Central Plains. A secondary surface low is forecast to
    develop near the triple point in northwest Oklahoma/southwest
    Kansas. This feature will serve as the southern extent of the more
    organized severe threat, with a conditional threat southward along
    the dryline.

    ... Central Plains ...

    Thunderstorms are expected to develop along an advancing cold
    front/dryline across portions eastern Nebraska into western Iowa,
    before expanding both north and south. MUCAPE values between
    1500-2500 J/kg and deep-layer shear on the order of 30-40 knots will
    support supercellular structures initially, but unidirectional
    profiles may favor splitting supercells, storm interference, and a
    tendency for upscale growth into one or more linear segments. While
    a few tornadoes may be possible early in the convective evolution,
    large hail and damaging winds should become the dominant threat with
    time.

    ... Southern Plains ...

    Convective initiation along the dryline south of the triple point
    remains uncertain due to stronger capping. However, any discrete
    cells that manage to initiate will do so in an environment
    characterized by MUCAPE values between 2000-3000 J/kg with 30-40
    knots of vertical shear. This will be more than sufficient to
    support supercells capable of very large hail.

    A secondary wave should approach the region overnight Thursday into
    Friday morning. Forecast soundings indicate a steepening of midlevel
    lapse rates associated with this feature and a subsequent increase
    in CAPE values. Depending on the evolution of thunderstorms during
    the afternoon and evening, additional thunderstorms may develop
    overnight. The severe potential of these storms is uncertain given
    the overnight timing of the wave and increasing convective
    inhibition. However, strong vertical shear would seem to support a
    hail and wind threat.

    ... Northern Plains/Upper Mississippi Valley ...

    As the cold front pushes into the more modest moisture and buoyancy
    profiles across northern Minnesota, the severe threat should be
    lesser than areas to the south. Still, proximity to the upper wave
    should support at least some threat for wind with any thunderstorms
    that develop.

    ..Marsh.. 04/21/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Tue Apr 21 19:38:18 2026
    ACUS03 KWNS 211938
    SWODY3
    SPC AC 211937

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0237 PM CDT Tue Apr 21 2026

    Valid 231200Z - 241200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
    MID-MISSOURI VALLEY VICINITY INTO SOUTHERN KANSAS AND NORTHERN
    OKLAHOMA...

    ...SUMMARY...
    Severe thunderstorms will be possible from northern Oklahoma into
    southern Minnesota on Thursday. Large hail to very large hail,
    damaging winds, and a few tornadoes are possible.

    ...Synopsis...
    Two shortwave troughs within a larger-scale trough over much of the
    Rockies will pivot northeast on Thursday. The initial shortwave will
    impact parts of the central Plains and mid-Missouri Valley. A
    second, compact shortwave will pivot into parts of Oklahoma and
    Kansas. At the surface, moisture return will continue ahead of a
    Pacific cold front in the central Plains. A weak surface low is
    expected to develop along the Oklahoma/Kansas border and track
    eastward. Attendant to this low, a dryline will drape southward into
    the Permian Basin.

    ...Central and southern Kansas...Oklahoma...
    With mid-level ascent arriving mid/late afternoon, storms are likely
    to initiate along the cold front as well as near the triple point
    associated with the weak surface low along the KS/OK border.
    Supercells are most likely near the triple point and could persist
    so long as storm interactions remain minimal. 40-45 kts of shear and
    2000-3000 J/kg MLCAPE will promote storms capable of all hazards,
    including tornadoes and very-large hail. A strong low-level jet will
    develop ahead of this activity during the evening. The tornado
    threat could increase for storms that can remain discrete.

    In Oklahoma, if and how many storms develop remains uncertain along
    the dryline. Northern portions of Oklahoma are more likely to have
    severe storms given the proximity to the surface low. A similar
    environment will exist east of the dryline as does farther north
    into southern Kansas. There is a conditional threat for all severe
    hazards.

    ...Mid-Missouri Valley...
    Storms are expected to develop along the cold front potentially as
    early as mid afternoon. However, capping appears strong enough in
    forecast soundings that initiation could delay until late afternoon.
    Steep mid-level lapse rates will be in place along and ahead of the
    front. Deep-layer shear will be 30-40 kts, but generally parallel to
    the front. Initial storms could be supercellular and produce large
    to very-large hail early in the convective cycle. Upscale growth
    appears likely to occur rather quickly. Damaging/severe winds would
    become the primary risk at that point. Tornadoes are also possible
    given the low-level shear, both with initial supercells and perhaps
    with QLCS circulations.

