• DAY1 Enhanced Risk Cen US

    From Dumas Walker@21:1/175 to All on Wed Oct 30 08:04:00 2024
    ACUS01 KWNS 301251
    SWODY1
    SPC AC 301250

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0750 AM CDT Wed Oct 30 2024

    Valid 301300Z - 311200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS
    EASTERN KANSAS...NORTHEAST OKLAHOMA...AND NORTHWEST MISSOURI...

    ...SUMMARY...
    Severe thunderstorms capable of producing large hail, damaging wind
    gusts, and a few tornadoes, are expected today into tonight across
    the middle Missouri Valley and central/southern Plains, including
    parts of eastern Kansas and Oklahoma into Missouri.

    ...Lower Missouri Valley/South-Central Plains...
    A relatively active severe-weather day is expected regionally,
    especially late this afternoon into evening, including some southern
    Plains areas in which there hasn't been severe-weather potential in
    over a month.

    The lead portion of an upper-level trough centered over the
    central/southern Rockies this morning will eject northeastward over
    the central Plains toward broader parts of the Upper Midwest and
    Corn Belt. A surface wave will evolve across the eastern Texas Panhandle/northwest Oklahoma vicinity. From this low, an east/southeastward-moving cold front will extend across Kansas into Iowa/Minnesota and eventually Wisconsin/western Missouri by this
    evening, with this front overtaking a dryline across the southern
    High Plains.

    Some severe-weather potential may increase as early as late morning
    into midday near the cold front across central Kansas into southeast
    Nebraska and Iowa, with a likely increase in surface-rooted
    convection and greater severe potential by mid/late afternoon as the
    front approaches east-central/northeast Kansas and northwest
    Missouri/southern Iowa. Pre-convective MLCAPE values should reach
    500-1250 J/kg within this corridor, with very strong deep-layer
    southwesterly winds supporting 40-50 kt effective shear and fast east-northeastward storm motions, which will largely parallel the
    front and its east-southeastward motion. Some severe hail will be
    possible during the day, but damaging winds and some tornado
    potential will be more prevalent into late afternoon and evening as
    a QLCS evolves with embedded bowing segments and potential
    mesovortices.

    Farther south, in closer proximity to the surface wave, somewhat
    more discrete thunderstorm development is expected across south-central/east-central Kansas including the I-35/135 corridors
    and north-central Oklahoma, with prospects for even more isolated
    initial supercellular development by around sunset southward into central/southern Oklahoma and North Texas. Surface temperatures in
    the upper 70s F, combined with mid 60s F dewpoints, will contribute
    to 1500-2000 J/kg MLCAPE by peak heating. Storms that develop/mature
    in this environment will likely be supercells in the presence of 45+
    effective shear, highlighted by a dramatic strengthening (50-65 kt)
    of 2-3 km AGL (surface-700 mb) southwesterly winds toward/after
    sunset. Storm mergers will result in squall line development over
    time, with a longer duration of more discrete development with
    southward extent across Oklahoma. A few tornadoes are plausible
    regionally, and a strong tornado or two could occur, particularly
    within a couple of hours of sunset. The severe threat should
    transition to more of a damaging wind threat as the squall line
    matures, although line-embedded QLCS tornadoes will remain possible
    this evening, and possibly overnight.

    ...Southeast Texas...
    There is some potential that a few stronger/potentially rotating
    storms could materialize today across the region within a very moist
    and confluent low-level flow regime. This would be as low-level
    lapse rates diurnally steepen coincident with a moderate degree of
    low-level hodograph length and curvature. Modest-strength winds
    above 2km AGL should limit the sustainability and intensity for any showers/thunderstorms that may exhibit rotating characteristics, and
    the overall severe potential should remain limited.

    ..Guyer/Leitman.. 10/30/2024

    $$
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