• DAY1SVR: Day 1 Convective Outlook Corr 1

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Mon Jul 14 16:36:49 2025
    ACUS01 KWNS 141636
    SWODY1
    SPC AC 141635

    Day 1 Convective Outlook CORR 1
    NWS Storm Prediction Center Norman OK
    1135 AM CDT Mon Jul 14 2025

    Valid 141630Z - 151200Z

    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
    MID-ATLANTIC AS WELL AS FAR EAST-CENTRAL WYOMING...SOUTHWEST SOUTH
    DAKOTA...AND THE FAR NORTHERN NEBRASKA PANHANDLE...

    CORRECTED FOR INCORRECT GEOGRAPHIC DESCRIPTION IN HEADLINE

    ...SUMMARY...
    Strong to severe thunderstorms are possible across parts of the
    northern Plains as well as the Mid-Atlantic States this afternoon
    into tonight. Isolated strong to severe thunderstorms are possible
    across the Mid-South, southeast Arizona, and Florida.

    ...Mid-Atlantic into the Northeast...
    A belt of stronger mid-level flow extends from the north-central CONUS/south-central Canadian Prairies through the Northeast, with
    some modest cyclonic curvature. A more defined shortwave trough is
    currently progressing into the Upper OH Valley/central Appalachians,
    along the southern periphery of the belt of stronger, broadly
    cyclonic flow. Showers and isolated thunderstorms are currently
    ongoing just ahead of this shortwave.

    Expectation is for this shortwave trough to continue
    eastward/northeastward throughout the day, with the modest upper
    troughing farther north shifting eastward as well. A reservoir of
    ample low-level moisture (i.e. dewpoints in the low to mid 70s) is
    in place ahead of this shortwave. This low-level moisture will
    support airmass destabilization and moderate buoyancy this afternoon
    despite widespread cloudiness and tempered daytime heating.
    Thunderstorm development is anticipated as large-scale ascent
    attendant to the approaching shortwave (and larger upper trough)
    moves into the region. Additionally, recent surface analysis places
    a trough axis from the northern NY/VT border southwestward through
    central PA. Low-level convergence along this axis could augment the
    large-scale ascent. All of these factors will act to support
    scattered to numerous thunderstorms this afternoon.

    While mid-level flow and related deep-layer shear are both expected
    to remain fairly modest, some of this convection could congeal into
    multiple loosely organized clusters. Steepened low-level lapse rates
    and water loaded downdrafts could support isolated strong to
    damaging winds as thunderstorms spread generally eastward through
    the afternoon and evening. Highest thunderstorm coverage and
    greatest relative chance for damaging gusts is expected from eastern
    PA through central VA.

    ...Northern Plains to Northern Minnesota...
    Satellite imagery shows a vorticity maximum drifting slowly across
    the central Intermountain West. Large-scale ascent attendant to this
    vorticity maximum will augment low-level convergence along a
    sharpening lee trough, likely resulting in enough lift to promote
    thunderstorm development across eastern WY during the late
    afternoon. This area is on the southern periphery of a belt of
    stronger westerlies, and there appears to be just enough westerly
    flow aloft for updraft organization and persistence into the better
    moisture and buoyancy farther east. As such, there is a risk for
    strong to severe gusts within this deeply mixed airmass throughout
    the afternoon and evening.

    Thunderstorm development also appears possible along a surface
    trough that arcs from western MT to a low in southwest SD. A
    conditional severe risk exists with any storms that develop near the
    surface low over ND this afternoon, but the greater thunderstorm
    coverage is anticipated later this evening and overnight as warm-air
    advection across the frontal zone strengthens. Elevated
    thunderstorms are also expected tonight as an
    upper trough overspreads the northern Rockies. Given ample shear and
    buoyancy, isolated hail is possible in both of these regions
    tonight.

    ...Eastern GA into the FL Peninsula...
    Ample low-level moisture and robust diurnal heating will result in
    strong buoyancy from eastern GA southward across the entire FL
    Peninsula this afternoon. A modest cyclone drifting westward towards
    the GA/FL coast will interact with this airmass, contributing to
    widespread thunderstorm development this afternoon. Convection
    should develop along/near the Atlantic Coast before spreading south-southwestward and inland across much of the FL Peninsula this afternoon/evening. Several clusters capable of producing isolated
    strong to severe winds are possible.