    ..Wendt.. 04/21/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Wed Apr 22 07:22:54 2026
    ACUS03 KWNS 220722
    SWODY3
    SPC AC 220721

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0221 AM CDT Wed Apr 22 2026

    Valid 241200Z - 251200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

    ...SUMMARY...
    A few severe thunderstorms will be possible across portions of the
    Southern Plains into the Lower Mississippi Valley on Saturday. Large
    hail and damaging wind gusts should be the primary threats.

    ... Synopsis ...

    A persistent longwave trough will remain situated across the
    northern US on Friday, maintaining a broad regime of cyclonic
    midlevel flow over the western two-thirds of the country. Within
    this broad flow, neutral to modest midlevel height rises are likely
    across the Southern Plains. This evolution suggests a lack of robust large-scale forcing for ascent, with subtle subsidence potentially
    acting as a limiting factor for widespread convective coverage.

    ... Southern Plains into the Lower Mississippi Valley ...


    At the start of the forecast period, convective activity may be
    ongoing across portions of northeast Oklahoma, southeast Kansas,
    southern Missouri, or northern Arkansas along a consolidated outflow boundary/cold front. These storms should slowly weaken during the
    morning with the loss of large-scale ascent and a weakening
    low-level jet. The outflow boundary/cold front should slowly sag
    south through the morning before stalling somewhere in the vicinity
    of the I40 corridor. This feature will serve as the primary focus
    for subsequent development later in the afternoon, with residual
    outflow or differential heating boundaries being a secondary source
    of initiation.

    South of the frontal boundary, a highly unstable airmass will remain
    in place across the warm sector. Strong diabatic heating of a moist
    boundary layer will yield pockets of moderate-to-strong instability,
    with MUCAPE values potentially in the 2000-3000 J/kg range. While
    deep-layer shear is forecast to remain relatively modest (30-35
    knots), the degree of instability will be sufficient to support
    robust updrafts.

    Given the modest shear and lack of stronger synoptic support, storm
    modes will likely be multicell clusters or transient supercells. Any
    persistent cell will be capable of producing large hail and
    localized damaging wind gusts

    ... Lower Mississippi Valley ...

    Convection that develops across Oklahoma and Arkansas during the
    afternoon is expected to persist into the evening as it moves slowly east-southeast toward Mississippi and Tennessee. Although
    instability is not as great with eastward extent, it should remain
    sufficient enough to support some potential for sporadic wind and
    hail through the overnight hours.

    ..Marsh.. 04/22/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Wed Apr 22 19:31:59 2026
    ACUS03 KWNS 221931
    SWODY3
    SPC AC 221930

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 PM CDT Wed Apr 22 2026

    Valid 241200Z - 251200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
    SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY...

    ...SUMMARY...
    A few severe thunderstorms will be possible across portions of the
    Southern Plains into the Lower Mississippi Valley on Friday. Large
    hail and damaging wind gusts should be the primary threats.

    ...Southern Plains into the Lower MS Valley...
    Storms may be ongoing at the start of the period Friday morning from
    parts of OK into AR/MO, and possibly into the lower OH Valley. While
    a general weakening trend is expected during the morning, the
    strongest early-day storms could pose a threat of isolated hail and
    localized strong/damaging gusts.

    The primary severe threat is expected to develop from the afternoon
    into the evening, along the primary outflow/cold front and any other
    residual boundaries left over from the morning convection. The
    strongest heating/destabilization is expected from parts of TX into
    southeast OK, where MLCAPE of 2000-3000 may develop, with moderate
    instability expected as far east as the lower MS/OH Valleys.

    At this time, the greatest diurnal storm coverage is expected from
    eastern OK/northeast TX into AR, where a weak midlevel shortwave
    trough and potential MCV may overlap moderate to strong buoyancy.
    Effective shear will be relatively modest (generally 30-35 kt), but
    sufficient to support some storm organization. Initial diurnal
    development in this region could pose a threat for hail and locally
    damaging wind. Low-level flow/shear will generally remain weak, but storm/boundary interactions could also support a low tornado threat.
    With time, consolidating outflows could support modest upscale
    growth and a potential increase in damaging-wind potential into the
    early evening as storms spread east-southeastward.

