• DAY1SVR: Day 1 Convective

    From Mike Powell@618:250/1 to All on Wed Aug 6 09:19:14 2025
    ACUS01 KWNS 061240
    SWODY1
    SPC AC 061238

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0738 AM CDT Wed Aug 06 2025

    Valid 061300Z - 071200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE NORTHERN/CENTRAL PLAINS TO THE MID-MISSISSIPPI VALLEY. AND PART
    OF NORTHERN MINNESOTA...

    ...SUMMARY...
    Isolated strong to severe thunderstorms are possible across parts of
    the northern/central Plains to the Mid-Mississippi Valley, and over
    part of northern Minnesota today and tonight.

    ...Northern/Central Plains into the Mid MS Valley...
    An MCS continues to push southward across the Mid MO Valley this
    morning. The current motion, particularly the westward backbuilding
    of storms into more of east-central NE, have oriented this system
    favorably to a moist low-level jet, which should support maintenance
    of this line for the next few hours. Echo tops within this system
    remain fairly cool and occasionally strong updrafts have persisted
    for the last several hours. Additionally, a notable rise/fall
    pressure couplet exists with this system, as sampled by the +4 mb
    pressure rise as SUX. These factors indicate the MCS remains mature
    and could still occasionally produce damaging gusts over the next
    few hours across southeast NE, southwest IA, northwest MO, and far
    northeast KS. This MCS should begin to weaken later this morning
    when the low-level jet weakens.

    The region will be within the mostly zonal flow between the upper
    ridging centered over NM and a shortwave trough moving through SK
    and MB. Some rising heights are possible during the second half of
    the period as the pattern amplifies ahead of a shortwave trough
    moving into the northern Rockies. A belt of stronger mid-level flow
    (i.e. around 40 kt at 500 mb) will extend across the region, and
    diurnal heating of the moist airmass in place will foster moderate
    to strong buoyancy. The resulting combination of buoyancy and shear
    would favor strong to severe thunderstorms, but the satellite
    imagery lacks any notable disturbances upstream and the large-scale
    ascent is nebulous. The surface pattern also lacks any well-defined
    features, with only weak troughing sampled from the central Dakotas
    to a weak low over northeast CO.

    As such, when and where convective initiation occurs, if it occurs
    at all, is uncertain. Convective initiation appears most likely near
    the Black Hills into western NE within southeasterly low-level
    upslope flow within a very moist/unstable airmass. Environmental
    conditions support supercells with a conditional risk for large hail
    and damaging winds. However, given the uncertainty regarding
    coverage, will maintain Marginal risk (level 1 of 5).

    ...Northern MN...
    A few storms may develop along the southern periphery of the
    Canadian Prairies shortwave upper trough and surface low. Lapse
    rates will be weaker across this area and the favorable
    thermodynamic environment will be narrow. Any stronger storms will
    likely remain close to the international border, but could produce
    locally strong gusts or marginal hail.

    ..Mosier/Bentley.. 08/06/2025

    $$
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  • From Mike Powell@618:250/1 to All on Mon Aug 11 08:34:50 2025
    ACUS01 KWNS 111248
    SWODY1
    SPC AC 111246

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0746 AM CDT Mon Aug 11 2025

    Valid 111300Z - 121200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE SOUTHERN PLAINS...AND OVER PORTIONS OF NORTH DAKOTA INTO
    NORTHERN MINNESOTA...

    ...SUMMARY...
    Isolated strong to severe thunderstorms may pose some risk for
    severe winds and hail across parts of the southern Plains, and
    separately from North Dakota into northern Minnesota, mainly this
    afternoon and evening.

    ...Southern Plains...
    Convection has generally weakened this morning across eastern KS,
    with a outflow reinforced front advancing southward across the
    southern High Plains. This boundary is forecast to stall through the
    morning and early afternoon, and it will likely serve as a focus for
    renewed thunderstorm development later today. The southern extent of
    upper troughing that exists over much of the Plains is forecast to
    advance eastward across the southern High Plains this afternoon.
    Initial development over the higher terrain of north-central into
    northeast NM should occur in a modest low-level upslope flow regime,
    with steep lapse rates aloft contributing to moderate instability.
    Weak low-level winds will gradually veer to west-northwesterly and
    modestly strengthen with height through mid/upper levels, supporting
    modest deep-layer shear and some updraft organization.

    Isolated severe hail may occur with initially more cellular
    development across the southern High Plains, before some clustering
    potentially occurs late this afternoon/evening farther east into the
    TX Panhandle and northwest TX with more of a wind threat. While
    deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered
    thunderstorms developing with moderate to locally strong instability
    amid ample daytime heating. Isolated damaging winds via strong
    downbursts and marginally severe hail appear possible with the
    stronger cores given seasonably cool temperatures aloft (around -10C
    at 500 mb with the 12Z OUN observed sounding), and the Marginal Risk
    has been expanded eastward for this possibility.

    ...North Dakota into Northern Minnesota...
    Within upper troughing already established over the northern/central
    Plains and central Canada, a mid-level shortwave trough and related
    surface cold front are forecast to move east-southeastward over ND
    and northern MN through the period. Modest low-level moisture
    characterized by mid 50s to perhaps low 60s surface dewpoints should
    be present ahead of the front across these areas. Diurnal heating
    and modestly steepened lapse rates aloft should aid in the
    development of weak instability this afternoon. Thunderstorms should
    gradually increase in coverage along/ahead of the front this
    afternoon/evening as they spread eastward over parts of ND into
    northern MN. The stronger cells may produce marginally severe hail,
    with sufficient deep-layer shear present for some convective
    organization. With time, some clustering/upscale growth along the
    front appears probable, with isolated strong to severe gusts
    possible. The lack of stronger instability should tend to temper the
    overall severe threat.

    ...Missouri/Iowa...
    An MCV generated by overnight/early morning convection across the southern/central Plains should develop northeastward into parts of
    northern MO and IA by this afternoon. It remains unclear whether
    sufficient instability to support robust thunderstorms will be able
    to develop today ahead of this feature given ongoing convection and
    cloud debris. Regardless, some enhancement to the low/mid-level flow
    and related deep-layer shear could support updraft organization if surface-based thunderstorms can develop. Given the continued
    uncertainty regarding this potential, have held off on inclusion of
    low severe probabilities across this region with this update.

    ..Gleason/Leitman.. 08/11/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Aug 12 08:47:30 2025
    ACUS01 KWNS 121150
    SWODY1
    SPC AC 121148

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0648 AM CDT Tue Aug 12 2025

    Valid 121300Z - 131200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST...

    ...SUMMARY...
    Strong to occasionally severe thunderstorms may impact parts of the
    upper Great Lakes/Midwest today with both damaging winds and hail
    possible. Gusty winds may also occur over southeast Arizona and
    southwest New Mexico.

