Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1229 AM CDT Wed Mar 11 2026
Valid 111200Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
MISSISSIPPI VALLEY...ACROSS THE TENNESSEE/OHIO VALLEY INTO THE
MIDDLE ATLANTIC...
...SUMMARY...
Isolated to scattered severe thunderstorms are expected today from
the ArkLaTex and Lower Mississippi Valley northeastward through the
Ohio Valley and Mid-Atlantic.
...Ohio Valley/Middle Atlantic...
Northern-stream trough is digging east-southeast across the northern
Rockies/High Plains early this morning and should advance into the
upper MS Valley by 18z as a 500mb speed max translates through the
base of the trough, then increases in intensity as it moves across
lower MI during the afternoon. Large-scale height falls will
overspread the Great Lakes/OH-TN Valley region as southwesterly flow
strengthens across the downstream warm sector. Latest model guidance
suggests the sharp cold front associated with this feature will
extend across lower MI-central IL-northern MO at the start of the
period. This boundary will serve as a primary focus for thunderstorm
development through the period. By mid day, the front will have
surged into northwest OH-central IN and modest boundary layer
heating is expected across the warm sector downstream.
Current thinking is modest destabilization will be noted across much
of the OH/TN Valley such that MLCAPE values should be on the order
of 1500 J/kg within a strongly sheared environment. Forecast
soundings support this and supercells are expected to develop, in
addition to possible line segments and clusters. Large hail is
possible with supercells, along with damaging winds and a risk for a
few tornadoes. This activity will spread east toward the Middle
Atlantic by late afternoon.
...Gulf States...
Positive-tilt short-wave trough is shifting east across west
TX/northeast Mexico. However, this feature is expected to become
more negative tilt by late afternoon as it ejects toward the lower
Sabine River Valley. Seasonally cool 500mb temperatures are noted
with this feature and a focused 70kt midlevel jet is forecast to
translate along the Gulf coast during the latter half of the period.
Left-exit region of this jet will encourage ascent/deep convection.
Latest guidance suggests a surface low may evolve in response,
tracking from the upper TX coast, across southern LA into southern
MS by 12/06z. Some LLJ response is also expected which should aid
organized thunderstorms across the southern Gulf states. Strong
shear favors severe winds along with a risk for tornadoes. Some
consideration was given to increasing severe probabilities ahead of
this feature. This may be done in later outlooks if conditions
continue to evolve toward an organized squall line.
..Darrow/Lyons.. 03/11/2026
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