• DAY1 2/5 Risk Area Posted

    From Mike Powell@618:250/1 to All on Thu Aug 28 09:02:04 2025
    ACUS01 KWNS 281251
    SWODY1
    SPC AC 281249

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0749 AM CDT Thu Aug 28 2025

    Valid 281300Z - 291200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST
    OKLAHOMA AND ARKLATEX...

    ...SUMMARY...
    Strong thunderstorms, with an isolated hail and severe wind threat,
    are possible across parts of southern Oklahoma and northern Texas to
    the Arklatex this afternoon and evening. Isolated severe
    thunderstorms will also be possible across eastern Colorado and the
    adjacent High Plains.

    ...Southern Oklahoma/North Texas to ArkLaTex...
    Showers/thunderstorms are prevalent this morning across
    northern/eastern Oklahoma into the Ozarks to the north-northeast of
    a warm front. Within a belt of moderately strong northwesterly flow
    aloft, a shortwave trough will continue to dig southeastward from
    the south-central Plains toward the Ozarks by this evening. Related
    dynamical response and the early day convection will shunt the front
    southward later today, with ample heating/moderate destabilization
    on the southwest flank of this boundary.

    While mid-level temperatures are seasonally warm (-4C at 500 mb),
    and lapse rates are not that steep, severe hail and damaging wind
    gusts can be expected with the more robust convection as general intensification occurs by mid/late afternoon. A few initial
    supercells may occur, and some tornado risk could also exist with
    convection immediately along the boundary and east of the weak
    surface front. Clustering/upscale-quasi-linear growth should occur
    by early evening as storms progress southeastward and continue to
    pose a damaging wind risk for a time this evening.

    ...Eastern Colorado and adjacent High Plains...
    The large-scale pattern is not expected to change appreciably as
    upper ridging will hold across the southern/central Rockies. While
    mid-level flow is not that strong across Colorado, low-level upslope
    flow is expected to contribute to scattered thunderstorm development
    as boundary layer heats later this afternoon. This activity will
    spread southeastward with an attendant risk for isolated severe hail
    and gusty winds.

    ..Guyer/Kerr.. 08/28/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Sep 5 10:57:40 2025
    ACUS01 KWNS 051211
    SWODY1
    SPC AC 051209

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0709 AM CDT Fri Sep 05 2025

    Valid 051300Z - 061200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
    THE TENNESSEE VALLEY AND UPPER OHIO VALLEY...

    ...SUMMARY...
    Scattered damaging winds, isolated severe hail, and a brief tornado
    or two are possible from the Upper Ohio to Tennessee Valleys during
    the late afternoon and evening.

    ...Upper OH to TN Valleys...
    Water-vapor imagery shows a large gyre centered over Ontario and
    cyclonic flow over much of eastern North America. A series of
    mid-level disturbances/speed maxima will rotate through its base
    during the Day-1 period, and there are two lead impulses over the
    St. Lawrence Seaway and the Upper Great Lakes this morning. A
    weaker impulse associated with convection early this morning over KS
    will rapidly move east into the northern part of the OH Valley
    through this evening and immediately ahead of a more notable
    shortwave trough moving southeast from the Dakotas into the Great Lakes.

    A cold front oriented mostly north-south over the Great Lakes from a
    surface low will push east during the day, while the trailing
    southern portion of the boundary that is west-east oriented,
    gradually pushes south and eventually overtakes a residual frontal segment.

    Heating ahead of the aforementioned low-amplitude impulse and
    strengthening low-level convergence along the boundary will likely
    yield scattered to numerous showers/thunderstorms developing in the
    late afternoon to early evening. Much of the stronger mid-level
    flow will remain spatially displaced from the warm sector in the
    post-frontal airmass except over the Upper OH Valley. Moderate
    buoyancy will favor strong to severe multicells and some supercells
    (where shear is stronger). Isolated severe gusts (55-70 mph) seem
    probable which will result in scattered wind damage accompanying the
    stronger thunderstorm cores and line segments. Models differ on the
    character of mixing and hodograph size over the southeast OH/WV
    portion of the Slight Risk, but low-tornado potential may be
    greatest here compared to farther south/southwest over the TN
    Valley. The severe threat will diminish towards late evening given
    the extensive overturning and lack of stronger low-level flow/shear
    to sustain the threat overnight.

    ...North TX to Mid-South...
    An elongated mid-level thermal trough, characterized by 500-mb
    temperatures of -10 to -12 C, will extend into north TX, well to the
    south of a persistent vertically stacked cyclone over northern
    Ontario. A copious amount of high cloud cover will tend to result
    in high-level lapse rates becoming weaker during the period. Model
    data implies a messy storm mode as isolated to locally scattered
    storm coverage ensues during the late afternoon/evening. An
    isolated wind/hail risk may accompany the stronger storms.

    ..Smith/Broyles.. 09/05/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sat Sep 6 09:45:25 2025
    ACUS01 KWNS 061230
    SWODY1
    SPC AC 061229

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0729 AM CDT Sat Sep 06 2025

    Valid 061300Z - 071200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN MID-ATLANTIC REGION INTO NEW ENGLAND...

    ...SUMMARY...
    Scattered severe thunderstorms are possible from eastern
    Pennsylvania and New Jersey into New England this afternoon. The
    primary hazards will be strong to severe gusts capable of wind
    damage and a tornado or two.