    ...Great Lakes/Midwest...
    A band of thunderstorms associated with an MCV tracked northeastward
    across parts of IA into northern IL and southern WI early this
    morning while remaining mostly sub-severe. Still, there may be some
    potential for strong to locally damaging winds with this activity as
    it continues northeastward across Lake Michigan into parts of Lower
    MI this morning/early afternoon as daytime heating gradually
    destabilizes the boundary layer. Otherwise, additional convection
    should develop later this afternoon along/ahead of a weak front over
    parts of WI and the U.P. of MI as the southern portion of a
    mid/upper-level trough moves eastward over the Upper Midwest/Great
    Lakes. Instability is forecast to remain fairly modest ahead of the
    front, but enough deep-layer shear should exist to support some
    organized convection. Initial cells may be capable of producing
    marginally severe hail, before clustering potentially increases the
    threat for occasional strong to damaging winds.

    A separate area of thunderstorms is forecast to develop this
    afternoon farther south and ahead of the front from portions of the
    Midwest into Lower MI. While this region will have relatively weaker
    mid-level westerly flow and related deep-layer shear compared to
    locations farther north, greater low-level moisture and instability
    are expected to be present. As low-level lapse rates become
    steepened with diurnal heating of the moist airmass, loosely
    organized clusters may become capable of producing isolated damaging
    winds as they spread generally east-northeastward through the
    afternoon and early evening.

    ...Southwest...
    Strong daytime heating should encourage diurnally driven convection
    over the higher terrain of southeast AZ and southwest NM this
    afternoon. With weak flow aloft and negligible shear, thunderstorms
    should drift slowly southward. Still, occasional gusty winds may
    occur with the more robust convection given steepened lapse rates.

    ..Gleason/Leitman.. 08/12/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sun Aug 17 10:11:07 2025
    ACUS01 KWNS 171221
    SWODY1
    SPC AC 171220

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0720 AM CDT Sun Aug 17 2025

    Valid 171300Z - 181200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN
    NEW ENGLAND....

    ...SUMMARY...
    One or two clusters of thunderstorms may develop and gradually pose
    a risk for damaging wind gusts from the northern High Plains into
    the Midwest this afternoon and tonight. Damaging thunderstorm wind
    gusts may also occur across parts of the northern Mid Atlantic into
    southern New England late this afternoon and evening.

    ...Northern Plains into Upper Midwest...
    A broad upper ridge remains in place over southern/central U.S
    today. Several weak perturbations will top the ridge during this
    forecast period, affecting much of the northern Plains and upper
    Midwest. Each of these smaller-scale shortwave troughs will
    potentially be associated with a cluster of thunderstorms.
    Sufficient low-level moisture and 25-35 knots of westerly flow aloft
    pose some conditional risk of severe storms throughout this region,
    but considerable uncertainty on the timing and placement of
    convection precludes upgrading any areas to SLGT at this time.
    Multiple areas of ongoing convection this morning further complicate
    the forecast. Perhaps by 1630z, areas of stronger daytime heating/destabilization will allow better focus of the severe
    outlook.

    ...Mid Atlantic into southern New England...
    A cold front currently extends from OH northeastward into the St.
    Lawrence Valley. Forecast soundings ahead of the front show weak
    mid-level lapse rates and limited mid-level dry air. However,
    strong heating into the 80s and 90s F, coupled with dewpoints near
    70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow
    aloft and frontal forcing may be sufficient for isolated strong
    storms capable of locally gusty/damaging winds this afternoon.

    ..Hart/Dean.. 08/17/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Aug 19 09:03:10 2025
    ACUS01 KWNS 191255
    SWODY1
    SPC AC 191253

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0753 AM CDT Tue Aug 19 2025

    Valid 191300Z - 201200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    SOUTH-CENTRAL PLAINS AND OZARKS TO OHIO VALLEY AND NORTHERN ROCKIES...

    ...SUMMARY...
    Scattered strong to severe thunderstorms capable of damaging winds
    will be possible across the south-central Great Plains and Ozarks to
    the Ohio Valley this afternoon and evening. Isolated severe
    thunderstorms may also occur across parts of the northern Rockies
    including western and northern Montana.

    ...South-central Plains and Ozarks to Ohio Valley...
    Outside of a few areas of lingering early day convection/small-scale
    outflows, a hot air mass and relatively high moisture content will
    reside to the south of a synoptic front extending from the
    south-central Plains to the Midwest/Ohio Valley. Moderate to strong
    buoyancy with daytime heating, beneath a residual plume of
    relatively steep lower/mid-tropospheric lapse rates, will exist
    particularly across parts of the south-central Plains to Ozark
    Plateau, including parts of Kansas/Oklahoma to Arkansas/southern
    Missouri. As storms diurnally develop/increase, upscale-growing
    thunderstorm development should occur during the mid to late
    afternoon and early evening. While weak deep-layer winds and shear
    are likely to limit the risk for organized severe convection,
    thermodynamic profiles will be conducive for downbursts and
    severe-caliber wind gusts with the stronger storms, particularly
    this afternoon through around sunset.

    ...Northern Rockies including western/northern Montana...
    The late-day arrival of weak height falls and approaching mid-level perturbation should influence isolated thunderstorm development late
    this afternoon, and more so into this evening, across parts of
    northern Idaho in western and eventually northern Montana.
    Sufficient moisture/buoyancy near and behind a surface front, along
    with strengthening flow aloft, will support the possibility of some
    severe storms, and potentially some clustering/organization to the
    storms as they progress across western/northern Montana.
    West-southwesterly mean flow strengthening to 30-40+ kt in the
    cloud-bearing layer, and a residual deep sub-cloud mixed-layer, will
    likely be sufficient for downward mixing of momentum to contribute
    to a few strong to severe wind gusts.

    ..Guyer/Dean.. 08/19/2025

    $$
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  • From Mike Powell@618:250/1 to All on Wed Aug 20 08:36:07 2025
    ACUS01 KWNS 201231
    SWODY1
    SPC AC 201230

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0730 AM CDT Wed Aug 20 2025

    Valid 201300Z - 211200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    TEXAS/DEEP SOUTH AND NORTHERN PLAINS...

    ...SUMMARY...
    Scattered thunderstorms from Texas across the Lower Mississippi
    Valley and Gulf Coast states may pose a risk for localized damaging
    wind gusts this afternoon and evening. Isolated severe thunderstorms
    may also occur across eastern Montana and northern North Dakota.

    ...Texas to Lower Mississippi Valley/Gulf Coast States...
    A convectively augmented effective front will continue to progress
    southward, southward-shifting the potential for microburst-related
    wind damage regionally. Diurnal heating of a moist boundary layer
    will result in a moderately to strongly unstable and weakly capped
    airmass by afternoon, with the strongest buoyancy (2500+ J/kg
    MLCAPE) expected across central/east Texas east-northeastward to Mississippi/western Alabama/southern Tennessee. Some small-scale
    clusters may evolve, but weak vertical shear will otherwise tend to
    keep the overall pulse-type damaging wind potential very isolated.

