U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 241722 
Storm Prediction Center ac 241721 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1121 am CST Sat Feb 24 2018 

Valid 251200z - 261200z 

..there is a marginal risk of severe thunderstorms from the Texas 
coast to the southern Appalachians... 

Thunderstorms associated with a few strong wind gusts will be 
possible on Sunday across portions of the southeast. A few other 
strong to briefly severe thunderstorms may produce marginally severe 
hail near the Texas/Louisiana coasts Sunday afternoon through the 

An expansive cyclonic mid-level regime will expand over much of the 
contiguous US Sunday, owing to the translation of multiple compact 
shortwave troughs around its periphery. One of these will continue 
lifting northeast from the Great Lakes into southern Canada, 
progressively acquiring more of a negative tilt. To its southwest, 
another impulse will advance from The Four Corners region eastward 
to the Southern Plains, although it will gradually shear as it does 
so. Lastly, a strong northerly jet maximum and associated vorticity 
Max will drop south across the Pacific northwest. 

The surface response will feature a ridge building eastward over the 
mid-south, with a cold front pushing towards the East Coast and 
gradually stalling near portions of the Gulf Coast. 

..central Gulf Coast to the southern Appalachians... 
A broken/decaying band of convection will likely stretch from parts 
of the central Gulf Coast northeastward to the Appalachians Sunday 
morning. Although low/mid-level lapse rates will be poor, surface 
dew points in the low/mid 60s just ahead of the line may Foster 
around 100-300 j/kg of MLCAPE. Stronger southwesterly low-level flow 
will be departing to the northeast, but remaining 850mb winds around 
30-50 kt and any persistent linear organization may yield a 
localized gusty/ damaging wind threat, primarily Sunday morning. 

Atop a near-surface stable layer behind the composite front/outflow 
boundary, an uptick in warm-air advection will promote blossoming 
convection across southeast Texas and western Louisiana late Sunday 
into the overnight hours, with the activity slowly evolving eastward 
thereafter. 700-500mb lapse rates around 6.5-7 c/km and ample 
effective shear may promote a couple vigorous updrafts with 
mid-level rotation, and any such cell may produce a few instances of 
severe hail. 

.Picca.. 02/24/2018