• DAY2 2/5 Risk Area Posted

    From Mike Powell@618:250/1 to All on Tue Sep 2 09:18:25 2025
    ACUS02 KWNS 020601
    SWODY2
    SPC AC 020600

    Day 2 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0100 AM CDT Tue Sep 02 2025

    Valid 031200Z - 041200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
    CENTRAL INTO EASTERN KANSAS...

    ...SUMMARY...
    A risk of severe storms exists for portions of the central Plains.
    Severe wind and hail are the primary threats, and an instance or two
    of 2+ inch diameter hail is also possible.

    ...Synopsis...
    A mid-level trough will rapidly amplify across the MS Valley region
    while upper ridging persists over the Interior West tomorrow
    (Wednesday). The central U.S. will be located within a deep-layer
    northwesterly flow regime. A surface cold front will surge southward
    across the central Plains, acting as a low-level lifting source (via convergence) for seasonal low-level moisture over the region. At
    least scattered strong thunderstorms are expected ahead of the cold
    front during the afternoon. Given strong flow/shear and colder
    temperatures aloft overspreading the pre-frontal airmass with the
    passage of an embedded impulse, some of the storms are expected to
    be severe.

    ...Central Plains...
    As the surface cold front approaches central and eastern KS from the
    north, surface temperatures may exceed 80 F amid mid to upper 60s F
    dewpoints. With 7-8 C/km mid-level lapse rates overspreading this
    airmass, MLCAPE may reach as high as 2500 J/kg in spots.
    Kinematically speaking, veering low-level flow, overspread by strong northwesterlies will yield curved and elongated hodographs with
    40-50 kts of effective bulk shear. The stronger storms are expected
    to become supercells, accompanied by severe wind and hail. There are
    some indications that a couple of stronger, sustained supercells may
    develop across eastern KS during the late afternoon to early evening
    hours. Given both the vertical shear profiles and colder
    temperatures aloft, a couple instances of 2+ inch hail and perhaps a
    tornado are possible.

    ..Squitieri.. 09/02/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sun Sep 21 09:00:48 2025
    ACUS02 KWNS 210617
    SWODY2
    SPC AC 210616

    Day 2 Convective Outlook CORR 1
    NWS Storm Prediction Center Norman OK
    0116 AM CDT Sun Sep 21 2025

    Valid 221200Z - 231200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE
    EASTERN TEXAS/OKLAHOMA PANHANDLES...

    ...SUMMARY...
    Scattered severe thunderstorms will be possible on Monday across
    portions of the central and southern High Plains.

    ...Synopsis...
    On Monday, a mid-level trough will move from the upper
    Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the
    period. Farther west, a more complicated pattern will develop as a
    ridge builds into the Pacific Northwest. As this ridge builds, a
    mid-level jet streak will be shunted south across the central
    Rockies. This will deepen a mid-level low with a closed circulation
    likely developing across the central High Plains region by 12Z
    Tuesday. In addition, a closed low will persist off the southern
    California coast for much of the period. High pressure will be
    present across much of the western CONUS with weak lee troughing
    along the central and southern High Plains. The surface pattern will
    be somewhat less defined farther east with a weak remnant front
    likely through the Upper Midwest to the western Great Lakes. High
    pressure will dominate areas east of the Appalachians.

    ...Central Plains...
    Moderate to strong instability will develop by Monday afternoon in
    the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings
    show a strongly capped airmass across Kansas/Oklahoma and given the
    relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the
    mid-level trough will start to overspread the Plains with a
    strengthening low-level jet potentially approaching 50 knots.
    Cooling temperatures aloft and strong isentropic ascent should
    result in thunderstorm development after sunset Monday evening. Seep
    mid-level lapse rates and strengthening effective shear (40 to 50
    knots) will support the potential for supercells with some hail
    threat. As upscale growth continues, the severe wind threat should
    increase and continue into the overnight period into portions of central/northern Oklahoma.

    ...NE/IA to Lake Michigan...
    Diurnal thunderstorm development is possible along a diffuse frontal
    zone from Nebraska to southern Wisconsin. Modest lapse rates and
    moderate instability along this zone will support some multicells
    capable of some hail or damaging wind gusts. However, mostly weak
    deep-layer shear (20 knots) and weak upper forcing should keep the
    overall threat along this zone relatively isolated.

