• MESO: Mesoscale Discussion 2301

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Sat Dec 28 17:48:04 2024
    ACUS11 KWNS 281747
    SWOMCD
    SPC MCD 281747=20
    LAZ000-TXZ000-281915-

    Mesoscale Discussion 2301
    NWS Storm Prediction Center Norman OK
    1147 AM CST Sat Dec 28 2024

    Areas affected...portions of eastern Texas into far western
    Louisiana

    Concerning...Tornado Watch 718...719...

    Valid 281747Z - 281915Z

    The severe weather threat for Tornado Watch 718, 719 continues.

    SUMMARY...The severe threat continues across Tornado Watches
    718-719. All severe hazards remain possible. The best chance for
    tornadoes will exist with supercells embedded in confluence bands.

    DISCUSSION...Multiple storms along a confluence band, including a
    supercell with a history of producing at least one tornado, persist
    along a Walker to Matagorda County, TX line while a QLCS is
    developing farther to the west amid an increase in synoptic forcing.
    Storms in both regimes are overspreading a destabilized boundary
    layer, characterized by 70s F surface temperatures and dewpoints,
    yielding over 2000 J/kg MLCAPE with minimal MLCINH per 17Z
    mesoanalysis. Latest regional VADs show hodographs with elongation,
    but modest low-level curvature, indicating an environment favorable
    for damaging gusts, large hail, and perhaps a few tornadoes.=20

    Latest mesoanalysis shows an 80+ kt 500 mb speed max pivoting the
    base of the mid-level trough, and is poised to overspread the TX/LA
    border over the next few hours. A low-level mass response is
    expected, with intensification of the low-level jet to well over 40
    kts likely. As this occurs, enlargement of the hodographs should
    occur, especially closer to LA. Subsequently, the potential for
    damaging gusts and tornadoes (including the risk of a strong
    tornado) should increase later this afternoon. The best chance for
    any strong tornadoes will likely be with any sustained supercell
    structures associated with the confluence band, especially if a
    supercell can avoid detrimental interference from nearby storms.
    Otherwise, the damaging gust/tornado threat will also increase with
    an approaching/intensifying QLCS, which will eventually overtake
    preceding warm-sector confluence bands/storms.

    Convection continues to oscillate in intensity farther east in the
    free warm sector. Confidence is not overly high in robust severe
    thunderstorms developing in this corridor. However, any storm that
    manages to develop could become supercellular, posing a threat for
    all severe hazards.

    ..Squitieri.. 12/28/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6O9zXn1YEOzp4ep9Es7qQV0H3H-TuMhJwQCRXfOY3xk4Dt4bfqk046icy1W9OZM7zSwhT5ktT= NINTPLZZbFgDY6j-IM$ for graphic product...

    ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

    LAT...LON 30059718 31629636 32019506 31999418 31679325 31109274
    30649256 30099298 29789413 29749556 30059718=20


    =3D =3D =3D
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