• DAY48SVR: Day6 Severe Ris

    From Mike Powell@618:250/1 to All on Tue Mar 25 08:01:00 2025
    ACUS48 KWNS 250911
    SWOD48
    SPC AC 250909

    Day 4-8 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0409 AM CDT Tue Mar 25 2025

    Valid 281200Z - 021200Z

    ...DISCUSSION...
    Medium-range models appear to be in reasonably good agreement into
    the Day 7 period (Monday March 31), with respect to
    evolution/progression of large-scale features.

    Day 4/Friday, a southern-stream trough is forecast to continue
    moving slowly eastward across the south-central states, reaching the
    lower Mississippi Valley Saturday morning. Showers and
    thunderstorms will accompany this feature, but the lack of robust
    CAPE/shear likely to be associated with this feature suggests that
    severe potential should remain subdued.

    Farther north, weak disturbances moving through anticyclonic flow
    aloft across the Upper Midwest/Upper Great Lakes/Ohio Valley will
    likely combine with warm advection near the northward-advancing warm
    front to support areas of deep convection, with some potential for
    hail. Risk however appears too low to warrant an areal inclusion.


    Saturday (Day 5), an upper trough will continue advancing across the
    Rockies. However, models forecast the main surface low to remain
    over the eastern Colorado vicinity into the evening hours, with a
    capped warm sector residing across eastern Kansas/Oklahoma/Texas and
    the Ozarks area (i.e. yesterday's Day 6 outlook area) in a zone of
    subsidence in the wake of the slow-moving southern-stream trough.
    As such, storm initiation now appears likely to remain largely
    hindered through Sunday morning.

    The primary severe risk appears likely to evolve Sunday/Day 6, from Missouri/Arkansas/northern Louisiana, spreading eastward through the
    day, and eventually approaching the west slopes of the Appalachians.
    As the western U.S. upper trough emerges into the Plains,
    supporting deepening of surface low pressure, a moist warm sector
    will destabilize through the day, likely yielding storm development
    initially west of the Mississippi Valley, and then spreading
    eastward through the evening. The favorable thermodynamic
    environment will combine with strong/veering flow through the middle troposphere, suggesting of severe storms including supercells, and
    attendant, all-hazards severe potential.

    By Monday, models begin to diverge with respect to speed of
    surface-frontal advancement east of the Appalachians. Still, enough destabilization should occur east and southeast of the front to
    allow storms to spread across the Southeast, along with attendant
    severe risk.

    Tuesday, model differences continue to increase, with the front
    residing off the Atlantic and Gulf Coasts per the GFS, while
    lingering over parts of the Southeast and the Gulf Coast region per
    the ECMWF. Given the uncertainty/predictability issues, no risk
    areas will be included.

    ..Goss.. 03/25/2025

    $$
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