- Day Three
acus02 kwns 011729
Storm Prediction Center ac 011728
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1228 PM CDT Monday Sep 01 2014
Valid 021200z - 031200z
..there is a slight risk of severe thunderstorms from parts of New York to Kentucky...
strong to isolated severe storms primarily producing damaging winds
are possible from the northern Appalachians southwest to the
middle-south on Tuesday. Marginally severe hail may occur on Tuesday
night over parts of Kansas and northern Oklahoma.
A shortwave impulse embedded within a broad modest-amplitude trough
should eject across parts of the Midwest to lower Great Lakes during
the first half of the period. In the wake of this impulse...a
largely zonal pattern will envelop most of the Continental U.S.. at the
surface...a weak cold front will shift east in tandem with the
shortwave impulse. Trailing portion will be quasi-stationary near
the Ozark Plateau and advance north as a warm front Tuesday night.
..nrn Appalachians to the mid-south...
Scattered convection should be ongoing at 12z/Tuesday from the Midwest
to Ozark Plateau...likely displaced ahead of the cold front.
While this activity is not expected to be strong...extensive clouds
should limit downstream destabilization...especially from the Ohio
Valley northward. Here middle/upper-level lapse rates will be poor...but a
strong belt of 700-500 mb winds will overspread this region. This
should support an increase in convective intensity as renewed
development occurs along convective outflow/differential heating
corridors by late morning into afternoon. This activity should
organize into line segments/clusters that should yield at least
isolated damaging winds...warranting an upgrade to a categorical
risk designation. With southern/western extent...progressively weaker shear
will limit the risk for organized storms.
..cntrl/eastern Kansas to north OK...
Low-level warm air advection will strengthen Tuesday night as a relatively diffuse warm
front advances north. Isolated to scattered elevated convection should
form along the periphery of a gradually expanding High Plains eml.
Most guidance suggest westerlies within the cloud-bearing layer will
slacken late in the period...probably only supporting multicells at
best. But amidst moderate buoyancy...initial updrafts may produce
marginally severe hail.