- Day Three
acus03 kwns 210738
Storm Prediction Center ac 210737
Day 3 convective outlook
National Weather Service Storm Prediction Center Norman OK
0237 am CDT Tue may 21 2019
Valid 231200z - 241200z
..there is an enhanced risk of severe thunderstorms ...
..There is a slight risk of severe thunderstorms over a portion of
the southern and Central Plains as well as the Ohio Valley and
Severe storms with large hail, damaging wind and tornadoes will be
possible over a part of the central and Southern Plains Thursday.
Other strong to severe storms with damaging wind and large hail
might occur from a portion of the northeast states into the Ohio
A significant shortwave trough will rotate through the base of an
upper low centered over the Great Basin 12z Thursday and into the
Central High plains Thursday afternoon and evening. Farther east, a
low-amplitude shortwave trough will crest an upper ridge anchored
over the southeast U.S. And move through the Great Lakes before
turning southeast into the northeast states Thursday evening. At the
surface a warm or stationary front will likely extend from the
middle MS valley region southwest into central or southern Kansas. A
dryline will reside near the Texas/nm border. The warm front is
expected to lift north into southeast NE, while the dryline mixes
through West Texas during the day. Farther east a surface low attending
the northern-stream shortwave trough will move through southern
Canada while trailing cold front advances southeast through the
Great Lakes. A warm front will advance east into a portion of the
..central and Southern Plains...
A very moist and unstable airmass with dewpoints in the upper 60s to
around 70 f will reside in the warm sector from Kansas to OK and Texas
beneath 7-7.5 c/km mid-level lapse rates, contributing to moderate
to strong instability (2500-3000 j/kg mlcape). While much of the
warm sector across this region may remain capped, forcing for ascent
attending the northeast-migrating upper jet will likely promote
thunderstorm development over the central and southern High Plains.
Models suggest early timing of this feature and initiate storms near
and north of the warm front from the Texas Panhandle into southwest Kansas
early in the period. Some of this activity may intensify as it
develops northeast, and additional storms are expected to develop
along the dryline as well as along and north of the warm front.
Vertical wind profiles and the thermodynamic environment will
support organized storms including supercells with all hazards
..northeast states through Ohio Valley...
The warm sector will gradually moisten west of the warm front during
the day with low 60s f dewpoints beneath 6.5 c/km lapse rates along
with diabatic warming contributing to moderate instability during
the day. Current indications are that storms will most likely
develop over the Great Lakes along southeast-advancing cold front
and spread southeast into the Ohio Valley and northeast states by late
afternoon and evening. Winds will strengthen as the mid-level speed
Max attending the shortwave trough approaches the region with
effective shear supporting supercells. These storms may produce
large hail and damaging wind as they move southeast through the
region later Thursday afternoon into the evening.