• DAY1 3/5 Risk Area Posted

    From Dumas Walker@21:1/175 to All on Fri May 2 09:02:00 2025
    ACUS01 KWNS 021258
    SWODY1
    SPC AC 021257

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0757 AM CDT Fri May 02 2025

    Valid 021300Z - 031200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
    CENTRAL/EAST TEXAS TO THE LOWER MISSISSIPPI VALLEY AND TENNESSEE
    VALLEY...

    ...SUMMARY...
    Widespread strong thunderstorm development is expected from parts of
    central and eastern Texas to the lower Mississippi and Tennessee
    Valleys, and into the Cumberland Plateau by evening. This includes
    potential for large hail and damaging wind gusts.

    ...Southern Plains to Lower Mississippi Valley/Tennessee Valley...
    A residual MCS, with diminished intensity since early on the
    overnight, persists at daybreak along the Red River and
    Texas/Oklahoma border region eastward into the Mid-South largely
    paralleling I-40, with a probable related MCV across eastern
    Oklahoma. A relatively isolated severe potential will initially
    exist with these storms this morning. However, an intensification of related/downstream storms is expected by midday, potentially
    spanning parts of Arkansas into western/Middle Tennessee, western
    Kentucky, and northern Alabama. Additional severe storm development
    will be possible this afternoon northeastward into the middle Ohio
    Valley and toward the Cumberland Plateau, as increasing
    low-level/deep-layer southwesterly winds overlie a moderately
    unstable boundary layer. Multiple organizing storm clusters can be
    expected regionally this afternoon into evening.

    Farther southwest across central/eastern Texas, while considerable
    drying and stabilization is still apparent in observational data
    after last evening's MCS, the air mass should steadily recover with
    moistening and relatively aggressive destabilization into peak
    heating. Initial thunderstorm development will be accompanied by the
    potential for large hail, with supercells capable of very large hail
    possible especially with west-southwestward extent into the Edwards
    Plateau and toward the Rio Grande. Damaging wind potential will also
    increase as convection organizes and spreads southeastward into this
    evening across central/southeast Texas, and possibly Deep South
    Texas tonight.

    ..Guyer/Jewell.. 05/02/2025

    $$
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  • From Dumas Walker@21:1/175 to All on Thu Aug 7 08:03:48 2025
    ACUS01 KWNS 071251
    SWODY1
    SPC AC 071250

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0750 AM CDT Thu Aug 07 2025

    Valid 071300Z - 081200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
    NORTH DAKOTA...

    ...SUMMARY...
    Scattered severe thunderstorms are expected later today into tonight
    across the northern Plains. The most likely corridor is centered on
    North Dakota, where a few tornadoes, very large hail, and
    significant severe gusts are possible.

    ...Northern Plains...
    Elevated thunderstorms are ongoing across northeastern MT this
    morning, supported by warm-air advection throughout the northwestern
    periphery of surface low over southeast MT. Steep mid-level lapse
    rates remain in place downstream of these storms, and southwesterly
    mid-level flow will persist, so the general expectation is for these
    storms to continue through the morning into the early afternoon.
    Cloud cover associated with these storms could result in a
    differential heating zone that with create a warm-front-like feature
    across northern ND. At the same time, moisture low-level
    southeasterly flow will continue across the northern Plains, with
    dewpoints likely in the upper 60s/low 70s across much of the region
    by the early afternoon.

    The surface low over southeast MT is forecast to drift eastward this
    morning towards the MT/WY/SD border intersection vicinity. To the
    north of this low, the combination of low-level moisture convergence
    and strengthening large-scale ascent will likely result in
    convective initiation by the early afternoon. Surface dewpoints in
    the upper 60s/low 70s and surface temperatures in the 80s beneath
    steep mid-level lapse rates will result in an impressive
    thermodynamic environment from the MT/ND border downstream into more
    of ND. Most guidance suggests MLCAPE from 3000 to 4000 J/kg.
    Moderate shear is also expected within this initiation zone,
    supporting an initially supercellular storm mode. All severe hazards
    would be possible with these supercells, including very large hail
    exceeding 2" in diameter, significant severe gusts around 75 mph,
    and tornadoes. Clustering and upscale growth appears probable, with
    the resulting MCS then tracking eastward across ND.

    Given the extreme buoyancy and moderate westerly flow aloft, there
    is some potential for the development of a robust rear inflow jet
    and resulting MCS that could be qualified as a derecho. However,
    confidence in the development of derecho is too low to increase wind probabilities with this outlook. Regardless, significant wind gusts
    appear possible, particularly if the previously mentioned
    warm-front-like feature develops and acts as a favored corridor for
    MCS propagation. Low-level southeasterly flow is also expected to be
    strong enough for some potential for line-embedded tornadoes.

    Additional elevated thunderstorms are possible in the wake of this
    MCS amid modest warm-air advection atop the MCS outflow. Some large
    hail is possible within these storms.

    ...Northern High Plains...
    Farther west, isolated to widely scattered supercells may develop
    within a moderately unstable post-frontal regime from central into
    eastern MT. Elongated hodographs and steep lapse rates will support
    severe hail and wind potential with these cells. Some clustering
    remains possible within this regime as well, and depending on the
    evolution of downstream convection, storms that initiate in MT may
    eventually spread into western/central ND late tonight with a
    continued severe threat.

    ...Northern MO/IA into the Upper Midwest...
    Elevated thunderstorms are currently ongoing across southern IA and
    northern MO, supported by warm-air advection resulting from a
    low-level jet that extends from the TX Panhandle through eastern KS.
    Steep mid-level lapse rates are present across much of the region
    (sampled by the 12Z TOP sounding), and these storms will likely
    continue through the afternoon. An isolated strong wind gusts is
    possible with these storms.

    Additional thunderstorms are possible later this evening farther
    northeast in central/southern WI and northern IL as the low-level
    jet strengthens again. Deep-layer flow will be relatively modest,
    but rich moisture and moderate to strong buoyancy will support a
    threat for at least isolated hail and damaging wind.

    ..Mosier/Bentley.. 08/07/2025

    $$
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