    ...Northeast...
    Water-vapor imagery this morning shows a potent mid-level shortwave
    trough moving east-northeast across Lower MI and embedded within a
    larger scale cyclonic flow field over eastern North America. This
    mid-level disturbance will move into southeast Quebec by this
    evening. A weak frontal wave is forecast to evolve near the
    NY/MA/VT border by early afternoon as a cold front sharpens and
    begins to push towards the coast. A relatively moist airmass is
    evident in surface observations this morning with dewpoints in the
    lower 70s along the southern New England coast with mid to upper 60s
    farther inland.

    Despite some low cloud cover, sufficient heating will promote
    moderate destabilization by early afternoon. Convection will likely
    focus along the wind shift/cold front with scattered to numerous
    storms eventually developing by mid-late afternoon. Model guidance
    shows 35-40 kt southwesterly 700-mb flow and forecast soundings show
    hodographs enlarging in the vicinity of the weak low as it migrates north-northeast across portions of southern New England into
    southern ME. Several supercells are possible and have introduced
    5-percent tornado probabilities this outlook to highlight where the
    greatest low-level mesocyclone threat (i.e., possibility for a
    tornado or two) is forecast. Otherwise, strong to severe gusts
    capable of wind damage are expected from both supercells and the
    more organized/intense cores and line segments. As the disturbance
    becomes displaced from the region by early evening and with the loss
    of heating, the severe risk will likely diminish.

    ...Mid-Atlantic states into the Carolinas/GA...
    Southern extension of stronger flow will gradually taper with south
    extent from the Mid-Atlantic states into the Carolinas. However,
    sufficient destabilization of a seasonably moist airmass will favor
    widely scattered to scattered thunderstorms evolving into a few
    bands of thunderstorms this afternoon. The primary risk with the
    more intense thunderstorms will be strong to locally severe gusts
    capable of wind damage. This activity will likely weaken by the
    early evening.

    ..Smith/Broyles.. 09/06/2025

    $$
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  • From Mike Powell@618:250/1 to All on Mon Sep 8 08:01:32 2025
    ACUS01 KWNS 081221
    SWODY1
    SPC AC 081219

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0719 AM CDT Mon Sep 08 2025

    Valid 081300Z - 091200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    THE CENTRAL AND SOUTHERN HIGH PLAINS...

    ...SUMMARY...
    Isolated large to very large hail and severe gusts are forecast over
    portions of southwestern Kansas, northwest Oklahoma, and the Texas
    Panhandle late this afternoon into the evening.

    ...Central/Southern High Plains...
    Morning water-vapor imagery shows a mid-level shortwave trough
    moving east-southeast across the central High Plains. Scattered showers/thunderstorms are ongoing from northern KS into the
    northeast TX Panhandle associated with low-level warm-air advection.
    This convection will likely remain weak and slowly shift
    east-southeast before largely diminishing 18-21z. As the
    aforementioned disturbance moves into central KS by late afternoon,
    a differential heating zone arcing northward in wake of the
    convection will intersect with a moisture plume extending northward
    from west TX into the TX/OK/KS border region.

    Heating will contribute to a moderate to very unstable airmass
    (2000-3000 J/kg MLCAPE) from the TX Panhandle into southwest KS.
    Weak low-level convergence should prove instrumental in convective
    initiation late this afternoon into the early evening. Isolated to
    scattered thunderstorms are probable with the locally highest risk
    for severe in the northeast TX Panhandle into adjacent parts of
    northwest OK and southwest KS. Model forecast hodographs are
    elongated, which will favor supercells and hail growth given the
    magnitude of buoyancy. Large to very large hail (1 to 3 inches in
    diameter) is possible with the stronger storms. A brief tornado
    cannot be ruled out during the early evening transition when
    low-level shear increases. Severe gusts may also accompany the
    stronger cores through much of the evening before this activity
    diminishes 03-05z.

    ...Upper MS Valley Vicinity...
    Northern stream short-wave trough is forecast to dig southeast
    across southern MB/ND into the upper Red River region by early
    evening. This should aid in the development and intensification of
    a southwesterly LLJ forecast to overspread the Upper Midwest during
    the period. Large-scale forcing favors elevated convection along
    the nose of this jet, especially across the Arrowhead of MN/Lake
    Superior. Relatively steeper lapse rates may permit a few robust
    updrafts to evolve shortly after peak heating with an attendant risk
    for isolated marginally severe hail.

    ...Central OR...
    A mid- to upper-level shortwave trough located to the west of the
    northern CA coast will move east-northeast into southwest OR by late
    tonight. Heating coupled with large-scale ascent associated with
    the disturbance will favor scattered thunderstorms developing this
    afternoon near and east of the Cascades. Forecast soundings show
    500-mb temperatures around -15 deg C and weak buoyancy. A couple of
    the stronger updrafts may yield a near-severe hail threat (0.50-1.00
    inch in diameter) for a few hours.

    ..Smith/Broyles.. 09/08/2025

    $$
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  • From Mike Powell@618:250/1 to All on Thu Sep 11 08:48:34 2025
    ACUS01 KWNS 111206
    SWODY1
    SPC AC 111205

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0705 AM CDT Thu Sep 11 2025

    Valid 111300Z - 121200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN
    MONTANA INTO WESTERN NORTH DAKOTA...

