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Storm Prediction Center Mesoscale Discussion 321

   Mesoscale Discussion 0321
   NWS Storm Prediction Center Norman OK
   1018 AM CDT Wed Apr 07 2021

   Areas affected...Parts of western/central Missouri and adjacent
   portions of eastern Kansas...northeastern Oklahoma and northwestern

   Concerning...Severe potential...Watch likely 

   Valid 071518Z - 071715Z

   Probability of Watch Issuance...80 percent

   SUMMARY...The initiation of strong to severe thunderstorm
   development appears possible by early this afternoon.  A severe
   weather watch likely will be needed at some point, perhaps as early
   as Noon-1 PM CDT.

   DISCUSSION...In the wake of an initial weakening mid-level
   perturbation and associated thunderstorm development, the primary
   upstream short wave impulse is in the process of pivoting eastward
   across western Kansas/Oklahoma and northwest Texas, and forecast to
   gradually take on a neutral to negative tilt across the central
   Great Plains through 18-20Z.  Between these two mid-level features,
   an area of enhanced lower/mid tropospheric warm advection may be
   contributing to renewed thunderstorm development near/above a
   remnant outflow boundary across the Lake of the Ozarks vicinity. 
   There appears at least some potential for this activity to intensify
   through mid day, while spreading northeastward through central
   Missouri, perhaps aided by inflow emanating from a destabilizing
   boundary layer to the southwest.  In the presence of at least modest
   cloud-bearing layer and shear, and steepening mid-level lapse rates,
   this may be accompanied by a risk for severe hail.

   However, the primary concern appears to be the potential for the
   initiation of vigorous thunderstorms within a corridor of
   strengthening deep-layer forcing for ascent, just ahead of the
   eastward advancing cold front approaching the western
   Missouri/Arkansas border vicinity.  While it appears possible that
   this may occur as far north as areas near/northeast of the cold
   front/outflow boundary intersection (currently south of Kansas
   City), more substantive warm sector boundary-layer warming may
   remain confined to  areas south through southeast of the Lake of the

   While the timing of this new thunderstorm development could wait
   until a bit later this afternoon, it appears possible as early as
   17-18Z.  Once this occurs, wind profiles including 30-50+ kt flow in
   the 850-500 mb layer, and modestly large and clockwise curved
   low-level hodographs, in the presence of mixed-layer CAPE in excess
   of 1000 J/kg, will be conducive to organized severe thunderstorm
   development.  This includes the potential evolution of supercell
   structures capable of producing severe hail and, gradually,
   increasing risk for damaging wind gusts and perhaps a couple of

   ..Kerr/Hart.. 04/07/2021

   ...Please see for graphic product...


   LAT...LON   35839440 37629452 38129480 39229492 39789479 39689376
               39429286 39379208 38669157 37319239 35999333 35839440