ACUS02 KWNS 100657
SWODY2
SPC AC 100656

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CST Tue Dec 10 2024

Valid 111200Z - 121200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN NC
INTO SOUTHERN NEW ENGLAND...

...SUMMARY...
Strong to isolated severe thunderstorms are possible along and ahead
of a cold front from eastern North Carolina into southern New
England on Wednesday.

...Synopsis...
A deep upper trough is expected to extend from central Canada
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.

An associated surface low will deepen as it moves northeastward from
northern VA through the Hudson Valley into NH/VT. An attendant cold
front is forecast to sharpens as it moves quickly eastward, moving
off the East Coast by Wednesday evening.

...Eastern North Carolina to southern New England...
Low to mid 60s dewpoints are expected to advect northward into the
Carolinas and northern Mid-Atlantic States ahead of the approaching
cold front, with mid to upper 50s possible farther north into
southern New England. These dewpoints will support modest buoyancy,
with the overall buoyancy tempered by poor mid-level lapse rates and
widespread precipitation. Even so, a strongly forced convective line
is still expected to develop along the front as it moves quickly
eastward across the region during the afternoon. Deeper convection
is anticipated in this line when increasing large-scale ascent
aligns with the low-level forcing along the front. Guidance differs
on when and where this occurs, with some guidance suggesting it
occurs primarily offshore. Even so, there is still enough potential
for this occur onshore to maintain probabilities for strong gusts.
Expectation is for this deeper convection to combine with the robust
kinematic fields to provide a large reservoir of high-momentum air
capable of mixing down to the surface. Given the strength of the
forcing, this potential exists as far north across southern New
England where buoyancy is expected to be very low.

Additionally, some potential exists for surface-based storms within
the warm sector ahead of the front, provided that antecedent
precipitation does not entirely stabilize the low levels. Some
guidance suggests a pre-frontal band of surface-based storms
develops with low-level confluence within the warm sector over
coastal NC and the Outer Banks.

..Mosier.. 12/10/2024

$$
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