    ...SUMMARY...
    Scattered severe thunderstorms are possible over eastern Montana
    into western North Dakota late this afternoon through the evening.
    The primary hazards are severe gusts and large hail.

    ...Synopsis...
    Water-vapor imagery shows a large cyclone over the West with a
    downstream ridge over the Great Plains, and a trough centered over
    the Lower Great Lakes. Southwesterly mid to high-level flow extends
    from the base of the larger-scale western U.S. trough northeastward
    through the Great Basin and into the northern Great Plains. A
    mid-level disturbance implied in morning water-vapor imagery over
    western WY, is forecast to move northeast into eastern MT/western ND
    towards this evening.

    In the low levels, a plume of seasonably rich moisture will protrude
    northward from the central Plains into the Dakotas and eastern MT.
    A lee trough will extend southward from a surface low over the
    northern High Plains.

    ...Rockies into the northern Plains...
    An ongoing cluster of weak thunderstorms associated with warm-air
    advection near the ND/Manitoba border will continue to move
    east-northeastward into southern Canada ahead of a pair of MCVs over
    western ND/eastern MT. Diurnal heating over the higher terrain from
    near the Four Corners northward into southern MT will favor
    scattered thunderstorms developing during the midday into the early
    afternoon. Storm coverage will probably increase further over the
    central Rockies during the afternoon, with the stronger storms
    capable of an isolated hail/wind threat. As the airmass
    destabilizes over the plains, particularly across eastern MT within
    the moist plume primarily north of the surface low, isolated to
    scattered storms are forecast by mid to late afternoon. This
    initial activity will probably develop near the MT/WY border with
    upscale growth into a cluster possible during the evening.
    Deep-layer shear supporting organized storm modes coupled with steep
    lapse rates, will combine to aid in several stronger storms capable
    of a hail/wind threat. The wind threat will probably continue into
    ND during the evening within the terminus region of a 35-40 kt
    southerly LLJ. A gradual transition to increasingly elevated
    convection is expected late as convective inhibition increases and
    the overall severe risk lessens.

    ..Smith/Broyles.. 09/11/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Sep 12 13:15:56 2025
    ACUS01 KWNS 121641
    SWODY1
    SPC AC 121639

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1139 AM CDT Fri Sep 12 2025

    Valid 121630Z - 131200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FOUR
    CORNERS AREA AND NORTHERN HIGH PLAINS...

    ...SUMMARY...
    Isolated severe storms will be possible today across the Four
    Corners area and central Rockies, with an increasing risk for severe
    storms into late afternoon and tonight across the northern Plains.

    ...Four Corners Region/central Rockies...
    Ahead of the prominent upper trough centered over the Great Basin
    and Lower Colorado River Valley, a lead mid-level impulse and
    related height falls and a strengthening of cyclonic flow aloft will
    influence the region. Cooling mid-level temperatures and a modestly
    warming boundary layer will further steepen lapse rates diurnally,
    with strong to severe storms expected to further develop into the
    afternoon. Relatively strong flow aloft with 40+ kt effective shear
    will support some supercell structures, with a related enhanced
    potential for severe hail, aside from locally gusty thunderstorm
    winds. More severe-favorable ingredients and a somewhat higher
    potential for severe storms appears to exist across the Four Corners
    vicinity including northwest New Mexico across western Colorado
    through the afternoon.

    ...Northern Plains including Eastern Montana/western Dakotas...
    Thunderstorm development/intensification is expected by late
    afternoon, initially on an isolated basis across central/eastern
    portions of Montana and Wyoming. Cooling mid-level temperatures and
    surface dew points in the 50s F will contribute to 500-1000 J/kg
    MLCAPE. Southwesterly deep-layer shear averaging 20-35 kt will be
    favorable for isolated storms with hail potential. Storm coverage
    should steadily increase into the evening toward the western
    Dakotas, aided by the arriving influence of greater forcing for
    ascent as located over the central Rockies early today. Hail
    potential will become more common this evening, with localized
    severe wind potential also modestly increasing. Strong/locally
    severe storms will potentially persist overnight across the western
    and central Dakotas.

    ...Northern/central Minnesota to northwest Wisconsin...
    Very isolated elevated severe storms, with hail as the most probable
    hazard, may continue east-southeastward today, semi-focused by
    elevated moisture transport well to the north of a warm front.

    ..Guyer/Jirak.. 09/12/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Sep 12 18:17:24 2025
    ACUS01 KWNS 122002
    SWODY1
    SPC AC 122000

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0300 PM CDT Fri Sep 12 2025

    Valid 122000Z - 131200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FOUR
    CORNERS VICINITY AND ALSO ACROSS THE NORTHERN HIGH PLAINS...

    ...SUMMARY...
    Isolated severe storms remain possible this afternoon across the
    Four Corners area and central Rockies, with an increasing risk for
    severe storms into late afternoon and tonight across the northern Plains.

    ...Four Corners vicinity into the Southwest...
    The Slight Risk has been expanded westward into parts of
    southeast/east-central UT, where favorable deep-layer shear and
    modest but sufficient instability remains in place this afternoon.
    Occasional small supercells will continue to be possible, with a
    threat of hail and localized strong/severe gusts. See MCD 2066 for
    more details.

