• DAY1 4/5 RISK AREA POSTED

    From Mike Powell@618:250/1 to All on Fri May 16 08:40:00 2025
    ACUS01 KWNS 161247
    SWODY1
    SPC AC 161246

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0746 AM CDT Fri May 16 2025

    Valid 161300Z - 171200Z

    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EAST-CENTRAL AND SOUTHEAST MISSOURI...WESTERN AND CENTRAL
    KENTUCKY...SOUTHERN ILLINOIS AND INDIANA...SOUTHWEST
    OHIO...NORTHWEST TENNESSEE...AND NORTHEAST ARKANSAS...

    ...SUMMARY...
    A regional outbreak of severe thunderstorms is likely this afternoon
    into tonight across parts of the mid Mississippi, Ohio and Tennessee
    Valleys. This will include intense supercells associated with
    tornadoes, large hail and wind damage. Several strong tornadoes are
    expected, and a long-track high-end tornado will be possible. From
    the evening into the overnight, a bowing line segment is expected to
    form with potential for tornadoes and damaging winds, some possibly
    greater than 75 mph.

    ...Mid Mississippi and Ohio Valley/Tennessee Valley Region...
    As an upper-level low near the MN/ND border shifts east today, a
    mid-level jet streak will move from the Plains into the
    mid-Mississippi Valley. A surface cold front will move east across
    the Great Lakes, Midwest and OH/TN Valley region this afternoon and
    tonight. An expansive warm/moist sector will destabilize during the
    day, setting the stage for a regional severe weather outbreak this
    afternoon and tonight.

    Scattered severe thunderstorms, with a history of large hail, were
    ongoing at 13z from northeast AR into eastern KY. Clusters of severe
    storms, including supercells, will continue moving northeast within
    this corridor through at least early afternoon. The eventual
    longevity of these storms remains uncertain, however downstream
    diurnal destabilization could allow storms with a severe hail/wind
    threat to move into WV/western VA this afternoon.

    In the wake of these morning storms, destabilization will occur as a
    warm front lifts north, with strong instability (MLCAPE in excess of
    2500 J/kg) developing from portions of eastern MO east into the
    OH/TN Valley region, and south in advance of the front into eastern
    TX. The presence of strong mid-level flow will contribute to
    deep-layer shear averaging 50 kts or higher across a large area.

    Vigorous redevelopment of severe storms is expected by early
    afternoon across southern/eastern MO as height falls overspread the
    area. More isolated development is expected southward along the cold
    front towards 00Z. Initial storm development will strongly favor
    supercell storm mode with all severe hazards possible, including the
    potential for strong tornadoes across the Moderate/Enhanced Risk
    areas where low-level shear will be strongest. Large to very large
    hail will also be possible with mature supercells this afternoon
    through early evening. As storms continue moving east across the
    OH/TN Valley region, eventual upscale growth into multiple bowing
    segments is expected. The tornado threat will continue, especially
    with QLCS circulations, and significant severe gusts will also be possible.

    ...Ark-La-Tex/Lower Mississippi Valley...
    Warm mid-level temperatures will tend to delay thunderstorm
    initiation along the southward-trailing cold front into northeast TX
    until later in the day, however at least isolated development is
    expected towards 22z-00z. MLCAPE in excess of 3000 J/kg and 45-55
    kts of deep-layer shear oriented favorably relative to the front
    suggests a supercell mode with large to very large hail, along with
    damaging gusts. Although weaker low-level shear will be present in
    this area, some potential for a tornado will exist with any mature
    supercell. With time, storms may increase in coverage and begin to
    cluster in an environment favorable for a continued severe wind/hail threat.

    ...Portions of the Mid-Atlantic/northern DelMarVa Peninsula...
    As the southern portion of the long-lived MCS over PA/NY continues
    moving east/southeast today, the potential will exist for
    re-development of organized storms, including supercells, over
    portions of southeast PA/southern NJ and the northern DelMarVa
    peninsula. With moderate west/northwest flow in place to the east of
    the upper level ridge, RAP/HRRR forecast soundings depict sufficient
    deep shear and moderate instability for a severe hail and wind risk.
    Some consideration was given for higher severe probabilities in this
    area, however uncertainty remains on the location of a corridor of
    greater risk.

