Mesoscale Thunderstorm development Discussion affecting the Chicago area north of Interstate-80 into southern Wisconsin

 Mesoscale Discussion 0313
   NWS Storm Prediction Center Norman OK
   0628 PM CDT Thu Mar 23 2017

   Areas affected...Southeast Wisconsin and Northern Illinois

   Concerning...Severe potential...Watch unlikely 

   Valid 232328Z - 240100Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Thunderstorms will continue this evening. isolated large
   hail will be the primary threat.

   DISCUSSION...Elevated thunderstorms are developing across the upper
   Midwest on the nose of the 850-millibar moist, warm-air advection.
   These thunderstorms are on the eastern edge of the steeper mid-level
   lapse rates (between 7-8 C/km) and will continue to move generally
   eastward toward a more stable environment over/near Lake Michigan.
   Until then, over the next 1-2 hours, isolated large hail will be
   possible with the strongest thunderstorm cores. Given the limited
   spatio-temporal nature of the remaining threat, a watch is currently
   not anticipated.