    Storm coverage may remain quite isolated across western portions of
    the Level 2/Slight Risk area, due to weak large-scale ascent, but
    isolated development will be possible as CINH weakens. The strongly
    unstable and sufficiently sheared environment will conditionally
    favor a severe threat across parts of southern OK and north TX, if
    storms can be sustained.

    ..Dean.. 04/22/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Thu Apr 23 07:28:32 2026
    ACUS03 KWNS 230728
    SWODY3
    SPC AC 230727

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0227 AM CDT Thu Apr 23 2026

    Valid 251200Z - 261200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF SOUTH-CENTRAL KANSAS INTO CENTRAL AND EASTERN OKLAHOMA AND FAR
    NORTHWEST ARKANSAS...

    ...SUMMARY...
    Severe thunderstorms will likely develop across portions of Oklahoma
    and Kansas during the evening. These storms will pose a risk of very
    large hail, damaging winds, and a couple of tornadoes. Isolated
    severe thunderstorms may also develop across portions of North Texas
    during the afternoon.

    ... Synopsis ...

    Increasingly diffluent southwest flow will overspread the Southern
    and Central Plains on Saturday as the midlevel pattern responds to a
    strong shortwave trough/vorticity maximum moving into the Southwest.
    This will induce strong southerly winds across the Plains, helping
    to quickly draw an old frontal boundary northward. This boundary
    should be oriented from northwest to southeast across portions of
    Oklahoma by late Saturday.

    ... Portions of Kansas, Oklahoma, and western Arkansas ...

    Most of the day should be devoid of thunderstorms as mid-level
    heights rise downstream of a digging trough across the Southwest. At
    the same time, strong southerly winds will transport Gulf moisture
    northward from the far Southern Plains into the Central Plains.
    Diurnal heating of this airmass will result in the development of
    strong instability across much of the area, as maximum SBCAPE values
    approach 4000 J/kg across portions of north Texas into central
    Oklahoma.

    During the late evening a subtle perturbation within the southwest
    flow is forecast to approach Oklahoma. In response to this, the
    low-level jet is forecast to increase to between 30 and 40 knots. As
    it crosses the northward moving warm front, this warm-air
    advection/isentropic ascent will combine with modest large-scale
    ascent from the approaching midlevel perturbation to support
    scattered thunderstorm develop on the north side of the moisture
    gradient. Although differences exist between the various models, the
    generic depiction of forecast soundings show long hodographs with
    varying degrees of low-level curvature in the presence of 2000-3000
    J/kg of MUCAPE. Thus, any storm that develops within the environment
    will be capable of producing all hazards initially. With time,
    thunderstorms should grow upscale into one or more southeast moving
    bowing segments capable of producing damaging winds with perhaps a
    QLCS tornado threat.

    ... North Texas into Southern Oklahoma ...

    Diurnal heating of a moist airmass to the east of a dryline will
    result in an extremely unstable airmass developing by the afternoon.
    Although the region will be devoid of large-scale forcing for
    ascent, temperatures in the 90Fs to the west of the dryline may be
    sufficient to induce dryline circulations capable of initiating
    isolated thunderstorms. Any thunderstorm that develops will be
    capable of producing very large hail.

    ..Marsh.. 04/23/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Thu Apr 23 19:31:37 2026
    ACUS03 KWNS 231931
    SWODY3
    SPC AC 231930

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 PM CDT Thu Apr 23 2026

    Valid 251200Z - 261200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
    SOUTH-CENTRAL KANSAS INTO CENTRAL/EASTERN OKLAHOMA AND FAR NORTHWEST ARKANSAS...

    ...SUMMARY...
    Severe thunderstorms will likely develop across portions of Oklahoma
    and Kansas during the late afternoon and evening. These storms will
    pose a risk of very large hail, damaging winds, and a couple of
    tornadoes. Isolated severe thunderstorms may also develop across
    portions of Texas.

    ...Synopsis...
    Increasingly diffluent southwest flow will overspread parts of the
    southern and central Plains on Saturday, as the midlevel pattern
    responds to a strong shortwave trough/vorticity maximum moving into
    the Southwest. This will induce strong southerly winds across the
    Plains, helping to draw an outflow-influenced frontal boundary
    northward. This boundary is currently forecast to be oriented from
    northwest to southeast across portions of Oklahoma by late Saturday.