    The Marginal Risk has been expanded slightly westward across
    southeast AZ, based on trends on visible satellite. The 18Z TUS
    depicted a favorable conditional environment for severe storms, with
    moderate MLCAPE and deep-layer shear. While the threat should
    generally remain rather isolated, a supercell or two will be
    possible, with an attendant threat of hail and localized severe
    gusts. See MCD 2065 for more information.

    ...Northern High Plains vicinity...
    Only modest adjustments have been made to the Marginal Risk across
    the northern High Plains vicinity, with no changes to the Slight
    Risk. An isolated threat for hail and strong/severe gusts may
    develop later this afternoon, with some increase in coverage of the
    severe threat expected into this evening. See MCD 2067 and the
    previous discussion below for more details.

    ...East-central MN into northwest WI...
    Much of the Marginal Risk across MN and northwest WI has been
    removed. An earlier cluster of storms has generally weakened this
    afternoon across east-central MN, though modestly steep midlevel
    lapse rates and relatively favorable effective shear could still
    support a threat for small to near-severe hail and locally gusty
    winds as these storms move into northwest WI. Additional elevated
    convection may develop later tonight across the same general region,
    but severe potential with the later storms appears limited at this time.

    ..Dean.. 09/12/2025

    .PREV DISCUSSION... /ISSUED 1139 AM CDT Fri Sep 12 2025/

    ...Four Corners Region/central Rockies...
    Ahead of the prominent upper trough centered over the Great Basin
    and Lower Colorado River Valley, a lead mid-level impulse and
    related height falls and a strengthening of cyclonic flow aloft will
    influence the region. Cooling mid-level temperatures and a modestly
    warming boundary layer will further steepen lapse rates diurnally,
    with strong to severe storms expected to further develop into the
    afternoon. Relatively strong flow aloft with 40+ kt effective shear
    will support some supercell structures, with a related enhanced
    potential for severe hail, aside from locally gusty thunderstorm
    winds. More severe-favorable ingredients and a somewhat higher
    potential for severe storms appears to exist across the Four Corners
    vicinity including northwest New Mexico across western Colorado
    through the afternoon.

    ...Northern Plains including Eastern Montana/western Dakotas...
    Thunderstorm development/intensification is expected by late
    afternoon, initially on an isolated basis across central/eastern
    portions of Montana and Wyoming. Cooling mid-level temperatures and
    surface dew points in the 50s F will contribute to 500-1000 J/kg
    MLCAPE. Southwesterly deep-layer shear averaging 20-35 kt will be
    favorable for isolated storms with hail potential. Storm coverage
    should steadily increase into the evening toward the western
    Dakotas, aided by the arriving influence of greater forcing for
    ascent as located over the central Rockies early today. Hail
    potential will become more common this evening, with localized
    severe wind potential also modestly increasing. Strong/locally
    severe storms will potentially persist overnight across the western
    and central Dakotas.

    ...Northern/central Minnesota to northwest Wisconsin...
    Very isolated elevated severe storms, with hail as the most probable
    hazard, may continue east-southeastward today, semi-focused by
    elevated moisture transport well to the north of a warm front.

    $$
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  • From Mike Powell@618:250/1 to All on Sun Sep 14 10:12:10 2025
    ACUS01 KWNS 141242
    SWODY1
    SPC AC 141240

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0740 AM CDT Sun Sep 14 2025

    Valid 141300Z - 151200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
    THE NORTHERN AND CENTRAL GREAT PLAINS...

    ...SUMMARY...
    Isolated severe thunderstorms are possible across a broad portion of
    the Great Plains this afternoon to early evening. A more
    concentrated threat for a couple tornadoes is evident over parts of
    the Dakotas and for large hail along the Nebraska-Kansas border.

    ...Dakotas/Western Minnesota...
    Within a meridional mid-level flow regime, a surface low is forecast
    to lift north across the central Dakotas this afternoon/evening. A
    low-level jet will strengthen across the eastern Dakotas towards
    evening, while moist easterly surface flow will exist north of the
    low. These processes will result in a relatively confined corridor
    of enhanced SRH lifting north from north-central SD into central ND
    later today. In the wake of ongoing precipitation this morning,
    renewed thunderstorm development is expected this afternoon across
    the Dakotas along a cold front as ascent with the consolidating and increasingly negatively-tilted upper trough intensifies. Although
    the primary risks will be isolated strong/severe gusts and hail with
    multicell or transient supercell structures, storms near the
    aforementioned surface low/Slight Risk could plausibly acquire
    sufficient low-level rotation resulting in some tornado potential.
    Overall intensities should diminish later this evening.

    ...Central Great Plains...
    In the wake of overnight storms, boundary-layer heating of a
    seasonably moist boundary layer will contribute to moderate-strong
    buoyancy east of a cold front this afternoon. Although stronger wind fields/greater shear will be displaced to the east, sufficient
    overlap is expected, with the potential for both multicell and
    supercell characteristics resulting in severe hail/wind potential. A
    confined plume of steeper mid-level lapse rates (in excess of 7 deg
    C/km) southeast of the consolidating trough will promote a more
    concentrated risk for severe hail, centered near the NE/KS border
    Slight Risk area.

    ...Southern High Plains...
    Scattered thunderstorms are expected to develop this afternoon
    within a moderate-strongly buoyant air mass amid modest westerly
    cloud-bearing layer shear. Both multicell and brief supercell
    structures are possible with a risk for isolated severe wind and
    hail, however warmer mid-level temperatures south of the upper
    trough should tend to temper overall coverage.

