• MESO: Severe potential

    From Weather Alert@618:250/1 to All on Thu Mar 25 15:58:00 2021
    ACUS11 KWNS 251930
    SWOMCD
    SPC MCD 251929
    TNZ000-ALZ000-MSZ000-252130-

    Mesoscale Discussion 0257
    NWS Storm Prediction Center Norman OK
    0229 PM CDT Thu Mar 25 2021

    Areas affected...far northern Mississippi into Middle Tennessee

    Concerning...Severe potential...Tornado Watch likely

    Valid 251929Z - 252130Z

    Probability of Watch Issuance...80 percent

    SUMMARY...The threat of severe storms including tornadoes will
    increase by late afternoon into Middle Tennessee and persist through
    the evening. A watch may be issued by 21Z.

    DISCUSSION...Surface analysis currently shows a warm front into far southwestern TN extending east/southeast into northern AL.
    Meanwhile, another warm front extended from the developing surface
    low from southern IL into central KY.

    In between these two fronts, gradual warming is taking place, with
    temperatures now into the low 70s F. MUCAPE currently remains below
    1000 J/kg as a result of dewpoints near 60 F.

    Strengthening 850 mb winds out of the southwest later today should
    aid moisture advection out of MS into Middle TN, with areas of
    heating helping to destabilize as well. Shear will become
    increasingly favorable for tornadic supercells in the 21-03Z time
    frame, and a few tornadoes are anticipated as the mid 60s F
    dewpoints arrive later today. With the more unstable air in place,
    effective SRH may reach 400-500 m2/s2.

    ..Jewell/Hart.. 03/25/2021

    ATTN...WFO...OHX...HUN...MEG...

    LAT...LON 35048892 35238887 35668872 36178799 36478647 36318583
    36008560 35548590 35368661 35378741 35278780 34998804
    34718875 34798891 35048892

    $$
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  • From Weather Alert@618:250/1 to All on Thu Mar 25 16:02:00 2021
    ACUS11 KWNS 251933
    SWOMCD
    SPC MCD 251933
    INZ000-KYZ000-TNZ000-ILZ000-MOZ000-252130-

    Mesoscale Discussion 0258
    NWS Storm Prediction Center Norman OK
    0233 PM CDT Thu Mar 25 2021

    Areas affected...The mid-Mississippi River Valley and lower Ohio
    River Valley Region

    Concerning...Severe potential...Tornado Watch likely

    Valid 251933Z - 252130Z

    Probability of Watch Issuance...80 percent

    SUMMARY...A tornado watch is likely in the coming hours as a surface
    low and associated warm front continue to lift northward through the
    late afternoon.

    DISCUSSION...Surface observations over the past couple of hours have
    shown 2-3 mb surface pressure falls over northeast AR into the lower
    OH River Valley region. The surface low located over northeast AR
    continues to consolidate and is expected to deepen further as it
    lifts to the north/northeast. As this occurs, an associated surface
    warm front will lift to the north and allow a higher theta-e air
    mass (noted by temperatures and dewpoints in the 60s) to overspread
    the mid-MS River Valley and lower OH River Valley regions and allow
    MLCAPE to increase into the 500-1000 J/kg range. Storms are forecast
    to develop along the surface warm front and surface trough in the
    vicinity of the low, and southwesterly 60-70 knots of effective bulk
    shear will help support discrete to semi-discrete storm modes. Along
    with a hail/wind threat, backed low-level winds within the open warm
    sector will support ESRH values on the order of 300 m2/s2 and a
    tornado threat with any discrete convection that can develop. Recent
    guidance suggests storm initiation within this region may occur
    within the 22-00 UTC time frame. A tornado watch will likely be
    needed in the coming hours to address this concern.

    ..Moore/Hart.. 03/25/2021

    ATTN...WFO...LMK...OHX...IND...PAH...ILX...MEG...LSX...

    LAT...LON 36498774 36148863 35988936 36238974 36718989 37438983
    38008958 38438912 38778824 38788726 38348672 37528679
    37008706 36498774

    $$
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  • From Weather Alert@618:250/1 to All on Sat Apr 10 10:28:00 2021
    ACUS11 KWNS 101359
    SWOMCD
    SPC MCD 101358
    FLZ000-GAZ000-101530-

    Mesoscale Discussion 0360
    NWS Storm Prediction Center Norman OK
    0858 AM CDT Sat Apr 10 2021

    Areas affected...the Florida Panhandle and parts of far southern
    Georgia

    Concerning...Severe potential...Watch likely

    Valid 101358Z - 101530Z

    Probability of Watch Issuance...95 percent

    SUMMARY...Severe risk continues across the portions of WW 89 that
    remain in effect, with some risk evident eastward across the
    remainder of the Florida Panhandle. A new WW will likely be issued.