    ...Northern Plains...
    The region will be influenced by late-day/nighttime height falls as
    a shortwave trough emerges eastward from the Canadian Rockies, with
    an eastward-advancing cold front moving across eastern Montana into
    North Dakota tonight. A narrow corridor of moderate to large
    buoyancy is expected along/ahead of the surface cold front, and near
    a pre-frontal surface trough. Beneath a plume of warm elevated
    mixed-layer air, mid/upper-level support for the initiation of
    boundary-layer based thunderstorm development is forecast to
    generally remain north of the international border.

    One exception may be in the post-frontal environment across eastern
    Montana, the environment would be conducive to a few severe storms
    capable of hail/wind. While the risk for severe thunderstorms
    appears largely conditional into North Dakota where stronger
    destabilization is expected, isolated deeper convective development
    is plausible across northwestern North Dakota in proximity to the
    surface low/front late this afternoon, and more so this evening.
    Should this occur, forecast soundings indicate the environment would
    support isolated supercell development and related severe-weather risks.

    ..Guyer/Marsh.. 08/20/2025

    $$
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  • From Mike Powell@618:250/1 to All on Thu Aug 21 08:27:29 2025
    ACUS01 KWNS 211253
    SWODY1
    SPC AC 211251

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0751 AM CDT Thu Aug 21 2025

    Valid 211300Z - 221200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    NORTHERN PLAINS/UPPER MIDWEST AND SOUTHERN ARIZONA...

    ...SUMMARY...
    Isolated severe thunderstorms are possible across portions of the
    northern Plains and Upper Midwest this afternoon and evening, with
    severe wind gusts and hail the primary concerns. A few strong to
    severe storms could also occur across southern Arizona.

    ...Northern Plains/Minnesota...
    Late-day height falls are expected regionally in relation to an
    amplifying shortwave trough over the Canadian prairies. While the
    primary large-scale forcing will be north of the international
    border, high-level diffluent flow is expected across the eastern Dakotas/Minnesota, coincident with the front that will be draped
    across the region at peak heating. Short-term models (HRRR/RRFS) are
    tending to limit late-afternoon/evening convective development,
    while most global models and most HREF constituents are a bit more
    aggressive, which is plausible and lends credence to the potential
    for at isolated severe storms within a moderately to strongly
    unstable environment near the front. Deep-layer should be sufficient
    to potentially yield a few supercells. Increasing storm coverage
    later into the evening/overnight will be supported by an increasing
    low-level jet.

    ...North-central High Plains including eastern Wyoming...
    Northeasterly low-level upslope flow evolving within the
    post-frontal environment, and differential heating in vicinity of
    higher terrain, are expected to influence widely scattered
    thunderstorm development by late afternoon, particularly across
    eastern Wyoming. While forecast buoyancy is not expected to be
    particularly strong, adequate deep-layer shear will prove supportive
    of organized updrafts that could generate hail/wind, including the
    possibility that a couple of eastward-moving clusters could evolve
    by early evening.

    ...Southern Arizona...
    The upper ridge should shift slightly northward regionally, with a
    modest enhancement to mid-level easterly flow late today
    particularly across southeast Arizona. With isolated storm
    development expected initially over the rim/mountains this
    afternoon, storms should drift west-southwestward into a moist/very
    hot boundary layer, with the potential for outflows/blowing dust to
    reach the desert floor.

    ..Guyer/Marsh.. 08/21/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Aug 22 10:01:17 2025
    ACUS01 KWNS 221251
    SWODY1
    SPC AC 221250

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0750 AM CDT Fri Aug 22 2025

    Valid 221300Z - 231200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    CENTRAL HIGH PLAINS TO THE UPPER MIDWEST AS WELL AS ARIZONA...

    ...SUMMARY...
    Strong to locally severe thunderstorms are possible from parts of
    the central and northern High Plains to the Upper Midwest, and
    across parts of Arizona.

    ...Upper Midwest/Upper Great Lakes...
    Upper trough amplification will continue to occur over
    Manitoba/northern Ontario through tonight, with consequential height
    falls over the upper Great Lakes. A cold front will continue to
    advance southeastward regionally, with a semi-moist air mass
    preceding it. A consequential factor for portions of the region will
    be an MCS centered across far eastern South Dakota early this
    morning, which will continue to disturb the frontal zone and nearby
    warm sector for the first part of the day. This may especially be
    the case across southern Minnesota and vicinity.

    But on the periphery of the MCS-influenced corridor, potential
    severe storm development could occur by late afternoon, perhaps most
    likely across eastern Nebraska and western Iowa, but also across
    northwest Wisconsin/Upper Michigan where vertical shear will be
    stronger but with more modest buoyancy. Hail and damaging winds
    would be possible in both scenarios, but likely on a relatively
    isolated basis.

    ...Wyoming/Colorado and central High Plains...
    A subtle ridge-peripheral disturbance noted in water vapor imagery,
    along with strong surface heating, should aid thunderstorm
    development initially across Wyoming/Colorado. This activity should
    propagate east-southeast toward lower elevations in the presence of
    moist low-level upslope flow. Hail and wind are possible with this
    activity, especially within a corridor across interior/southeast
    Wyoming into northeast/east-central Colorado.

    ...Arizona...
    The upper high will shift west-northwestward through tonight,
    maintaining and potentially strengthening easterly mid-level winds
    across southern Arizona, in addition to the possibility of slightly
    cooler (degree or two C) mid-level temperatures. Lingering morning
    cloud cover should gradually abate into the afternoon, with a very hot/residually moist boundary layer contributing to widely scattered thunderstorm development, initially over higher terrain.
    West/southwestward spreading storms will pose the potential for
    strong wind gusts/blowing dust onto the desert floor.

    ..Guyer/Kerr.. 08/22/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Aug 22 13:07:24 2025
    ACUS01 KWNS 221632
    SWODY1
    SPC AC 221630

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1130 AM CDT Fri Aug 22 2025

    Valid 221630Z - 231200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
    THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT
    LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA...

    ...SUMMARY...
    Strong to locally severe thunderstorms may occur today from parts of
    the northern and central High Plains to the Upper Midwest/Great
    Lakes, and separately across parts of Arizona. Damaging winds and
    occasional hail should be the main threats.

    ...Synopsis...
    A mid/upper-level trough/low centered over Manitoba late this
    morning will move east-southeastward across Ontario and the Upper
    Midwest/Great Lakes through the period. At the surface, a weak cold
    front is forecast to develop southeastward across the
    northern/central High Plains and Upper Midwest this afternoon and
    evening. This boundary should serve as a focus for additional
    thunderstorm development later today, some of which could become
    strong to severe. A mid/upper-level anticyclone will remain anchored
    over the Four Corners region today, with modest easterly mid-level
    flow persisting over parts of AZ.

    ...Northern/Central High Plains to the Upper Midwest/Great Lakes...
    A broad zone of isolated strong to severe thunderstorm potential
    remains evident today, generally along/near a convectively
    reinforced cold front extending from the central High Plains
    east-northeastward to the Upper Midwest/Great Lakes. Within this
    broad zone, three somewhat separate regimes of severe potential are apparent.

