SPC Mar 22, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0734 PM CDT Sat Mar 21 2026

Valid 220100Z - 221200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Ongoing thunderstorms across the southern Appalachians will continue
to pose a threat for lightning into the Carolinas this evening.

... 01Z Update ...

Showers and thunderstorms associated with a subtle mid-level trough
will continue to move across the southern Appalachians into the
Carolinas this evening. Recent mesoanalysis suggests deep-layer
shear is around 30 knots and most-unstable CAPE up to 500 J/kg.
However, ongoing convection has struggled to maintain robust
updrafts within this environment. Given weak forcing for ascent,
increasing convective inhibition, and decreasing instability this
evening, any severe wind or hail potential should remain less than
5% coverage.

Thunderstorms should dissipate later this evening into the early
morning.

..Marsh.. 03/22/2026


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SPC Mar 21, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


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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SPC Mar 21, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat Mar 21 2026

Valid 211630Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN APPALACHIANS INTO THE CAROLINAS...

...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.

...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.

..Mosier/Chalmers.. 03/21/2026


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SPC Mar 21, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... 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


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