SPC AC 090830
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CST Mon Dec 09 2024
Valid 111200Z - 121200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunderstorms are possible along and ahead of a cold front
from the Mid-Atlantic into the Florida Peninsula on Wednesday.
...Synopsis and Discussion...
Deep upper troughing is expected to extend from Saskatchewan/western
Ontario southward along the length of the MS Valley into the western
Gulf early Wednesday morning. A shortwave trough embedded within the
base of this larger troughing is forecast to move quickly
northeastward from the Lower MS Valley into the Mid-Atlantic. In
response, the parent upper troughing will shift eastward while also
deamplifying. Strong mid/upper flow is anticipated throughout the
eastern periphery of this troughing, with a 100-110 kt 500 mb jet
shifting northeastward from the Southeast into the Mid-Atlantic
throughout the day.
At the surface, a cold front will likely stretch from eastern PA
southwestward through northern FL early Wednesday morning. This
front is expected to move quickly eastward throughout the day,
moving off the Mid-Atlantic coast by the late afternoon. Mid 60s
dewpoints are forecast to be in place across the Mid-Atlantic ahead
of the cold front, and there could be a narrow window for a few
surface-based storms Wednesday morning across coastal NC and the
Outer Banks. Given the strength of the kinematic fields, even
near-surface-based storms could produce strong enough downdrafts to
penetrate any low-level stability that remains in place. However,
buoyancy is expected to remain low, suggesting that updrafts will
remain brief and shallow, limiting their potential to produce strong
downdrafts. This limited buoyancy coupled with uncertainty regarding
frontal position merits precluding any severe probabilities in this
outlook. This region will be reassessed closely in future outlooks,
and low severe probabilities may be needed if buoyancy trends
higher.
..Mosier.. 12/09/2024
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NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z