ACUS48 KWNS 210831

SWOD48

SPC AC 210829



Day 4-8 Convective Outlook  

NWS Storm Prediction Center Norman OK

0329 AM CDT Sat Mar 21 2026



Valid 241200Z - 291200Z



...DISCUSSION...

...Tuesday/Day 4 to Thursday/Day 6...

An upper-level trough is forecast to move eastward into the western

Atlantic from Tuesday into Wednesday, as a surface high moves

eastward across the eastern U.S. A dry airmass is forecast across

most of the U.S., which should be unfavorable for thunderstorms in

most areas.



On Thursday, a low is forecast to develop in the northern U.S., as

low-level moisture returns quickly northward into the parts of the

Great Plains and Mississippi Valley. Thunderstorms will be possible

across this unstable airmass, mainly Thursday night, along the

southern edge of a passing mid-level jet streak. The greatest

potential for severe thunderstorms is expected from the mid

Mississippi Valley into the Ohio Valley along and near a cold front.

At this time, the amount of spread concerning potential outcomes is

substantial. An area may need to be added once model solutions begin

to agree more, and confidence increases concerning where the

greatest severe threat will be.



...Friday/Day 7 and Saturday/Day 8...

On Friday, the front is forecast to move southward across the

Tennessee Valley, where isolated to scattered strong thunderstorms

will be possible during the day. The front is forecast to move

southward to near the Gulf Coast by Saturday. Isolated storms would

again be possible near the front. Although the current thinking is

that any severe threat will be marginal on Friday and Saturday,

uncertainty is substantial due to the extended range in the forecast

period.



..Broyles.. 03/21/2026