    ...Mid-South/Mid-MS Valley...
    Ample buoyancy along and southwest of a warm front should aid in a
    few strong gusts and small hail with scattered late afternoon
    storms. Deep-layer shear will remain rather weak within the
    mid-level ridge, suggesting a predominant pulse mode, supporting a
    minimal threat for organized severe storms.

    ..Bunting/Broyles.. 09/14/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Sep 16 10:04:01 2025
    ACUS01 KWNS 161234
    SWODY1
    SPC AC 161233

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0733 AM CDT Tue Sep 16 2025

    Valid 161300Z - 171200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS FAR
    NORTHEAST CO...WESTERN/CENTRAL NE...AND EXTREME NORTHWEST KS...

    ...SUMMARY...
    Scattered severe thunderstorms are possible this afternoon into
    early evening across a portion of the central Great Plains. Large
    hail, severe gusts, and a tornado or two may occur.

    ...Synopsis...
    Early morning satellite imagery shows a fairly amplified upper
    pattern across CONUS, consisting of two ridge/trough pairs. The
    westernmost pair features ridging that extends from just off the
    central CA coast north through southern BC and a shortwave trough
    that extends from central MT into northeast NV/northwest UT. The
    eastern most pair features ridging from the southern Plains through
    the Upper Great Lakes and a modest cyclone centered over central NC.
    Despite this amplified upper pattern, flow is generally modest, with
    the strongest flow extending through the base of the western
    shortwave from northern UT into eastern WY.

    The surface analysis reveals a relatively nondescript surface
    pattern free of any sharp gradients or notable features, aside from
    a weak low just off the northeast NC coast. Moderate moisture (i.e.
    mid/upper 60s dewpoints) does extend from the southern Plains
    through the Lower MO Valley into southern IA.

    ...Central High Plains into the Central Plains ...
    The western shortwave trough mentioned in the synopsis is forecast
    to progress slowly eastward throughout the day, evolving towards a
    more closed mid/upper level circulation as it does. Eastern
    periphery of ascent associated with this shortwave will impinge on
    the western periphery of the better low-level moisture and buoyancy,
    resulting in scattered to numerous thunderstorms from eastern WY/CO
    into western NE/KS. The best buoyancy across the region will likely
    reside from far northeast CO into central NE where low to mid 60s
    dewpoints beneath steep mid-level lapse rates will support MLCAPE
    around 2000-2500 J/kg. Low-level convergence along a weak cold front
    is anticipated in this area as well. The resulting combination of
    lift, instability, and modest shear (i.e. around 35 kt of effective
    bulk shear) will support strong to severe storms. Large hail appears
    to be the most prominent hazard, but some clustering could lead to a
    few strong gusts as well. Presence of a surface low and potential
    backed low-level flow will result in a low-probability tornado risk
    as well.

    ...Eastern SD to northeast MN...
    Steep lapse rates atop moderate low-level moisture will support
    moderate to strong buoyancy along a weak front zone forecast to
    extend from eastern SD into north-central MN this afternoon.
    Low-level convergence along the front will be modest, with warm low
    to mid-level temperatures (and resultant capping) likely keeping
    storm coverage isolated. Mid-level flow will be modest across most
    of the region, but the strong buoyancy could still result in an
    isolated threat for severe hail and damaging winds with any storms
    that develop. A relatively higher severe potential exists across
    northeast NM, where stronger mid-level flow through southern
    peripheral of a shortwave trough moving over far northwest Ontario
    will be in place this evening.

    ...VA Tidewater and far northeast NC...
    A weak cyclone east of the Outer Banks is progged to drift
    northwestward today, reaching the NC/VA border area by this
    afternoon. Low-level flow enhancement through its northwest
    periphery will promote potential for strong to marginally severe
    gusts with any sustained convection. However, the more buoyant air
    is expected to remain offshore and displaced east of this stronger
    low-level flow, thermodynamically limiting the spatial extent of any
    severe threat. Meager surface-based instability may glance the coast
    from later this morning through the afternoon before low-level wind
    fields subside and the severe risk becomes negligible.

    ..Mosier/Bentley.. 09/16/2025

    $$
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  • From Mike Powell@618:250/1 to All on Wed Sep 17 08:51:24 2025
    ACUS01 KWNS 171255
    SWODY1
    SPC AC 171254

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0754 AM CDT Wed Sep 17 2025

    Valid 171300Z - 181200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST
    CO...NORTHEAST NM...AND THE WESTERN TX/OK PANHANDLES...

    ...SUMMARY...
    Isolated severe thunderstorms are possible, mainly during late
    afternoon to mid-evening, across parts of the south-central High and
    Great Plains. The most likely corridor is from the Raton Mesa into
    the western Texas and Oklahoma Panhandles, where large hail, severe
    gusts, and a brief tornado are possible.

    ...Synopsis...
    Early morning satellite imagery shows a broad cyclone centered over
    WY and another more defined cyclone over the Mid-Atlantic. Modest
    ridging exists between these cyclones from the southern Plains
    through the Mid MS Valley and into the Upper Great Lakes. The
    eastern cyclone is forecast to devolve into an open wave throughout
    the day while gradually lifting northeastward. Several shortwave
    troughs are forecast to rotate around the western cyclone while it
    shifts eastward into more of NE/SD and deepens slightly.