    ...AZ...
    High pressure over the southern Great Basin will contribute to
    around 20-25 kt of northeasterly mid-level flow across southern AZ
    this afternoon. This mid-level flow will take storms that develop
    across the higher terrain southwestward into the deeply mixed
    boundary layer over southeast AZ. A few strong to severe gusts are
    possible, but overall coverage will likely be sparse.

    ...South-Central/Southeast TX into the Mid-South...
    A trio of MCVs is apparent on radar and satellite imagery this
    morning. One is centered over Real and Uvalde Counties in the TX
    Hill Country, with another over Denton and Collin Counties in north
    TX, and the third farther north over northeast AR. At least
    scattered thunderstorms are possible this afternoon/evening with
    each of these MCVs as they progress eastward/northeastward. Vertical
    shear will be weak, but discrete storm propagation along the
    stronger outflows could result in occasionally strong/damaging
    downbursts.

    ..Mosier.. 07/14/2025

    $$

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  • From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Tue Aug 12 20:15:23 2025
    ACUS01 KWNS 122014
    SWODY1
    SPC AC 122012

    Day 1 Convective Outlook CORR 1
    NWS Storm Prediction Center Norman OK
    0312 PM CDT Tue Aug 12 2025

    Valid 122000Z - 131200Z

    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
    GREAT LAKES REGION...

    CORRECTED FOR NDFD

    ...SUMMARY...
    Strong to locally severe thunderstorms are possible over parts of
    the Great Lakes/Midwest this afternoon with both damaging winds and
    hail possible.

    ...20Z Update...
    Given the weak mid/upper-level flow, the potential for organized
    severe wind gusts appears very limited in southeast
    Arizona/southwest New Mexico. Steep low-level lapse rates may still
    support strong/gusty outflow however. Elsewhere only minor update
    the general thunderstorm area were made. See the previous discussion
    for additional details.

    ..Wendt.. 08/12/2025

    .PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Aug 12 2025/

    ...Great Lakes/Midwest...
    Midday satellite/radar composite show a weakened thunderstorm band
    moving east-northeast across the eastern part of Lower MI. Surface
    analysis indicates rain-cooled air north of a gust front/outflow
    that has become draped from southeast Lower MI into the Michiana
    region. Heating south of this boundary has resulted in temperatures
    warming through the mid-upper 80s with dewpoints in the lower 70s.
    Additional storms will probably develop along the trailing outflow
    and gradually move east-northeast with the mean wind. Considerably
    weaker deep-layer shear is present across the eastern part of the
    Corn Belt into the Lower MI vicinity compared to farther north over
    the U.P. of MI in closer proximity to a shortwave trough.
    Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to
    perhaps locally severe/damaging gusts this afternoon.

    Farther north in WI into the U.P. of MI, a weak cold front will move
    into the region later this afternoon. Model guidance shows widely
    scattered storms developing as filtered sunshine leads to a
    destabilizing boundary layer. A few stronger thunderstorms are
    possible and could yield a localized risk for marginally severe hail
    and damaging gusts during the mid afternoon to early evening period.

    ...Southeast AZ/southwest NM...
    Strong heating should result in widely scattered thunderstorms
    developing near terrain-favored areas. Weak shear will result in
    disorganized storms, but the development of very steep surface to
    500-mb lapse rates will promote strong evaporative cooling with the
    more intense downdrafts. Isolated severe gusts are possible.

    $$

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  • From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Sun Aug 24 13:11:57 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...

    CORRECTED FOR GRAPHICS

    ...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

    $$

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  • From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Thu Sep 11 17:12:16 2025
    ACUS01 KWNS 111712
    SWODY1
    SPC AC 111710

    Day 1 Convective Outlook CORR 1
    NWS Storm Prediction Center Norman OK
    1210 PM CDT Thu Sep 11 2025

    Valid 111630Z - 121200Z

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

    CORRECTED FOR PROB GRAPHICS

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

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

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

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

    ..15_ows.. 09/11/2025

    $$

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