ACUS01 KWNS 211933

SWODY1

SPC AC 211932



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0232 PM CDT Sat Mar 21 2026



Valid 212000Z - 221200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ...



...SUMMARY...

Isolated strong to severe thunderstorms may produce marginally

severe hail and damaging winds this afternoon and evening from the

southern Appalachians into the Carolinas.



...20Z Update...

The previous forecast (see below), remains on track. Please see

Mesoscale Discussion 283 for short-term information on the severe

threat across portions of the southern Appalachians.



..Squitieri.. 03/21/2026



.PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Mar 21 2026/



...Southern Appalachians into the Carolinas...

Recent satellite imagery shows a somewhat subtle and broad shortwave

trough progressing southeastward through the MS Valley, along the

far northeast periphery of the upper ridging covering much of the

Southwest and southern Plains. Limited low-level moisture precedes

this wave, with recent surface analysis sampling dewpoints ranging

from the upper 50s across much of AL to the mid 40s across much of

the Carolinas. Modest low-level moisture advection is anticipated

today ahead of this wave. However, this advection will be countered

by diurnal mixing, and the general expectation is for dewpoints to

be in the upper 40s/low 50s from eastern TN into the Carolinas as

the wave moves in the area this afternoon. Even with this limited

low-level moisture, cool mid-level temperatures and associated steep

mid-level lapse rates will support weak buoyancy and the potential

for isolated to widely scattered thunderstorms this afternoon and

early evening. 



Large-scale ascent will be modest, supporting an initially more

cellular, loosely organized storm mode. This region will be on the

southern periphery of the stronger mid-level flow, likely resulting

in sufficient shear for organization within any deeper, more

persistent updrafts. As such, updrafts are expected to gradually

intensify as they move into the western and central Carolinas.

Marginally severe hail is possible with the strongest cores. A trend

towards a more linear/line segment mode is expected with time, and

persistent steep low-level lapse rates may support occasional strong

to damaging downdraft winds as well. The onset of nocturnal

boundary-layer stabilization should result in a decreasing severe

threat as the storms move into the coastal Carolinas.



$$