General Weather/Earth Sciences Topics > Severe Weather

Severe Weather Day Saturday March 15, 2025 LA/MS/AL

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Michael W:
ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 120845
   SPC AC 120845

   Day 4-8 Convective Outlook 
   NWS Storm Prediction Center Norman OK
   0345 AM CDT Wed Mar 12 2025

   Valid 151200Z - 201200Z

   ...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/SAT...

   ...DISCUSSION...
   ...Day 4/Sat - Central Gulf Coast States to the Ohio Valley...

   A strong large-scale upper trough is forecast to quickly move across
   the Plains to the MS Valley on Saturday. An intense jet streak will
   move across the Deep South into the OH Valley as this occurs. At the
   surface, a low secondary to the 980 mb low over the Upper Midwest is
   forecast to develop during the late morning/early afternoon across
   the mid-South. This will aid in further northward transport of rich
   Gulf moisture into portions of the Lower MS Valley and TN Valleys.
   Atop this moisture-primed boundary layer, cold 500 mb temperatures
   are forecast. This may support fairly steep lapse rates, which would
   foster moderate instability across portions of MS/AL amid supercell
   wind profiles. However, some uncertainty remains tied to the
   evolution of convection in the Day 3/Fri period into the morning
   hours of Saturday. Some forecast guidance suggests a relatively
   pristine warm sector will be maintained, or if only isolated
   convection develops overnight/early Saturday, recovery could occur.
   If this scenario unfolds, a concerning severe weather setup
   supporting all-hazard severe could unfold across portions of
   LA/MS/AL through the day and into evening, and eventually spreading
   east into GA overnight. Trends will be monitored closely over the
   coming days and further adjustments to the 30 percent/Enhanced risk
   area may be needed in future outlooks.

   With northward extent, instability will become more limited.
   Nevertheless, sufficient moisture amid intense deep-layer flow will
   support swaths of strong/damaging winds into the Ohio Valley and
   portions of the central Appalachians Saturday and Saturday night.
   Higher outlook probabilities may be needed in subsequent outlooks if
   confidence increases.

   ...Day 5/Sun - North Florida into the Carolinas and Mid-Atlantic...

   A strong upper trough will shift east across the Midwest and
   Southeast on Sunday. Strong deep-layer southwesterly flow ahead of
   the trough will overspread much of the eastern U.S. atop a moist
   boundary layer. Bands of convection will likely produce swaths of
   strong to severe gusts ahead of an eastward-advancing cold front.

   ...Days 6-8/Mon-Wed...

   An upper trough will move offshore over the Atlantic on Monday,
   while a broad upper ridge spreads across the Plains in its wake.
   Another large-scale upper trough will move across the western U.S.
   on Tuesday, ejecting across the Plains and into the MS Valley on
   Wednesday. Some severe potential could return to parts of the
   central or south-central states toward the end of the period with
   this system, but current model forecasts suggest moisture return in
   the wake of the Day 4/5 system will remain poor. Trends will be
   monitored over the coming days.

   ..Leitman.. 03/12/2025

   CLICK TO GET WUUS48 PTSD48 PRODUCT

Michael W:
 [ You are not allowed to view attachments ] SPC AC 141730

   Day 2 Convective Outlook 
   NWS Storm Prediction Center Norman OK
   1230 PM CDT Fri Mar 14 2025

   Valid 151200Z - 161200Z

   ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS IN CENTRAL/SOUTHERN
   PARTS OF MS/AL...

   ...SUMMARY...
   A tornado outbreak is likely on Saturday across the central Gulf
   Coast States and Deep South into the Tennessee Valley. Numerous
   significant tornadoes, some of which should be long-track and
   potentially violent, are expected on Saturday afternoon and evening.
   The most dangerous tornado threat should begin across eastern
   Louisiana and Mississippi during the late morning to afternoon,
   spread across Alabama late day into the evening, and reach western
   parts of the Florida Panhandle and Georgia Saturday night.

   ...Central Gulf Coast/Deep South/TN Valley...
   After collaboration with WFOs BMX/JAN/MOB, an upgrade to a level
   5-HIGH risk appears warranted for the most likely corridor of
   potentially violent tornadoes, peaking tomorrow afternoon and
   evening. A broader level 4-MDT risk has been expanded somewhat
   eastward for the nocturnal significant tornado threat.