    ...Parts of KS/OK/TX into the ArkLaTex and Lower MS Valley...
    No changes have been made to the Enhanced Risk. Rich moisture, steep
    midlevel lapse rates, and diurnal heating will result in strong
    destabilization across parts of the southern Plains, with at least
    moderate destabilization into parts of KS. Large-scale ascent will
    be subtle at best during the day, but isolated storm development
    will be possible by late afternoon in the vicinity of the diffuse
    warm front extending from eastern OK into southern KS and vicinity.
    Favorable deep-layer shear combined with the moderate to strong
    buoyancy will favor initial supercell development, with a threat of
    very large hail and potentially a couple tornadoes (especially near
    the remnant boundary).

    Some upscale growth will be possible into the evening, with
    potential for an organized cluster or MCS to move southeastward
    along the instability gradient towards parts of the ArkLaTex, and
    potentially the lower MS Valley, before weakening. This evolution
    could be accompanied by an increasing damaging-wind threat, along
    with isolated hail and/or tornado potential with any embedded
    supercells.

    Farther south, a conditionally favorable environment will be in
    place during the afternoon along/east of the effective dryline, from
    southwest OK into TX. Despite the lack of notable large-scale
    ascent, isolated storms may develop due to weakening CINH and
    heating to convective temperatures. Any storms that can mature
    within this environment could evolve into supercells with large to
    very large hail potential. The Marginal Risk has been expanded
    southwestward across TX, where some global and extended CAM guidance
    shows a signal for sustained development during the late afternoon.

    ..Dean.. 04/23/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Fri Apr 24 07:31:42 2026
    ACUS03 KWNS 240731
    SWODY3
    SPC AC 240730

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 AM CDT Fri Apr 24 2026

    Valid 261200Z - 271200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SUNDAY EVENING
    INTO SUNDAY NIGHT ACROSS MUCH OF KANSAS AND ADJACENT PORTIONS OF
    NORTHERN OKLAHOMA...WESTERN MISSOURI...

    ...SUMMARY...
    Widely scattered severe storms with potential to produce large hail
    and a couple of strong tornadoes are possible by early Sunday
    evening across parts of the central and southern Great Plains,
    before one or two organizing clusters of storms spread toward the
    middle/lower Missouri Valley with potentially damaging wind gusts.

    ...Discussion...
    A remnant elongated cyclonic mid-level circulation/shear axis may
    tend to shift north-northeastward through Saskatchewan/Manitoba
    through this period, while larger-scale troughing along an axis
    inland of the U.S. Pacific coast through the Hudson Bay vicinity
    weakens through this period. However, mid/upper ridging across southern/central Mexico into portions of the southern Great Plains
    and lower Mississippi Valley appears likely to maintain considerable
    strength, while a notable short wave perturbation accelerates out of
    the southern Great Basin/lower Colorado Valley, within strong
    southwesterly flow between the two features.

    Models suggest that stronger mid-level height falls will generally
    overspread the eastern Colorado/western Kansas/southwest Nebraska
    vicinity of the high plains late Sunday afternoon into evening,
    before reaching southern portions of the middle Missouri Valley by
    12Z Monday, accompanied by a developing low within the northern
    portion of deepening surface troughing extending southward into the
    southern Great Plains. Another low, developing by Sunday afternoon
    across the southeastern Colorado/Texas and Oklahoma Panhandle region
    may reach portions of central Kansas.

    In response to these developments, seasonably moist low-level air,
    initially confined to the southern Great Plains, perhaps as far
    north as central Oklahoma at the outset of the period, may tend to
    advect in a corridor ahead of a sharpening dryline across western
    Oklahoma into western Kansas by late afternoon. Downstream, models
    suggest that a warm frontal zone may become better defined by early
    Sunday evening across southern Kansas into the Ozark Plateau
    vicinity, before tending to shift northward.

    ...Great Plains...
    Although though there is not a strong signal yet evident within
    latest model output concerning potential convective evolution during
    this period, at least isolated to perhaps widely scattered supercell development may initiate along the dryline as far south as northwest
    Texas by late Sunday afternoon, in the presence of destabilization
    and strengthening shear. By early Sunday evening, this probably
    will include enlarging, clockwise curved low-level hodographs
    beneath a strengthening southerly low-level jet. This may become
    supportive of increasing potential for a couple of strong tornadoes,
    in addition to large hail, with increasing storm coverage probable
    across the western Kansas vicinity.

    Gradually, large-scale forcing for ascent, focusing along the warm
    front, may support one or two upscale growing clusters of storms
    spreading into the middle/lower Missouri Valley overnight, with
    damaging wind gusts becoming the more prominent severe hazard along
    with perhaps some continuing risk for tornadoes.

