Day 1 Severe Weather Outlook

Valid 171300Z – 181200Z


Isolated severe thunderstorms are possible from portions of northern
Florida to eastern North Carolina today.

Large-scale height falls will overspread much of the eastern CONUS
through tonight via a positive tilt trough extending from the
Appalachians southwestward to the Lower Mississippi Valley. A weak
surface wave along a cold front will continue to shift east of the
Appalachians and influence the mid-Atlantic region and Carolinas,
while the cold front otherwise continues east-southeastward and
clears the coastal Southeast by early/mid-evening with the exception
of the Florida Peninsula.

…Southeast States…
Although convection near the front has not been particularly intense
or organized early today, a southwest/northeast-oriented corridor of
stronger convection including episodic/transient supercells has
existed in the pre-frontal environment across the western Florida
Panhandle into far southeast Alabama since the overnight. This same
general regime will shift eastward as the prefrontal warm/moist
sector also expands east/northeastward today particularly across
northern Florida and southern/eastern Georgia. Although low-level
shear will tend to weaken into this afternoon, mid/high-level flow
will be more than adequate for sustained, potentially rotating
updrafts. Isolated damaging wind gusts and/or a tornado or two are
concerns, especially across far southeast Alabama and the Florida
Panhandle/northern Florida into southern Georgia where a categorical
Slight Risk has been introduced.

Farther north, while stronger shear will exist across the Carolinas,
latest thinking is that instability will remain too weak to justify
higher severe probabilities, particularly given existing early-day
showers and some thunderstorms ahead of the front.

..Guyer/Dial.. 12/17/2019


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