Storm Prediction Center Mesoscale Discussion 726

   Mesoscale Discussion 0726
   NWS Storm Prediction Center Norman OK
   0541 PM CDT Fri May 15 2026

   Areas affected...western and central Wisconsin into the western UP
   of Michigan

   Concerning...Severe potential...Watch possible 

   Valid 152241Z - 160045Z

   Probability of Watch Issuance...40 percent

   SUMMARY...The threat for large hail and/or strong to severe wind
   gusts is expected to increase this evening. Greatest storm coverage
   and attendant severe-weather risk is expected across southwest
   Wisconsin, with decreasing severe-weather potential with
   northeastward extent into the western UP of Michigan. Convective
   trends are being monitored for a possible watch.

   DISCUSSION...Early-evening visible satellite shows a growing cumulus
   field from west-central into north-central WI, ahead of a weak cold
   front moving into the northwest part of the state. The
   boundary-layer remains relatively dry with dewpoints largely in the
   40s. However, the presence of steep low/mid-level lapse rates is
   resulting in a marginally unstable air mass across west-central into
   southwest WI with MUCAPE of 500-1000 J/kg. 

   Latest short-term model guidance is suggestive that isolated to
   widely scattered thunderstorms may emerge from the deepening cumulus
   field west through north of La Crosse within the next hour or two
   with additional, more isolated storm development possible across the
   WI North Woods into the western UP of MI, along and ahead of the
   front. Despite the loss of diurnal insolation, increasing
   boundary-layer moisture content along a strengthening low-level jet
   is expected to support additional air mass destabilization this
   evening amid a kinematic environment featuring vertically veering
   wind profiles with strengthening deep-layer shear with northward
   extent across the discussion area. As such, the potential exists for
   some storm organization with an associated risk for large hail
   and/or locally strong to severe wind gusts. Convective trends are
   being monitored for a possible Severe Thunderstorm Watch.

   ..Mead/Smith.. 05/15/2026

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...MQT...GRB...MKX...DLH...ARX...MPX...

   LAT...LON   44709199 45809138 46319017 46428936 46508838 46098790
               45298848 42948944 42669002 42759077 43659102 44159158
               44709199 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN