U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 100712 
Storm Prediction Center ac 100711 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0111 am CST Tue Dec 10 2019 

Valid 121200z - 131200z 

..no severe thunderstorm areas forecast... 

isolated to scattered thunderstorms are expected across portions of 
the deep south and central Gulf Coast eastward to the Florida 

Broad, cyclonically curved mid-level flow will encompass much of the 
lower 48 from the Central Plains through the East Coast. A 
shortwave trough will migrate through this flow from the Central 
Plains to the mid-Mississippi Valley. The approaching mid-level 
trough will induce modest cyclogenesis across the northern Gulf of 
Mexico, with increasing low-level flow atop a shallow cool boundary 
layer across the southeast encouraging development of showers and a 
few thunderstorms across the lower Mississippi Valley in the 
afternoon - spreading eastward toward the southern Appalachians 
through the night. Isolated thunderstorms will also develop across 
the Florida Peninsula during the afternoon as well, and very cold 
air aloft may result in a couple lightning flashes across western 
Washington state. 

..coastal areas of southeast Louisiana through Alabama... 
The combination of surface cyclogenesis across the north-central 
Gulf of Mexico and increasing low-level flow across the region will 
result in eventual northward evolution of a moist low-level airmass 
characterized by near 70s f dewpoints. The northward progression of 
this airmass will likely demarcate the northern limit of any 
potential for surface-based convection, and most models suggest that 
this risk of surface-based activity should hold off over land areas 
until after 12z Friday. A faster northward progression of this 
airmass may result in a brief window for supercellular development 
near coastal areas, however, given vertically veering wind profiles 
and modest buoyancy. Pending evolution of this airmass, low severe 
probabilities may be needed in later outlooks. 

.Cook.. 12/10/2019