US Mesoscale Discussions

Storm Prediction Center Mesoscale Discussion 381

   Mesoscale Discussion 0381
   NWS Storm Prediction Center Norman OK
   0212 PM CDT Sun Apr 07 2024

   Areas of southeast Missouri...southern
   Illinois...northeast Arkansas and adjacent portions of western

   Concerning...Severe potential...Watch possible 

   Valid 071912Z - 072145Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Scattered strong thunderstorm activity is expected to
   continue to develop through 4-6 PM CDT.  This may include the
   evolution of a couple widely scattered supercells, posing a risk for
   severe hail and potential for a tornado or two.

   DISCUSSION...While a weak cold front advancing eastward toward the
   mid/lower Mississippi Valley is becoming increasingly diffuse, a
   rather sharp low-level moisture gradient is being maintained along a
   lingering wind shift now slowly advancing across portions of east
   central and southeastern Missouri through central Arkansas.  Ahead
   of the wind shift, surface dew points are increasing through the
   lower/mid 60s in a narrow plume across eastern Arkansas, and the
   leading edge of this moisture return may nose across the Missouri
   Bootheel into southern Illinois through 21-23Z.  

   Although ascent associated with weak low-level warm advection within
   this regime continues to contribute to considerable cloud cover,
   breaks in the overcast are allowing for some insolation beneath the
   southeastern periphery of a broad pocket of cool mid-level air which
   has overspread much of the northern Great Plains into upper
   Mississippi Valley.  This is contributing to weak destabilization
   and bands of deepening convective development.  With further
   destabilization through late afternoon (mixed-layer CAPE forecast to
   exceed 500 J/kg and perhaps locally approach 1000 J/kg), convective
   development appears likely to continue to gradually intensify. 

   Although wind fields to the southeast of a broad and initially deep,
   but filling, surface cyclone centered over northeastern Nebraska are
   forecast to undergo notable weakening through early evening,
   south-southwesterly to west-southwesterly flow in the 850-500 mb
   layer appears likely to remain on the order of 30-60+ kt across the
   destabilizing air mass.  With increasing low-level inflow of
   unstable air, the evolution of widely scattered supercell structures
    seems possible by late afternoon.  These may eventually become
   capable of producing marginally severe hail, and at least some risk
   for producing a tornado, before diminishing this evening.

   ..Kerr/Goss.. 04/07/2024

   ...Please see for graphic product...


   LAT...LON   35209125 37139059 38638966 38708832 37968820 36068891
               35328989 35209125 

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