• DAY3 3/5 RISK AREA POSTED

    From Mike Powell@618:250/6 to All on Wed Apr 15 08:48:08 2026
    ACUS03 KWNS 150729
    SWODY3
    SPC AC 150728

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0228 AM CDT Wed Apr 15 2026

    Valid 171200Z - 181200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF NORTHERN OKLAHOMA AND EASTERN KANSAS...MISSOURI...IOWA...AND FAR
    NORTHWEST ILLINOIS...

    ...SUMMARY...
    Widespread severe thunderstorms are expected from parts of the
    southern Plains to the Middle and Upper Mississippi Valley vicinity
    on Friday and Friday night. All severe hazards will be possible.

    ...Southern Plains to MS Valley...

    A robust upper trough will eject eastward from the northern High
    Plains and central Rockies to the Upper Midwest and central Plains
    on Friday. As this occurs, strong deep-layer southwesterly flow will
    overspread portions of the central/southern Plains to the Mid/Upper
    MS Valley and Great Lakes. Flow at 850-700 mb around 40-60 kt will
    be common. At the surface, a cold front will extend from northern MN
    to a low over eastern NE Friday morning. Meanwhile, a dryline will
    extend southwest from the NE low into central KS, northwest OK and
    western TX. A warm front initially arcing across central IA into
    south-central IL will lift northward through the period ahead of the eastward-advancing surface low tracking across northern IA/southern
    MN into WI. A warm sector characterized by mid/upper 60s F dewpoints
    will be in place across the southern Plains to the Mid-MS Valley by
    midday, with a narrow plume of low 60s F dewpoints extending north
    into portions of eastern MN and WI. Steep midlevel lapse rates (7-8
    C/km) will overspread this moist boundary layer, resulting in
    moderate to strong destabilization.

    As strong ascent overspreads the aforementioned surface boundaries
    by mid afternoon, widespread thunderstorm development is expected.
    While initial supercells are possible given a favorable
    thermodynamic environment and supercell vertical wind profiles,
    linear forcing along the front combined with strong deep-layer
    southwesterly flow parallel to the initiating boundary may result in
    rapid upscale development into a QLCS, particularly from northeast
    KS/northwest MO into IA. A well-organized line of convection will
    pose a damaging wind risk along with possible QLCS tornadoes as
    convection develops eastward through the afternoon/evening. If any
    discrete supercells develop, an all-hazards risk will also accompany
    that activity.

    Further south across southern KS into OK, supercell development may
    be more probable, at least initially. Convection will initially
    develop along the dryline prior to the cold front overtaking this
    boundary later in the evening. Any supercells that develop and can
    maintain discrete characteristics will pose a risk for very large
    hail, strong tornadoes, and damaging winds. With time, the cold
    front will overtake the dryline during the evening and move
    southeast overnight. Linear convection is expected along the front,
    posing a damaging wind and isolated tornado risk during the
    nighttime hours.

    Capping, weakening large-scale ascent and more modest vertical shear
    with southern extent may limit storm potential along the dryline in western/west-central TX.

    ..Leitman.. 04/15/2026

    $$
    --- MultiMail/DOS
    * Origin: Project Scorpio TEST (618:250/6)
  • From Mike Powell@618:250/6 to All on Thu Apr 23 08:35:18 2026
    ACUS03 KWNS 230728
    SWODY3
    SPC AC 230727

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0227 AM CDT Thu Apr 23 2026

    Valid 251200Z - 261200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF SOUTH-CENTRAL KANSAS INTO CENTRAL AND EASTERN OKLAHOMA AND FAR
    NORTHWEST ARKANSAS...

    ...SUMMARY...
    Severe thunderstorms will likely develop across portions of Oklahoma
    and Kansas during the evening. These storms will pose a risk of very
    large hail, damaging winds, and a couple of tornadoes. Isolated
    severe thunderstorms may also develop across portions of North Texas
    during the afternoon.

    ... Synopsis ...

    Increasingly diffluent southwest flow will overspread the Southern
    and Central Plains on Saturday as the midlevel pattern responds to a
    strong shortwave trough/vorticity maximum moving into the Southwest.
    This will induce strong southerly winds across the Plains, helping
    to quickly draw an old frontal boundary northward. This boundary
    should be oriented from northwest to southeast across portions of
    Oklahoma by late Saturday.

    ... Portions of Kansas, Oklahoma, and western Arkansas ...

    Most of the day should be devoid of thunderstorms as mid-level
    heights rise downstream of a digging trough across the Southwest. At
    the same time, strong southerly winds will transport Gulf moisture
    northward from the far Southern Plains into the Central Plains.
    Diurnal heating of this airmass will result in the development of
    strong instability across much of the area, as maximum SBCAPE values
    approach 4000 J/kg across portions of north Texas into central Oklahoma.

