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 170224 

Mesoscale discussion 1712 
National Weather Service Storm Prediction Center Norman OK 
0824 PM CST sun Dec 16 2018 

Areas affected...portions of New England and eastern New York 

Concerning...winter mixed precipitation 

Valid 170224z - 170630z 

Summary...winter mixed precipitation is expected to continue/develop 
across portions of New England and eastern New York overnight. 
Freezing rain, sleet, and snow are all possible across the area. 

Discussion...a surface cyclone is centered south-southeast of Long 
Island with an associated upper-level trough located almost directly 
overhead. Forcing for ascent is spreading over much of New England 
and portions of New York where precipitation has continued for 
multiple hours. Surface temperatures are hovering near/above 
freezing across much of the interior of New England and New York. 
Radar imagery shows bright banding/melting layer at 3000-4500 ft. 
Above ground level across central New England. However, the melting layer is 
lowering with indications the warm nose is eroding aloft as cold air 
advection and precipitation cools this layer. Additionally, kenx is 
displaying characteristics of the melting layer lowering with 
sleet/snow becoming more likely at the surface and across the higher 
terrain with freezing rain also possible within the transition zone. 
Trends toward winter mixed precipitation developing/expanding across 
portions of New England are favorable overnight as the upper-level 
trough/surface low track east-northeast. 

.Nauslar/Mosier.. 12/17/2018 

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


Latitude...Lon 42037321 42107352 42357402 42747418 43037412 43317378 
43457349 43597308 43747239 43867167 44057095 44087055 
43987025 43747023 43547035 43307054 43187076 43017102 
42787157 42667220 42567249 42427285 42227304 42037321