    Thunderstorms have recently developed across parts of
    central/eastern MN and far northwest WI ahead of a remnant
    MCV/subtle mid-level shortwave trough. The airmass downstream from
    this activity across northern WI into the U.P. of MI is only weakly
    unstable, with scattered to broken mid/upper-level clouds present.
    Stronger mid-level flow is also forecast to generally lag behind the
    surface cold front across this region. Still, a small cluster or two
    may eventually evolve from the ongoing convection in MN, and spread
    eastward through the afternoon/early evening. Occasional damaging
    winds should be the main threat, but some hail may also occur with
    the stronger cores given cool mid-level temperatures and around
    25-35 kt of deep-layer shear aiding updraft organization. Considered
    adding a Slight Risk for severe/damaging winds across parts of
    northern WI and vicinity, but confidence in more robust
    destabilization occurring remains low. Trends will be monitored for
    a possible upgrade at 20Z, if needed.

    Outflow from earlier thunderstorms continues to advance southward
    across parts of eastern NE and northwest IA per recent surface
    observations and visible satellite imagery. The effect of this
    outflow surge on additional thunderstorm development this afternoon
    remains unclear, as the primary cold front lags the outflow by a
    considerable extent. Some guidance suggests that a couple of
    supercells or perhaps a small cluster may develop over far southeast
    SD into eastern NE and western IA later today as the airmass across
    these areas gradually destabilizes. At least an isolated risk for
    severe hail and damaging winds will exist if this occurs. But, the
    overall severe threat remains too uncertain for a categorical
    upgrade with this outlook update.

    Farther west, a subtle mid-level ridge-peripheral disturbance noted
    in water vapor imagery across southern WY and northwest CO, along
    with strong daytime heating, should aid thunderstorm development
    initially across the higher terrain of the central Rockies later
    this afternoon. This activity should propagate east-southeastward
    toward lower elevations in the presence of moist, post-frontal
    low-level upslope flow. Isolated severe hail and winds are possible
    with this activity, especially within a corridor across
    interior/southeast WY into northeast/east-central CO.

    ...Arizona...
    A fair amount of convective cloud debris is present today across
    parts of AZ per recent visible satellite imagery. This may tend to
    delay diurnal heating and related steepening of low-level lapse
    rates to some extent. But, eventual airmass recovery is still
    expected by late afternoon/early evening, with seasonably moist
    low-levels still noted on the 12Z observed PHX sounding.
    Thunderstorms should once again form initially along the higher
    terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern
    AZ through the evening. Sufficient instability, a very well-mixed
    boundary layer, and modest easterly mid-level flow should all
    support an isolated threat for severe/damaging winds with this activity.

    ..Gleason/Moore.. 08/22/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sat Aug 23 09:04:58 2025
    ACUS01 KWNS 231247
    SWODY1
    SPC AC 231246

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0746 AM CDT Sat Aug 23 2025

    Valid 231300Z - 241200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE/CENTRAL HIGH PLAINS...

    ...SUMMARY...
    Isolated severe storms are possible near the Colorado/Wyoming Front
    Range and central High Plains this afternoon and evening.

    ...Front Range/Central High Plains...
    Multiple subtle upper ridge-peripheral impulses and a belt of
    moderately strong northwesterly winds aloft will influence the
    region as low-level upslope flow increases late today within the
    post-frontal environment. At least widely scattered thunderstorm
    development is expected initially over the mountains, with
    subsequent intensification as storms develop east-southeastward into
    a moderately unstable air mass, with buoyancy maximized
    near/immediately east of the urban corridor/I-25. Steep mid-level
    lapse rates and 40+ kt effective shear will support the possibility
    of isolated supercells capable of large hail and some locally
    stronger wind gusts through early evening.

    ...Midwest/Great Lakes...
    A few showers and thunderstorms will likely develop along a cold
    front as it moves across the Great Lakes/Midwest this afternoon.
    Warm 700mb temperatures in the presence of only low 60s dewpoints
    will limit overall buoyancy and updraft strength, likely keeping
    severe-storm potential minimal.

    ..Guyer/Kerr.. 08/23/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sun Aug 24 09:20:52 2025
    ACUS01 KWNS 241311
    SWODY1
    SPC AC 241310

    Day 1 Convective Outlook CORR 1
    NWS Storm Prediction Center Norman OK
    0810 AM CDT Sun Aug 24 2025

    Valid 241300Z - 251200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    SOUTH-CENTRAL PLAINS AND NORTHEAST...

    ...SUMMARY...
    A few severe storms are expected this afternoon and evening across
    the south-central High Plains spanning eastern Colorado into western
    Oklahoma. Scattered strong to severe storms are also possible across
    portions of Pennsylvania and New York.

    ...South-central High Plains..
    Within an amplified upper flow regime, a moderately strong belt of northwesterly winds aloft will exist over the region, with one or
    more low-amplitude ridge-peripheral disturbances expected to pivot
    eastward later today over the central Rockies. A pronounced surface
    anticyclone will settle into the northern Plains, forcing the
    leading edge of more continental air into the southern Plains by the
    end of the period. A corridor of low-level warm advection will
    become established from southern Wyoming into western Oklahoma
    coincident with the northwest/southeast-oriented front.

    Widely scattered generally non-severe elevated storms will probably
    persist this morning across western Kansas, with some potential that
    the storms may help focus some renewed/increasing convective
    potential later today from southwest Kansas into western
    Oklahoma/eastern Texas Panhandle. Aided by increasing low-level
    upslope flow, other potentially severe storms are expected to
    develop across the Colorado Front Range vicinity by late afternoon
    and drift southeastward through early/mid-evening. A couple of
    supercells will initially be possible, before storms tend to cluster
    by evening. Large hail and damaging winds are the primary concerns
    regionally, although current thinking is that overall potential
    should remain relatively isolated.

    ...Northeast including New York/Pennsylvania...
    A prominent upper-level trough over Ontario/Quebec and Great Lakes
    will shift eastward today. An associated surface front is forecast
    to advance into western portions of New York/Pennsylvania by early
    afternoon. Modest boundary-layer heating is expected to aid
    destabilization ahead of the front and convective temperatures
    should be breached by around 20-21z; although, deep-layer lapse
    rates are not expected to be particularly steep (0-6 km values
    around 6.5 C/km). These storms could generate locally strong winds,
    and perhaps some hail, with the main risk from mid-afternoon into
    early evening.

    ..Guyer/Kerr.. 08/24/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Mon Aug 25 08:52:56 2025
    ACUS01 KWNS 251240
    SWODY1
    SPC AC 251238

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0738 AM CDT Mon Aug 25 2025

    Valid 251300Z - 261200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
    ARIZONA...

    ...SUMMARY...
    Isolated severe wind gusts are possible over parts of south-central
    Arizona this afternoon through early evening. Otherwise, the
    potential for severe storms is low across the remainder of the
    continental U.S.

    ..Synopsis...
    A large upper-level trough will continue to amplify across the
    eastern CONUS today. High pressure, currently analyzed across the
    northern Plains early this morning will expand slowly southward
    through the day which will push the polar front off the Atlantic
    coast and perhaps into the Gulf. A persistent upper-level ridge will
    exist across the Southwest and into the Great Basin/Rocky Mountains.
    Beneath this ridge, a continued monsoon push will result in
    widespread thunderstorm activity this afternoon/evening.

