• Heavy Rain TX Coast flooding possible

    From Mike Powell@618:250/6 to All on Thu May 21 08:24:52 2026
    AWUS01 KWNH 211120
    FFGMPD
    TXZ000-211419-

    Mesoscale Precipitation Discussion 0202
    NWS Weather Prediction Center College Park MD
    719 AM EDT Thu May 21 2026

    Areas affected...portions of the middle Texas Coast

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

    Valid 211119Z - 211419Z

    Summary...Areas of slow-moving, banded thunderstorm activity may
    produce local rain rates of 2-3.5 inches per hour this morning.
    Flash flooding is possible if this activity occurs over sensitive locales.

    Discussion...A mature MCS is making slow, steady progress along
    portions of the lower Texas Coast and south Texas - generally
    extending from near Corpus Christi southward to Brownsville. Slow
    movement (around 20 knots - locally slower) and abundant
    moisture/instability downstream over adjacent Gulf waters was
    aiding efficient precipitation rates (around 3 inches/hr) in the slowest-moving, northern end of the complex.

    Meanwhile, a new band has developed downstream of this complex
    near Port Lavaca. This band is oriented more parallel to steering
    flow aloft and perpendicular to the approaching complex from the
    west. 2+ inch/hr rain rates are already being estimated with this activity.

    Over the next 1-3 hours, the forward propagation of the mature MCS
    and slow-movement of the downstream convective band will promote a
    prolonged period of heavy rainfall especially along/near the
    middle Texas Coast. FFG thresholds of 2.5 inch/hr should be
    eclipsed with this activity, and local totals of 5+ inches cannot
    be ruled out through 14Z/9a central this morning. Flash flooding
    is possible - especially if these rainfall totals occur over any
    sensitive or low-lying/flood prone areas.

    Cook

    ATTN...WFO...CRP...HGX...

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

    LAT...LON 29209606 29159493 28569474 28449491 28289597
    27999679 27399667 27369726 27739758 28459782
    28959718

    $$
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    * Origin: Project Scorpio TEST (618:250/6)