• Heavy Rain/Flood TX Coast

    From Mike Powell@618:250/1 to All on Wed May 28 08:09:00 2025
    AWUS01 KWNH 281147
    FFGMPD
    TXZ000-281700-

    Mesoscale Precipitation Discussion 0326
    NWS Weather Prediction Center College Park MD
    746 AM EDT Wed May 28 2025

    Areas affected...Upper Texas Coast

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

    Valid 281145Z - 281700Z

    SUMMARY...Approaching complex of thunderstorms producing 1-2"/hr
    rainfall rates may produce urbanized areas of flash flooding,
    especially around the Houston metro area.

    DISCUSSION...Vigorous thunderstorm activity along the Lower Texas
    Coast is propagating northeast along a 925mb theta-e gradient that
    is oriented SW-NE just south of I-10. The mean 925-850mb wind
    field over the western Gulf is out of the SE with these winds
    intersecting the nearby surface front located north of I-10 this
    morning. This persistent SE flow will overrun the frontal boundary
    and continue to act as a trigger for additional thunderstorm
    activity. RAP mesoanalysis shows between 1,000-2,000 J/kg of
    MUCAPE while PWs are steadily on the rise thanks to a southerly
    IVT that is on the order of 300-500 kg/m/s. This allows for PWs to
    rise above 1.75" along the Upper Texas Coast this morning with
    some isolated areas approaching 2.0". RAP soundings are also
    indicating highly saturated soundings and warm cloud layers up to
    12,000ft deep in some cases.

    The storms may extend farther inland to the north of I-10 as SErly
    850mb winds accelerate. However, the concern for rainfall rates
    2"/hr is most likely along and south of I-10 where there greatest
    instability is present. 06Z HREF probabilistic guidance shows a
    bullseye of 30-50% values for 3-hr QPF > 3-hr FFGs near the
    Houston metro late morning into early afternoon. As much as 1-3"
    of rainfall is anticipated with localized amounts as high as 4"
    possible within the highlighted threat region. These rates are
    also coming around the morning rush hour within a densely
    populated area. Flash flooding is possible this morning,
    particularly in the more urbanized communities and poor drainage
    areas of Southeast Texas.

    Mullinax

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