• STRMDISC: Tropical Storm Jerry Discussion Number 11

    From COD Weather Processor@1:2320/105 to [email protected] on Fri Oct 10 02:57:22 2025
    657
    WTNT45 KNHC 100256
    TCDAT5

    Tropical Storm Jerry Discussion Number 11
    NWS National Hurricane Center Miami FL AL102025
    1100 PM AST Thu Oct 09 2025

    Jerry remains a disheveled tropical storm this evening. Most of the
    deep convection is displaced to the southeast of the low-level
    circulation, which continues to run out ahead due to continued
    northwesterly vertical wind shear. Air Force reconnaissance
    observations indicate a highly asymmetric wind field, with the peak
    850 mb flight level winds of 56 kt in the northeastern quadrant, and
    very little wind on the western side of the circulation. The flight
    level winds support lowering the initial intensity to 50 kt this
    advisory. The surface pressure has been rising as well, with the
    latest dropsonde data supporting a minimum value of 1005 mb.

    Jerry appears to finally be moving northwestward now, estimated at
    315/15 kt. The track reasoning remains about the same as this
    afternoon, as Jerry's track should gradually bend more poleward as
    it moves along the western side of a subtropical ridge. On the
    forecast track, Jerry is making its closest approach to the Leeward
    Islands currently, and its asymmetric wind field means that the
    majority of the stronger winds will stay east of the island chain.
    Early next week, a faster eastward or east-northeastward motion is
    forecast in the mid-latitude westerlies. Jerry is expected to pass
    east of Bermuda in a few days, and given its expected eastward
    asymmetry, significant impacts still remain unlikely there. The NHC
    track forecast is quite similar to the prior one, and is a rough
    blend between the slower and further west HCCA guidance and the
    faster and further east Google DeepMind Mean (GDMI).

    The tropical storm is struggling mightily against the unfavorable
    northwesterly vertical winds shear, and its current poor structure
    also does not bode well for future short-term intensification. After
    the storm passes the northern Leeward Islands, the vertical wind
    shear does decrease to 10-15 knots, but given the current structure,
    it may take some time for the system to recover. Nonetheless,
    gradual intensification is shown beginning in 36 hours, though the
    intensity forecast is lower than the previous advisory. Shear
    increases towards the end of the forecast and sea-surface
    temperatures decrease as Jerry recurves into the mid-latitude
    westerlies, and some weakening is shown again in 120 h. This remains
    a low confidence intensity forecast, and on the high side of the
    overall guidance envelope.

    The most significant hazard expected from Jerry over the next few
    days is heavy rainfall, even after Jerry passes to the north due to
    its current structure with most of the significant weather to the
    south and east of the tropical cyclone.


    KEY MESSAGES:

    1. Tropical storm conditions are expected in the warning area and
    are possible in the watch area this evening through Friday morning.

    2. Heavy rainfall will impact portions of the Leeward Islands,
    British Virgin Islands, U.S. Virgin Islands, and Puerto Rico through
    Friday, which could result in flash flooding, particularly in urban
    areas and in steep terrain.


    FORECAST POSITIONS AND MAX WINDS

    INIT 10/0300Z 18.2N 61.6W 50 KT 60 MPH
    12H 10/1200Z 19.7N 62.5W 50 KT 60 MPH
    24H 11/0000Z 22.1N 63.1W 50 KT 60 MPH
    36H 11/1200Z 24.5N 63.1W 55 KT 65 MPH
    48H 12/0000Z 27.1N 62.8W 60 KT 70 MPH
    60H 12/1200Z 29.5N 62.2W 65 KT 75 MPH
    72H 13/0000Z 31.3N 60.5W 65 KT 75 MPH
    96H 14/0000Z 31.8N 57.3W 65 KT 75 MPH
    120H 15/0000Z 32.5N 51.7W 60 KT 70 MPH

    $$
    Forecaster Papin


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