U.S. Severe Weather Forecast (Convective Outlook)

Day Three

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Storm Prediction Center ac 230053 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0753 PM CDT sun Oct 22 2017 

Valid 230100z - 231200z 

..there is a marginal risk of severe thunderstorms across portions 
of the central and eastern Gulf Coast region... 

Isolated damaging gusts and a brief tornado or two remain possible 
tonight across parts of southern Alabama and the Florida Panhandle, 
and possibly into southwest Georgia. 

A large area of pre-frontal convection continues across parts of the 
southeast U.S. This evening. Prior rotating storms near the 
Alabama/Florida Panhandle coast have weakened, as the loss of 
diurnal heating and increasingly widespread convection have reduced 
the already modest available instability. 

With that said, ample shear -- including some turning in the lowest 
couple of km with height -- will persist across the area into the 
overnight hours. As such, will maintain a marginal risk area for 
locally gusty winds or even a brief tornado or two, and will expand 
this risk area a bit eastward -- into southwest Georgia and the remainder 
of the Florida Panhandle -- per latest cam runs suggesting an increase in 
warm-advection-driven storms over the next few hours across this 

.Goss.. 10/23/2017 


Mesoscale Discussion

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sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 221900 

Mesoscale discussion 1736 
National Weather Service Storm Prediction Center Norman OK 
0200 PM CDT sun Oct 22 2017 

Areas affected...portions of southern Alabama and th western Florida 

Concerning...severe potential...watch unlikely 

Valid 221900z - 222030z 

Probability of watch issuance...20 percent 

Summary...a few strong wind gusts and a brief/weak tornado or two 
may occur across southern Alabama into the western Florida Panhandle 
through the afternoon and early evening. A watch is not expected at 
this time. 

Discussion...heating ahead of a cluster of storms currently located 
over southwest Alabama has allowed for weak destabilization (less than 
1000 j/kg) across the Florida Panhandle into southern Alabama. While 
midlevel lapse rates are unremarkable, convection is likely being 
enhanced by an embedded mesoscale convective vortex (noted earlier in the morning over 
southeast ms). Near the apex of the bowing structure over Baldwin 
County, Alabama some stronger wind gusts will be possible as the storm 
cluster tracks east-northeast as low level lapse rates have 
steepened sufficiently. Additionally, a narrow zone of effective srh 
values around 200 m2/s2 will shift northeast across southern Alabama and 
the Florida Panhandle. A few briefly rotating cells have already been 
noted moving inland east of Mobile and this trend should continue as 
the system tracks northeast. Given the overall marginal nature of 
the thermodynamic and kinematic environment and transient/weak 
nature of any rotating cells, a watch is not expected at this time. 

.Leitman/Thompson.. 10/22/2017 

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


Latitude...Lon 30048707 30118764 30288797 30888803 31248785 31518752 
32018668 32128597 32108547 31988518 31588504 30878512 
30098554 29888573 30048707