• MESO: Mesoscale Discussion 1212

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Monday, June 09, 2025 00:23:12
    ACUS11 KWNS 090023
    SWOMCD
    SPC MCD 090022=20
    TXZ000-OKZ000-090145-

    Mesoscale Discussion 1212
    NWS Storm Prediction Center Norman OK
    0722 PM CDT Sun Jun 08 2025

    Areas affected...portions of northern Texas

    Concerning...Severe Thunderstorm Watch 396...397...

    Valid 090022Z - 090145Z

    The severe weather threat for Severe Thunderstorm Watch 396, 397
    continues.

    SUMMARY...A significant severe wind risk is increasing with merging
    supercells. A bow echo may develop and produce a derecho, with peak
    gusts in the 80-100 mph range possible.

    DISCUSSION...Multiple supercells, with reported severe hail across
    the southeastern TX Panhandle, are beginning to merge. Multiple West
    Texas Mesonet stations have reported peak 10-m gusts in roughly the
    60-75 mph range, and this trend should continue to increase if these
    storms successfully morph into a bow echo over the next couple of
    hours. While supercells have occurred downstream of the southeast TX
    Panhandle storms, it does not appear that large-scale tropospheric
    overturning has occurred. As such, a very unstable warm sector
    precedes the upscale-growing storms, with 3000-5000 J/kg MLCAPE and
    50 kts of effective bulk shear being common (as also shown by the
    00Z FWD observed sounding). The effective bulk shear vectors are
    oriented roughly orthogonal to the merging line, which should
    further encourage bow echo development.=20

    Assuming bow echo development ensues over the next few hours, a
    strong cold pool could encourage intense rear-inflow jet
    development, which upon downward momentum transport could support a
    derecho. In this scenario, widespread 60+ mph sustained winds may be
    expected, with multiple embedded gusts peaking somewhere in the
    75-100 mph range. The derecho could begin somewhere in the 01-03Z
    period, and last for several hours downstream, the evolution of
    which may need to be covered with a downstream PDS Severe
    Thunderstorm Watch across much of north-central into northeast TX.

    ..Squitieri.. 06/09/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9O1tkNfgVpHf1LZNN25UUHQkfUCXSVJmBWrxweRpBgQn2Fm7krRZ7WVyun4yQZZy0CzM3zssb= Nrf93G-ZMyf8OBL7GY$ for graphic product...

    ATTN...WFO...FWD...OUN...SJT...LUB...MAF...

    LAT...LON 34200052 33929778 33639726 33239725 32569766 32119826
    32159921 32419995 32650054 33050107 34200052=20

    MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
    MOST PROBABLE PEAK WIND GUST...85-100 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


    =3D =3D =3D
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