• MESO: Mesoscale Discussion 1657

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Sat Jul 12 19:36:30 2025
    ACUS11 KWNS 121936
    SWOMCD
    SPC MCD 121935=20
    TXZ000-122130-

    Mesoscale Discussion 1657
    NWS Storm Prediction Center Norman OK
    0235 PM CDT Sat Jul 12 2025

    Areas affected...central Texas and the Texas Hill Country

    Concerning...Severe potential...Watch unlikely=20

    Valid 121935Z - 122130Z

    Probability of Watch Issuance...20 percent

    SUMMARY...Widespread thunderstorms will be capable of sporadic
    damaging gusts and small hail this afternoon/evening. A WW is not
    anticipated.

    DISCUSSION...Across portions of west-central TX, numerous
    thunderstorms have redeveloped/intensified ahead of a weak cold
    front and MCV. Strong diurnal heating of a very moist air mass
    (dewpoints in the mid 70s F) is supporting moderate destabilization
    despite poor mid-level lapse rates. Numerous thunderstorms with
    occasional stronger updrafts are expected. Deep-layer shear is weak
    with flow aloft generally blow 20 kt. This should keep storm
    organization transient at best. Still, deep, saturated thermodynamic
    profiles and PWATS near 1.8-2 inches will favor heavily water-loaded
    downdrafts in these storms. This could support sporadic damaging
    gusts with wet microbursts, along with small hail and localized
    torrential rainfall rates (see WPC MPD: #0660).

    Severe potential will be maximized where storm coverage is highest.
    This is most likely ahead of the MCV and along the sagging front
    across central TX and the western Hill Country. As downdrafts
    intensify, gradually consolidation into more persistent clusters
    that spread eastward with time is likely. While some severe risk is
    possible, the negligible deep-layer shear and localized risk for
    damaging gusts and hail suggests a severe watch is unlikely.

    ..Lyons/Mosier.. 07/12/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7KN9mIEmW-61WWXemgdVExx3amKheWi37zw4PKlpsI-xfnCgmGBAFzhi4UKl4dsfBKUuwFUf3= G4ZNWxFe65V_eFh6o0$ for graphic product...

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

    LAT...LON 30300155 32250118 33359976 33629832 32829725 31739706
    29909838 29140007 29580070 30300155=20

    MOST PROBABLE PEAK WIND GUST...55-70 MPH
    MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


    =3D =3D =3D
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