RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Wed Mar 11 2026
Valid 112000Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
FROM THE GULF COAST TO PARTS OF THE MID-ATLANTIC...
...SUMMARY...
Isolated to scattered severe thunderstorms are expected through
tonight from the Gulf coast into parts of the Mid-Atlantic.
...20z update...
Storm coverage has been a bit more limited compared to earlier
expectations for the OH Valley into the Appalachians, though widely
scattered storms persist in an environment with relatively straight
hodographs and weak-moderate buoyancy. Some tornado/wind threat
persists with perhaps a locally greater threat for a couple of
tornadoes in PA where storms interact with a diffuse north-south
baroclinic zone.
Otherwise, storm clusters/line segments are more concentrated across
middle TN and extreme southeast TX. The TN storms will pose mainly
a wind/marginal hail threat for the next few hours, while the
southeast TX storms will spread eastward with some uptick in the
wind/tornado threat overnight as the upstream midlevel trough begins
to accelerate eastward. A separate/small area with some wind/hail
threat will be associated with the midlevel cold core later this
afternoon across interior southeast TX.
..Thompson.. 03/11/2026
.PREV DISCUSSION... /ISSUED 1131 AM CDT Wed Mar 11 2026/
...OH Valley/Appalachians through late evening...
A surface cyclone now in southeast Lower MI will move northeastward
across the lower Great Lakes/Saint Lawrence Valley and deepen, in
advance of an amplifying northern-stream shortwave trough now over
the upper MS Valley. The warm sector of the cyclone is
characterized by boundary-layer dewpoints in the low-mid 60s into
OH/western PA/WV as of midday. Clouds/convection have been
prevalent this morning across OH/western PA in advance of a subtle
MCV, and the warmer surface temperatures have been confined to areas
immediately south of this morning convection. Additional
thunderstorm development is expected by early afternoon from
southern IN/northern KY into southern OH/WV/western PA, and storms
will spread generally eastward within the warm sector through this
evening. SBCAPE of 1000-1500 J/kg and wind profiles with long
low-level hodographs will support of a mix of line segments and
supercells capable of producing a few tornadoes and swaths of
damaging gusts before the threat begins to diminish by late evening.
...Southeast TX to MS/AL through tonight...
Thunderstorms are ongoing along a surface trough approaching
southeast TX, and additional convection extends northeastward along
a residual outflow/differential heating zone into the Ark-La-Miss.
Daytime heating/destabilization and forcing for ascent downstream
from a midlevel trough (now over the Edwards Plateau) will support a
continued increase in storm coverage/intensity this afternoon from
southeast TX into the Ark-La-Miss. Though regional soundings are
limited in the main part of the moist sector this morning, surface
observations and model forecast soundings suggest a corridor of
moderate buoyancy (MLCAPE near 1500 J/kg) through the afternoon in
advance of the ongoing storms. Deep-layer southwesterly shear,
largely oriented along the convective band, will help maintain
clusters and line segments, though embedded supercells are also
possible. Low-level hodographs will be long enough to justify the
potential for a few tornadoes with embedded circulations and/or
favorable storm mergers into the band of storms. Otherwise, wind
damage will be the main threat with the line segments through
tonight.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1222 PM CDT Wed Mar 11 2026
Valid 121200Z - 131200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FLORIDA
PANHANDLE INTO CENTRAL GEORGIA AND THE CAROLINAS...
...SUMMARY...
Isolated strong to severe thunderstorms may produce damaging winds
across parts of the Southeast on Thursday morning into the
afternoon.
...Synopsis...
A strong synoptic cold front is evident in latest surface
observations pushing east/southeast across the OH Valley and lower
MS Valley. Thunderstorm development will become increasingly focused
along the front across the lower MS Valley and Southeast
today/tonight, and will likely be still ongoing by 12 UTC Thursday.
Thunderstorm potential will become increasingly confined to the FL
peninsula by the evening hours as the front moves off shore.
...Florida Panhandle into central Georgia...
Strong (40-50 knot) deep-layer wind shear will likely be in place
across far southeast AL into southwest GA and the FL Panhandle at
the start of the forecast period. While buoyancy will be marginal, a
few isolated strong to severe thunderstorms appear possible within a
convective band based on latest HREF/REFS ensemble output. A steady
weakening trend is expected through the day as the band drifts into
an environment with poor lapse rates over the FL peninsula/southeast
GA, but a few instances of damaging winds appear possible during the
12-16 UTC period.
...Carolinas...
Heating ahead of the approaching cold front will likely support
SBCAPE values of around 500 J/kg across the central to coastal
Carolinas by mid-afternoon. Meager buoyancy/lapse rates will
generally modulate convective intensity as thunderstorms develop
along the front. However, 40-50 knot flow near the top of the
boundary layer and around 40 knots of 0-3 km BWD may support loosely
organized cells/clusters capable of sporadic damaging wind gusts
before the front pushes off the coast.
...Northern Plains...
Sporadic lightning flashes appear likely during the late afternoon
hours amid low-level heating under a pocket of cold temperatures
aloft associated with a robust clipper low. Strengthening winds
within the lowest 0.5-1 km may support very localized stronger
gusts, but confidence in a more robust severe threat remains
limited.
..Moore.. 03/11/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0217 PM CDT Wed Mar 11 2026
Valid 131200Z - 141200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Friday.
...Synopsis...
A cold front currently pushing across the Ohio Valley and lower MS
Valley will migrate off the East Coast and down the FL peninsula
through Thursday before stalling over southern FL early Friday
morning. A dry/cool air mass overspreading much of the CONUS in the
wake of this front will mitigate thunderstorm potential for most
areas aside from the southern FL peninsula. Although lapse rates
will be very marginal, rich low-level moisture coupled with
negligible capping should yield a thermodynamic environment
supportive of deep convection. 20-30 knot flow above 6 km may
support some degree of storm organization, but very weak low-level
winds/convergence should generally limit storm coverage and modulate
overall convective intensity.
..Moore.. 03/11/2026
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