    DISCUSSION...Latest radar loop shows the northeastern portion of a
    northern Gulf of Mexico band of storms now crossing central portions
    of the Florida Peninsula west of Tallahassee. Gusty/damaging wind
    risk remains apparent -- per WSR-88D imagery, where outflow in
    excess of 50 kt is indicated just off the surface across parts of
    Washington and Bay counties.

    Very limited heating of the relatively moist airmass just downstream
    is supporting mixed-layer CAPE values of 500 to 1000 J/kg. While a
    more stable/drier airmass exists into the northern Florida
    Peninsula, it appears at this time that a sufficiently unstable
    environment downstream into the Big Bend region will support a
    continued eastward advance of storms. Locally damaging winds will
    remain the primary severe risk, though a QLCS-type tornado or two
    will remain possible. With storms expected to move out of the
    existing watch within the next hour, a new WW will be issued
    shortly.

    ..Goss/Thompson.. 04/10/2021

    ATTN...WFO...JAX...TAE...

    LAT...LON 30548604 30998546 30878418 30938356 30608328 29748299
    29198324 29498512 29798596 30548604
    $$
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  • From Weather Alert@618:250/1 to All on Wed Apr 14 14:02:00 2021
    ACUS11 KWNS 141744
    SWOMCD
    SPC MCD 141743
    TXZ000-141945-

    Mesoscale Discussion 0382
    NWS Storm Prediction Center Norman OK
    1243 PM CDT Wed Apr 14 2021

    Areas affected...portions of the Texas Coastal Plain

    Concerning...Severe potential...Watch possible

    Valid 141743Z - 141945Z

    Probability of Watch Issuance...40 percent

    SUMMARY...Storm development over the next couple of hours will be
    accompanied by some increase in risk for large hail and locally
    strong/damaging wind gusts through this afternoon. A WW may be
    required.

    DISCUSSION...Latest surface analysis shows a cold front across
    western portions of the Texas Coastal Plain/eastern fringes of the
    Hill Country, and then westward into the Edwards Plateau.
    Meanwhile, a sea-breeze boundary has pushed into coastal counties,
    with high theta-e marine air along and east of this boundary.

    Though capping (near 700 mb) remains established across the area,
    continued heating/mixing of the boundary layer will weaken the cap
    locally -- particularly near the aforementioned surface boundaries
    where ascent is locally maximized. With steep lapse rates overlying
    this region above the capping layer, the destabilizing environment
    -- represented by mixed-layer CAPE values now in excess of 2500 J/kg
    across the region per RUC-based objective analyses -- combined with
    the weakening cap will support local/robust updraft development.

    While deep-layer shear is not excessive, partially owing to modest
    low-level flow, ample (around 30 kt) mid-level west-southwesterlies
    are contributing to shear sufficient for multicell organization, and
    even some mid-level updraft rotation. As such, potential for hail
    and/or locally strong outflow winds will be possible with a few of
    the strongest storms. We will continue to monitor development, for
    signs that convective development/coverage may warrant WW issuance.

    ..Goss/Thompson.. 04/14/2021

    ATTN...WFO...HGX...CRP...EWX...

    LAT...LON 29279811 29559761 29829683 29909598 30189492 29659475
    28749616 28169709 28299783 28449828 28839839 29279811

    $$
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  • From Weather Alert@618:250/1 to All on Wed May 5 15:36:00 2021
    ACUS11 KWNS 051929
    SWOMCD
    SPC MCD 051929
    OKZ000-KSZ000-TXZ000-COZ000-052200-

    Mesoscale Discussion 0545
    NWS Storm Prediction Center Norman OK
    0229 PM CDT Wed May 05 2021

    Areas affected...Portions of southwest Kansas...extreme southeast Colorado...Oklahoma Panhandle

    Concerning...Severe potential...Watch unlikely

    Valid 051929Z - 052200Z

    Probability of Watch Issuance...20 percent

    SUMMARY...Scattered strong storms are expected through the
    afternoon. Damaging gusts and perhaps some marginally severe hail
    may accompany the stronger storms. A WW issuance is not currently
    anticipated.

    DISCUSSION...Convective initiation is underway along a surface cold
    front across western Kansas into eastern Colorado, just south of a
    CBK-GLD-ITR line, and is gradually propagating southeast. Convection
    will continue to gradually deepen and intensify with continued
    strong diurnal heating and associated boundary-layer mixing.
    Deep-layer steep lapse rates are in place, with the latest RAP PFCs
    suggesting boundary-layer mixing past 700 mb. 8-9 C/km lapse rates
    are present within the lowest 2 km, overspread by 7.5-8.5 C/km lapse
    rates in the mid levels. Relatively stronger flow aloft (i.e. 50+
    kts) is contained roughly above 500 mb. Still, the presence of a
    deep, dry sub-cloud layer will promote enough evaporative cooling
    for efficient downward momentum transport of the mid-level flow with
    any of the stronger storm cores that can develop. A brief instance
    or two marginally severe hail is also possible given the steep
    mid-level lapse rates.

