SPC AC 150738

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0238 AM CDT Wed May 15 2024

   Valid 171200Z - 181200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FAR SOUTHEAST
   TEXAS INTO MUCH OF LOUISIANA...CENTRAL/SOUTHERN MISSISSIPPI...AND
   WESTERN...

   ...SUMMARY...
   Severe thunderstorms are possible from far southeast Texas into much
   of Louisiana, central/southern Mississippi, and western Alabama on
   Friday.

   ...East/Southeast TX through the Lower MS Valley and into the TN
   Valley/Southeast...
   A southern-stream shortwave trough is forecast to extend from
   central OK southwestward through Far West TX and into northeast
   Mexico early Friday morning. A belt of moderate to strong
   southwesterly flow aloft will likely extend through the base of this
   shortwave, from northeast Mexico through east/southeast TX and the
   Lower MS Valley into the TN Valley/Southeast. This belt of stronger
   flow will persist throughout much of the day as its parent shortwave
   trough shifts eastward/northeastward.

   The surface pattern is a bit more uncertain, with the progression of
   an early morning MCS potentially influencing conditions
   significantly. General expectation is for moderate to strong
   buoyancy to develop during the afternoon and evening, ahead of the
   weak front associated with the approaching shortwave trough. Strong
   vertical shear will be in place as well, supporting the potential
   for organized storms, including supercells. Upscale growth into a
   convective line is possible as well. Highest probability for severe
   currently appears to be from far southeast TX across much of LA and
   central/southern MS into western AL. Some severe potential could
   extend farther north into the TN Valley, but uncertainty regarding
   moisture return and the track of the surface low precludes
   introducing anything higher the Marginal/5% severe probabilities
   with this outlook.

   ...Northern Plains into the Upper MS Valley...
   A northern-stream shortwave trough is forecast to move through the
   northern Rockies on Friday, reaching the northern High Plains by
   early Saturday morning. An attendant surface low will move eastward
   just ahead of the shortwave, moving across southern Saskatchewan and
   Manitoba. Surface lee troughing will sharpen ahead of the shortwave
   trough as well, with cyclogenesis anticipated across western SD. A
   few high-based thunderstorms may develop along the cold front
   connecting these two surface low. Strong outflow is possible within
   these storms, although low coverage and limited magnitude precludes
   introducing any severe probabilities with this forecast.

   ..Mosier.. 05/15/2024

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z