• DAY2SVR: Enhanced Risks

    From Dumas Walker@21:1/175 to All on Sun Mar 31 08:46:00 2024
    ACUS02 KWNS 310601
    SWODY2
    SPC AC 310600

    Day 2 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0100 AM CDT Sun Mar 31 2024

    Valid 011200Z - 021200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE SOUTHERN AND CENTRAL PLAINS EAST-NORTHEASTWARD INTO THE LOWER
    OHIO VALLEY...

    ...SUMMARY...
    A widespread severe threat, with a potential for large hail, wind
    damage and tornadoes, is expected on Monday and Monday night from
    parts of the southern Plains northeastward into the mid Mississippi
    Valley. Very large hail will be possible across parts of the
    southern Plains and Ozarks. The greatest tornado threat is expected
    from southern Missouri into southern Illinois Monday evening. The
    severe threat is also expected to impact parts of the Ohio Valley,
    especially during the evening and overnight period.

    ...Southern and Central Plains/Ozarks/Mid Mississippi Valley/Lower
    Ohio Valley...
    A positively tilted upper-level trough will move through the Desert
    Southwest on Monday, as an 80 to 100 knot mid-level jet moves
    through the base of the system. The exit region of the mid-level jet
    will overspread a moist and unstable airmass across the southern
    Plains during the afternoon. At the surface, a low will deepen in
    west Texas, moving eastward into Oklahoma by mid to late afternoon.
    Surface dewpoints in the mid to upper 60s F will be in place across
    the eastern half of Texas, and from central and eastern Oklahoma
    extending eastward into the mid Mississippi Valley. Moderate
    instability is expected to develop by afternoon to the east of a
    dryline from north Texas northward to near a triple point in central
    Oklahoma. The airmass should be uncapped, allowing for widespread
    convective development from the mid to late afternoon into the
    evening. Thunderstorms will also likely develop in the Ozarks and
    mid Mississippi Valley during the evening, as the mid-level jet
    approaches the region from the southwest.

    Within the exit region of the mid-level jet, a plume of steep
    mid-level lapse rates is forecast to advect quickly eastward across
    the southern Plains during the late afternoon and early evening.
    Forecast soundings in east-central Oklahoma at 00Z/Tuesday suggest
    that 700-500 mb lapse rates within this plume will be in the 7.5 to
    8 C/km range. This, combined with strong deep-layer shear, will
    support a large-hail threat with supercells. Hailstones of greater
    than 2 inches in diameter will be possible with the more dominant
    and intense storms. The potential for very large hail may extend as
    far northeast as the Ozarks, as the exit region of the mid-level jet
    passes over the area during the early to mid evening.

    From southern Missouri into southern Illinois, a warm front will
    likely be in place. The surface low is forecast to move
    east-northeastward along this corridor. Forecast soundings ahead of
    the surface low from 03Z to 06Z/Tuesday suggest that 0-3 km
    storm-relative helicity will increase into 250 to 350 m2/s2 range,
    as a 50 to 60 knot low-level jet strengthens. This should be
    favorable for tornadoes with the more dominant supercells that
    interact with the warm front. A potential for strong tornadoes will
    exist. A large MCS is forecast to organize from the southern Plains
    into the mid Mississippi Valley during the evening. The stronger
    storms within this MCS will also have wind-damage potential.

    ...Mid to Upper Ohio Valley/Central Appalachians/Mid-Atlantic...
    An anticyclonic mid-level flow pattern will be in place on Monday
    across the eastern U.S. At the surface, a quasi-stationary front is
    forecast to be located from southern Ohio east-southeastward into
    the Mid-Atlantic. This boundary will likely be a focus for
    convective development from the daytime hours into the overnight
    period. Although instability is forecast to remain weak near the
    boundary, strong deep-layer shear will be in place. This should
    support an isolated severe threat, potentially persisting for an
    extended period of time. Hail and isolated damaging gusts will
    likely be the primary concerns. The severe threat will likely be
    more isolated with eastward extent, mainly due to more limited
    low-level moisture content across the Mid-Atlantic.