    ..Bunting/Marsh.. 05/16/2025

    $$
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  • From Mike Powell@618:250/1 to All on Mon May 19 08:19:00 2025
    ACUS01 KWNS 191253
    SWODY1
    SPC AC 191251

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0751 AM CDT Mon May 19 2025

    Valid 191300Z - 201200Z

    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FAR NORTH
    TEXAS...MUCH OF CENTRAL AND EASTERN OKLAHOMA...SOUTHEAST
    KANSAS...AND THE OZARKS...

    ...SUMMARY...
    Significant severe weather is likely from the central/southern
    Plains into the the Ozarks today into tonight. All severe weather
    hazards are expected, to include tornadoes (some potentially strong
    to intense), very large hail, and severe winds.

    ... Synopsis ...

    A large, amplified trough over the Rockies will shift slowly
    eastward into the Plains today. Embedded within this longwave
    trough, a complex evolution is expected. Downstream of the trough, a
    negatively tilted shortwave trough will deepen and close off across
    the northern Plains. Meanwhile, upstream, a closed low currently
    over Idaho will dig southeastward, open up, and eject into the
    central Plains.

    As this evolution occurs, strong midlevel flow (in excess of 50
    knots) will remain across much of the central and southern Plains
    through the forecast period. By late in the afternoon, midlevel flow
    will strengthen to perhaps 70 knots in response to the ejecting low
    into the central Plains.

    At the surface, the main synoptic low will be somewhat
    diffuse/elongated over northwest Kansas into southwest Nebraska this
    morning. Extending southward from this low, a dryline will stretch
    through western Kansas into the Oklahoma and Texas Panhandles,
    continuing into west Texas. A warm front will extend eastward near
    the Kansas-Nebraska border before curving southeastward into
    Missouri into the southern Appalachians.

    The surface low is expected to gradually fill today as it slowly
    moves east/northeast into south-central Nebraska, Despite this, rich
    Gulf moisture will be maintained across the central and southern
    Plains. Dewpoint temperatures at or above 70F will advect northward
    from Texas through Oklahoma perhaps to as far north as northeast Kansas.

    During the afternoon, strong diurnal heating along the dryline may
    result in a sub-synoptic low developing across northwest Oklahoma.
    This low will slowly progress east along the Oklahoma-Kansas border
    during the afternoon, weakening with time.

    ... Southern and Central Plains into the Ozarks ...

    A strongly sheared atmosphere will already be in place at the start
    of the forecast period. As diurnal heating commences and 70F
    dewpoints advect northward, the atmosphere across much of the
    central and southern Plains will become strongly to extremely
    unstable as well, with surface-based CAPE values between 3000-5000
    J/kg across the region.

    Multiple rounds of storms are expected across the region today. One
    such initiating mechanism looks to be a subtle shortwave trough
    embedded in the larger scale flow currently across eastern New
    Mexico. This wave should initiate thunderstorms across eastern
    Oklahoma northward into eastern Kansas by midday. It is unclear if
    these storms will initially be elevated, but as they move east and
    the atmosphere destabilizes further ahead of the line, a transition
    to more surface-based convection should occur. At the same time, the
    low-level jet is forecast to strengthen/reorganize across eastern Oklahoma/western Arkansas into western Missouri. This will yield
    ample low-level curvature to the hodograph. Thus, given the strongly
    sheared environment in place, supercells capable of producing all
    severe hazards, including strong tornadoes, will be possible with
    this first round of storms.

    By mid-to-late afternoon, 30-60 meter mid-level height falls should
    overspread the dryline as it mixes east into central Kansas
    southward into western north Texas. Rapid thunderstorm development
    is expected along the dryline given the forecast extreme
    instability. These thunderstorms should develop west of the better
    low-level jet/flow, where the low-level flow is expected to be a
    little more veered than across eastern Kansas/Oklahoma. This veered
    low-level flow still will result in a strongly sheered environment,
    but with more straight hodographs and less low-level curvature. The
    result should be another round of supercells, albeit with a tendency
    to split. These supercells will be capable of producing very large
    hail and tornadoes. The number of supercells across the dryline
    combined with a propensity to split, may result in destructive
    interference and result in a more episodic hail and tornado threat.

    In addition to the hail and tornado threat, the number of expected thunderstorms in the presence of a very moist and unstable
    atmosphere with steep lapse rates may result in strong downdraft
    winds. The most likely region for this will be across portions of
    northeast Oklahoma, northwest Arkansas, southeast Kansas, and
    southwest Missouri. A 45% wind area was included in this outlook.

    ... Southern Illinois into Southern Appalachians ...

