(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 200858
SPC AC 200858
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Thu Mar 20 2025
Valid 231200Z - 281200Z
...DISCUSSION...
...Sunday/Day 4 and Monday/Day 5...
A large-scale cyclonic flow pattern will be in place across much of
the continental U.S. on Sunday. An upper-level low will develop over
the Great Lakes, as an associated trough moves southeastward from
the Great Plains to the Mississippi Valley. A cold front is forecast
to move southeastward into the Ozarks. Ahead of the front, moisture
advection is forecast to occur over the Sabine and lower Mississippi
Valleys, where surface dewpoints will likely be in the 60s F and
moderate instability is expected to develop. Scattered thunderstorms
appear likely to initiate ahead of the front Sunday evening from the
Sabine River Valley northeastward into the Tennessee Valley, with an
MCS developing Sunday evening. Moderate deep-layer shear will likely
support severe thunderstorm development, with a potential for severe
wind gusts, isolated large hail. A tornado threat may also develop.
A cold front is forecast to move through the Gulf Coast region
Sunday morning. Isolated severe storms could develop ahead of the
front early in the day from the Texas Coast eastward to the central
Gulf Coast and Florida Panhandle. Predictability remains low
concerning where the greatest severe threat will be along this
corridor. The severe threat should end during the day as the front
moves southward into the Gulf.
...Tuesday/Day 6 to Thursday/Day 8...
On Tuesday, a mid-level trough is forecast to dig southeastward into
the Mississippi Valley. At the surface, a moist airmass will remain
over the Gulf Coast region. Isolated strong to severe storms could
occur along the northern edge of this moist airmass. The greatest
potential for severe could be across the Sabine River Valley, where
some solutions have moderate instability Tuesday afternoon. This
appears to be a conditional severe threat, and predictability is
low.
From Wednesday into Thursday, a relatively dry airmass is forecast
over much of the nation. The exception could be across south Texas,
where thunderstorm development will be possible. Although an
isolated severe threat would be possible there, predictability at
this extended range in the forecast cycle is low.
..Broyles.. 03/20/2025
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