    ...Southern Arizona...
    Thunderstorms are forecast to develop this afternoon/evening across
    much of the Southwest amid weak to moderate instability (1000-1500
    J/kg MLCAPE) as temperatures cool aloft. A belt of stronger
    mid-level southeasterly flow (20-25 kt) is forecast to overspread
    the region and provide ample shear for some multicell storm
    clusters. Initial storms which are expected to form across the
    higher terrain in southeast Arizona may result in congealing outflow
    with a damaging wind threat as storms move generally
    west-northwestward through the evening.

    ..Guyer/Kerr.. 08/25/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Tue Aug 26 09:42:39 2025
    ACUS01 KWNS 261249
    SWODY1
    SPC AC 261248

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0748 AM CDT Tue Aug 26 2025

    Valid 261300Z - 271200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Organized severe storms are not expected across the continental U.S.
    today.

    ...Synopsis...
    An expansive upper-level trough will persist across the eastern
    CONUS today, where a cool, dry airmass and high pressure
    will be prevalent and limit thunderstorm potential aside from
    Florida. Monsoon-related scattered thunderstorms will be common
    across much of the non-coastal West.

    ...Southern Arizona/Lower Colorado River Valley...
    A northward-moving mid-level impulse/MCV will spread from the Lower
    Colorado River Valley/northern Arizona this morning into Utah,
    allowing for subsequent clearing/heating across southern Arizona
    toward the Lower Colorado River Valley. Thunderstorms will again
    develop and increase this afternoon especially in vicinity of higher
    terrain. A few instances of strong thunderstorm winds/wet
    microbursts could occur regionally this afternoon into evening, but
    the overall potential is expected to remain quite isolated and
    marginal overall.

    ..Guyer/Kerr.. 08/26/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Wed Aug 27 08:05:38 2025
    ACUS01 KWNS 271254
    SWODY1
    SPC AC 271253

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0753 AM CDT Wed Aug 27 2025

    Valid 271300Z - 281200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN COLORADO...

    ...SUMMARY...
    Some strong to locally severe storms may occur across eastern
    Colorado and the central High Plains late this afternoon and early evening.

    ...Eastern Colorado/Central High Plains...
    Prevalent cloud cover and some lingering mostly light precipitation
    should eventually abate later this afternoon, with thunderstorms
    expected to develop/increase initially over the mountains by around mid-afternoon. These storms will spread east-southeastward toward
    the instability axis across the adjacent High Plains through early
    evening. Moderately strong mid-level flow could support some
    semi-organized storms, and a couple of clusters could evolve by
    evening. Localized instances of marginally severe hail and/or wind
    could occur, although locally heavy rainfall may be more of a
    prevalent concern.

    ...Upper Midwest...
    A region of moderate instability is forecast to develop from eastern
    South Dakota into southern Minnesota this afternoon. But this will
    be in the wake of a southeastward-moving shortwave trough, with weak
    height rises and subsidence in its wake. Nonetheless, isolated storm development may occur by late afternoon/early evening, and a few
    strong storms are conceivable.

    ..Guyer/Kerr.. 08/27/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Fri Aug 29 10:06:13 2025
    ACUS01 KWNS 291254
    SWODY1
    SPC AC 291252

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0752 AM CDT Fri Aug 29 2025

    Valid 291300Z - 301200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    CENTRAL/SOUTHERN HIGH PLAINS AND SABINE RIVER VALLEY...

    ...SUMMARY...
    Thunderstorms capable of large hail and isolated severe wind gusts
    will be possible mainly late this afternoon into evening across
    parts of the southern and central High Plains. A few marginally
    severe storms could also occur today over parts of the Sabine River Valley.

    ...Central/southern High Plains...
    Multiple ridge-riding mid/upper-level disturbances will transition
    generally east/eventually southeastward from the central Rockies and
    northern High Plains today. Weak lee-side low development will occur
    across southeast Colorado and also perhaps farther north across the
    central High Plains, with modestly sharpening low-level convergence
    in vicinity of the lee trough. This will lead to a gradual
    enhancement of low-level upslope flow particularly across east-central/southeast Colorado and northeast New Mexico.

    Storms should develop/increase by mid-afternoon and gradually move
    eastward off the Colorado mountains/Raton Mesa vicinity, with other
    development occurring near the surface boundary extending
    north-northeastward into west-central Nebraska/southern South
    Dakota. Surface dewpoints in the lower to mid 60s F will contribute
    to an axis of moderate instability by peak heating. With moderately
    strong northwesterly mid-level flow persisting regionally, 35-40 kt
    or greater effective shear will exist from the Raton Mesa vicinity
    across the central High Plains into west-central Nebraska. A few
    supercells capable of large hail may occur, with the additional
    possibility of wind damage, especially with a probable clustering of
    storms across eastern Colorado/northeast New Mexico toward western
    Kansas and the Oklahoma/Texas Panhandles.

    ...Sabine River Valley...
    A relatively widespread corridor of showers/thunderstorms are
    ongoing this morning across northeast Texas to central/southeast
    Louisiana to the north of a front that will settle southward today
    across the region. A related cloud canopy will extend southward into
    the warm sector, but moderate destabilization should occur into the
    afternoon south of the front and on the south/southwest flank of the
    residual early day storms. Some stronger storms could persist and/or
    develop near the front this afternoon, with isolated instances of
    damaging winds a possibility as low-level lapse rates steepen.

    ..Guyer/Bentley.. 08/29/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sat Aug 30 08:49:52 2025
    ACUS01 KWNS 301250
    SWODY1
    SPC AC 301248

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0748 AM CDT Sat Aug 30 2025

    Valid 301300Z - 311200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    SOUTHERN HIGH PLAINS...

    ...SUMMARY...
    Some strong to locally severe thunderstorms may occur late this
    afternoon and evening across the southern High Plains.

    ...Southern High Plains...
    A belt of moderate-strength west-northwesterly flow aloft will
    persist atop a moist airmass regionally. Post-MCS air mass
    influences and lingering cloud cover/outflows may be factors into
    the afternoon, but RAP/HRRR-related guidance has trended a bit more
    unstable and potentially more conducive to some isolated severe
    storms later today. While confidence in forecast details are not
    particularly high, this potential appears to be mainly focused in a
    corridor across northeast New Mexico into the Texas Panhandle/Texas
    South Plains, and possibly western Oklahoma later this afternoon
    into evening. This is where locally moderate destabilization may
    occur coincident with effective shear magnitudes that may reach
    30-40 kt, with storm development focused near the surface trough
    and/or influenced by differential heating. A few instances of severe
    hail and/or wind will be possible.

    ..Guyer/Bentley.. 08/30/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sat Aug 30 13:58:12 2025
    ACUS01 KWNS 301628
    SWODY1
    SPC AC 301626

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1126 AM CDT Sat Aug 30 2025

    Valid 301630Z - 311200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF EASTERN NM...THE TX PANHANDLE...AND FAR WESTERN OK...