    Along the northern periphery of shortwave ridging over the
    Southeast, a midlevel jet streak will cross the southern
    Appalachians during the afternoon. Here, an influx of steep midlevel
    lapse rates atop rich boundary-layer moisture will yield strong
    surface-based instability along/south of a warm front draped across
    the region. Scattered thunderstorms will spread east-southeastward
    along/south of the front from TN into the southern Appalachians,
    where the favorable buoyancy and around 40-50 kt of effective shear
    will promote organization into clusters and a couple splitting
    supercell structures. Damaging winds and large hail will be possible
    with the strongest storms.

    Overnight, additional thunderstorms may develop across southern
    Illinois and western Kentucky in association with warm-air advection
    ahead of the main area of thunderstorms to the west. These
    thunderstorms will also pose the potential for small hail and
    isolated wind damage.

    ..Marsh/Smith.. 05/19/2025

    $$
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  • From Mike Powell@618:250/1 to All on Sun Jun 8 10:10:00 2025
    ACUS01 KWNS 081208
    SWODY1
    SPC AC 081207

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0707 AM CDT Sun Jun 08 2025

    Valid 081300Z - 091200Z

    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
    AND EVENING FROM THE EASTERN TEXAS PANHANDLE INTO SOUTHERN OKLAHOMA
    AND NORTHWEST/NORTH-CENTRAL TEXAS...

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
    FROM THE MID-ATLANTIC REGION INTO GEORGIA....

    ...SUMMARY...
    A severe weather outbreak is possible across the southern Plains
    today. A few tornadoes, destructive wind gusts of 80-100 mph, and
    giant hail up to 5 inches in diameter are likely. Strong gusts, and
    perhaps a couple of tornadoes, are also possible along portions of
    the East Coast.

    ...OK/TX...
    Broad west-northwesterly flow is present today across the
    central/southern Plains states, with a surface cold front sagging
    southward across KS. Ahead of the front, a very moist
    boundary-layer air mass is in place across much of OK and TX, with
    dewpoints in the upper 60s and lower 70s. Strong daytime heating
    and near dry-adiabatic low/mid-level lapse rates will yield a large
    reservoir of extremely high CAPE values across western OK and
    northwest TX.

    Rapid development of intense thunderstorms will ensue by mid/late
    afternoon along the cold front over northwest OK and along a complex
    dryline structure over the eastern TX Panhandle. Strong deep layer
    shear will favor supercells, despite rather weak low-level winds.
    Very large hail, damaging winds, and a few tornadoes will be
    possible as these storms track southeastward across western/central
    OK and congeal into one or more bowing segments. Recent CAM
    solutions suggest pockets of deep boundary-layer mixing, with some
    areas heating into the mid 90s while dewpoints drop into the 50s.
    If this scenario develops, significant wind and hail would remain a
    concern, but the overall risk of tornadoes would be reduced.

    The risk of widespread destructive winds will increase through the
    evening as the convective complex tracks into northwest and
    north-central TX. The activity make remain intense as far east as northern/central LA tonight.

    ...Central/North TX early afternoon...
    A cluster of strong thunderstorms is ongoing this morning between
    ABI and LBB. Other isolated cells are forming in eastern NM north
    of TCC. Given the very unstable environment, any one of these
    clusters of storms could potentially persist through the day and
    track southeastward into parts of central TX. Large hail and
    damaging winds would be the main concerns.

    ...Mid Atlantic Region...
    A shortwave trough currently over OH will track eastward today, with large-scale ascent overspreading the Mid-Atlantic states by
    afternoon. A moist surface air mass is present across much of
    VA/MD/NC and vicinity with dewpoints in the upper 60s. Persistent
    clouds and weak mid-level lapse rates will limit destabilization.
    However, it appears likely that storms will develop off the Blue
    Ridge by mid afternoon and spread eastward toward the coast.
    Forecast soundings show sufficient low and deep layer shear for
    supercell structures capable of damaging wind gusts and perhaps a
    few tornadoes.

    ...GA/SC...
    A large MCS has persisted overnight across parts of AL/GA, with a
    few strong storms along its leading edge. Given a few hours of
    daytime heating, these storms may pose a risk of damaging wind gusts
    as they spread eastward toward the coast.

    ..Hart/Bentley.. 06/08/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Jun 17 09:02:00 2025
    ACUS01 KWNS 171259
    SWODY1
    SPC AC 171258

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0758 AM CDT Tue Jun 17 2025

    Valid 171300Z - 181200Z

    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
    KANSAS AND NORTHERN OKLAHOMA...

