RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
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
Read more
