• Heavy Rain/Flooding LA/TX

    From Mike Powell@618:250/1 to All on Fri Jun 13 07:53:00 2025
    AWUS01 KWNH 131117
    FFGMPD
    LAZ000-TXZ000-131716-

    Mesoscale Precipitation Discussion 0427
    NWS Weather Prediction Center College Park MD
    717 AM EDT Fri Jun 13 2025

    Areas affected...southern Louisiana, far southeast Texas

    Concerning...Heavy rainfall...Flash flooding likely

    Valid 131116Z - 131716Z

    Summary...A cluster of slow-moving storms have produced estimated
    4-6 inch rainfall totals near Lafayette, Louisiana this morning.
    This cluster is expected to very slowly evolve within a very
    unstable airmass, posing a risk for flash flooding through
    17Z/noon CDT.

    Discussion...Scattered thunderstorms have managed to evolve into a
    persistent, slow-moving cluster near Lafayette this morning. The
    storms are embedded in deep south-southwesterly steering flow of
    around 20-25 knots, but have managed to backbuild locally due to
    1) confluent 850mb wind fields evident via objective analyses, 2)
    a weak surface boundary extending from near Galveston, TX
    east-northeastward through Lafayette to near Hammond, LA, and 3)
    strong instability/weak inhibition along and south of that subtle
    boundary. Impressive moisture/instability content within the
    pre-convective airmass (2000 J/kg MLCAPE, 2 inch PW values) were
    contributing to impressive local rain rates exceeding 2.5
    inches/hr at times. With 4-6 inches of rain having already
    fallen, some impacts are likely with the ongoing activity in the
    short term.

    Through 17Z/noon CDT, the reinforcement of a surface/outflow
    boundary near the convection (due to cold pool formation) will
    likely enable continued development and training of cells. Some
    propagation of this cluster is expected, and both westward and
    eastward development of storms toward areas near Lake Charles and
    near/south of Baton Rouge can be expected. Another 3-5 inches of
    rainfall can be expected beneath the heavier, slower-moving
    thunderstorm bands as well. Locally higher amounts cannot be
    ruled out in a few spots.

    Cook
    ATTN...WFO...HGX...LCH...LIX...

    ATTN...RFC...FWR...ORN...NWC...

    LAT...LON 30509132 30289060 29989016 29599001 29229034
    29169115 29539237 29659388 29469442 29779450
    30179381 30479252

    $$
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