U.S. Severe Weather Forecast (Convective Outlook)

Day Three

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Storm Prediction Center ac 170031 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0631 PM CST sun Dec 16 2018 

Valid 170100z - 171200z 

..no severe thunderstorm areas forecast... 

severe thunderstorms will not occur tonight. 

Early evening water vapor imagery shows a mid-level trough over the 
eastern Pacific and this feature will move ashore tonight and reach 
interior portions of California/or by early Monday morning. A plume of 
moisture from the eastern Pacific may contain a few embedded 
thunderstorms within a rain shield over central coastal CA, and a 
few flashes are possible with weak convection near the far northern 
California coast northward into western Washington. Elsewhere, tranquil conditions 
will prevail over a large part of the contiguous U.S. 

.Smith.. 12/17/2018 


Mesoscale Discussion

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sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 142350 

Mesoscale discussion 1711 
National Weather Service Storm Prediction Center Norman OK 
0550 PM CST Fri Dec 14 2018 

Areas affected...west-central Florida 

Concerning...Severe Thunderstorm Watch 438... 

Valid 142350z - 150145z 

The severe weather threat for Severe Thunderstorm Watch 438 

Summary...severe risk continues for locally damaging winds gusts and 
perhaps a tornado across portions of west-central Florida within 

Discussion...the line of storms west of the Florida Peninsula 
continue to move slowly eastward with most of the line still 
offshore. Shear values (effective bulk shear of 45-60 knots) and 
hodographs with 200-300 m2/s2 0-1 km storm relative helicity per 
mesoanalysis/rap soundings remain supportive of embedded supercells 
and bowing segments. However, these features have yet to materialize 
within the line of storms. Subtle height falls aloft have helped 
maintain marginal buoyancy (500-1000 j/kg of mlcape) across the area 
even with the loss of insolation. As the storms continue slowly 
moving eastward, locally damaging wind gusts and a brief tornado 
remain possible through 03z across ww438. 

.Nauslar/Edwards.. 12/14/2018 

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


Latitude...Lon 28338305 28708231 29078147 28748144 27888146 27628146 
27298219 26998279 26888308 27588309 28338305