U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 141614 
Storm Prediction Center ac 141613 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1013 am CST Fri Dec 14 2018 

Valid 141630z - 151200z 

..there is a slight risk of severe thunderstorms over parts of the 
Florida Peninsula... 

Isolated severe thunderstorms will be possible across the 
western/north-central Florida Peninsula through the afternoon and 
evening, and possibly across southeastern Georgia and the coastal 
Carolinas tonight. Locally damaging winds should be the main threat. 

No changes have been made to the ongoing forecast. Morning radar 
loop shows widespread showers and thunderstorms affecting the West 
Coast of the Florida Peninsula, with activity spreading eastward across 
the slight risk region. This will significantly limit 
heating/destabilization. Nevertheless, forecast soundings show weak 
but sufficient cape values and strong deep-layer shear today into 
tonight. This may result in a few organized cells within the 
broader precipitation shield. Rotating/bowing segments capable of 
damaging winds, or perhaps a tornado spinup are the main concerns 
today. The threat should end from west to east across the Florida 
Peninsula this afternoon and evening. 

.Carolina coast... 
Strong surface pressure-falls are forecast over the eastern 
Carolinas later today. This will result in strengthening southerly 
low level winds and rapid destabilization along the immediate coast. 
Model solutions suggest multiple clusters of thunderstorms offshore 
this evening and tonight. If a few of these stronger storms can 
spread inland, a marginal risk of damaging winds would be present. 

.Hart/Broyles.. 12/14/2018 


Mesoscale Discussion

acus11 kwns 141921 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 141920 

Mesoscale discussion 1710 
National Weather Service Storm Prediction Center Norman OK 
0120 PM CST Fri Dec 14 2018 

Areas affected...west central Florida coastal area 

Concerning...severe potential...watch possible 

Valid 141920z - 142145z 

Probability of watch issuance...40 percent 

Summary...threat for isolated damaging wind and a tornado or two 
will undergo a modest increase this afternoon into early evening 
over the west central Florida coastal area. It remains uncertain 
whether a ww will be needed in the short term, but trends will 
continue to be monitored. 

Discussion...early this afternoon a warm front or rain cooled 
boundary extends across the Florida Peninsula from near Daytona Beach 
southwest to just north of the Tampa area. South of this boundary, 
the surface layer is destabilizing with upper 60s f dewpoints and 
temperatures rising through the 70s. The upper low remains cutoff 
well to the west of Florida with minor shortwave ridging above the warm 
sector and relatively warm temperatures aloft resulting in weak 
700-500 mb lapse rates, limiting MLCAPE to 500-1000 j/kg. The 
northern end of a line of organized storms with a bowing segment is 
in the process of moving onshore and will soon affect Citrus County. 
Tendency has been for storms to weaken as they move inland where 
weak instability exists north of the warm front. However, as the 
warm sector continues to destabilize, the chances for storms to 
survive and remain organized farther inland should gradually 
increase into early evening. Tampa wind profiles show large 
hodographs with 300-400 m2/s2 0-1 km storm relative helicity and 43 
kt 0-6 km shear supportive of supercells and bowing segments, but 
conditional upon the development of sufficient instability. Trends 
will continue to be monitored this afternoon as storms approach the 
west central Florida coast. 

.Dial/Hart.. 12/14/2018 

..please see www.Spc.NOAA.Gov for graphic product... 


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