A consensus of
model forecasts suggests the greatest instability will develop from
central North Carolina into southern and central Virginia, where
MLCAPE values appear likely to reach the 2000 to 3000 J/kg range. In
addition to moderate instability, NAM forecast soundings near
Richmond, Virginia and Raleigh, North Carolina have steep mid-level
lapse rates with relatively cool temperatures aloft. This, combined
with 0-6 km shear in the 30 to 35 knot range will likely support
supercell development. The potential for supercells will be greatest
early in the afternoon, before storms merge into a line. Hailstones
of greater than 2 inches in diameter will be possible with
supercells that develop in areas that destabilize the most. The
current thinking is that a relatively quick transition to a line
will occur. This line is forecast to become organized, moving
eastward across the Piedmont into the Raleigh/Durham and Richmond
areas during the late afternoon. Wind-damage will be likely along
the leading edge of the stronger parts of this line segment.