U.S. Severe Weather Forecast (Convective Outlook)

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acus01 kwns 200039 
swody1 
Storm Prediction Center ac 200037 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0637 PM CST sun Nov 19 2017 


Valid 200100z - 201200z 


..no thunderstorm areas forecast... 


... 
there appears to be negligible risk for thunderstorms across the 
U.S. Tonight. 


..01z outlook update... 
Latest observational data and model output continue to indicate the 
presence of dry and/or stable conditions across much of the 
contiguous U.S., With negligible potential for convection capable of 
producing lightning. Little change is expected through and beyond 
12z Monday. 


.Kerr.. 11/20/2017 


$$ 

Mesoscale Discussion


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acus11 kwns 182324 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 182324 
tnz000-gaz000-alz000-190130- 


Mesoscale discussion 1773 
National Weather Service Storm Prediction Center Norman OK 
0524 PM CST Sat Nov 18 2017 


Areas affected...portions of Tennessee and northern Alabama 


Concerning...Severe Thunderstorm Watch 517... 


Valid 182324z - 190130z 


The severe weather threat for Severe Thunderstorm Watch 517 
continues. 


Summary...a squall line will continue east within and near watch 517 
this evening, with an attendant threat of a few damaging gusts and 
perhaps a tornado. The line should gradually weaken with eastward 
extent this evening, such that downstream watch issuance is not 
currently anticipated. 


Discussion...a nearly continuous line of thunderstorms is advancing 
across Tennessee and northern Alabama early this evening. Over the 
last hour, there was a localized uptick in tornado potential 
south/east of the Nashville area, with three distinct tornadic 
debris signatures in Rutherford, Wilson, and Trousdale counties. 
While cells will continue to outpace remaining low-level buoyancy, 
impressive low-level shear may still yield a quick tornado across 
middle Tennessee over the next hour. Otherwise, an isolated damaging 
wind threat will likely persist through the 01z expiration time of 
watch 517. 


Farther south, convection has at times consolidated into a few 
stronger segments over northern Alabama. Local observations have yet 
to indicate severe wind gusts, but considering the strength of 
low-level flow and presence of weak mixed-layer cape, isolated 
damage will remain possible for the next couple hours, before 
surface-based buoyancy is shunted farther south. 


.Picca.. 11/18/2017 


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


Attention...WFO...mrx...ffc...ohx...bmx...hun... 


Latitude...Lon 34048819 36588602 36588440 36278421 34978545 34268621 
33988719 33918800 34048819