U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 230536 
Storm Prediction Center ac 230535 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1235 am CDT Mon Apr 23 2018 

Valid 231200z - 241200z 

..there is a marginal risk of severe thunderstorms from eastern 
Georgia into central South Carolina... 

A few strong to severe storms are possible across parts of Georgia 
and South Carolina. Isolated thunderstorms will also be possible 
over parts of the High Plains. 

..synopsis and discussion... 
An upper low will drift eastward from the lower MS valley toward the 
Tennessee and Ohio valleys, with a weak surface trough extending from western 
Tennessee into Georgia by late afternoon. A warm front will lift north across 
eastern Georgia into central SC, with mid 60s f dewpoints to the south. 
Meanwhile, a cold front will extend from the Alabama/Georgia border southward 
across the western Florida Panhandle. 

Precipitation and clouds are expected across the marginal risk area 
during the morning, driven by low-level warm advection and a 40+ kt 
southeasterly low-level jet. Most of the early storms are expected 
to be north of the warm front, with little severe threat. 

Later in the day, strong heating over Georgia will result in steep 
low-level lapse rates and perhaps 1000 j/kg MUCAPE, with scattered 
afternoon storms likely. Wind profiles will be mainly unidirectional 
west of the warm front, with cellular activity producing marginal 
hail or wind. A few storms could become supercells near the warm 
front where low-level srh will be greatest, but may quickly become 
elevated as storm motions will be to the northeast. Still, a low 
threat of a tornado exists, along with the marginal hail and wind. 

.Jewell/Gleason.. 04/23/2018 


Mesoscale Discussion

acus11 kwns 230011 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 230011 

Mesoscale discussion 0284 
National Weather Service Storm Prediction Center Norman OK 
0711 PM CDT sun Apr 22 2018 

Areas affected...portions of the Florida Panhandle...extreme southeast 
Alabama...extreme southwest Georgia 

Concerning...Tornado Watch 56... 

Valid 230011z - 230115z 

The severe weather threat for Tornado Watch 56 continues. 

Summary...the greatest short-term tornado risk will likely focus 
near the maritime/warm front in the Alabama-GA-FL tri-state region. 

Discussion...latest subjective surface analysis places a warm front 
from Apalachee Bay northwest near Tallahassee and into southeast Alabama. 
A very moist airmass with weak buoyancy (590 j/kg MLCAPE per the 
evening tlh raob) characterizes this area. Surface dewpoints are in 
the upper 60s-70 degrees f range along and south of the boundary and 
in the middle 60s east and northeast of the boundary. As stronger 
updrafts move northeast within the warm conveyer convective plume 
and interact within the warm frontal zone, the backed low-level flow 
and augmented hodographs will support a greater threat for low-level 
mesocyclones and the possibility for a couple of weak/short-track 
supercell tornadoes. The main concern/uncertainty at this time is 
the cessation of the tornado risk and the watch expiration time. 
Either a local watch extension-in-time or a watch replacement may 
need to be considered in the next 60-90 minutes since the watch 
expires at 9pm CDT/10pm EDT. 

.Smith.. 04/23/2018 

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


Latitude...Lon 30368468 30998532 31458504 31418455 30648417 30368468