U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 081934 
Storm Prediction Center ac 081933 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0133 PM CST Thu Dec 08 2016 

Valid 082000z - 091200z 

..no severe thunderstorm areas forecast... 

no severe thunderstorms are expected across the contiguous U.S. 
Through tonight. 

No changes have been made to the ongoing forecast. 

.Cohen.. 12/08/2016 

Previous discussion... /issued 1029 am CST Thu Dec 08 2016/ 

Broad cyclonic flow currently covers the Continental U.S. With enhanced flow 
arcing from northern California through the Central Plains, Ohio 
Valley, and northeast. Strongest flow within this belt currently 
exists at the base of a shortwave trough tracking through the Ohio 
Valley. This shortwave trough and associated jet streak are expected 
to continue northeastward off the northeast coast by Friday morning 
while the broadly cyclonic flow persists. Surface pattern is 
characterized by a strong polar high, currently centered over the 
northern High Plains and extending through the Southern Plains and 
lower Mississippi River valley. This high is expected to gradually 
shift eastward throughout the day. 

Cold and stable airmass associated with the surface high will keep 
overall thunderstorm prospects very low. Cold front has pushed off 
the South Coast of Florida, with observations at mth and eyw both 
reporting north winds. A strike or two is possible with any 
afternoon convection that develops as a result of a second frontal 
push but weak lapse rates and cool surface conditions are expected 
to keep thunder coverage below 10%. Weak upper forcing may glance 
the region during the second half of the period but the elevated 
nature of this convection and overall continued weak lapse rate 
should preclude thunder. 

Isolated lightning strikes are also possible over and/or in the Lee 
of Lake Erie and Ontario within any lake effect bands. Conditions 
for lake effect snow band induced lightning appears most favorable 
along and in the Lee of Lake Ontario, where long wind fetches and 
slightly cooler temperatures aloft exist. As mentioned in the 
previous outlook discussion, anticipated lightning coverage is on 
the margins for inclusion, but it is close enough to maintain 
consistency with previous products. 


Mesoscale Discussion

acus11 kwns 060832 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 060831 

Mesoscale discussion 1872 
National Weather Service Storm Prediction Center Norman OK 
0231 am CST Tuesday Dec 06 2016 

Areas affected...the Florida Panhandle...far southeastern Alabama...and 
southwest Georgia 

Concerning...Tornado Watch 516 

Valid 060831z - 061030z 

The severe weather threat for Tornado Watch 516 continues. 

Summary...a threat of localized damaging wind gusts may be 
developing across western portions of the Tornado Watch along a cold 
front...with brief/weak tornado threat perhaps along the stationary 

Discussion...remote wind sensors indicate winds through about 850 mb 
have veered over the last few hours...resulting in mainly 
straight-line hodographs across the warm sector from the Florida 
Panhandle into far southern Georgia. A marginally unstable air mass 
remains south of the stationary front...with around 500 j/kg MUCAPE 
per sfcoa. 

Recent radar trends show some increase in storm coverage along the 
cold front from southeast Alabama into the Gulf of Mexico...although 
lightning has not been particularly frequent. As the upper trough 
continues east-northeastward...wind fields aloft will increase 
further. This could result in some uptick in wind threat...as mean 
winds increase. 

The stationary front will make little if any northward progress 
through early morning...with the main severe threat immediately along 
and south of it. A brief/weak tornado cannot be ruled out especially 
along this boundary where low-level shear will be augmented... 
however...stable surface air exists to the north which will minimize 
any tornado threat unless storms can maintain motions roughly along 
the front. 

.Jewell.. 12/06/2016 

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


Latitude...Lon 29058695 30348613 31148580 31098466 31488349 31638275 
31548227 31278194 30658212 29368343 29358384 29188521