    Recent surface analysis reveals a weak front extending from a low
    over the northern TX Panhandle north-northeastward to another weak
    low over northwest KS and then more northeastward across central NE
    into southwest MN. Portion of this front across KS and NE is
    forecast to slowly push eastward/southeastward today while
    consolidation into a more define and deeper surface low occurs
    across northeast NE and southeast SD.

    ...South-central High Plains...
    The shortwave trough currently rotating southward through western WY
    is forecast to continue south/south-southeastward today. Lift
    preceding this shortwave will contribute to thunderstorm development
    within the buoyant post-frontal airmass across southeast CO and
    northeast NM (in the Raton Mesa vicinity) during the late
    afternoon/early evening. Slightly stronger mid-level flow will
    accompany this shortwave as well, resulting in moderate deep-layer
    vertical shear. Buoyancy will be modest, with the stronger buoyancy
    anticipated ahead of the cold front, but the combination of buoyancy
    and shear over the region should still be sufficient for organized
    updrafts capable of large hail and damaging gusts. There is some
    potential for this activity to interact with the western portion of
    the cold front that is expected to arc back west/northwest across
    the TX/OK Panhandles into far northeast NM/southeast CO. If this
    occurs, the easterly surface winds and increased vorticity along the
    boundary could result in a localized area of low-probability tornado risk.

    ...Southeast NE...Central/Eastern KS...Northwest OK...Eastern TX
    Panhandle...

    Showers and thunderstorms are ongoing along and ahead of the cold
    front extending across the region. At least one MCV is noted within
    this precipitation over far north-central KS. Cloud cover associated
    with this precipitation will likely delay heating across much of KS
    and NE, leading to some uncertainty whether the airmass will
    destabilize ahead of the cold front later this afternoon.
    Destabilization looks more probable from central KS across the
    eastern TX Panhandle and northeast OK. This entire region will be on
    the eastern periphery of the stronger mid-level flow, with the
    modest shear supportive of some strong to severe storms capable of
    damaging gusts and isolated hail in areas where the airmass destabilizes.

    ...IA and southern MN...
    Forcing for ascent is expected to spread across the region from the
    southwest as a shortwave trough rotates through the broader
    troughing over the northern/central Plains. Like areas farther
    southwest, cloud cover and limited diurnal heating results in
    uncertainty regarding airmass destabilization. Even so, some
    guidance shows strong heating, deep mixing, and destabilization
    ahead of the approaching shortwave. This could result in some
    high-based storm capable of damaging downbursts. However, the
    overall conditionality of this scenario precludes introducing any
    severe probabilities with this outlook.

    ..Mosier/Bentley.. 09/17/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sun Sep 21 09:00:48 2025
    ACUS01 KWNS 211246
    SWODY1
    SPC AC 211245

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0745 AM CDT Sun Sep 21 2025

    Valid 211300Z - 221200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    NORTH TEXAS AND SOUTHERN OKLAHOMA...

    ...SUMMARY...
    Large hail may occur with supercells that develop this afternoon
    across parts of north Texas and southern Oklahoma. Isolated strong
    to severe thunderstorms are possible this afternoon and evening
    across a broad portion of the southern Plains into the Ozarks, mid
    Mississippi Valley, Ohio Valley, and Great Lakes, and also from the
    mid Missouri Valley into southern Minnesota and northern Iowa.

    ...Southern Plains into the Ozarks and Mid Mississippi Valley...
    Showers and thunderstorms are ongoing this morning across parts of western/central OK and western north TX in association with a weak
    MCV and modest low-level warm/moist advection. Convectively
    reinforced outflow from this morning activity should be draped
    along/near the Red River this afternoon, with a rich low-level
    moisture present to its south. Northwesterly mid/upper-level flow
    should gradually strengthen through the day across north TX/southern
    OK as a weak mid-level perturbation moves southeastward from the southern/central High Plains. A favorable combination of moderate
    instability aided by modestly steepened mid-level lapse rates and
    daytime heating, along with 35-45 kt of deep-layer shear, will
    likely prove favorable for thunderstorm organization. Most guidance
    suggests multiple thunderstorms will develop and become
    supercellular this afternoon across parts of north TX and southern
    OK. Scattered severe hail should be the main threat with this
    convection as it spreads southeastward through the early evening.
    Strengthening MLCIN with time this evening should result in a
    weakening trend as this activity approaches the DFW metroplex, but
    isolated large hail and gusty winds will remain possible until
    convection dissipates. Given increased confidence in supercells
    developing, have added a focused Slight Risk for large hail with
    this update.

    Weak mid-level troughing with multiple embedded perturbations will
    move eastward today across the central Plains into the Ozarks and
    mid MS Valley. One notable MCV with ongoing convection is also noted
    this morning across central KS. Filtered diurnal heating should aid
    in the development of weak to locally moderate instability this
    afternoon along/south of a front that should be draped across
    northern KS/MO. As modest large-scale ascent overspreads the warm
    sector, at least scattered thunderstorms are forecast to develop
    this afternoon in a weakly sheared environment, with modest
    enhancement provided by the eastward-moving MCV across MO. Isolated
    hail and damaging winds may occur with the stronger cores, with some
    potential for eventual clustering towards the MS River by early
    evening.