    ...SUMMARY...
    Severe thunderstorms producing numerous to widespread damaging
    winds, scattered large hail (isolated 2+ inches), and a few
    tornadoes are expected today across parts of the central/southern
    Plains and lower/mid Missouri Valley. The greatest threat for
    destructive gusts up to 70-100 mph is forecast across portions of
    Kansas and northern Oklahoma.

    ...Central/Southern Plains into the Lower/Mid Missouri Valley...
    A small but intense bow echo that moved south-southeastward across
    parts of KS overnight should continue to weaken this morning across
    northeast OK. But in the short term, an isolated threat for severe
    winds may continue until the cluster fully dissipates. Across
    eastern CO, occasional severe hail may occur with marginal
    supercells for another hour or two before additional weakening
    occurs. The net effect of this overnight/early morning convection on
    the severe potential across the southern/central Plains remains
    uncertain. But, a trailing outflow boundary from the decaying MCS
    now in northeast OK may prove instrumental in focusing significant
    severe potential this afternoon/evening.

    A subtle mid-level shortwave trough over the eastern Great Basin and
    central Rockies will continue to move eastward over the adjacent central/southern High Plains by this evening. At the surface,
    further deepening of a low over southeast CO is anticipated through
    the day, with this low forecast to develop into the TX Panhandle by
    early evening. A lee trough/dryline will extend southward from this
    low, while a convectively reinforced boundary should extend
    somewhere along/near the KS/OK border by mid to late afternoon, and
    potentially northeastward into eastern KS as well. The airmass
    across east-central CO into western KS was generally not
    convectively overturned yesterday into early this morning, with the
    12Z sounding from DDC still showing around 2800 J/kg of MUCAPE available.

    Convective development and evolution remain uncertain later today.
    Still, it appears likely that initially high-based thunderstorms
    will develop over the higher terrain of central CO this afternoon,
    and then spread east-southeastward over the adjacent High Plains
    through the evening. Much of eastern CO and vicinity will be in a
    post-frontal regime. But steep mid-level lapse rates and sufficient
    low-level moisture should support the development of moderate
    instability. Strong deep-layer shear should foster supercells
    initially, with associated threat for mainly large to isolated very
    large hail. Some upscale growth may eventually occur with this
    activity as it spreads into western KS this evening, along with an
    increased threat for severe/damaging winds.

    Farther east into central/eastern KS and MO, severe potential
    remains highly uncertain, with a myriad of possible solutions
    offered by various high-resolution guidance. In general, current
    expectations are for an increasing threat for numerous to
    potentially widespread severe/damaging winds across parts of KS into
    northern OK, with one or more intense clusters potentially
    developing in tandem with a strengthening low-level jet this evening
    across the southern/central Plains. Significant severe gusts of 75+
    mph remain possible, along with a few tornadoes with any sustained
    supercells along/near the boundary this evening as low-level shear
    strengthens. Overall, severe probabilities have been expanded
    southward some across the OK/TX Panhandles and northern/central OK,
    in an attempt to account for where the outflow boundary/front may be
    present this afternoon/evening. Additional adjustments to risk areas
    are likely with later outlook updates pending additional
    observational and model data.

    ...Mid-Atlantic into the Tennessee Valley/Southeast...
    Diurnal heating of a seasonally moist low-level airmass will occur
    today across the central Appalachians/southern Mid-Atlantic within a
    modestly sheared environment. Thunderstorms are expected to develop
    over higher terrain by early afternoon, and subsequently spread
    eastward through the evening. Some of this activity may form into
    loosely organized clusters. Occasional strong/damaging winds should
    be the main severe threat with this activity, particularly across
    parts of VA/MD where stronger instability is forecast.

    Farther south into the TN Valley/Southeast, a weak mid/upper-level
    trough with multiple embedded perturbations should advance slowly
    eastward through the day. Similar to yesterday, daytime heating of a
    moist airmass should foster moderate to locally strong instability
    this afternoon. Around 25-30 kt of mid-level southwesterly flow and
    similar values of deep-layer shear should support some loose
    convective organization with multiple thunderstorm clusters that can
    develop. Have expanded the Marginal Risk for isolated damaging winds southwestward to account for this potential.

