- Day Three
acus02 kwns 211715
Storm Prediction Center ac 211714
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1214 PM CDT Tuesday Oct 21 2014
Valid 221200z - 231200z
..no severe thunderstorm areas forecast...
isolated thunderstorms are forecast across the upper Mississippi
Valley...middle Missouri River valley...Central Plains and southward
into the southern High Plains and Rio Grande Valley Wednesday. A few
storms will also be possible over southern Florida...the middle
Atlantic coast into coastal New England and a small part of the
Eastern U.S. Upper trough will evolve into a closed low and stall off
the middle Atlantic coast. Meanwhile...upper trough currently moving
through the northern and central rockies will phase with a weak southern stream
trough and continue through the plains Wednesday...reaching the MS
valley area later Wednesday night.
The northern stream trough will be accompanied by a cold front that will
advance through the northern and Central Plains...reaching the upper MS
valley region Wednesday night. An occluded surface low expected to be
just off the middle-Atlantic Seaboard Wednesday morning will develop
northward during the day.
..plains through upper MS valley...
Owing to offshore near surface winds over the Gulf...instability will
remain limited over the plains and MS valley. Nevertheless...at
least weak MUCAPE /200-400 j/kg/ will exist ahead of the upper
trough within plume of 6.5-7 c/km middle-level lapse rates and modest
moisture being drawn northeastward above the surface layer. Scattered showers and
isolated thunderstorms will likely develop over the plains as zone
of deeper ascent shifts east...reaching the upper MS valley
Wednesday afternoon and evening.
A few showers and isolated thunderstorms will be possible in
vicinity of a weak front over southern Florida...in association with closed
upper low along the middle-Atlantic and southern New England coasts as well
as over coastal Washington state.