SPC AC 291448

   Day 1 Convective Outlook RESENT 1
   NWS Storm Prediction Center Norman OK
   0948 AM CDT Thu Jun 29 2023

   Valid 291300Z - 301200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH THIS
   EVENING FROM NORTHERN MO TO IL...SOUTHWEST IN AND WESTERN KY...

   ...SUMMARY...
   Swaths of damaging winds of 60-80 mph, large hail up to 2.5 inches
   in diameter, and a couple of tornadoes will all be possible today
   from northern Missouri into Illinois and adjacent areas of southwest
   Indiana and western Kentucky.  Other severe storms with large hail
   and damaging gusts will also be possible farther west into the
   central High Plains.

   ...MO/IL/IN/KY/TN through this evening...
   Severe storm clusters, with embedded supercells, have been moving
   eastward early this morning near KS/NE border and are expected to
   continue eastward through late morning across northern MO and
   extreme southern IA, near a stalled front.  A moist/unstable air
   mass is present along and south of the front, with MLCAPE of
   3000-4000 J/kg across northern MO, driven by boundary-layer
   dewpoints in the low-mid 70s beneath midlevel lapse rates of 9 C/km.
    These favorable thermodynamic profiles will favor continued strong
   updraft formation within the clusters as they move along the front
   and the north edge of the warmest elevated mixed layer, coincident
   with the southern fringe of the stronger midlevel westerlies. 
   Isolated very large hail to 2.5 inches in diameter will be possible
   through the morning with the supercells, while large DCAPE favors a
   continuation of severe outflow gusts (60-80 mph).  Though the
   details are still a bit uncertain, there is the potential for some
   upscale growth into a bowing MCS with swaths of significant wind
   damage from northern MO into IL and southwest IN.

   Once the expected MCS reaches central IL, the tendency should be for
   more southeastward motion with time, around the periphery of the
   midlevel ridge.  The ongoing storms from eastern IL into southwest
   IN have shown some tendency to cluster this morning, and may persist
   for a few more hours while moving southeastward toward KY. 
   Rain-cooled air from these morning storms could also provide a
   corridor for the upstream convection to move along this afternoon. 
   The main threat with the morning storms will be large hail,
   primarily with elevated supercells, though some wind damage will
   also be possible.  Damaging winds will be the main threat with the
   expected MCS this afternoon, and a couple of tornadoes may also
   occur with embedded circulations.

   ...Central High Plains this afternoon/evening...
   Post-frontal, upslope flow is established across eastern CO, and
   low-level moisture has spread west to the Front Range (aided by
   outflow from overnight storms).  Modification of the rain-cooled air
   and breaks in the low clouds will support moderate buoyancy by mid
   afternoon (MLCAPE of 1000-2000 J/kg), when thunderstorm development
   will become more probable immediately east of the higher terrain
   from CO into southeast WY. The moderate buoyancy and relatively long
   hodographs with effective bulk shear in excess of 40 kt will support
   supercells capable of producing large hail of 1-2 inches in
   diameter.  Some upscale growth into a few clusters will be possible
   this evening, with an attendant threat for isolated damaging winds. 
   Though the details are fairly uncertain, some of the evening
   convection may persist into the overnight hours across southern
   NE/northern KS with some threat for isolated large hail/wind damage.

   ..Thompson/Gleason.. 06/29/2023

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