SPC AC 191950

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0250 PM CDT Fri Apr 19 2024

   Valid 192000Z - 201200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   THE SOUTHEAST...

   ...SUMMARY...
   Sporadic strong to marginally severe storms are possible over parts
   of the Southeast this afternoon into the early evening.

   Little change made to the outlook at 20Z.

   ...Southeast...
   Strong heating continues well ahead of the cold front, beneath
   modest west/northwest flow aloft. Midlevel lapse rates are poor, but
   sufficient instability coupled with the heated boundary layer and
   sufficient flow should support a few storms capable of damaging
   gusts or marginal hail with the more robust cells. Convergence near
   a weak low and a zone of mid 60s F dewpoints over central NC/eastern
   SC may yield the strongest cells.

   See mesoscale discussion 494 for more details.

   ..Jewell.. 04/19/2024

   .PREV DISCUSSION... /ISSUED 1126 AM CDT Fri Apr 19 2024/

   ...Southeast this afternoon/evening...
   Late morning water-vapor imagery shows a mid-level shortwave trough
   moving east across the southern Appalachians.  This feature will
   reach the VA/NC coast early tonight.  Farther northwest, a closed
   midlevel low will evolve into an open wave as it moves eastward over
   the Great Lakes and OH Valley.  An associated surface cold front
   will continue to move slowly southeastward from TX to the southern
   Appalachians.  Isolated to widely scattered thunderstorms will be
   possible with the disturbance over the Carolinas this afternoon. 
   Other than the front pushing into portions of AL/GA, little
   larger-scale forcing for ascent is expected farther southwest. 
   Additional storm development will be associated with the front and
   orographic lift along the spine of the Appalachians.  Overall
   weak-moderate buoyancy, modest deep-layer shear and steepening
   low-level lapse rates will support some potential semi-organized
   storms capable of producing isolated wind damage and marginally
   severe hail for a few hours this afternoon/evening.

   ...TX through tonight...
   --No change needed to previous forecast discussion--
   Weak upslope flow along a slow moving cold front will favor
   thunderstorm development over the east slopes of the Sierra Madre
   Oriental/Sierra del Burro this afternoon, with the potential for a
   couple of supercells.  However, it is not clear that storm motions
   will bring the convection across the Rio Grande, and lingering
   convective inhibition suggests storms will likely weaken if they
   manage to cross the border.  Later tonight in northwest TX, elevated
   convection will likely develop atop the frontal surface, in a warm
   advection regime downstream from a weak shortwave trough over AZ/NM.
   Some small hail may occur given lingering steep midlevel lapse rates
   and modest cloud-layer shear, but the potential for severe hail
   appears too low to warrant an outlook area.

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