- Day Three
acus03 kwns 230729
Storm Prediction Center ac 230728
Day 3 convective outlook
National Weather Service Storm Prediction Center Norman OK
0228 am CDT Fri Aug 23 2019
Valid 251200z - 261200z
..there is a marginal risk of severe thunderstorms across portions
of the northern and Southern Plains...
Isolated severe thunderstorms are possible on Sunday across portions
of the northern and Southern Plains.
Medium-range guidance is in good agreement that a strong shortwave
trough embedded within the enhanced westerlies moves from the
northern rockies through the northern plains on Sunday. This results
in a deepening of the cyclonic flow across the north-central Continental U.S..
this pattern evolution will also push a cold front eastward/
southeastward through much of northern plains.
Elsewhere, warm and moist conditions will persist across much of
Southern Plains and southeast while weakening high pressure across
much of the eastern Continental U.S. Will allow for some moisture return into
the Ohio Valley.
Air mass across the region will be warm, very moist, and strongly
buoyant. Strengthening northwesterly flow aloft will also contribute
to moderate vertical shear. Overall environment would support severe
potential as long as forcing exists for storm initiation. Current
guidance suggests a mesoscale convective system will be moving out of Kansas early in the
period, with a resulting severe threat anticipated downstream. Low
(i.E. 5%) severe probabilities will be introduced with this
forecast. More model consistency is needed before issuing higher
Ample low-level moisture (i.E. Dewpoints in the mid to upper 60s)
will be in place over the region ahead of the approaching cold
front. Even so, relatively warm low to mid-level temperatures will
likely limit destabilization, particularly across southern portions
of the region where less large-scale forcing for ascent (from the
approaching shortwave trough) is expected. The environment supports
a severe threat where deep updrafts persists but uncertainty
regarding coverage currently precludes higher than 5% probability.