• DAY1 ENHANCED RISK Areas

    From Mike Powell@618:250/1 to All on Sun Mar 30 08:08:00 2025
    ACUS01 KWNS 301247
    SWODY1
    SPC AC 301245

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0745 AM CDT Sun Mar 30 2025

    Valid 301300Z - 311200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
    THE LOWER/MID MISSISSIPPI VALLEY INTO THE OHIO VALLEY AND SOUTHERN
    GREAT LAKES...

    ...SUMMARY...
    Numerous severe thunderstorms are expected today and tonight across
    a broad portion of the Southeast and lower/mid Mississippi Valley
    into the Ohio Valley and southern Great Lakes. Multiple swaths of
    widespread damaging winds appear likely. Large to very large hail
    and several tornadoes will also occur with supercells. A few of
    these tornadoes could be strong.

    ...Synopsis...
    A broad area of severe potential remains apparent today and tonight,
    with all severe hazards likely. The main mid-level shortwave trough
    of interest will move quickly northeastward from the Ozarks/mid MO
    Valley to the Upper Midwest and Great Lakes today, as larger-scale
    upper troughing gradually becomes more established over the MS
    Valley through the period. At the surface, the primary surface low
    over eastern IA this morning is expected to develop northeastward
    towards northern Lower MI by this evening, and eventually into
    southern Ontario/Quebec late tonight. An attendant cold front will
    sweep east-southeastward over much of the Midwest/OH Valley and
    mid/lower MS Valley through the period, while a warm front lifts
    northward in tandem with the surface low over portions of the Great
    Lakes. A dryline will mix eastward this afternoon across parts of
    north-central to south-central TX.

    ...Midwest/Ohio Valley to the Great Lakes...

    Mainly elevated thunderstorms are ongoing this morning across parts
    of northeast MO in associated with the northeastward-advancing
    shortwave trough. This activity should generally remain sub-severe,
    although isolated strong/gusty winds could occur with modest daytime
    heating this morning. Otherwise, a corridor of weak to moderate
    instability is expected to develop ahead of the cold front by early
    afternoon. Robust convection appears likely to initiate by 18-19Z,
    and it will spread quickly northeastward across much of the OH
    Valley and southern Great Lakes regions this afternoon and evening.
    A 50-70 kt southwesterly mid-level jet attendant to the shortwave
    trough will provide ample deep-layer shear for organized convection.

    Current expectations are for an initially more discrete mode, with
    supercells posing a threat for large to very large hail (around
    1.5-2.5 inch diameter) given the presence of steep mid-level lapse
    rates and favorable deep-layer shear. A fairly quick transition
    (within a few hours of initiation) to a more linear/cluster mode is
    anticipated as the cold front surges eastward. Multiple swaths of
    numerous to potentially widespread severe/damaging winds appear
    likely as one or more clusters moves quickly east-northeastward over
    the OH Valley and southern Lower MI. With a 35-45 kt
    south-southwesterly low-level jet also present, strong low-level
    shear will likely support a threat for tornadoes, both with initial
    supercells and any lines/clusters that eventually form. Given the
    strength of the low-level flow, some of the tornadoes could be
    strong, especially with sustained supercells in the lower OH Valley
    vicinity. The threat for damaging winds and tornadoes should
    continue this evening into the overnight hours, until convection
    outpaces the low-level moisture return and eventually weakens over
    the upper OH Valley and central Appalachians.

    ...Central/East Texas into the Lower/Mid Mississippi
    Valley/Mid-South and Southeast...

    A band of mostly elevated convection developed earlier this morning
    over portions of north-central/east TX, likely in association with
    large-scale ascent preceding a westerly mid/upper-level jet nosing
    into central TX. While the overall environment remains quite
    favorable for organized severe convection, messy convective modes
    have tended to keep the severe hail threat isolated so far. Still,
    some risk for hail will continue through the morning. Strong
    destabilization is anticipated today ahead of this convection and a
    separate area of elevated thunderstorms over southern MO. Mid to
    upper 60s surface dewpoints will continue to stream northward across
    TX ahead of the dryline, and the lower/mid MS Valley and Southeast
    ahead of the cold front. This rich low-level moisture, combined with
    very steep (8-9 C/km) mid-level lapse rates and daytime heating, are
    expected to foster around 2000-3000 MLCAPE by early to mid afternoon.