    ...SUMMARY...
    Some strong to locally severe thunderstorms may occur late this
    afternoon and evening across the southern High Plains.

    ...Synopsis and Discussion...
    Recent surface analysis places a pair of highs across the CONUS, one
    over southern Lower MI and another in the eastern ID/southwest MT
    vicinity. A reservoir of low-level moisture, characterized by
    dewpoints above 60 deg F, exists between these two features, from
    the southern CONUS up through the Plains. The low-level moisture
    will help foster thunderstorm development over much of this area,
    with the highest coverage anticipated along the surface troughing
    that extends from a pair of surface lows over the central Plains
    into the southern High Plains.

    A belt of moderate west-northwesterly flow aloft will extend
    eastward from eastern CO/far northeast NM across KS into the Ozarks.
    Southern periphery of this stronger flow will help support moderate
    effective bulk shear across northeast NM and the TX Panhandle/TX
    South Plains. Despite residual cloud cover and poor lapse rates,
    ample low-level moisture will help support modest buoyancy across
    the region as well. The resulting environmental conditions may
    result in a few stronger storms capable of hail (likely below 1" in
    diameter) and/or damaging gusts.

    ..Mosier/Dean.. 08/30/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sun Aug 31 08:32:11 2025
    ACUS01 KWNS 311250
    SWODY1
    SPC AC 311249

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0749 AM CDT Sun Aug 31 2025

    Valid 311300Z - 011200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Overall severe weather potential is expected to be low today and
    tonight.

    ...Discussion...
    Modest-strength mid-level northwesterly winds aloft will persist
    over the Great Plains, to the east of the Rockies-centered upper
    ridge and an upper low off the coastal Pacific Northwest. Weak convergence/subtle surface troughing will be prevalent in
    association with a persistently moist air mass across the southern
    Plains. Although a few strong storms could occur across parts of Kansas/Oklahoma into Texas this afternoon into evening, the
    combination of only modest instability and relatively weak
    deep-layer shear should limit the overall severe-weather potential.
    A few strong storms could also develop across southwest New Mexico
    and southeast Arizona later this afternoon into this evening, with
    some stronger wind gusts a possibility.

    ..Guyer/Bentley.. 08/31/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Mon Sep 1 09:35:10 2025
    ACUS01 KWNS 011253
    SWODY1
    SPC AC 011252

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0752 AM CDT Mon Sep 01 2025

    Valid 011300Z - 021200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
    SOUTHERN PLAINS...

    ...SUMMARY...
    Isolated severe storms may occur across the southern Plains this
    afternoon and early evening, including parts of southern Kansas and
    western Oklahoma.

    ...Southern Plains including southern Kansas/western Oklahoma...
    A shortwave trough centered over eastern Nebraska this morning will
    progress southeastward toward the south-central Plains and
    eventually the Ozarks by tonight. This will be in association with a strengthening belt of north-northwesterly mid-level winds (35 kt at
    500 mb). While the related low-level/surface response will be muted,
    a weak surface front/wind shift will progress southward from Kansas
    into Oklahoma, with a relatively moist air mass preceding the
    advancing front. Morning low clouds/stratus will abate by afternoon,
    yielding to ample insolation and probably a corridor of moderate buoyancy/steepening lapse rates, particularly across southwest
    Kansas/northwest Oklahoma. Increasing/widely scattered thunderstorm
    development is probable into mid-afternoon near the front/wind shift
    as the boundary layer warms. The enhanced north-northwesterly flow
    aloft will contribute to 35+ kt effective shear, which could yield
    some marginal supercells aside from evolving multicellular clusters.
    Isolated instances of severe hail/damaging wind will be possible
    through early evening as storms develop south-southeastward from
    southern Kansas into western/northern Oklahoma.

    ..Guyer/Bentley.. 09/01/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Tue Sep 2 09:18:25 2025
    ACUS01 KWNS 021234
    SWODY1
    SPC AC 021233

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0733 AM CDT Tue Sep 02 2025

    Valid 021300Z - 031200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
    THE UPPER MIDWEST...

    ...SUMMARY...
    Thunderstorms with potential for isolated severe wind gusts and
    marginally severe hail will be possible this afternoon into the
    early evening across parts of the Upper Midwest.

    ...Upper Midwest...
    An upper trough initially over central Canada will dig southeastward
    into the Upper Midwest/Lake Superior vicinity during the period.
    Showers and weak thunderstorms ongoing this morning over MN, aided
    by an MCV over northern MN, will gradually dissipate with
    differential heating/residual outflow arcing from southern MN west-northwestward towards the Dakotas/MN border by mid afternoon.
    A cold front initially over ND will advance southeastward
    into an adequately moist airmass, featuring surface dewpoints in the
    lower to mid 60s F ahead of it. Diurnal heating will likely yield
    moderate SBCAPE (1500-2000 J/kg) ahead of the front by mid-late
    afternoon. Model guidance is consistent in showing a band of
    scattered thunderstorms developing from the eastern half of SD into
    central MN by the mid-late afternoon. Upscale growth with higher
    storm coverage is expected from near the MN/SD border eastward into
    central and southern MN during the 22-02 UTC period. The stronger
    mid- and upper-level flow will likely lag behind the surface front
    and limit effective shear magnitudes (at or below 25 kt). However,
    a few organized multicells could be associated with isolated severe
    wind gusts and hail before this activity subsides during the
    early-mid evening.

    ..Smith/Bentley.. 09/02/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Wed Sep 3 08:26:44 2025
    ACUS01 KWNS 031158
    SWODY1
    SPC AC 031157

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0657 AM CDT Wed Sep 03 2025

    Valid 031300Z - 041200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
    KANSAS INTO WESTERN MISSOURI...

    ...SUMMARY...
    Scattered thunderstorms with potential for large to very large hail
    and severe wind gusts are expected this afternoon and evening across
    parts of the central Plains and lower Missouri Valley.

    ...Central Plains/Lower Missouri Valley...
    Water-vapor imagery this morning shows a mid-level shortwave trough
    over southern SD moving quickly southeast as a larger-scale mid- to
    upper-level low moves from western ON to near Lake Superior during
    the period. The smaller-scale disturbance is forecast to reach the
    lower MO Valley by late afternoon with an attendant belt of
    moderately strong northwesterly mid- to high-level flow
    overspreading the central Plains into the mid MS Valley.

    In the low levels, a cold front will advance southward across the
    central Plains and lower Missouri Valley with 60s deg F surface
    dewpoints ahead of the boundary. Diurnal heating will contribute to
    moderate buoyancy by mid afternoon with convective inhibition
    eroding near the front. Scattered thunderstorms are forecast to
    develop from central KS eastward into the lower MO Valley during the
    20-00 UTC period.

