...OH Valley...
Water-vapor imagery loop overnight showed a southern-stream
short-wave trough associated with this morning's severe thunderstorm
activity straddling the OH River in central KY and southern IN.
This early-day thunderstorm complex will probably pose a risk for
wind damage and perhaps a couple of tornadoes before it moves into
the central Appalachians towards midday (see MCD #341 for short-term
details). In its wake, a trailing outflow boundary/effective warm
frontal zone will likely advance northward into IN/OH later today
with lower to mid 60s progged to near I-70. Models continue to show
an appreciable window of opportunity in which cloud breaks/heating
and increasing low-level moisture contribute to moderate
destabilization during the afternoon. Have adjusted the western
envelope of severe probabilities farther west across IN to account
for greater destabilization than earlier forecast, but otherwise
have left the outlook unchanged across the OH Valley. Scattered
thunderstorms will likely develop by early to mid afternoon with
discrete supercells evolving from the more intense updrafts.
Tornadoes, large to very large hail, and damaging gusts are expected
with the supercells that mature across the warm sector. Enlarged
and elongated hodographs imply fast storm motions and the
possibility for several cyclic tornadic supercells, some of which
may yield strong and long-lived tornadoes.