   An intense mid-level jet, 100-110 kts at 500 mb, will eject through
   the basal portion of a broad southern Great Plains shortwave trough.
   This will induce secondary cyclogenesis along an initially
   slow-moving baroclinic zone from the Ark-La-Tex to the central Great
   Lakes. Another day of air mass modification ahead of this wave will
   yield a pronounced plume of rich northwest Gulf moisture that should
   be pristine across southeast LA and southern MS through late
   morning. As mid-level height falls overspread the diurnally warming
   air mass, increasing convective development is expected along the
   deepening baroclinic zone, as well as residual outflows to its
   northeast in the TN Valley from prior late D1 convection.

   Steep mid-level lapse rates atop the richly moist boundary layer
   will yield at least moderate MLCAPE from 1500-2500 J/kg across
   eastern LA into central MS. Vertically veering wind profiles with
   strong anvil-level divergence amid the favorable instability should
   support robust updrafts and intense supercells. Low-level shear will
   strengthen midday through the afternoon, yielding potential for a
   tornado outbreak.

   The most probable convective corridor will be along the effective
   outflow boundary across central/northern parts of MS into north AL
   and south TN. Along and south of this will be the most favored
   corridor for long-tracked, discrete supercells. These will likely
   develop within north/south-oriented confluence bands as increasing
   large-scale ascent becomes coincident with the peak heating cycle.
   A volatile combination of kinematic/thermodynamic parameters will
   support potential for long-track, EF3+ tornadoes. The overall
   spatial extent of this threat will be modulated by the degree of
   boundary-layer heating within the mid to upper 60s dew point plume,
   along with where exactly the large-scale outflow boundary sets up
   from late D1/early D2.

   Significant tornado potential, along with very large hail and
   destructive damaging wind gusts, should persist into Saturday night.
   Greater potential for a broken to linear band of thunderstorms is
   anticipated by this time, but wind profiles will still strongly
   favor supercells. As such, a mix of all three hazards may continue
   with sig severe hail potential favored south and sig severe wind
   favored north as the convective band spreads towards the southern
   Appalachians and the northeast Gulf Coast.

   ...OH Valley to central Great Lakes...
   Forecast confidence remains low with regard to severe potential
   north of the TN Valley. Guidance continues to differ on the degree
   of diurnal destabilization in the wake of the D1 shortwave trough
   and deep cyclone tracking into northern Ontario. With increasingly
   widespread Mid/Deep South to TN Valley thunderstorms during the day
   Saturday, the northward extent of appreciable surface-based
   instability appears highly questionable within a predominately
   meridional deep-layer wind profile. Given the fast flow regime
   though, even weak convection late afternoon through Saturday night
   will pose some risk for locally strong gusts and a tornado.

   ..Grams.. 03/14/2025

Michael W:
THIS IS A PARTICULARLY DANGEROUS SITUATION   URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 36
   NWS Storm Prediction Center Norman OK
   730 PM CDT Fri Mar 14 2025

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of
     Northeast Arkansas
     Southern Illinois
     Far Southwest Indiana
     Western Kentucky
     Southeast Missouri
     Northern Mississippi
     Western Tennessee

   * Effective this Friday night and Saturday morning from 730 PM
     until 300 AM CDT.

   ...THIS IS A PARTICULARLY DANGEROUS SITUATION...

   * Primary threats include...
     Several tornadoes and a few intense tornadoes likely
     Widespread damaging winds and scattered significant gusts to 80
       mph likely
     Scattered large hail and isolated very large hail events to 2.5
       inches in diameter likely

   SUMMARY...Severe thunderstorms are expected to develop across the
   watch area over the next several hours. Environmental conditions are
   very favorable for supercells capable of all severe hazards,
   including very large hail (i.e. greater than 2" in diameter) and
   strong (EF2+) tornadoes. If storms can remain discrete, potential
   exists for a few long-track tornadoes.

   The tornado watch area is approximately along and 75 statute miles
   east and west of a line from 40 miles west northwest of Evansville
   IN to 25 miles southwest of Oxford MS. For a complete depiction of
   the watch see the associated watch outline update (WOUS64 KWNS
   WOU6).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

   &&

   OTHER WATCH INFORMATION...CONTINUE...WW 31...WW 32...WW 33...WW
   34...WW 35...

   AVIATION...Tornadoes and a few severe thunderstorms with hail
   surface and aloft to 2.5 inches. Extreme turbulence and surface wind
   gusts to 70 knots. A few cumulonimbi with maximum tops to 500. Mean
   storm motion vector 24035.

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