    The aforementioned strong northwesterly flow in the 500 to 300 mb
    layer (35-55 kt) will yield effective shear supporting organized
    updrafts. A few supercells will probably evolve across KS and
    perhaps into western MO where the main risk will be large to very
    large hail. Severe wind gusts will also be possible with
    supercells, or small clusters/bowing segments where 0-2 km lapse
    rates are steepest (i.e., KS). The severe threat is expected to
    persist into the mid evening as several small clusters move
    southeastward into southeast Kansas and adjacent portions of
    northern OK and southwest Missouri.

    ..Smith/Bentley.. 09/03/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Thu Sep 4 08:14:40 2025
    ACUS01 KWNS 041233
    SWODY1
    SPC AC 041231

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0731 AM CDT Thu Sep 04 2025

    Valid 041300Z - 051200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
    EAST AND THE MIDDLE MISSOURI VALLEY...

    ...SUMMARY...
    Isolated damaging winds are possible across parts of the Northeast
    to the southern Appalachians and Tennessee Valley from late morning
    through the afternoon. Isolated severe gusts are possible across
    parts of the middle Missouri Valley late this afternoon into the
    early evening.

    ...Southern Appalachians/TN Valley to the Northeast...
    Isolated to scattered showers/thunderstorms are ongoing this morning
    from the Lower Great Lakes southward into the southern Appalachians. Water-vapor imagery shows a vertically stacked cyclone over Ontario
    with a disturbance rotating through the basal portion of the larger
    scale trough. This mid-level feature will quickly move from the
    upper OH Valley into the NY/central Appalachians by the late afternoon.

    Despite weak mid-level lapse rates, some diurnal heating ahead of
    this activity should yield gradual intensification of thunderstorms
    and increased storm coverage by late morning across parts of the
    southern Appalachians. Locally damaging winds and marginally severe
    hail are possible, centered on the eastern TN vicinity.

    Isolated to scattered multicell clusters and short-line segments may
    also evolve in the afternoon from convection along/ahead of the cold
    front and lee trough. Weak MLCAPE and poor mid-level lapse rates
    will temper convective vigor, with damaging wind potential locally
    augmented to where pockets of deeper boundary-layer heating occur.

    ...Mid-MO Valley...
    An intense mid-level speed max/shortwave trough will quickly move
    from the southern part of the Prairie provinces into the mid MO
    Valley by this afternoon, before moving into the southwest Great
    Lakes by early Friday morning. Some model spread exists on the
    magnitude of destabilization immediately ahead of a cold front
    forecast to sweep through the region late this afternoon into the
    evening. However, weak buoyancy appears likely to develop and
    low-level lapse rates may become adequately steep to support a
    narrow corridor of low-topped storms capable of isolated severe gusts.

    ...KS...
    An accelerating and sharpening cold front will sweep south across
    the central High/Great Plains tonight. Undercut/elevated convection
    should form to the cold side of this boundary early Friday morning.
    Locally strong surface gusts may accompany this activity amid robust
    low-level northerlies.

    ..Smith/Bentley.. 09/04/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sun Sep 7 08:48:02 2025
    ACUS01 KWNS 071210
    SWODY1
    SPC AC 071209

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0709 AM CDT Sun Sep 07 2025

    Valid 071300Z - 081200Z

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

    ...SUMMARY...
    A few stronger thunderstorms capable of marginally severe wind
    gusts/hail are possible across portions of the central and southern
    High Plains late this afternoon through the early evening.

    ...Central/Southern High Plains...
    Morning water-vapor imagery shows a low/trough over the eastern
    Pacific with a downstream ridge over the Rockies. A couple of weak disturbances are cresting the ridge and may aid in storm development
    later this afternoon/evening over the central High Plains later
    today.

    In the low levels, a lee trough and an associated moisture plume
    over the High Plains will provide a focus for isolated to widely
    scattered storms. Strong heating over the High Plains will
    contribute to weak to moderate buoyancy by late afternoon.
    South-southeasterly low-level winds veering to around 20-kt
    northwesterly mid-level flow will support some modest updraft
    organization. The stronger storms may yield an isolated severe-hail
    (diameter 1.5 inches or less) and wind-gust (55-65 mph) threat. A
    small cluster or two is expected to evolve during the evening
    coincident with an increase in the LLJ. This activity will likely
    move east-southeast into western KS and the OK/TX Panhandles, where
    a cooling boundary layer and increasing CINH will act to limit
    severe potential by mid-late evening.

    ..Smith/Broyles.. 09/07/2025

    $$
    --- SBBSecho 3.28-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Wed Sep 10 08:03:04 2025
    ACUS01 KWNS 101247
    SWODY1
    SPC AC 101245

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0745 AM CDT Wed Sep 10 2025

    Valid 101300Z - 111200Z

    ...NO SEVERE THUNDERSTORM AREAS FORECAST...

    ...SUMMARY...
    Scattered showers and thunderstorms are possible over parts of the
    Northwest and northern Rockies with more isolated storms over the
    High Plains. Severe potential is generally low.

    ...Synopsis...
    Water-vapor imagery this morning shows an upper low situated over
    northern CA, and it will remain nearly stationary during the period
    with a large area of cyclonic flow extending from southern CA into
    the eastern Great Basin and central Rockies. A downstream upper
    ridge over the High Plains will feature a lee trough that will act
    to focus isolated to scattered thunderstorms from MT southward into
    the central High Plains.

    Strong heating and weak upslope flow beneath the aforementioned
    upper-level ridge will favor a few isolated cells developing during
    peak heating. A couple of the more vigorous storms may be capable
    of localized strong gusts near 1) NM/OK/TX/CO border, 2) east of the
    CO Front Range in the High Plains, and 3) in eastern WY. Warming
    aloft is expected to mitigate the overall potential with these
    storms. Farther west, a mid-level shortwave trough will move
    through the base of the West Coast mid- to upper low/trough and to
    near the UT/NV border by late afternoon/early evening. A
    corresponding belt of 50-kt southwesterly 500-mb flow will
    overspread western UT. Isolated dry microbursts may accompany the
    stronger storms over central UT into western CO during the 22-02z period.

    Elsewhere, scattered afternoon storms will occur beneath the upper
    trough from northern NV into OR and western ID, and a few of these
    storms could produce at least small hail given such cool
    temperatures aloft and modest deep-layer shear.

    ..Smith/Broyles.. 09/10/2025

    $$
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  • From Mike Powell@618:250/1 to All on Fri Sep 12 09:25:56 2025
    ACUS01 KWNS 121244
    SWODY1
    SPC AC 121243

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0743 AM CDT Fri Sep 12 2025

    Valid 121300Z - 131200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
    MONTANA EAST ACROSS MUCH OF THE DAKOTAS...AND IN THE FOUR CORNERS REGION...

    ...SUMMARY...
    A few storms capable of isolated severe wind gusts and hail are
    possible across the Four Corners region, and from eastern Montana
    into the Dakotas.

    ...Synopsis...
    An upper trough will remain over the Intermountain West, making slow
    eastward progress through tonight. An embedded disturbance is
    forecast to move from CO into the Dakotas late in the day, while a
    midlevel jet rounds the base of the trough across AZ overnight.
    Gradual height falls will occur across the length of High Plains
    primarily overnight as the upper-level ridge to the east gradually
    weakens.