    ..Broyles.. 03/31/2024

    $$
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  • From Dumas Walker@21:1/175 to All on Sun Mar 31 18:27:00 2024
    ACUS02 KWNS 311727
    SWODY2
    SPC AC 311725

    Day 2 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1225 PM CDT Sun Mar 31 2024

    Valid 011200Z - 021200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
    OKLAHOMA INTO THE LOWER OHIO VALLEY...

    ...SUMMARY...
    Severe weather is expected to occur over a broad region from the
    southern Plains, the Ozarks, portions of the Ohio Valley, and into a
    small part of the Mid-Atlantic. Large to very-large hail, damaging
    winds, and tornadoes are possible. The severe threat will peak afternoon/evening in the southern Plains with the greatest threat
    for the Ohio Valley vicinity being the evening/overnight period.

    ...Synopsis...
    A rather broad, positively tilted upper trough will be positioned
    within the Four Corners region. A mid-level jet streak will move
    northeastward through the Trans-Pecos and into Red River region by
    early evening. This feature is forecast to be weakening during the
    afternoon as it shifts northeast. As the mid-level jet moves into
    the Midwest during the evening, a short-wave trough is expected to
    intensify in the Upper Midwest, with mid-level winds increasing
    across the Ohio Valley. At the surface, a modest surface mass
    response is anticipated in the southern Plains. Guidance generally
    depicts a modest surface low developing in western/central Oklahoma.
    A dryline will be pendant from this feature and provide a focus for
    convective development during the afternoon. This surface low will
    track northeastward along with its parent upper trough along nearly
    stationary boundary from the Ozarks into the Ohio Valley and
    Mid-Atlantic. Some deepening of this low may occur very late in the
    period as the upper wave intensifies.

    ...Southern High Plains...
    As the upper-level trough ejects into the region, sufficient
    moisture for high-based convection should exist in the Texas
    Panhandle and parts of the South Plains. A few convectively enhanced
    gusts may occur with this activity. Buoyancy should remain too
    limited for more than small hail.

    ...Oklahoma/Texas...
    Between cloud cover and a capping inversion aloft, storm development
    along the dryline should hold off until the mid/late afternoon when
    greater mid-level ascent arrives. Strong deep-layer shear should
    promote supercell storm structures at least initially. Hodographs
    will be long and generally straight, but there are also veer-back
    signatures that could indicate some potential for a messier storm
    mode. Even so, potential for large to very-large hail is evident
    given the shear and mid-level lapse rates. The tornado risk should
    be mitigated to some extent by the overall weak low-level shear.
    That being said, supercells that can be maintained into the early
    evening (00-03Z) will see a brief window of increased tornado
    potential as the low-level jet modestly strengthens.

    Farther south into central Texas, forcing will be a bit weaker and
    capping a touch stronger. Storms that do develop will likely have
    supercellular characteristics. Large-hail and damaging winds are the
    most likely hazards.

    ...Ozarks into Ohio Valley...
    Some warm advection driven convection may be ongoing early in the
    period across parts of these regions. These storms will likely be
    elevated with a risk for large hail and isolated damaging winds. By
    the afternoon, greater potential for surface-based storms will exist
    from the triple point near the KS/OK border and along the cold front
    in southeast Kansas into Missouri. These storms will at least
    initially be supercells with potential for very-large hail. Storms
    are expected to grow upscale with a greater risk of damaging winds.
    While not overly strong, low-level shear should remain sufficient
    for a threat of QLCS circulations/tornadoes.

    It is possible that initially elevated storms may become near
    surface based during the afternoon in the Ohio Valley. Additional
    storms will likely move in from the west later in the evening
    overnight as the shortwave trough/surface low move northeastward.
    Damaging winds and QLCS tornadoes would be possible with this
    activity. The hail threat is a bit uncertain given the potential for
    more linear storm modes. However, large hail will remain possible.

    ...Parts of Mid-Atlantic...
    Overall storm coverage is uncertain given the generally neutral
    mid-level height changes through the period. Some model solutions do
    produce convection along the stationary surface boundary. Given
    strong mid-level winds and modestly steep lapse rates aloft,
    marginally severe hail and isolated damaging winds could occur with
    the stronger storms.

