SPC Jan 5, 2025 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1144 PM CST Sat Jan 04 2025

Valid 051200Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE LOWER MISSISSIPPI VALLEY...

...SUMMARY...
Strong/severe thunderstorms are expected this afternoon and evening
from the Sabine River Valley into the Mid-South and lower
Mississippi Valley. Severe wind gusts, tornadoes and hail will be
the primary threats.

...Sabine River Valley to central Gulf States...

Late-evening water-vapor imagery depicts a well-defined short-wave
trough advancing east across CO/NM. This feature is forecast to
strengthen as it progresses into eastern KS/OK, with a closed low
expected to form as deepens. By 18z, the 500mb low should be over
southeastern KS with subsequent movement into southern IL by the end
of the period. This deepening low will be reflected at the surface
by a sharp cold front that will extend from eastern OK into central
TX at sunrise. The boundary will surge east during the day serving
as the primary focus for organized convection.

Early in the period, elevated convection is expected along a
corridor of strong warm advection from eastern KS into western TN.
Intense LLJ will be focused across the lower MS Valley through 18z,
then shift east, extending across northern MS into southern KY by
early evening. Boundary-layer moistening is expected to be aided by
LLJ, with gradual destabilization forecast ahead of the front,
especially across the lower MS Valley. Latest data does, however,
maintain a cooler, stable boundary layer across much of TN where
poor low-level trajectories will inhibit destabilization.

Latest thinking is the greatest potential for boundary-layer
destabilization will be across east TX/LA into portions of MS. Given
the strong, dynamic short wave and intense mid-level height falls, a
forced line of convection should develop along the cold front,
possibly as early as late morning. Scattered convection may initiate
across the warm sector over eastern OK shortly after 12z, then
gradually expand in areal coverage with a broken squall line, or
QLCS, likely by 18-20z from northern AR-northwest LA-southeast TX.
Strong shear favors organized squall line, and embedded supercells.
Additionally, if adequate warm-sector destabilization occurs,
isolated supercells may develop ahead of the squall line. Severe
wind gusts and tornadoes are the greatest concern, though some risk
for marginally severe hail is also possible. Organized QLCS should
propagate across the lower MS Valley into western AL during the
evening where it will encounter a more stable air mass. Severe
probabilities are notably lower across this lower buoyancy
environment.

..Darrow/Wendt.. 01/05/2025

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