• Flash flooding likely TX/LA/MS

    From Mike Powell@618:250/6 to All on Sat May 23 09:18:30 2026

    AWUS01 KWNH 231336
    FFGMPD
    MSZ000-LAZ000-TXZ000-231935-

    Mesoscale Precipitation Discussion 0215
    NWS Weather Prediction Center College Park MD
    935 AM EDT Sat May 23 2026

    Areas affected...Far Eastern TX...Central and Southern LA...Far
    Southwest MS

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

    Valid 231335Z - 231935Z

    SUMMARY...Expanding areas of heavy showers and thunderstorms, with
    some localized cell-training will result in an increasing flash
    flood threat through the mid-afternoon hours. Rainfall rates of 2
    to 3 inches/hour are expected, with localized totals of 3 to 5
    inches possible.

    DISCUSSION...GOES-E satellite imagery and radar shows some small
    scale MCS activity over far eastern TX along with an embedded MCV
    that will be moving east into areas of western LA over the next
    few hours. The latest surface data suggests a surface
    trough/outflow boundary near the southern LA coast that extends
    west-southwest back toward the Upper TX coast.

    Meanwhile, the airmass is moderately buoyant with a nose of MLCAPE
    values reaching 1500 to 2000+ J/kg across far eastern TX and
    across much of western LA in association with modest, but
    persistent southerly flow off the Gulf ahead of the upstream
    convection. Moisture is heavily entrenched through the column
    based off the latest OSPO ALPW data, with PWs overall running up
    to near 1.75 inches.

    The approaching convection and associated MCV energy is expected
    to interact with this surface trough near the Gulf Coast, and
    favor a general increase in warm air advection/isentropic ascent
    that coupled with the nose of instability should favor an increase
    in the coverage of heavy showers and thunderstorms. The latest
    Corfidi vector analysis suggests at least some low-end threat for
    backbuilding and training convection over the next several hours
    as the convection increases across areas of central and southern
    LA, and perhaps areas as far northeast as southwest MS.

    High rainfall rates are expected that could reach 2 to 3
    inches/hour with the stronger convective cores, and with any
    cell-training, some localized storm totals going through early to
    mid-afternoon could reach 3 to 5 inches. FFG is rather high across
    the region overall, with moderate soil moisture (50 to 70 percent)
    in the 0-10cm layer according to NASA SPoRT. However, with the
    high rainfall rates and localized storm total potential, some
    areas of flash flooding will tend to become likely over the next
    several hours. This will especially be the case for the more
    sensitive urban corridors.

    Orrison

    ATTN...WFO...JAN...LCH...LIX...SHV...

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

    LAT...LON 31979285 31679154 31059027 30288969 29688969
    29369007 29269094 29589253 29629308 29789379
    30719441 31249432 31819377

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