    ..Wendt.. 03/31/2024

    $$
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  • From Dumas Walker@21:1/175 to All on Mon Apr 1 08:44:00 2024
    ACUS02 KWNS 010600
    SWODY2
    SPC AC 010558

    Day 2 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1258 AM CDT Mon Apr 01 2024

    Valid 021200Z - 031200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE OHIO AND TENNESSEE VALLEYS...

    ...SUMMARY...
    A severe threat is expected on Tuesday from the Ohio and Tennessee
    Valleys eastward into the Mid-Atlantic, and southward into the
    central Gulf Coast states. Wind damage and isolated large hail will
    be possible across a broad area. The tornado threat is expected to
    be greatest from middle Tennessee north-northeastward into central
    and northern Kentucky.

    ...Ohio and Tennessee Valleys/Central Gulf Coast States/Central
    Appalachians...
    An upper-level trough is forecast to move eastward into the mid to
    upper Mississippi Valley on Tuesday, as a cold front advances
    eastward toward the Ohio and Tennessee Valleys. By afternoon, a
    north-to-south corridor of maximized low-level moisture is forecast
    to be in place from the northern Gulf Coast States to central
    Kentucky, where surface dewpoints are expected to be in the mid 60s
    F. As instability increases along this corridor, numerous
    thunderstorms will likely develop, with a linear MCS organizing and
    moving eastward across the Ohio and Tennessee Valleys during the
    afternoon and evening. This large MCS should reach the central
    Appalachians by early to mid evening.

    A 90 to 100 knot mid-level jet will likely move northeastward into
    the Ohio Valley during the afternoon. This jet will create strong
    deep-layer shear across most of the region. Forecast soundings by
    21Z from middle Tennessee to central Kentucky have 0-6 km shear in
    the 70 to 80 knot range. The wind shear and strong large-scale
    ascent, associated with the mid-level jet, will be favorable for the development of a squall line Tuesday afternoon. This linear MCS will
    likely have numerous embedded severe storms with the greatest threat
    being wind damage. The wind-damage threat is expected to maximize
    during the late afternoon and early evening. QLCS tornadic
    circulations will be possible along some parts of the line,
    especially near bowing segments. An isolated large hail threat is
    also expected in areas where the squall line interacts with locally
    stronger instability, and with isolated rotating cells that develop
    ahead of the line. The severe threat is expected to decrease during
    the mid to late evening as the line moves through the central
    Appalachians.

    ...Central Gulf Coast States...
    An upper-level trough will move eastward across the southern Plains
    on Tuesday, as a cold front moves eastward into the lower
    Mississippi Valley. Surface dewpoints should be in the mid to upper
    60s F ahead of the front, where some models suggest that MLCAPE will
    peak in the 1000 to 1200 J/kg range during the afternoon. Scattered thunderstorm development appears likely to take place ahead of the
    front early in the day, with an organized line segment or cluster
    moving eastward across the central Gulf Coast States during the
    afternoon. Strong deep-layer shear will be in place, and low-level
    lapse rates will steepen during the late morning and early
    afternoon. The environment will likely support a wind-damage and
    isolated large-hail threat. An isolated tornado threat will also be
    possible, especially in the northern Gulf Coast states near the
    southern edge of the low-level jet. Large-scale ascent and
    deep-layer shear are forecast to be somewhat weaker across the
    central and southern Gulf Coast states, which should result in a
    more isolated severe threat with southward extent.

    ...Mid-Atlantic...
    An anticyclonic flow pattern is forecast across the Eastern Seaboard
    on Tuesday. At the surface, a relatively cold airmass is forecast
    across much of the Mid-Atlantic due to cold air damming. Above the
    cold surface air, elevated instability is forecast to increase
    during the evening, as the exit region of the mid-level jet moves
    through the central Appalachians. Thunderstorms that form in the
    unstable air aloft, may have a potential for marginally severe hail
    during the evening into the early overnight period.

    ..Broyles.. 04/01/2024

    $$
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