Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Tue Mar 26 2024
Valid 261200Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
SOUTHERN GREAT LAKES AND FOR PORTIONS OF THE CENTRAL GULF COAST...
...SUMMARY...
Isolated severe thunderstorms are probable this afternoon across
parts of the Midwest and southern Great Lakes and across portions of
the central Gulf Coast today.
...OH Valley/Southern Lower MI...
A potent deep-layer cyclone over the Midwest will continue northeast
during the day over parts of the Upper Great Lakes. Concurrently, a
surface low will occlude while a trailing frontal zone extends
southward into the OH Valley. Ahead of the front, a warm conveyor
will promote widespread clouds and scattered showers over the OH
Valley northward into Lower MI. A plume of moderately steep 700-500
mb lapse rates (near 7 deg C/km) are forecast to protrude
northeastward from the lower OH Valley into the southern Great Lakes
during the day, in wake of the early clouds/rain. Cloud breaks will
foster some diurnal heating with temperatures likely warmer (into
the mid 50s to lower 60s) than the cool-biased NAM model depiction.
Shallow convection is forecast to deepen near the front with
thunderstorms gradually intensifying as the airmass becomes weakly
unstable (100-300 J/kg MUCAPE). Although the 0-3km shear vector
will be oriented mostly parallel to the front and resulting
convection, convection-allowing models generally show an elongated
low-topped thunderstorm band from IN/OH northward into Lower MI
during the afternoon. Given the strength of background flow fields
and the potentially adequate steepening of lapse rates immediately
preceding the convection, damaging gusts (peaking in the 55-70 mph
range) are possible. This activity will likely diminish during the
early evening owing to the loss of daytime heating and while
encountering weaker instability farther east.
...Southern AL into Southeast GA and the FL Panhandle...
Ongoing convective line is expected to extend from central AL into
coastal AL and the far western FL Panhandle early this morning. It
is unclear whether this activity will pose a severe risk during the
morning owing to the diurnal minimum in instability. Nonetheless,
the airmass is forecast to destabilize during the day ahead of the
line with some strengthening possible, especially during the midday
to afternoon period. Damaging gusts and perhaps a brief tornado are
the primary hazards with this activity. As upper forcing continues
to be displaced from the region, a general waning in both storm
organization and intensity is expected as the band of storms moves
from the western to central part of the FL Panhandle.
..Smith/Squitieri.. 03/26/2024
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