    Rapid and intense thunderstorm initiation will likely occur by
    18-21Z from parts of north-central/east TX to the Mid-South/mid MS
    Valley. Supercells are expected initially, with 40-50+ kt of
    deep-layer shear supporting robust updraft organization and
    rotation. A very favorable setup remains apparent for large to very
    large hail, as strong instability and deep-layer shear combine with
    steep mid-level lapse rates and low freezing levels. Some of this
    very large hail could reach up to 2-3 inches in diameter. With the
    primary shortwave trough ejecting to the northeast, low-level winds
    are forecast to remain fairly subdued through the afternoon and
    early evening, before gradually strengthening again tonight through
    early Monday morning. A risk for several tornadoes should be focused
    over parts of the Mid-South, a few of which could be strong given a
    favorable supercell mode. Similar to farther north in the OH Valley,
    a transition to more linear/cluster mode is expected this evening
    and overnight as the cold front continues advancing southeastward. A
    risk for line-embedded tornadoes should continue, and an increase in
    the severe/damaging wind threat is likely through the end of the
    period. Based on latest guidance trends, and to overlap with the Day
    2 Convective Outlook, adjustments have been made to the
    southern/eastern extent of the risk areas across the lower MS Valley
    and Southeast.

    ...Florida Peninsula...

    A weak mid-level perturbation will move eastward over FL today.
    Modestly enhanced winds aloft, and a veering profile with height
    through mid levels, should support sufficient deep-layer shear for
    some thunderstorm organization. Any convection that develops in
    tandem with daytime heating this afternoon and early evening could
    pose an isolated threat for severe hail and damaging winds. Some
    adjustments have been made to the Marginal Risk across the FL
    Peninsula based on latest guidance trends.

    ..Gleason/Leitman.. 03/30/2025

    $$
    --- SBBSecho 3.20-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sun Mar 30 12:28:00 2025
    ACUS01 KWNS 301622
    SWODY1
    SPC AC 301621

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    1121 AM CDT Sun Mar 30 2025

    Valid 301630Z - 311200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
    THE LOWER/MID MISSISSIPPI VALLEY INTO THE OHIO VALLEY AND SOUTHERN
    GREAT LAKES...

    ...SUMMARY...
    Numerous severe thunderstorms are expected through tonight across a
    broad portion of the Southeast and lower/mid Mississippi Valley into
    the Ohio Valley and southern Great Lakes. Multiple swaths of
    widespread damaging winds appear likely. Large to very large hail
    and several tornadoes will also occur with supercells. A few of
    these tornadoes could be strong.

    ...Synopsis...
    Water-vapor imagery late this morning shows a lead mid-level
    shortwave trough moving quickly northeastward across MO, while an
    upstream disturbance over the TX Panhandle/western OK rounds the
    base of a larger-scale trough over the central U.S. Surface
    analysis places a cyclone near the IA/IL/WI border with a trailing
    cold front south-southwestward through the lower MO Valley and into
    eastern OK and north TX. This front will push east through the OH
    Valley and into the lower MS Valley by early Monday morning and
    focus thunderstorm development.

    ...Midwest/Ohio Valley to the Great Lakes...

    Visible-satellite imagery shows cloud breaks to the immediate east
    of the lead mid-level disturbance as a moist/warm conveyor (40-kt
    southwesterly LLJ) maintains a fetch of seasonably rich moisture
    into the region. Additional thinning cloud cover and heating
    through the early to mid afternoon will lead to thunderstorms
    developing and intensifying. A belt of 50-80 kt 500-mb flow will
    overspread the destabilizing airmass and yield ample deep-layer
    shear for organized convection.

    The stronger early storms will favor supercell and banded linear
    modes, with the supercells posing a threat for large to very large
    hail (around 1.5-2.5 inch diameter) given the presence of steep
    mid-level lapse rates and favorable deep-layer shear. Meridional
    upper-level flow from I-70 northward will favor a quicker transition
    to linear structures compared to farther south/southwest, where
    hodographs will promote a longer window of opportunity for cellular
    (discrete and clusters) storm modes. The tornado risk will be
    greatest with quasi-discrete supercells (potentially a few strong
    tornadoes) near and south of the OH River, but some tornado threat
    will probably develop with a squall line as it matures through the afternoon/evening. As storm coverage increases, multiple swaths of
    numerous to potentially widespread severe/damaging winds appear
    likely as one or more clusters moves quickly east-northeastward over
    the OH Valley and southern Lower MI. The threat for damaging winds
    and tornadoes should continue this evening into the overnight hours,
    until convection outpaces the low-level moisture return and
    eventually weakens over the upper OH Valley and central Appalachians.

