US Mesoscale Discussions

Storm Prediction Center Mesoscale Discussion 1291

   Mesoscale Discussion 1291
   NWS Storm Prediction Center Norman OK
   0342 PM CDT Sun Jun 16 2024

   Areas affected...northern Illinois and adjacent southeastern

   Concerning...Severe Thunderstorm Watch 424...

   Valid 162042Z - 162245Z

   The severe weather threat for Severe Thunderstorm Watch 424

   SUMMARY...There appears increasing risk for potentially damaging
   wind gusts as an organizing cluster of storms accelerates into the
   Greater Chicago and Milwaukee metro areas through 5-6 PM CDT.

   DISCUSSION...Based on 20Z surface observations, the
   convectively-generated cold pool remains modest in strength. 
   However, a notable intensification of convection along its leading
   edge appears underway, and this seems likely to be sustained
   east-northeastward into the southern Lake Michigan vicinity through
   22-23Z, aided by easterly low-level inflow of unstable air
   characterized by CAPE in excess of 1500 J/kg.  Boundary-layer mixing
   has lowered surface dew points into the 60s F, but lapse rates have
   become rather steep with temperatures rising through the lower/mid
   90s F.  With some further increase in temperature differential
   across the gust front, and strengthening rear inflow, it appears
   that the forward propagation of the organizing cluster may undergo
   acceleration toward the Greater Chicago and, perhaps, Greater
   Milwaukee metro areas through 22-23Z, accompanied by increasing risk
   for potentially damaging wind gusts.

   ..Kerr.. 06/16/2024

   ...Please see for graphic product...


   LAT...LON   41478742 41018848 40978915 41038940 41418926 41958925
               42338947 42908868 42738758 42058689 41478742 

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