• Heavy Rain/Flood Gulf Coa

    From Dumas Walker@21:1/175 to All on Fri Jul 19 08:46:00 2024
    AWUS01 KWNH 191227
    FFGMPD
    FLZ000-ALZ000-MSZ000-LAZ000-191730-

    Mesoscale Precipitation Discussion 0660
    NWS Weather Prediction Center College Park MD
    827 AM EDT Fri Jul 19 2024

    Areas affected...Central Gulf Coast

    Concerning...Heavy rainfall...Flash flooding possible

    Valid 191226Z - 191730Z

    Summary...Efficient thunderstorms with rainfall rates upwards of
    3"/hr at times are expected to persist this morning. Repeating of
    these storms may lead to some flash flooding.

    Discussion...Radar and IR imagery across the Central Gulf Coast
    continue to track an axis of showers and thunderstorms lifting
    northeastward at around 10-15 kts. A particularly efficient
    cluster of thunderstorms southwest of Mobile, AL contained
    estimated rainfall rates approaching 3"/hr earlier as individual
    cells merged near the coastline recently.

    This corridor of activity is likely forced by 1) an approaching
    shortwave to the west and 2) a diffuse northeast to southwest
    oriented offshore convergence axis, which is aligned with the mean
    wind vector. Amid the forcing from this low-level boundary, the
    RAP suggests a very moist and unstable airmass will continue to
    push inland along a tight gradient to maintain efficient rainfall
    rates, with 2.1-2.25" PWATS and 2000-2500 J/kg of MUCAPE expected
    along the coastline over the next few hours.

    While the rainfall footprint with this activity will be somewhat
    "popcorn" owing to a lack of appreciable vertical shear, the very
    efficient rainfall production will support some flash flooding
    risk this morning as cells repeat along the lingering convergence
    axis. CAM guidance is a bit all over the place with initializing
    the ongoing storms, although several pieces of high-res guidance
    (11Z HRRR, ARWs, FV3, and RRFS) are quite wet and suggest rainfall
    amounts of 3-5" are possible through this morning. While 1-3 HR
    FFGs are quite high in the area (2.5-4"), repeating instances of
    these efficient storms could realize these higher end amounts on a
    localized basis, indicating some flash flood threat through this
    morning.

    Asherman

    ATTN...WFO...LIX...MOB...

    ATTN...RFC...LMRFC...SERFC...NWC...

    LAT...LON 30978818 30878667 30148686 29398840 28818930
    29049008 29509009 30308934
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