    ...Central/East Texas into the Lower/Mid Mississippi
    Valley/Mid-South and Southeast...

    Strong destabilization is anticipated across the Ark-La-Tex east and northeastward into the Mid South. Rich low-level moisture (mid to
    upper 60s to around 70 deg F dewpoints) will stream northward across
    TX ahead of the dryline, and the lower/mid MS Valley and Southeast
    ahead of the cold front. Model guidance continues to indicate rapid
    and intense thunderstorm development during the afternoon from parts
    of north/east TX northeastward into AR. Supercells are expected
    initially, with 40-50+ kt of deep-layer shear supporting robust
    updraft organization and rotation. A favorable setup exists for
    large to very large hail with the stronger supercells.

    It appears the greatest risk for several tornadoes will focus
    over parts of the Mid-South from eastern AR into western TN on the
    southern periphery of an intensification of 850-mb flow towards
    evening. Forecast soundings show moderate to locally strong
    buoyancy (2000-3000 J/kg MLCAPE) on the northern rim of 66-68 deg F
    dewpoints, and co-located with strong southwesterly flow veering to
    westerly by early evening. It is during the 22-04 UTC period in
    which forecast hodographs enlarge in the low levels and become more
    favorable for discrete supercells. The strong tornado risk may
    maximize within this corridor from parts of eastern AR eastward into
    western and perhaps Middle TN during the evening. Additional severe
    storms are probable farther south as activity from the Ark-La-Tex
    moves east into the lower MS Valley and central Gulf Coast states
    during the late afternoon into tonight. In addition to large to
    very large hail, damaging gusts and a tornado risk will likely
    accompany the stronger storms with a gradual lessening in overall
    coverage and intensity during the late night.

    ...Florida Peninsula...

    A weak mid-level perturbation will move eastward over FL this
    afternoon. Modestly enhanced winds aloft, and a veering profile
    with height through mid levels, should support sufficient deep-layer
    shear for strong to severe multicells. The stronger diurnally
    driven storms may be capable of severe hail and damaging winds.

    ..Smith/Moore.. 03/30/2025

    $$
    --- SBBSecho 3.20-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)
  • From Mike Powell@618:250/1 to All on Sun Mar 30 17:18:00 2025
    ACUS01 KWNS 301940
    SWODY1
    SPC AC 301939

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0239 PM CDT Sun Mar 30 2025

    Valid 302000Z - 311200Z

    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
    THE LOWER/MID MISSISSIPPI VALLEY INTO THE OHIO VALLEY AND SOUTHERN
    GREAT LAKES...

    ...SUMMARY...
    Numerous severe thunderstorms are expected through tonight across a
    broad portion of the Southeast and lower/mid Mississippi Valley into
    the Ohio Valley and southern Great Lakes. Multiple swaths of
    widespread damaging winds appear likely. Large to very large hail
    and several tornadoes will also occur with supercells. A few of
    these tornadoes could be strong.

    ...20z Update...
    Minor adjustments were made to the D1 Outlook to remove portion of
    the Marginal across north-central Texas into Missouri behind the dry
    line. Further development along the dry line into Arkansas is
    expected through the afternoon/evening. Daytime heating has allowed
    an axis of MLCAPE around 1500-3000 J/kg to develop from far southern
    Texas into Louisiana. This will continue to nose northward into
    portions of Arkansas through time, with weakening of MLCIN.
    Supercell development is expected with potential for very large hail
    with any stronger discrete supercells.

    Further north, minor adjustments were made to the Marginal and
    Slight in the Midwest behind ongoing convection and cold front.A
    line of thunderstorms continues eastward across portions of Indiana
    and central/northern Illinois. This line has produced measured
    severe gusts 60-70 mph and will likely pose a continued damaging
    wind threat across central/northern Indiana/southern Michigan
    through the afternoon/evening. A favored corridor of stronger wind
    is possible across central/northern Indiana, as has been indicated
    in recent WoFS runs.

    See previous discussion for more information.

