...North Carolina/southeast Virginia this afternoon/evening...
The potential exists for a few thunderstorms capable of locally
damaging winds, and possibly a tornado, across the region this
afternoon into early evening, although the overall magnitude/extent
of today's severe risk should remain limited.
Associated with the base of a prominent east-central CONUS longwave
trough, a vorticity maxima and the entrance region of a strong
cyclonically curved polar jet will quickly transition
east-northeastward from the Tennessee Valley and Lower Ohio Valley
to the Appalachians by tonight. Modest cyclogenesis will occur in
the lee of the southern/central Appalachians as a cold front
continues to spread east of the mountains, and generally exits the
coast by early/mid-evening. A warm/moist sector with 70F dew points
will precede the cold front, with a north-northeastward expansion
across coastal portions of South Carolina/North Carolina today.
Even with this moist influx off the Atlantic, the relatively
small-inland warm sector remains mired by broken multi-layer cloud
cover at midday. Its potential persistence will temper lapse rates
and limited upward parcel accelerations even with near 70F surface
dewpoints, which casts uncertainty on how many mature/sustained
surface-based storms will develop and intensify within the warm
sector. That said, strengthening/gradually backing mid-level winds
and resultant 45-55 kt effective shear will be conditionally
supportive of fast-moving line segments capable of damaging winds,
with some supercell/non-zero tornado potential particularly across
eastern North Carolina in proximity to the warm front, should
adequate destabilization and storm development/maturation occur.