ACUS01 KWNS 211231

SWODY1

SPC AC 211230



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0730 AM CDT Sat Mar 21 2026



Valid 211300Z - 221200Z



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

THE SOUTHERN APPALACHIANS/SOUTHEAST...



...SUMMARY...

Isolated strong to severe thunderstorms may produce marginally

severe hail and damaging winds this afternoon and evening across

parts of the southern Appalachians/Southeast.



...Southern Appalachians/Southeast...

With upper ridging persisting over the Southwest and northern Mexico

today, a subtle mid-level shortwave trough will move southeastward

from the mid MS Valley/Mid-South this morning towards the southern

Appalachians vicinity by this evening. At the surface, a weak front

draped generally east-west across the OH Valley should lift

northward as a warm front through the afternoon, with modest

low-level moisture advancing northward across parts of the lower MS

Valley, TN Valley, and Southeast.



Large-scale ascent associated with the shortwave trough should

remain rather weak, but daytime heating and orographic circulations

over the southern Appalachians may aid isolated thunderstorm

development by mid to late afternoon (around 20-22Z). Most guidance,

with the exception of the NAM, suggests that boundary-layer moisture

will remain quite limited this afternoon, with surface dewpoints

generally in the 40s to low 50s. Even so, weak instability/steepened

low-level lapse rates may support occasional strong to damaging

downdraft winds with any thunderstorms that can develop from eastern

TN into parts of the Carolinas. Around 25-30 kt of effective bulk

shear may also aid modest updraft organization and marginally severe

hail with the strongest cores. The isolated severe threat should

wane through the evening with the loss of daytime heating.



..Gleason/Kerr.. 03/21/2026



$$