• DAY3SVR: Nws Storm Predic

    From Mike Powell@618:250/1 to All on Tue Apr 15 09:39:00 2025
    ACUS03 KWNS 150722
    SWODY3
    SPC AC 150721

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0221 AM CDT Tue Apr 15 2025

    Valid 171200Z - 181200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN IA/NORTHERN
    MO/EASTERN NE...

    ...SUMMARY...
    Scattered severe thunderstorms, with a primary threat of large hail,
    are possible on Thursday evening/night, centered on eastern
    Nebraska, northern Missouri, and Iowa.

    ...Synopsis...
    A longwave trough, consisting of multiple embedded shortwave
    impulses, will become established from the southern Prairie
    Provinces across the West to off the Baja CA coast. Peak surface
    cyclone amplitude is expected over western KS on Thursday afternoon,
    with a surface trough/baroclinic zone extending north-northeast into
    MN. A dryline will arc across eastern KS into the southern Great
    Plains. The cyclone will fill as it tracks east-northeast along the
    baroclinic zone towards the MO/IA border area Thursday night.

    ...IA/MO/NE...
    Along the leading edge of a stout EML and effective 700-mb warm
    front, isolated to scattered elevated convection should be ongoing
    at 12Z Thursday across parts of the Lower MO Valley. This activity
    may persist eastward through the morning and pose a threat for
    isolated severe hail. Neutral mid-level height change is anticipated
    in its wake, likely confining early evening surface-based storm
    potential to immediately downstream of the triple-point region in
    the KS/NE/MO/IA border area. While the spatial extent of MLCIN away
    from the dryline is a concern, another day of modifying moisture
    return northward from the western Gulf should yield a confined plume
    of upper 50s surface dew points and moderate buoyancy. A veering
    wind profile with height will foster strong deep-layer shear and
    supercell potential.

    As the low-level jet becomes rather strong across OK/KS/MO, greater
    convective coverage is anticipated Thursday night. Elevated storms
    producing large hail should be the primary hazard from the
    post-frontal environment in central/eastern NE to across the Mid-MS
    Valley by early morning Friday.

    ..Grams.. 04/15/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Apr 25 09:24:00 2025
    ACUS03 KWNS 250731
    SWODY3
    SPC AC 250730

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 AM CDT Fri Apr 25 2025

    Valid 271200Z - 281200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    CENTRAL NEBRASKA AND SOUTHERN SOUTH DAKOTA...

    ...SUMMARY...
    Isolated severe storms are possible across the southern High Plains
    and central Plains Sunday afternoon/evening. Scattered severe storms
    are possible across the northern Plains and Upper Midwest Sunday
    evening/night.

    ...Discussion...
    A moderately strong mid-level jet streak will extend from the
    Southwest and into the Central Plains on Sunday as a mid-level
    trough advances eastward through the Intermountain West. As this
    occurs, a strong surface cyclone will develop in the central High Plains/northern Plains. This strengthening cyclone will draw richer
    low-level moisture into the northern Plains while a dryline sharpens
    across the High Plains.

    Forecast guidance is consistent showing a sharp dryline extending
    from southwest Nebraska southward to the Texas Big Bend. Mid to
    upper 60s dewpoints east of this dryline and strong heating will
    support moderate to strong instability by Sunday afternoon. Forecast
    soundings show a weakly capped airmass along the entirety of the
    dryline. Therefore, weak height falls and a sharp dryline
    circulation will likely be sufficient for at least isolated
    supercell development along the dryline. At this time, storm
    coverage appears too sparse to support greater probabilities, but a
    favorable environment will support a conditional threat for all
    severe weather hazards wherever supercells can develop.

    Farther north, near the surface low, storm coverage probabilities
    increase due to stronger forcing. A slight risk has been introduced
    across portions of central Nebraska into southern South Dakota where
    the greatest potential for late afternoon/evening supercell
    development exists. As the low-level jet intensifies after 00Z, more
    widespread thunderstorm development is anticipated along and north
    of the warm front across the Dakotas and into western Minnesota
    Sunday night.

    ..Bentley.. 04/25/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Apr 29 08:16:00 2025
    ACUS03 KWNS 290718
    SWODY3
    SPC AC 290717

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0217 AM CDT Tue Apr 29 2025

    Valid 011200Z - 021200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
    TEXAS INTO THE MISSISSIPPI/OHIO VALLEY AND NORTHWARD TO THE GREAT LAKES...

