ACUS01 KWNS 111948
SWODY1
SPC AC 111946

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 PM CDT Mon May 11 2026

Valid 112000Z - 121200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE LOWER MISSISSIPPI VALLEY...THE FLORIDA ATLANTIC COAST...AND
THE CAROLINA COAST...

...SUMMARY...
Isolated severe storms with locally damaging wind gusts and hail are
possible this afternoon along the Carolina and Florida Atlantic
coasts as well as portions of the lower Mississippi Valley.

...20z Update...
The previous outlook largely remains on track with only minor
adjustments made. Risk probabilities were removed across eastern GA
where latest satellite imagery shows limited vertical development
within a broad cumulus field, likely owing to poor ascent given very
weak low-level convergence along a diffuse frontal zone. Latest
HRRR/RRFS guidance depicts negligible convective signals across this
region through tonight, suggesting the potential for severe
thunderstorms is low. Severe wind probabilities were similarly
trimmed across portions of southern LA where cold outflow associated
with a residual MCV over the northern Gulf is spreading northward.
Ahead of this boundary, temperatures warming into the low 80s within
a moist air mass may still support convection sufficiently deep for
a localized downburst concern (see MCD #706). Elsewhere, the
previous forecast (below) remains on track.

..Moore.. 05/11/2026

.PREV DISCUSSION... /ISSUED 1131 AM CDT Mon May 11 2026/

...Synopsis...
Upper pattern across the CONUS this morning consists of western
ridging and eastern troughing. A pair of shortwave troughs are
embedded within the parent trough, one moving through the middle OH
Valley and the other farther south across TX. A convectively
generated vorticity maximum moving across the western Gulf precedes
the TX shortwave. Farther west, a shortwave trough is moving through
the northern periphery of the upper ridging over northern MT and
adjacent southern Saskatchewan.

Recent surface analysis places a low over the eastern NC/SC border
vicinity, with a cold front extending southwestward through the
Southeast and southern AL through the far western Gulf into Deep
South TX. Another low exists farther northwest over southern
Saskatchewan, with a cold front extending south-southwestward from
this low across eastern into south-central MT.

...Eastern SC/Far Southern NC...
Regional radar imagery shows isolated thunderstorms currently
ongoing near the surface low over the eastern NC/SC border vicinity.
A modest increase in buoyancy is anticipated ahead of these storms
over the next few hours. This buoyancy coupled with strong shear
could result in a few bowing segments capable of damaging gusts.
Additional isolated thunderstorm development is anticipated late
this afternoon as the weak cold front moves eastward across SC.
Moderate buoyancy and shear will support the potential for a few
more robust/organized updrafts capable of isolated hail and/or
damaging gusts.

...Eastern FL...
Warm/moist conditions are expected today over the FL Peninsula, with
temperatures over the interior warming into the 90s. Deep westerly
flow will focus convergence along the east-coast sea-breeze, leading
to scattered afternoon thunderstorms. Sufficient deep-layer vertical
shear may result in isolated strong-severe storms producing
gusty/damaging winds and hail.

...Northern/eastern ND into eastern SD...
Despite limited low-level moisture, modest buoyancy may develop late
this afternoon/early this evening amid cooling mid-level
temperatures and increasing mid-level moisture. This buoyancy will
develop atop a deeply mixed boundary layer, supporting the potential
for strong gusts if any updrafts can deepen/mature. Given the weak
and elevated nature of the buoyancy, developing a mature updraft
capable of lightning will be difficult and the current expectation
is for most of this activity to be shallow and non-lightning
producing. That being said, gusty surface winds are possible with
any convection does develop atop the deeply mixed boundary layer.

...Coastal LA/MS/AL...
The convectively generated shortwave trough over the western Gulf
mentioned in the synopsis (and associated surface low) are expected
to progress eastward throughout the day, while the stronger
shortwave trough back across TX also progress east-southeastward.
Easterly/southeasterly low-level flow will be maintained north of
the Gulf low, increasing low-level convergence along the slow-moving
frontal zone. This convergence will be augmented by ascent attendant
to the TX shortwave, with numerous showers and thunderstorms likely.
Poor lapse rates will limit buoyancy, although moderate deep-layer
shear could support a few deeper, more organized updrafts. Primary
risk over this area is heavy rain (as noted in the WPC Day 1
Excessive Rainfall Outlook), but a few water-loaded downbursts
capable of wind damage are possible as well.

$$