SPC AC 210045
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 PM CDT Fri Jul 20 2018
Valid 210100Z - 211200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
TN AND KY...
The greatest threat for severe thunderstorms is shifting into the
Tennessee Valley regions and the Mid-South. Damaging gusts, large
hail and a few tornadoes remain possible.
Early-evening water vapor imagery depicts a well-defined region of
ascent/moistening across MO ahead of a pronounced short-wave trough.
This feature is digging southeast toward the western TN Valley and
associated 500mb speed max is forecast to spread into northern AL by
morning. A large reservoir of buoyancy is noted ahead of this
feature from the lower MS Valley into the western part of the TN
Valley where MUCAPE is in excess of 4000 J/kg across much of the
While severe thunderstorms have been primarily focused across the
OH/TN Valley region this afternoon, there remains concern that
severe thunderstorms could develop ahead of the aforementioned short
wave over the next few hours then spread southeast into the
north-central Gulf States later tonight. Large hail has been common
with supercells across KY/TN and soundings across this region remain
supportive of hail/wind. 00z soundings at BNA, BMX, and LZK all
exhibit strong instability with unusually strong deep-layer shear
for this time of year. Given these concerns will maintain
substantial severe probs along a corridor from the mid-South into
the TN Valley.
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