• DAY ENHANCED RISK SE TX

    From Dumas Walker@21:1/175 to All on Thu Dec 26 19:45:00 2024
    ACUS01 KWNS 261956
    SWODY1
    SPC AC 261954

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0154 PM CST Thu Dec 26 2024

    Valid 262000Z - 271200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS
    AFTERNOON/EVENING IN SOUTHEAST TEXAS...

    ...SUMMARY...
    Several tornadoes, including a strong (potentially EF2+) tornado or
    two, will be possible this afternoon/evening across southeast Texas.
    Damaging gusts of 60-70 mph and large hail of 1-1.75" in diameter
    will also be possible from east Texas this afternoon into Louisiana,
    southern Arkansas and far west central Mississippi overnight.

    ...20Z Update...
    Severe probabilities in parts of central Texas have been adjusted to
    account for the progression of ongoing convection. Quasi-discrete
    supercells continue in parts of southeast Texas as well as to the
    northwest of Houston. These storms will continue to post the
    greatest threat for tornadoes (potentially strong). See MCD 2284 and
    2285 for additional short-term, mesoscale details.

    ..Wendt.. 12/26/2024

    .PREV DISCUSSION... /ISSUED 1013 AM CST Thu Dec 26 2024/

    ...East TX/LA/southern AR through tonight...
    Elevated convection has already formed over north central TX this
    morning in a band of ascent preceding a midlevel shortwave trough
    moving eastward. New thunderstorm development is expected through
    the afternoon farther to the south and east across east/southeast
    TX, as the warm sector spreads northward in advance of a weak
    surface cyclone. Boundary-layer dewpoints in the mid-upper 60s
    beneath midlevel lapse rates near 8 C/km will drive MLCAPE ranging
    from 500 J/kg a little south of I-20 to 1500-2000 J/kg across
    southeast TX by late afternoon, where surface-based storms are
    likely with small breaks in the stratus. Vertical shear profiles
    will be characterized by sufficiently long hodographs (effective
    bulk shear in excess of 45 kt) and low-level hodograph curvature
    (effective SRH in excess of 200 m2/s2) for supercells.

    The initial storms will be more cellular across southeast TX with a
    gradual transition to a mixed mode/band of storms this evening into
    tonight as the storms spread eastward/northeastward across
    LA/southern AR. The surface-based supercells in southeast TX will
    be capable of producing tornadoes from early afternoon into late
    evening (including a strong/EF2+ tornado or two), along with
    isolated large hail (1-1.75 inches in diameter). With the gradual
    change in storms to a more linear mode, the potential for wind
    damage (and embedded tornadoes) will persist into tonight.

    $$
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