U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 210813 
Storm Prediction Center ac 210812 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0212 am CST Thu Nov 21 2019 

Valid 231200z - 241200z 

..no severe thunderstorm areas forecast... 

isolated to widely scattered thunderstorms are expected over a part 
of the southeast states Saturday. Threat for severe weather appears 
low at this time. 


A progressive southern-stream shortwave trough will move through the 
southeast states accompanied by a cold front Saturday. Weak 
cyclogenesis is expected over the Tennessee Valley early in the period, and 
this low is forecast to weaken as it moves northeast into the 
central Appalachians. Secondary cyclogenesis is forecast across NC 
and Virginia overnight as a strong vorticity maximum moves into the base 
of the upper trough and interacts with the baroclinic zone. 

..southeast states... 

Partially modified Gulf air with surface dewpoints generally in the 
low to mid 60s f will advect into the Gulf Coast states Saturday. 
This will result in some destabilization, but instability will 
remain very marginal (mucape below 500 j/kg) due to widespread 
clouds and poor low to mid-level lapse rates. It is likely that 
scattered showers with embedded thunderstorms will be ongoing along 
the warm conveyor along and just ahead of the cold front, and this 
activity will advance east during the day. Thunderstorm coverage 
will probably diminish with eastward extent due to more limited 
moisture and instability. However, a separate area of thunderstorms 
may develop over the coastal Carolinas late Saturday night as the 
front intercepts Richer low-level moisture. While vertical shear 
will be more than adequate to support storm organization, the very 
weak thermodynamic environment should remain a limiting factor for 
severe storms. 

.Dial.. 11/21/2019