U.S. Severe Weather Forecast (Convective Outlook)

Day Three

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Storm Prediction Center ac 180811 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0211 am CST Tue Dec 18 2018 

Valid 201200z - 211200z 

..there is a slight risk of severe thunderstorms across much of 

Severe thunderstorms are possible across the central and southern 
Florida Peninsula Thursday. Some low severe threat could develop 
over eastern North Carolina late in the day3 period. 


Strong mid-level flow is forecast to dig southeast across Texas into 
the southern Gulf basin during the day3 period. This process will 
ensure significant deepening of a larger trough that will translate 
east across MS valley into the southeastern US/eastern Gulf of 
Mexico by Friday morning. As this trough evolves, low-mid level 
trajectories will become increasingly favorable for higher Theta-E 
air mass to advance north across the Caribbean into the southern Florida 
Peninsula where near 70f surface dew points are likely to return. 
This air-mass recovery is expected to aid significant convection 
across the eastern Gulf basin early in the period along a pronounced 
surface front where strong large-scale forcing for ascent will be 
maximized. Very strong shear will develop across Florida ahead of the 
short wave which will encourage organized convection. Frontal 
convection will likely be linear in nature, but embedded supercells 
are expected. There is some concern that isolated pre-frontal 
supercells may also develop within an increasing warm advection 
regime over the peninsula. If moisture/instability returns to Florida as 
currently forecast, all severe hazards may be noted with this 
activity given the strength and geometry of this evolving trough. 

Later in the period, moisture may advance inland across eastern NC. 
If sufficient instability can spread into this region supercells may 
develop as low level jet strengthens across this region. 

.Darrow.. 12/18/2018