    ...Eastern MT into the Dakotas...
    Thunderstorm development/intensification is expected across MT/WY
    east of a mid-level trough axis, where cool mid-level temperatures
    and surface dew points in the 50s will lead to MLCAPE in the 500 -
    locally 1000 J/kg range. Southwesterly deep-layer shear averaging
    20-35 kts will be favorable for isolated storms with hail potential.
    As storms move/develop farther east across eastern MT/western
    ND/northwest SD towards evening, greater instability (MLCAPE on the
    order of 2000 J/kg) should result in a severe hail and wind risk
    with isolated stronger storms within a similarly-sheared
    environment. Although the low-level jet should be weaker in this
    area tonight, lingering instability across the western Dakotas
    suggests some continued severe risk, primarily for strong/damaging
    gusts, into the overnight hours.

    ...Four Corners Region...
    Scattered to numerous thunderstorms are expected to
    develop/intensify today from eastern AZ/southeast UT across western
    portions of NM/CO, within a moist plume on the eastern periphery of
    the mid-level trough. Cool mid-level temperatures will contribute to
    modest MLCAPE, with locally higher values (above 1000 J/kg) over
    southeastern AZ. A predominantly cellular or cluster mode is
    expected, with isolated stronger storms capable of marginally severe
    wind and hail. Storms should persist into the evening over western
    NM/CO, with a few stronger storms remaining possible.

    ..Bunting/Broyles.. 09/12/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sat Sep 13 09:39:03 2025
    ACUS01 KWNS 131243
    SWODY1
    SPC AC 131242

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0742 AM CDT Sat Sep 13 2025

    Valid 131300Z - 141200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW MEXICO
    NORTH INTO THE DAKOTAS...AND OVER PORTIONS OF THE MIDWEST...

    ...SUMMARY...
    Isolated severe wind and hail will be possible from the
    Southwest/southern Rockies to the northern Great Plains and a
    portion of the Midwest, mainly today into early tonight.

    ...Southwest/southern Rockies/High Plains...
    An increase in thunderstorm coverage is anticipated from CO south
    into NM today as ascent/mid-level cooling with the western U.S.
    upper trough and several embedded vorticity maxima overspread the
    region. Extensive cloud cover will tend to limit the potential for
    widespread significant destabilization, with generally modest MLCAPE
    (at or below 1000 J/kg) over much of the area from CO southward into northern/western NM. Over portions of southern/eastern NM, however,
    higher surface dew points surging northwest from southwestern TX
    should help to focus a region of greater instability, with MLCAPE of
    1000 to locally near 1500 J/kg possible by afternoon. Ongoing
    thunderstorms should expand in coverage and increase in intensity as
    diurnal destabilization occurs, with isolated severe hail and wind
    possible with the strongest storms.

    Over southern/eastern NM, deep-layer shear will be more supportive
    of organized updrafts as a belt of stronger mid-level flow develops
    near the base of the trough, resulting in elongated hodographs.
    Here, a somewhat more concentrated risk for severe hail and wind may
    develop with a couple storms developing supercell structures. Higher
    severe probabilities were considered for this area, however
    lingering concerns over the effects of ongoing storms and related
    cloud cover lowered confidence in increasing probabilities with this outlook.

    ...NE/SD/ND...
    Strong storms were ongoing this morning over portions of the western
    Dakotas in association with embedded impulses in advance of the
    upper trough. The resulting extensive cloud cover/outflows from
    multiple rounds of thunderstorms will tend to temper destabilization
    later today within a modestly-sheared environment. Nevertheless,
    some isolated severe wind/hail potential will exist as storms over
    central SD move into ND today. Thunderstorms are expected to
    redevelop across the central High Plains of NE/northeast CO later
    this afternoon and evening and move into western SD tonight. Here,
    sufficient diurnal destabilization in the wake of earlier convection
    may result in a continued risk for isolated severe storms with
    strong-damaging gusts and hail.

    ...IL/IN/WI...
    A small cluster of thunderstorms over northeast IL/northwest IN,
    associated with an earlier MCV over WI and ongoing/modest warm
    advection, is expected to continue moving SSE in the short term
    across eastern IL/far western IN. Some isolated severe wind and hail
    potential may develop as this cluster of storms moves along an
    intensifying instability gradient within a northwest flow regime
    through at least early afternoon as boundary layer heating commences.

    ..Bunting/Broyles.. 09/13/2025

    $$
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  • From Mike Powell@618:250/1 to All on Mon Sep 15 09:45:29 2025
    ACUS01 KWNS 151244
    SWODY1
    SPC AC 151242

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0742 AM CDT Mon Sep 15 2025

    Valid 151300Z - 161200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM WYOMING
    INTO WESTERN SOUTH DAKOTA...OVER FAR NORTHERN MINNESOTA...AND
    NORTHEAST NORTH CAROLINA...

    ...SUMMARY...
    Isolated severe gusts are possible across Wyoming into western South
    Dakota this afternoon to early evening. Isolated severe hail and
    damaging wind are possible across far northern Minnesota in the
    early to mid-afternoon. A brief tornado is possible in the northeast
    North Carolina vicinity in the early morning Tuesday.

    ...WY to western SD...
    A shortwave trough over western ID will move east across WY/western
    SD during the day, as several embedded vorticity maxima contribute
    regions of enhanced ascent. Steep mid-level lapse rates of 8-9 deg
    C/km, combined with diurnal heating, will result in MLCAPE of a few
    hundred J/kg across much of the area. Despite weak buoyancy, the favorably-timed ascent will contribute to thunderstorm development/intensification this afternoon as storms approach
    northeast WY/western SD. A deep and well-mixed boundary layer will
    lead to high-based convection capable of isolated strong/damaging
    gusts through early evening, with intensities diminishing thereafter
    as nocturnal cooling commences.

    ...Northeast NC/southeast VA vicinity...
    A surface low southeast of Cape Hatteras is forecast to move towards
    the NC coast through 12z Tuesday, with a belt of stronger low-level
    flow developing north/northwest of the low. Variability remains
    regarding the forecast location of the low and strength of low-level
    winds, however a conditional risk for a tornado would exist early
    Tuesday morning with stronger convective elements, should sufficient
    low-level hodograph curvature develop, as high theta-e air is
    advected west across the northeast NC/southeast VA vicinity.

    ...Far northern MN...
    Thunderstorm development is expected this afternoon within a northwest-southeast oriented arc from southeast Manitoba across
    northeast Ontario as a shortwave trough becomes increasingly
    negatively tilted while lifting northeast. Although development
    south of the international border is uncertain, some CAM guidance
    suggest isolated development is possible. Moderate buoyancy and
    effective shear of 35-40 kts over far northern MN suggests a
    conditional risk for severe wind/hail would exist should storm
    development occur in this area.

    ...MO/AR vicinity...
    A few strong gusts will be possible again today with pulse-type
    storms within a weakly-sheared but strongly unstable (MLCAPE of
    2500-3000 J/kg) environment.

    ..Bunting/Broyles.. 09/15/2025

    $$
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