SPC AC 031256

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0756 AM CDT Mon Jun 03 2024

   Valid 031300Z - 041200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
   FOR OK/NORTH TX EASTWARD TO THE ARK-LA-MISS...

   ...SUMMARY...
   Strong to severe thunderstorms are possible from much of the
   Mississippi Valley into the Ozark Plateau and southern Plains today.
   A more concentrated area of severe thunderstorm risk may become
   focused across southwest and southern Oklahoma this evening into
   early tonight.

   ...Southern Plains to the lower MS Valley through tonight...
   As has been the case for the past several nights across the Great
   Plains, nocturnal convection has persisted into the morning in a few
   different clusters.  The most substantial of these has been an MCS
   with a history of 60-80 mph measured gusts earlier this morning
   across southwest KS.  This MCS has weakened more recently, but some
   form of the convection should continue east-southeastward through
   the morning toward central OK, along the north edge of the MUCAPE up
   to 3000 J/kg.  Confidence in the details of the MCS evolution is
   low, though there is some potential for the storms to potentially
   reach the Ark-La-Tex and the western half of AR by this evening, and
   perhaps as far east as the Ark-La-Miss region early tonight before
   the storms weaken.

   Outflow trailing southwestward from these morning storms will likely
   provide a mesoscale focus for supercell development this afternoon
   along the stalling boundary in the vicinity of southwest OK border. 
   Here, rich low-level moisture (boundary-layer dewpoints in the
   low-mid 70s) and surface heating will drive MLCAPE to near 5000 J/kg
   with weakening convective inhibition after peak surface heating.  At
   least isolated thunderstorm development is expected late this
   afternoon/evening near the outflow/dryline intersection (close to
   the southwest OK/southeast TX Panhandle border), and storms will
   subsequently move southeastward along the stalled boundary.  Despite
   rather modest flow aloft, an enhanced easterly component to the
   low-level flow near the outflow boundary will contribute to
   sufficient hodograph length/curvature for right-moving supercells. 
   The extreme buoyancy, sufficiently low LCL heights and some
   enhancement to low-level shear along the boundary will favor the
   potential for a couple of tornadoes, in addition to isolated very
   large hail (up to 3 inches in diameter) and damaging gusts.  These
   evening storms, or additional storms associated with warm advection,
   will be possible tonight across southern and central OK.

   ...Southern WI and vicinity this afternoon/evening...
   A remnant MCV over IA will move northeastward over WI this
   afternoon, atop a subtle surface front/trough and differential
   heating zone.  As surface temperatures warm to 75-80 F in cloud
   breaks and boundary-layer dewpoints increase to 65-70 F, moderate
   buoyancy (MLCAPE near 1500 J/kg) will develop in the warm sector
   from eastern IA/northwest IL into southern WI.  Despite some
   localized enhancement to vertical shear with the remnant MCV,
   deep-layer vertical shear will generally remain weak (primarily
   supporting multicell clusters and low-end supercell structures). 
   Thus, expect a few clusters of storms capable of producing
   occasional wind damage and isolated large hail of 1-1.5 inches in
   diameter for a few hours this afternoon/evening.

   ..Thompson/Grams.. 06/03/2024

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