    During the late evening a subtle perturbation within the southwest
    flow is forecast to approach Oklahoma. In response to this, the
    low-level jet is forecast to increase to between 30 and 40 knots. As
    it crosses the northward moving warm front, this warm-air
    advection/isentropic ascent will combine with modest large-scale
    ascent from the approaching midlevel perturbation to support
    scattered thunderstorm develop on the north side of the moisture
    gradient. Although differences exist between the various models, the
    generic depiction of forecast soundings show long hodographs with
    varying degrees of low-level curvature in the presence of 2000-3000
    J/kg of MUCAPE. Thus, any storm that develops within the environment
    will be capable of producing all hazards initially. With time,
    thunderstorms should grow upscale into one or more southeast moving
    bowing segments capable of producing damaging winds with perhaps a
    QLCS tornado threat.

    ... North Texas into Southern Oklahoma ...

    Diurnal heating of a moist airmass to the east of a dryline will
    result in an extremely unstable airmass developing by the afternoon.
    Although the region will be devoid of large-scale forcing for
    ascent, temperatures in the 90Fs to the west of the dryline may be
    sufficient to induce dryline circulations capable of initiating
    isolated thunderstorms. Any thunderstorm that develops will be
    capable of producing very large hail.

    ..Marsh.. 04/23/2026

    $$
    --- MultiMail/DOS
    * Origin: Project Scorpio TEST (618:250/6)
  • From Mike Powell@618:250/6 to All on Fri Apr 24 09:08:44 2026
    ACUS03 KWNS 240731
    SWODY3
    SPC AC 240730

    Day 3 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0230 AM CDT Fri Apr 24 2026

    Valid 261200Z - 271200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SUNDAY EVENING
    INTO SUNDAY NIGHT ACROSS MUCH OF KANSAS AND ADJACENT PORTIONS OF
    NORTHERN OKLAHOMA...WESTERN MISSOURI...

    ...SUMMARY...
    Widely scattered severe storms with potential to produce large hail
    and a couple of strong tornadoes are possible by early Sunday
    evening across parts of the central and southern Great Plains,
    before one or two organizing clusters of storms spread toward the
    middle/lower Missouri Valley with potentially damaging wind gusts.

    ...Discussion...
    A remnant elongated cyclonic mid-level circulation/shear axis may
    tend to shift north-northeastward through Saskatchewan/Manitoba
    through this period, while larger-scale troughing along an axis
    inland of the U.S. Pacific coast through the Hudson Bay vicinity
    weakens through this period. However, mid/upper ridging across southern/central Mexico into portions of the southern Great Plains
    and lower Mississippi Valley appears likely to maintain considerable
    strength, while a notable short wave perturbation accelerates out of
    the southern Great Basin/lower Colorado Valley, within strong
    southwesterly flow between the two features.

    Models suggest that stronger mid-level height falls will generally
    overspread the eastern Colorado/western Kansas/southwest Nebraska
    vicinity of the high plains late Sunday afternoon into evening,
    before reaching southern portions of the middle Missouri Valley by
    12Z Monday, accompanied by a developing low within the northern
    portion of deepening surface troughing extending southward into the
    southern Great Plains. Another low, developing by Sunday afternoon
    across the southeastern Colorado/Texas and Oklahoma Panhandle region
    may reach portions of central Kansas.

    In response to these developments, seasonably moist low-level air,
    initially confined to the southern Great Plains, perhaps as far
    north as central Oklahoma at the outset of the period, may tend to
    advect in a corridor ahead of a sharpening dryline across western
    Oklahoma into western Kansas by late afternoon. Downstream, models
    suggest that a warm frontal zone may become better defined by early
    Sunday evening across southern Kansas into the Ozark Plateau
    vicinity, before tending to shift northward.

    ...Great Plains...

    Although though there is not a strong signal yet evident within
    latest model output concerning potential convective evolution during
    this period, at least isolated to perhaps widely scattered supercell development may initiate along the dryline as far south as northwest
    Texas by late Sunday afternoon, in the presence of destabilization
    and strengthening shear. By early Sunday evening, this probably
    will include enlarging, clockwise curved low-level hodographs
    beneath a strengthening southerly low-level jet. This may become
    supportive of increasing potential for a couple of strong tornadoes,
    in addition to large hail, with increasing storm coverage probable
    across the western Kansas vicinity.

    Gradually, large-scale forcing for ascent, focusing along the warm
    front, may support one or two upscale growing clusters of storms
    spreading into the middle/lower Missouri Valley overnight, with
    damaging wind gusts becoming the more prominent severe hazard along
    with perhaps some continuing risk for tornadoes.

    ..Kerr.. 04/24/2026

    $$
    --- MultiMail/DOS
    * Origin: Project Scorpio TEST (618:250/6)