557
FXUS62 KRAH 080549
AFDRAH
Area Forecast Discussion
National Weather Service Raleigh NC
150 AM EDT Thu Aug 8 2024
.SYNOPSIS...
A cold front across the mid-Atlantic will linger through Thursday.
The center of Tropical Storm Debby will move northwest and onto the
South Carolina coast this evening and then drift northward across
the central Carolinas on Thursday and Friday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 923 PM Wednesday...
* More widespread rain which will be heavy at times will spread into
central NC tonight beginning a 12 to 18 hour period of the
heaviest rain and greatest flash flood risk.
Negligible changes with the evening update.
The center of Debby is currently located just offshore near
Charleston, SC. Water vapor imagery continues to depict moistening
around the center of the circulation. As such, a persistent band of
heavier rainfall (mostly 1.5 to 2.5 in/hr rates) has developed just
to the southeast of Sampson county. CAMs continue to depict this
heavier band expanding north-northwest over the Sandhills/southern
Coastal Plain the next several hours, followed by up into the
Triangle by daybreak. Consequently, these areas have the best chance
to experience flash flooding overnight as strong 925 to 850 mb
moisture transport provides a continuous feed of >2.5 inches of
PWAT.
The other concern as we continue into the overnight period is the
chance for quick spin-up tornadoes. Thus far this evening, rotating
cells have largely remained to our south (although a few have
recently developed near southern Sampson county). Low-level SRH of
~150 m2/s2 remains anchored over the southern Coastal Plain. This
moderately-strong low-level kinematic field will expand further
northwest overnight. However, weak lapse rates and overall
instability will promote only occasional weak circulations through
Thursday morning.
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