    ...Midwest/Great Lakes...
    A broad zone of modest (20-30 kt) west-southwesterly mid-level flow
    will be maintained today over much of the Midwest/Great Lakes, on
    the southeast periphery of weak upper troughing over the Upper
    Midwest. Recent visible satellite imagery across these regions show
    generally widespread cloudiness, which may hinder diurnal
    destabilization to some extent. Mid-level lapse rates are also
    expected to remain rather poor (reference ILX/ILN/DTX observed 12Z
    soundings). Even with these thermodynamic limitations, it still
    appears possible that isolated damaging winds could occur with any thunderstorms that can develop this afternoon and spread generally east-northeastward. This activity should quickly weaken this evening
    with the loss of daytime heating.

    ...Mid Missouri Valley into Southern Minnesota/Northern Iowa...
    A compact mid/upper-level low will move southeastward from eastern
    ND into MN today. This low and attendant shortwave trough may aid in
    the development of isolated to widely scattered storms by early
    evening from southwest MN into adjacent southeast SD, northeast NE,
    and northwest IA, in the vicinity of a weak surface boundary. Cool
    temperatures aloft, weak to moderate instability, and effective bulk
    shear around 25-35 kt should support multicells and perhaps a couple
    splitting supercells. Hail is expected to the primary severe hazard
    with any thunderstorms that can be sustained, but confidence in this
    occurring before this evening is low.

    ..Gleason/Grams.. 09/21/2025

    $$
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  • From Mike Powell@618:250/1 to All on Mon Sep 22 09:18:51 2025
    ACUS01 KWNS 221242
    SWODY1
    SPC AC 221240

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0740 AM CDT Mon Sep 22 2025

    Valid 221300Z - 231200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE SOUTHERN/CENTRAL PLAINS...LOWER/MID MISSOURI VALLEY...AND OHIO VALLEY...

    ...SUMMARY...
    Scattered severe thunderstorms will be possible this afternoon into
    tonight across portions of the southern/central Plains, lower/mid
    Missouri Valley, and Ohio Valley. Large hail and severe/damaging
    winds should be the main threats.

    ...Synopsis...
    Weak upper troughing over the Upper Midwest is forecast to drift
    slowly eastward today across the upper Great Lakes, while upper
    ridging remains centered over Mexico and south TX. In between these
    two features, a broad zone of modestly enhanced west-northwesterly
    mid-level flow will persist through the period. Multiple
    low-amplitude mid-level perturbations should aid convective
    development today and tonight across portions of the
    southern/central Plains into the mid MO Valley and Upper Midwest,
    and across parts of the TN/OH Valleys into the lower Great Lakes.

    ...Southern/Central Plains...
    With a stout cap in place (reference 12Z DDC observed sounding) and
    weak large-scale ascent anticipated through much of the afternoon,
    robust thunderstorm development across the southern/central Plains
    will likely be delayed until early evening as a southerly low-level
    jet strengthens. Modest low-level moist advection will occur to the
    east of a weak lee trough and surface low over the central High
    Plains this afternoon, with generally mid 60s to low 70s dewpoints
    forecast across much of KS/OK. Diurnal heating of this moist airmass
    will support a corridor of moderate to locally strong instability
    extending from western KS southeastward into OK.

    It still appears probable that ascent associated with a southerly
    low-level jet will be needed to overcome the cap this evening, with
    most high-resolution guidance suggesting thunderstorm initiation
    occurring around 00-02Z or later. Even though westerly mid-level
    winds are not expected to be overly strong, sufficient deep-layer
    shear will be present to support organized updrafts. Current
    expectations are for initial development to pose some hail threat,
    with a couple of supercells possible. With time, scattered
    severe/damaging winds should become the main risk as convection
    grows upscale into a bowing cluster across western/south-central KS.
    This severe threat may continue overnight into parts of
    western/northern OK, with enhanced low-level shear potentially
    supporting a brief embedded tornado. The southern extent of the
    Marginal/Slight Risks across the southern Plains have been trimmed
    based on latest guidance trends.

    ...Lower/Mid Missouri Valley into the Upper Midwest...
    Thunderstorms ongoing this morning across far southeast MN into
    western WI remained sub-severe overnight. Still, they may pose an
    isolated hail/wind risk through the morning as they move eastward
    across WI amid a destabilizing airmass. Overall confidence in the
    development and evolution of convection from eastern NE into the
    Upper Midwest today remains fairly low, as stronger ascent aloft
    associated with the upper trough over the upper Great Lakes will
    tend to remain displaced to the north of the surface warm sector.
    Even so, additional convection should form along a front in northern
    IA this afternoon/evening. With cool temperatures aloft and modestly
    steepened mid-level lapse rates, this activity could pose a threat
    for mainly severe hail given gradually strengthening westerly winds
    with height through mid/upper levels. Other thunderstorms may form
    late this afternoon or early evening across eastern NE and vicinity.
    Greater instability should be present across this region compared to
    locations farther north, along with enough deep-layer shear to
    support some updraft organization. An initial hail threat with this
    activity should transition to more of a wind risk with time this
    evening as clustering occurs.