    ...Tennessee Valley to the eastern Great Lakes...
    A weak mid-level shortwave trough is forecast to move through the
    Ohio Valley on Monday with moderate instability forecast ahead of
    it. An uncapped airmass and some moderate upper-level support in a
    broader zone of weak, but persistent isentropic ascent should
    support scattered thunderstorm development. Lapse rates will be
    poor, but modest effective shear amid 30 to 35 knots of mid-level
    flow may support some organized multicells capable of damaging wind
    gusts Monday afternoon/evening.

    ..Bentley.. 09/21/2025

    $$
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  • From Mike Powell@618:250/1 to All on Mon Sep 22 09:18:51 2025
    ACUS02 KWNS 220559
    SWODY2
    SPC AC 220557

    Day 2 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1257 AM CDT Mon Sep 22 2025

    Valid 231200Z - 241200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
    OKLAHOMA...FAR NORTHEAST TEXAS...AND MUCH OF ARKANSAS...

    ...SUMMARY...
    Strong to severe storms are possible from the southern Plains to the
    Tennessee Valley on Tuesday. Strongest thunderstorm activity is
    expected across eastern Oklahoma into northeastern Texas and
    Arkansas, where supercells capable of all severe hazards are
    possible by afternoon.

    ...Synopsis...
    A positively tilted mid-level trough will begin the period across
    eastern Colorado and shift east through the day to the Missouri
    Valley region by 12Z Wednesday. A 40 to 50 knot mid-level jet streak
    associated with overnight convection Monday night across KS/OK will
    shift east across MO/AR during the day Tuesday and gradually weaken.
    In its wake, the primary mid-level jet streak will emerge across
    Oklahoma and strengthen Tuesday night as it moves from Oklahoma into
    Arkansas. A weak surface low is forecast to be across northwest
    Oklahoma Tuesday morning. This surface low and its associated cold
    front will drift slowly east through the day.

    ...Eastern Oklahoma into much of Arkansas and northeast Texas...
    A large MCS will likely be ongoing Tuesday morning across eastern
    Kansas, southwest Missouri, and northeast Oklahoma on the nose of a
    40 to 50 knot low-level jet. As the low-level jet weakens during the
    morning and storms move east of the greatest shear/instability,
    expect the MCS to weaken. Some isolated damaging wind gusts may
    persist across northern Arkansas/southern Missouri and into TN/KY,
    but expect this activity to remain mostly sub-severe.

    The primary severe weather concern will be Tuesday afternoon/evening
    across eastern Oklahoma and western Arkansas. Strong instability is
    forecast across this region in the wake of the morning MCS as cool
    temperatures aloft overspread low to mid 70s dewpoints. RAP/NAM
    forecast soundings show only modest heating is necessary to erode
    inhibition. Therefore, expect additional thunderstorm development
    during the afternoon along and ahead of the cold front as it moves
    across Oklahoma. Storm motion orthogonal to the front should favor
    movement along and perhaps off of the front and into the warm
    sector. Therefore, all severe hazards will be possible across this
    region in a favorable environment featuring strong instability,
    moderate deep-layer shear, and elongating, cyclonically curved
    hodographs.

    A conditional, potentially more volatile tornado threat is possible
    across eastern Oklahoma and western Arkansas if significant
    destabilization can occur north of any outflow boundary left by
    morning convection. 03Z RAP/00Z NAM forecast soundings near Fort
    Smith capture this conditional environment well and would
    potentially support strong tornadoes. However, this evolution is
    highly dependent on the evolution of Day 1 convection across Kansas
    and Oklahoma which still remains unclear. In addition, the time
    window for this favorable environment would be narrow which also
    adds conditionality to the risk. This scenario will be monitored
    closely and a Level 3/Enhanced Risk may be justified in later
    outlooks if this scenario appears more likely.

    ...Central Texas...
    Moderate instability is forecast across central/northern Texas
    Tuesday afternoon with eroding inhibition by mid-afternoon. Shear
    will be relatively weak, but will increase during the
    afternoon/evening as the mid-level jet streak drifts south. The most
    favorable zone for thunderstorm development will be the triple point
    where the cold front and dryline intersect across North Texas.
    However, additional isolated storms may also develop along the
    dryline and cold front. Isolated large hail and damaging wind gusts
    will be the primary threat from these storms Tuesday
    afternoon/evening.

    ...Tennessee Valley...
    A weak warm front may be a focus for storm development Tuesday afternoon/evening across western/middle Tennessee as moderate
    instability develops across the region. Deep-layer shear should
    remain quite weak (less than 20 knots) as the primary mid-level jet
    streak remains farther west. However, a few stronger storms capable
    of damaging wind gusts may develop during the afternoon/evening.

    ..Bentley.. 09/22/2025

    $$
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