Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0237 PM CDT Sat Mar 21 2026
Valid 212000Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN APPALACHIANS TO THE CAROLINAS...
CORRECTED FOR GEOGRAPHIC AREA HEADLINE
...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.
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