    ...Tennessee/Ohio Valleys to the Lower Great Lakes...
    A shortwave trough associated with ongoing convection over the
    Mid-South/lower OH Valley this morning will translate northeastward
    today across much of the OH Valley. Modestly enhanced southwesterly low/mid-level winds will exist this afternoon over this region, with
    20-30 kt of deep-layer shear supporting mainly loosely organized
    multicells. Multiple clusters should develop and gradually
    strengthen through the afternoon as they spread northeastward across
    a weakly unstable airmass. Even though poor lapse rates aloft are
    expected, somewhat steepened low-level lapse rates via filtered
    daytime heating should still promote some risk for isolated to
    scattered damaging winds with these clusters. Most guidance shows a
    greater concentration of strong convection across parts of
    central/eastern KY into OH and western WV this afternoon/early
    evening, in close proximity to the mid-level shortwave trough. A
    Slight Risk has been included across this area given increased
    confidence in a corridor of scattered damaging wind potential.

    ...Far Eastern Arizona into New Mexico...
    Moisture remains limited this morning across eastern AZ and much of southern/central NM, with surface dewpoints generally ranging from
    the 40s to mid 50s. Westerly mid/upper-level flow across this region
    is expected to gradually strengthen through the day as an upper
    trough/low digs southward from the northern Rockies across the Great
    Basin and towards the Four Corners region by late tonight. A weak
    perturbation embedded within the mid-level westerly flow may aid
    initial convective development this afternoon across the higher
    terrain of east-central AZ and vicinity. This activity will spread
    eastward across much of central NM through the remainder of the
    afternoon and into the evening. While instability will likely remain
    weak owing to limited low-level moisture, steepened low-level lapse
    rates with daytime heating and moderate to strong deep-layer shear
    should promote outflow-dominant convection with an isolated threat
    for strong to severe wind gusts.

    ..Gleason/Grams.. 09/22/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Sep 23 08:43:57 2025
    ACUS01 KWNS 230600
    SWODY1
    SPC AC 230559

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1259 AM CDT Tue Sep 23 2025

    Valid 231200Z - 241200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
    THE SOUTHERN PLAINS AND OZARKS TOWARD THE MID MISSISSIPPI VALLEY...

    ...SUMMARY...
    Severe storms are possible from the southern Plains to the Mid
    Mississippi Valley today and tonight. Supercells capable of all
    severe hazards are possible mainly from eastern Oklahoma into the
    Ozarks. Additional isolated severe storms with damaging gusts are
    possible over the Mid Atlantic.

    ...Eastern Oklahoma into the Ozarks and northeast Texas...
    A positive tilt large-scale trough will amplify over the southern
    Rockies and High Plains today, as several small-sale features
    embedded within the stronger westerly flow pass across KS/OK, over
    the Ozark Plateau and into the mid MS Valley today and tonight.
    Accompanying the lead shortwave, a 40-50 kt mid-level jet will aide
    in surface cyclogenesis along a southward moving cold front across
    the KS/OK border. Near the surface low, an early morning MCS will
    likely be moving into northwest AR and southwest MO ahead of a 30-40
    kt low-level jet. Isolated damaging winds and perhaps some hail will
    be possible with this initial activity. Some resurgence is possible
    through the morning along the AR/MO border with diurnal
    destabilization, especially along the southern flank. Regardless,
    outflow from the morning convection will likely develop into an
    east-west oriented effective boundary intersecting with the
    developing surface low from the AR/MO border region into eastern OK.

    As the shortwave trough approaches, robust destabilization is
    expected over much of the warm sector owing to heating amidst 70s F
    surface dewpoints. Afternoon MLCAPE of 2000-3000 J/kg should support
    rapid thunderstorm development along the per-frontal surface
    trough/wind shift and near the effective boundary. Semi-discrete
    supercells are expected with a continued 30+ kt southwesterly
    low-level jet helping to expand hodographs. Damaging gusts and some
    hail (occasional 2+ inch) are possible with initial storms from
    eastern OK into northeast TX where low-level flow is more veered and
    lapse rates are steeper. Tornado potential (conditionally
    significant) is likely to be maximized near the effective triple
    point and modifying outflow boundary from northeastern OK into
    western AR. Here, backed low-level flow, ESRH of 200-300 m2/s2 and
    the potential for higher low-level buoyancy could support locally
    stronger low-level mesocyclones. Higher tornado probabilities may be
    needed as confidence in final boundary positioning and
    destabilization, post MCS, becomes more clear.

    Upscale growth into one or more clusters is expected into the early
    overnight hours across eastern AR into the Mid MS Valley. Some risk
    for damaging winds and perhaps an embedded tornado or two may
    persist. However, increasingly strong low-level warm advection ahead
    of the deepening surface low should support widespread thunderstorm
    development which may limit instability.

    ...Mid Atlantic...
    Downstream of a broad mid-level trough, widely scattered
    thunderstorms are expected to develop by early afternoon within a moist/moderately unstable air mass east of the central Appalachians
    toward the mid Atlantic. Around 20-30 kt of deep-layer shear may
    promote a couple loosely organized clusters with a risk of locally
    damaging gusts before weakening into the evening hours.

    ...Central TX...
    As the surface low deepens and moves eastward, the cold front will
    continue southward across the TX Panhandle into central TX
    overnight. The primary upper trough over the southern Plains will
    pass overhead with moderate height falls and cooling aloft.
    Low-level isentropic ascent could support a few elevated storms
    along and north of the front with damaging wind and hail potential
    overnight.

    ..Lyons/Hart.. 09/23/2025

    $$
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