U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 120827 
Storm Prediction Center ac 120826 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0226 am CST Wed Dec 12 2018 

Valid 141200z - 151200z 

..there is a marginal risk of severe thunderstorms Friday into 
Friday night across parts of northern and central 
Florida...southeastern Georgia and the coastal Carolinas... 

Strong thunderstorms may impact parts of northern and central 
Florida, southeastern Georgia and the coastal Carolinas Friday into 
Friday night, accompanied by at least some risk for severe weather. 

Split westerlies will continue to emanate from the mid-latitude 
Pacific, with several embedded amplified waves. A couple of these 
are forecast to progress through one branch across the Pacific 
northwest into the Canadian prairies during this period. A more 
prominent perturbation within another branch, including a deep 
lower/mid tropospheric cyclone, appears likely to progress more 
slowly, east/northeastward across the lower Mississippi Valley. 

In association with this latter feature, a plume of increasingly 
moist air, emanating from a more substantively modifying boundary 
layer over the central/eastern Gulf of Mexico, appears likely to 
advect into much of the southeast, with highest moisture content 
overspreading southern and middle portions of the Atlantic Seaboard. 
This may include mid/upper 60s+ surface dew points within the warm 
sector of the cyclone, across much of Florida and perhaps parts of 
adjacent southeast Georgia into coastal areas of the Carolinas. 

Destabilization associated with the moistening, and large-scale 
ascent, is expected to support areas of scattered thunderstorm 
development Friday through Friday night. 

Considerable spread remains evident in model ensemble output, and 
among the various deterministic model output, concerning the 
evolution and progression of the cyclone, including possible 
secondary surface wave development inland across northern Florida 
into the Carolinas. Even where confidence is greatest concerning 
the most substantive boundary layer moistening, questions remain 
concerning the degree of associated boundary layer destabilization. 
This may ultimately mitigate the overall severe weather potential, 
but at least isolated severe storms appear possible, particularly 
Friday across parts of northern and central Florida. 

To varying degrees, models indicate that strengthening of lower/mid 
tropospheric wind fields coupled with boundary layer moistening and 
destabilization will precede the inland advance of vigorous 
thunderstorm activity off the northeastern Gulf of Mexico during the 
day Friday. As this occurs, it appears at least possible that the 
environment may become conducive to organized severe storm 
development, including supercells and a risk for a tornado or two, 
in addition to potential for severe hail and wind. 

.Kerr.. 12/12/2018