    ..Kerr.. 04/24/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Fri Apr 24 19:31:43 2026
    ACUS03 KWNS 241931
    SWODY3
    SPC AC 241930

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 PM CDT Fri Apr 24 2026

    Valid 261200Z - 271200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
    KANSAS INTO ADJACENT PORTIONS OF NORTHERN OKLAHOMA AND WESTERN
    MISSOURI...

    ...SUMMARY...
    Widely scattered severe storms with potential to produce large hail
    and a couple of strong tornadoes are possible by early Sunday
    evening across parts of the central and southern Great Plains,
    before one or two organizing clusters of storms spread toward the
    middle/lower Missouri Valley with potentially damaging wind gusts.

    ...Synopsis...
    A mid/upper-level shortwave and attendant jet maximum are forecast
    to emerge from the large-scale trough across the West, and begin to
    impinge upon a moist and potentially very unstable airmass across
    parts of the Great Plains on Sunday. A surface low is expected to
    consolidate and deepen across the south-central High Plains during
    the day, and then move toward the lower MO Valley by Monday morning.
    A surface front (whose initial position will be influenced by
    extensive Friday/Saturday convection) will move northward as a warm
    front across parts of the central Plains and Ozarks. A Pacific
    Front/dryline will extend southward from the surface low through
    late afternoon, with the northern portion of this boundary expected
    to push eastward across parts of KS/OK Sunday night.

    ...Great Plains...
    A volatile environment is still expected to develop across parts of
    KS/OK/TX Sunday afternoon and evening, with moderate to strong
    buoyancy and increasing low-level and deep-layer shear. However, the
    signal for diurnal warm-sector development remains rather muted in
    most guidance, with the strongest large-scale ascent and midlevel
    height falls expected to be displaced north of the stronger
    instability.

    Storm coverage through early evening may be maximized across parts
    of the central High Plains, in closer proximity to the ejecting
    shortwave trough. While low-level moisture will remain relatively
    modest in this area, backed low-level flow, steep midlevel lapse
    rates, and moderate buoyancy could support initial supercell
    development, with an attendant threat of all severe hazards. Storms
    in this area may consolidate into an MCS, resulting in an organized
    severe threat spreading toward the lower/mid MO Valley later Sunday
    night.

    Farther south, development along the dryline into parts of southern
    KS, OK, and TX remains more uncertain. If isolated supercells can
    develop and be sustained within this regime, they would be
    accompanied by a threat for tornadoes (possibly strong), very large
    hail, and localized severe gusts.

    A separate area of nocturnal storm development will be possible
    within a warm-advection regime from eastern KS into the Ozark
    region. Buoyancy and shear may be sufficient to support some severe
    threat with the strongest storms within this regime.

    ...Lower MS Valley...
    Nocturnal storms from D2/Saturday may persist into Sunday morning
    across the lower MS Valley, with additional diurnal development
    possible along the remnant surface boundary. Moderate buoyancy could
    support a localized severe threat across the region, within a modest northwesterly flow regime.

    ..Dean.. 04/24/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Sat Apr 25 07:29:46 2026
    ACUS03 KWNS 250729
    SWODY3
    SPC AC 250728

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0228 AM CDT Sat Apr 25 2026

    Valid 271200Z - 281200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MONDAY
    AFTERNOON AND EVENING ACROSS MUCH OF EASTERN IOWA...A PORTION OF
    SOUTHWESTERN WISCONSIN...MUCH OF EASTERN
    MISSOURI...ILLINOIS...WESTERN INDIANA...WESTERN KENTUCKY...WESTERN TENNESSEE...NORTHEASTERN ARKANSAS...

    ...SUMMARY...
    Widespread strong to severe thunderstorm development appears
    probable across the middle Mississippi into lower Ohio and Tennessee
    Valleys Monday afternoon and evening. At least initially, this may
    include several evolving supercells potentially capable of producing
    strong tornadoes across parts of southeastern Iowa into central
    through southern Illinois and adjacent east central and southeast
    Missouri.