    Nonetheless, the severe threat is expected to remain brief and
    sparse overall. A WW issuance is not currently expected.

    ..Squitieri/Grams.. 05/05/2021

    ATTN...WFO...OUN...DDC...GLD...AMA...PUB...

    LAT...LON 36470180 36890216 37340219 37830203 38290181 38510147
    38720086 38650036 38450003 37959977 37389973 36889982
    36639999 36500021 36470180
    $$
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  • From Weather Alert@618:250/1 to All on Sun May 9 15:58:00 2021
    ACUS11 KWNS 091832
    SWOMCD
    SPC MCD 091831
    TXZ000-NMZ000-COZ000-092100-

    Mesoscale Discussion 0569
    NWS Storm Prediction Center Norman OK
    0131 PM CDT Sun May 09 2021

    Areas affected...Northeast New Mexico...far southeast Colorado...and
    the far western Texas Panhandle

    Concerning...Severe potential...Watch unlikely

    Valid 091831Z - 092100Z

    Probability of Watch Issuance...20 percent

    SUMMARY...Thunderstorms developing across northeast New Mexico and
    far southeast Colorado over the next few hours will pose a threat
    for damaging winds and perhaps isolated hail. This threat will
    remain isolated, and a watch is not expected.

    DISCUSSION...A deepening cluster of cumulus within a post
    cold-frontal upslope flow regime across north/northeastern NM is
    noted in recent GOES imagery. A few lightning strikes have been
    noted in the past hour with transient convective cells, hinting that
    more robust convection is possible in the next 1-2 hours. Across the
    high Plains to the east, temperatures are gradually warming into the
    low 60s amid partly cloudy skies. Cool temperatures aloft atop the
    warming boundary-layer are steepening low-level lapse rates to 7-9
    C/km, and this trend should continue with eastward extent through
    the late afternoon. Although instability will remain somewhat
    limited due to minimal low-level moisture (only around 500 J/kg
    MLCAPE is expected), 30-45 knot effective bulk shear magnitudes may
    support some storm organization and an isolated hail threat adjacent
    to the higher terrain. Given the well-mixed boundary layer, strong
    downburst winds appear to be the more likely hazard. In general, the
    localized forcing for ascent and limited instability will likely
    result in only a few strong to severe storms that may propagate as
    far east as the NM/TX border by early evening. The overall severe
    threat is expected to remain isolated, precluding the need for a
    watch.

    ..Moore/Thompson.. 05/09/2021

    ATTN...WFO...LUB...AMA...PUB...ABQ...

    LAT...LON 34710551 35170586 35680611 36390582 36940551 37290510
    37470460 37450410 37130357 36620325 35960290 34930287
    34320307 34300453 34710551
    $$
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  • From Weather Alert@618:250/1 to All on Tue May 11 15:40:00 2021
    ACUS11 KWNS 111847
    SWOMCD
    SPC MCD 111846
    GAZ000-FLZ000-ALZ000-112045-

    Mesoscale Discussion 0593
    NWS Storm Prediction Center Norman OK
    0146 PM CDT Tue May 11 2021

    Areas affected...Southern Alabama...southwest Georgia...and the
    western Florida Panhandle

    Concerning...Severe potential...Watch unlikely

    Valid 111846Z - 112045Z

    Probability of Watch Issuance...20 percent

    SUMMARY...A loosely-organized squall line may be capable of damaging
    winds as it continues east along the Gulf Coast. However, confidence
    in this threat is low, and a watch is not expected.

    DISCUSSION...Recent velocity data from KMOB shows outflow associated
    with a weak and loosely organized squall line becoming slightly more
    organized as it propagates to the east across southwestern AL and
    into the FL Panhandle. VWP observations from KMOB show 20-30 knots
    winds in the lowest 2-3 km associated with this line, which is
    supported by recent observed wind gusts up to 25 knots at the
    surface. While severe winds do not appear likely in the near term,
    the potential for damaging winds may increase over the next 1-3
    hours as the line moves into southeast AL, southwest GA, and the FL
    Panhandle where low-level lapse rates are steepening to 7-8 C/km
    amid modest daytime heating. The environment ahead of this line
    remains supportive for storm maintenance, but it is not immediately
    clear if the damaging wind potential will be realized along the
    entire line - mainly due to weak low-level shear in the lowest 4 km.
    Pockets of intensification are noted in GOES IR imagery over the
    past 30 minutes, which suggests that at least localized strong winds
    are possible. Due to the low confidence in a more widespread/robust
    severe threat, a watch is not expected.

    ..Moore/Thompson.. 05/11/2021

    ATTN...WFO...FFC...TAE...BMX...MOB...

    LAT...LON 31398810 31858797 32168747 32368612 32418533 32298476
    31718439 31008445 30178501 30048536 30298602 30378661
    30328707 30278761 30288793 30928802 31398810
    $$
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