(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 130832
SPC AC 130832
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0332 AM CDT Thu Mar 13 2025
Valid 161200Z - 211200Z
...DISCUSSION...
...Day 4/Sun - Eastern U.S....
A large-scale upper trough near the MS Valley Sunday morning will
develop east to the Appalachians by early Monday. Strong deep-layer
south/southwesterly flow on the eastern side of the upper trough
will overspread much of the eastern U.S. Convection will likely be
ongoing Sunday morning from the Upper OH Valley into GA and northern
FL. This activity will move into a moist airmass, characterized by
60s F dewpoints from north FL toward the Chesapeake Bay vicinity
(50s F dewpoints further north into PA/NJ). Instability will be
greatest where deeper boundary layer moisture is forecast, but given
intense deep-layer flow, organized convection is expected with even
very modest instability. While linear convection producing damaging
gusts will be the main hazard for much of the region, tornado
potential will exist where sufficient boundary layer moisture
exists, most likely from the Carolinas southward.
...Days 6-7/Tue-Wed - OK/KS into the MS/OH/TN Valleys...
Another large-scale upper trough is forecast to move across the West
and into the Plains on Tuesday into early Wednesday, and then into
the Midwest by Thursday. This will bring some potential for severe
storms. However, a prior cold frontal intrusion deep into the Gulf
and surface high pressure east of the MS River in the wake of the
Day 4/Sun upper trough will limit moisture return into the
southern/central Plains on Tuesday. Modest moisture return is
possible further southeast on Wednesday, but forecast guidance
currently is unremarkable. Trends will be monitored, but the
probability for any more an isolated/marginal severe appears low at
this time.
..Leitman.. 03/13/2025
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