SPC AC 091257
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0657 AM CST Mon Dec 09 2024
Valid 091300Z - 101200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms are possible from the Lower Mississippi Valley into
much of the Southeast States today and tonight. The potential for
severe thunderstorms currently appears low.
...Southeast States...
Neutral height tendencies will tend to prevail over the region as a
low-amplitude shortwave trough over the Lower Ohio Valley and
Tennessee Valley races east-northward toward the Mid-Atlantic
seaboard. Convergence will tend to remain weak diurnally near a
northward-shifting warm front across the Tennessee Valley, until
modest surface cyclogenesis occurs tonight across the ArkLaMiss and
Mid-South, coincident with a stronger secondary cold front
accelerating southeastward across the ArkLaMiss/East Texas.
Semi-steady warm/moist advection will persist in/near the warm
sector spanning parts of Louisiana/Mississippi/Alabama into
eventually nearby portions of Georgia and Tennessee.
The persistent warm advection regime over the middle Gulf Coast will
maintain isolated thunderstorm chances through the day. Despite
40-50 knot mid-level flow, weak low to mid-level lapse rates will
modulate updraft intensities and tend to limit the likelihood of
overly organized convection for much of the day.
The potential for thunderstorms should regionally increase tonight
as the aforementioned upstream cold front/modestly deepening surface
low interact with higher theta-e air. Even with favorable low-level
moistening/destabilization trends, the scenario may not provide
sufficient destabilization for robust deep convection tonight. As
mentioned in the prior outlook discussion, most convection-allowing
guidance remains rather subdued as far as severe attributes, with
the typically aggressive FV3 being a modest exception.
Subsequent outlooks will closely reevaluate this scenario and the
potential need for low wind/tornado probabilities, as more favorable
destabilization trends could prompt more of a severe risk given the
severe-conducive deep-layer/low-level shear.
..Guyer/Broyles.. 12/09/2024
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