    ..Gleason/Kerr.. 06/17/2025

    $$
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  • From Mike Powell@618:250/1 to All on Tue Jun 17 15:49:00 2025
    ACUS01 KWNS 172001
    SWODY1
    SPC AC 172000

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0300 PM CDT Tue Jun 17 2025

    Valid 172000Z - 181200Z

    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
    OF NORTHERN OKLAHOMA AND SOUTHERN KANSAS...

    ...SUMMARY...
    Severe thunderstorms producing numerous to widespread damaging
    winds, scattered large hail (isolated 2+ inches), and a few
    tornadoes are expected this afternoon and evening across parts of
    the central/southern Plains. The greatest threat for destructive
    gusts up to 70-100 mph is forecast across portions of southern
    Kansas and northern Oklahoma.

    ...20z Update Southern Plains...
    A convective reinforced outflow boundary across west-central KS
    continues to slowly push southward across southwest portions of the
    state to near the OK border. This boundary will likely serve as the
    focus for robust convective development this afternoon and evening,
    as indicated by elevated development farther east. To the north of
    the primary surface heating, this initial activity may quickly grow
    upscale into one or more clusters before spreading southeast and
    becoming more surface-based with time. Large to very large hail,
    damaging gusts and some tornado risk are likely with these storms.

    Across northwest OK, and the northeastern TX Panhandle, additional,
    more isolated storms are likely this afternoon along the southern
    most modified outflow and pseudo-triple point area. Surface obs and
    18z AMA/LMN RAOBs show substantial low-level shear, large buoyancy
    and favorable deep-layer shear for supercells capable of very large
    hail and a few tornadoes across northern OK and far southern KS.
    Current expectations are still that initially cellular convection
    will rapidly develop and pose a severe risk through the afternoon,
    before growing upscale as it interacts with additional storms over
    KS this evening. One or more organized bows/clusters, capable of
    very strong damaging gusts, hail and a couple of tornadoes are
    likely this evening. Will maintain the MDT risk with minimal
    trimming on the northwest side near the advancing outflow.

    ...Southeast to the Mid Atlantic...
    Several clusters of strong to occasional severe storms are ongoing
    and expected to continue this afternoon/evening. Moderate buoyancy
    within a very moist air mass could support occasional damaging gusts
    from heavily water-loaded downdrafts. Some degree of organization
    into loose clusters could continue, especially across AL where
    storms have shown slightly stronger cold pools. However, the overall
    potential for storm organization is low with vertical shear
    remaining quite weak. The severe risk should begin to weaken through
    the early evening. Some minor trimming was made to the severe
    probabilities along the western edge of the MRGL.

    ...Rockies...
    Scattered severe storms, including a few supercells, will continue
    this afternoon. Confidence is highest in the severe threat remaining
    near the I-25 corridor where more substantial heating has taken
    place. Hail remains the primary risk, though a few damaging gusts
    and a brief tornado remain possible.

    ..Lyons.. 06/17/2025

    .PREV DISCUSSION... /ISSUED 1118 AM CDT Tue Jun 17 2025/

    ...KS/OK...
    Overnight and morning thunderstorm activity has significantly
    changed the overall forecast for severe storms across the central
    Plains for today. A severe MCS overspread parts of southeast KS and
    northeast OK a few hours ago, pushing an outflow boundary southward
    into central OK. Strong heating is occurring to the north of this
    boundary, where rapid destabilization is expected this afternoon
    across northern OK/southern KS. A consensus of 12z model guidance
    shows this to be the corridor of rapid and intense thunderstorm
    development. Forecast soundings show substantial low-level shear,
    steep lapse rates, and sufficient winds aloft for supercells capable
    of very large hail and a few tornadoes. Relatively warm
    temperatures in the 850-700mb layer are a negative factor for a
    greater tornado concern. Through the evening, congealing outflows
    will likely result in a larger MCS posing a risk of widespread
    damaging wind gusts into northeast OK and perhaps parts of northwest AR/southwest MO.

    ...Eastern CO/Southeast WY...
    Overnight storms also impacted the forecast for this region today.
    Easterly low-level winds (enhanced by outflow) have transported
    moisture westward into the foothills, where rapid thunderstorm
    development is expected by early afternoon. Steep mid-level lapse
    rates and seasonably cool mid-level temperatures, coupled with
    sufficiently strong westerly flow aloft, will promote a risk of very
    large hail in the strongest storms. A tornado or two is also
    possible. It is unclear how far east this activity can make it into
    the adjacent Plains, where persistent low-clouds and more stable
    conditions will likely prevail. Refer to MCD #1330 for further
    details.

    $$
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