U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 150536 
Storm Prediction Center ac 150534 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1134 PM CST Sat Dec 14 2019 

Valid 151200z - 161200z 

..no severe thunderstorm areas forecast... 

severe weather is not anticipated through early Monday morning. 

Surface high pressure will dominate most of the Continental U.S. With the 
exception of a weak area of low-pressure in the southern High Plains 
which will slowly drift eastward through the period. Ahead of this 
surface low, northward moisture advection will bring 60 f dewpoints 
as far north as Memphis, Tennessee by the end of the period. Weak height 
rises and a moderately strong capping inversion should limit 
warm-sector convective development Sunday afternoon. 

850mb flow will increase across the mid-Mississippi Valley late this 
afternoon and into the evening which will lead to strong warm air 
advection across a warm frontal zone. It appears some weak 
instability may develop along and north of the warm front which may 
be sufficient for a few storms late this evening and overnight. 
However, the weak instability should limit the overall severe 
weather threat until after 12z Monday. 

.Bentley.. 12/15/2019 


Mesoscale Discussion

acus11 kwns 141142 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 141142 

Mesoscale discussion 2198 
National Weather Service Storm Prediction Center Norman OK 
0542 am CST Sat Dec 14 2019 

Areas affected...central Florida 

Concerning...Severe Thunderstorm Watch 699... 

Valid 141142z - 141345z 

The severe weather threat for Severe Thunderstorm Watch 699 

Summary...a marginal tornado and wind-damage threat appear likely to 
continue through mid morning across central Florida. 

Discussion...latest surface analysis shows a cold front in northern 
Florida with a moist airmass in place ahead of the front across much 
of southern and central Florida. Surface dewpoints are mostly in the 
upper 60s and lower 70s f across central Florida where the rap is 
analyzing an axis of moderate instability. Thunderstorms have 
developed along the northwestern edge of the strongest instability. 
This line of storms is forecast to move east-southeastward across 
central Florida over the next 2 to 4 hours. In addition to the 
moderate instability shown by the rap, the Tampa Bay wsr-88 vwp has 
0-6 km shear at 50 kt and 0-1 km shear of nearly 30 kt. This should 
be enough to continue a marginal tornado threat with cells that 
rotate. An isolated wind-damage threat could also exist with the 
stronger segments along the line. 

.Broyles.. 12/14/2019 

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


Latitude...Lon 26888270 26968238 26788224 26858219 26958204 26868203 
26798201 26778155 26998155 27018128 27078127 27068118 
27168117 27188100 27378108 27508119 27698100 27768062 
27868009 28218027 28558018 29898095 29898134 30238138 
30128143 30168163 30008161 29888155 29778193 29748203 
29858221 29898235 29898249 29808260 29678261 29568261 
29518254 29488241 29368238 29268237 29258248 29258251 
29158247 29098245 29018237 28938227 28888222 28818220 
28738221 28708227 28748249 28738263 28588269 28278276 
28148283 28128310 28088316 27898319 27758314 27498303 
27258300 27128286 26888270