    ..Thornton.. 03/30/2025

    .PREV DISCUSSION... /ISSUED 1121 AM CDT Sun Mar 30 2025/

    ...Synopsis...
    Water-vapor imagery late this morning shows a lead mid-level
    shortwave trough moving quickly northeastward across MO, while an
    upstream disturbance over the TX Panhandle/western OK rounds the
    base of a larger-scale trough over the central U.S. Surface
    analysis places a cyclone near the IA/IL/WI border with a trailing
    cold front south-southwestward through the lower MO Valley and into
    eastern OK and north TX. This front will push east through the OH
    Valley and into the lower MS Valley by early Monday morning and
    focus thunderstorm development.

    ...Midwest/Ohio Valley to the Great Lakes...
    Visible-satellite imagery shows cloud breaks to the immediate east
    of the lead mid-level disturbance as a moist/warm conveyor (40-kt
    southwesterly LLJ) maintains a fetch of seasonably rich moisture
    into the region. Additional thinning cloud cover and heating
    through the early to mid afternoon will lead to thunderstorms
    developing and intensifying. A belt of 50-80 kt 500-mb flow will
    overspread the destabilizing airmass and yield ample deep-layer
    shear for organized convection.

    The stronger early storms will favor supercell and banded linear
    modes, with the supercells posing a threat for large to very large
    hail (around 1.5-2.5 inch diameter) given the presence of steep
    mid-level lapse rates and favorable deep-layer shear. Meridional
    upper-level flow from I-70 northward will favor a quicker transition
    to linear structures compared to farther south/southwest, where
    hodographs will promote a longer window of opportunity for cellular
    (discrete and clusters) storm modes. The tornado risk will be
    greatest with quasi-discrete supercells (potentially a few strong
    tornadoes) near and south of the OH River, but some tornado threat
    will probably develop with a squall line as it matures through the afternoon/evening. As storm coverage increases, multiple swaths of
    numerous to potentially widespread severe/damaging winds appear
    likely as one or more clusters moves quickly east-northeastward over
    the OH Valley and southern Lower MI. The threat for damaging winds
    and tornadoes should continue this evening into the overnight hours,
    until convection outpaces the low-level moisture return and
    eventually weakens over the upper OH Valley and central
    Appalachians.

    ...Central/East Texas into the Lower/Mid Mississippi
    Valley/Mid-South and Southeast...
    Strong destabilization is anticipated across the Ark-La-Tex east and northeastward into the Mid South. Rich low-level moisture (mid to
    upper 60s to around 70 deg F dewpoints) will stream northward across
    TX ahead of the dryline, and the lower/mid MS Valley and Southeast
    ahead of the cold front. Model guidance continues to indicate rapid
    and intense thunderstorm development during the afternoon from parts
    of north/east TX northeastward into AR. Supercells are expected
    initially, with 40-50+ kt of deep-layer shear supporting robust
    updraft organization and rotation. A favorable setup exists for
    large to very large hail with the stronger supercells.

    It appears the greatest risk for several tornadoes will focus
    over parts of the Mid-South from eastern AR into western TN on the
    southern periphery of an intensification of 850-mb flow towards
    evening. Forecast soundings show moderate to locally strong
    buoyancy (2000-3000 J/kg MLCAPE) on the northern rim of 66-68 deg F
    dewpoints, and co-located with strong southwesterly flow veering to
    westerly by early evening. It is during the 22-04 UTC period in
    which forecast hodographs enlarge in the low levels and become more
    favorable for discrete supercells. The strong tornado risk may
    maximize within this corridor from parts of eastern AR eastward into
    western and perhaps Middle TN during the evening. Additional severe
    storms are probable farther south as activity from the Ark-La-Tex
    moves east into the lower MS Valley and central Gulf Coast states
    during the late afternoon into tonight. In addition to large to
    very large hail, damaging gusts and a tornado risk will likely
    accompany the stronger storms with a gradual lessening in overall
    coverage and intensity during the late night.

    ...Florida Peninsula...
    A weak mid-level perturbation will move eastward over FL this
    afternoon. Modestly enhanced winds aloft, and a veering profile
    with height through mid levels, should support sufficient deep-layer
    shear for strong to severe multicells. The stronger diurnally
    driven storms may be capable of severe hail and damaging winds.

    $$
    --- SBBSecho 3.20-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)