    ...SUMMARY...
    Scattered thunderstorm development is expected from central Texas
    into the Mississippi and Ohio Valleys northward to the Great Lakes. Thunderstorms will pose a risk for strong to severe winds and hail.

    ...Discussion...
    A mid-level trough will eject across the Midwest into the
    Mississippi and Ohio Valleys region on Thursday, with a broad area
    of enhanced southwesterly flow extending from the lower Mississippi
    Valley into the Great Lakes region. A cold front will sag southward
    through this region, with potential for scattered thunderstorm
    development throughout the day Thursday across a broad region. A
    primarily marginal risk for wind and hail will be possible with this
    activity. This overall risk is limited by displacement of better
    shear northward through time with respect to the more favorable air
    mass across Tennessee southward into northern MS/AR/northern LA.
    Nonetheless, dew points in the mid 50s to 60s will extend as far
    north as the Great Lakes, where stronger deep layer shear is
    forecast which supports bringing the probabilities into this region.

    Early in the D3/Thursday period, a line of thunderstorms may be
    ongoing across northeastern Texas into central Arkansas. Some re-intensification of this activity will be possible through the
    afternoon as the air mass downstream warms and becomes favorably
    unstable. Weaker shear profiles and forcing gradually shifting
    northward through the afternoon/evening will likely keep this threat
    lower. Nonetheless, potential for damaging wind will be possible.

    Further west across the dryline in central Texas, deep layer flow
    will remain modest enough to support potential for some thunderstorm development by the late afternoon. While low level shear will be
    weak, deep layer flow will support potential for instances of severe
    hail, given steep low to mid-level lapse rates.

    ..Thornton/Bentley.. 04/29/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sat May 3 09:37:00 2025
    ACUS03 KWNS 030739
    SWODY3
    SPC AC 030738

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0238 AM CDT Sat May 03 2025

    Valid 051200Z - 061200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
    SOUTHERN HIGH PLAINS INTO CENTRAL TEXAS...

    ...SUMMARY...
    Severe thunderstorms are possible from the southern High Plains into
    parts of central Texas Monday afternoon and evening. Large to very
    large hail and severe winds are the primary threats. Additional
    strong to severe storms capable of large hail are possible along the
    eastern Florida Peninsula coast.

    ...Synopsis...
    With the upper-level blocking pattern still in place, movement of
    the upper lows in the Ohio Valley and Southwest will be slow. The
    Southwest upper low is expected to make enough progress eastward
    that stronger mid-level winds will spread more broadly across the
    southern Plains.

    ...Southeast Colorado into southern High Plains/central Texas...
    Moisture return will continue roughly along the Rio Grande Valley
    into portions of central Texas and the Permian Basin. Models differ
    on the northward advancement of this moisture, but generally agree
    that low 60s F dewpoints should reach southeast New Mexico and parts
    of the Trans-Pecos/Big Bend. As the mid-level shortwave trough
    ejects into the region by the afternoon, convection is expected to
    form within the Davis Sacramento Mountains as well as on the surface trough/dryline. These initial storms will likely be supercellular
    given 50-55 kts of effective shear and 1500-2500 J/kg MLCAPE. Large
    to very-large hail and isolated severe gusts would be the main
    threats. During the evening, the low-level jet and moisture
    advection will strengthen. Upscale growth into one or more clusters
    of storms will be possible as this occurs. This pattern would
    support MCS development and a greater risk for severe wind gusts,
    but with the placement of the theta-e gradient uncertain, an
    increase in severe probabilities will be withheld at this point.

    Additional strong/severe storms are possible along the pseudo warm front/moisture gradient in central Texas during the afternoon. There
    is some potential for additional activity during the evening
    overnight depending on the evolution of convective clusters/MCSs
    farther west.

    ...Florida...
    Moderately strong flow aloft will continue on Monday across the
    Florida Peninsula on the southern flank of the upper low.
    Temperatures aloft will remain relatively cool (-10 to -12 C at 500
    mb) and stronger surface heating should promote 1500 to perhaps 2000
    J/kg MLCAPE. As storms develop on the eastern sea breeze boundary, a
    few strong to severe storms will be capable of large hail and
    isolated damaging winds.

    ...Mid-Atlantic...
    Early day precipitation and cloud cover make afternoon
    destabilization uncertain in this region. Winds fields will support
    organized storms, however. If confidence increases in greater
    destabilization within parts of the Blue Ridge/Piedmont region, a
    marginal hail/wind risk may be warranted.

    ..Wendt.. 05/03/2025

    $$
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