    ...Discussion...
    Models indicate that significant surface cyclogenesis will proceed
    across the Upper Midwest/adjacent Great Lakes region during this
    period, as a notable short wave perturbation and associated 50-70 kt
    cyclonic 500 mb jet streak progress northeast of the middle/lower
    Missouri Valley region. Beneath a plume of warm/capping elevated
    mixed-layer air nosing northeastward across the middle Mississippi
    Valley, low-level warm sector moistening is generally forecast to
    contribute to moderate to strong potential instability. Although
    the details of the potential convective evolution remain unclear,
    the environment appears likely to become supportive of organized
    severe thunderstorm development, including supercells. Even if
    convection grows quickly upscale into one or more clusters/lines,
    embedded supercell structures will probably still pose potential for
    producing strong tornadoes. If an initially discrete supercell mode
    is maintained for a sustained period, tornadic potential could
    maximize, with a few long track, particularly damaging tornadoes
    possible.

    At this time, it appears that strongest thunderstorm development may
    initially focus in forcing for ascent associated with
    lower/mid-tropospheric warm advection, near the nose of the
    initially capping elevated mixed-layer across parts of southeastern
    Iowa into central Illinois. Enlarged, clockwise-curved low-level
    hodographs along this corridor, perhaps coinciding with a zone of
    stronger differential surface heating associated with a modifying
    outflow boundary, may become conducive to several strong tornadic
    supercells before convection tends to grow upscale while propagating southeastward into Monday evening.

    A dryline structure extending southwestward through portions of
    eastern Missouri may also support initially discrete supercell
    development, before activity tends to grow upscale ahead of an
    advancing cold front while spreading into the lower Ohio/Tennessee
    Valleys through Monday evening.

    ..Kerr.. 04/25/2026

    $$

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  • From COD Weather Processor@1:2320/107 to [email protected] on Sat Apr 25 19:31:54 2026
    ACUS03 KWNS 251931
    SWODY3
    SPC AC 251930

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 PM CDT Sat Apr 25 2026

    Valid 271200Z - 281200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR THE
    MID-MISSISSIPPI VALLEY...MID-SOUTH...AND LOWER OHIO VALLEY...

    ...SUMMARY...
    Widespread strong to severe thunderstorm development appears
    probable across the middle Mississippi into lower Ohio and Tennessee
    Valleys Monday afternoon and evening. At least initially, this may
    include several evolving supercells potentially capable of producing
    strong tornadoes across parts of southeastern Iowa into central
    through southern Illinois and adjacent east central and southeast
    Missouri.

    ...Synopsis...
    A potent shortwave trough will move into the mid-Mississippi Valley
    on Monday. A deepening surface low in the upper Mississippi Valley
    will draw rich moisture northward into a very broad warm sector.
    Strong deep-layer shear will promote numerous organized storms
    capable of all severe hazards.

    ...Mid-Mississippi Valley...
    A fairly well-timed shortwave trough will move into the region by mid-afternoon. A deepening surface low will lift northeastward into
    the upper Mississippi Valley. Associated with the cyclone, a cold
    front/dryline composite will drape southwestward through central
    Iowa/western Missouri. Within the warm sector, rich moisture
    (dewpoints in the upper 60s F) and mid-level lapse rates around 8
    C/km will promote MLCAPE of 2000-3000 J/kg. 60+ kts of effective
    shear is expected as the mid-level jet overspreads the region.
    Supercells are possible along the warm front, pre-frontal trough,
    and even the open warm sector given the forcing for ascent. All
    severe hazards will be possible including very-large hail,
    significant winds, and strong tornadoes. Potential for longer track
    tornadoes is not out of the question. There remains some uncertainty
    as to how convection will ultimately evolve during the afternoon
    given the potential for early morning thunderstorms. The NAM would
    suggest this activity clears out relatively quickly and development
    on the pre-frontal trough or front in the afternoon is probable. The
    latest ECMWF depicts convection lingering into the later
    morning/early afternoon, particularly in northern and parts of
    central Illinois. This would act to shift the primary corridor of
    severe risk farther south and east. The main zone of concern, when
    taking all guidance into account, appears to be from far southeast
    Iowa into central Illinois. With time, one or more stronger linear
    segments are expected to evolve where damaging winds and QLCS
    tornadoes would be possible. A categorical upgrade to Level
    4/Moderate was considered, but will await additional guidance which
    will hopefully clarify how early-day convection will evolve.

    ...Mid-South...
    Though this area will be displaced from the strongest mid-level
    ascent, rich moisture (upper 60s F to potentially low 70s F
    dewpoints) will promote 2500-3000 J/kg MLCAPE. A broad mid-level jet
    will nose into the region. Around 50 kts of effective shear can be
    expected. Supercells capable of all severe hazards will be possible.

    ..Wendt.. 04/25/2026

    $$

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