Storm Prediction Center Mesoscale Discussion 1395

   Mesoscale Discussion 1395
   NWS Storm Prediction Center Norman OK
   1034 AM CDT Tue Jun 30 2026

   Areas affected...Northeast Wisconsin to Northwest Lower Michigan

   Concerning...Severe Thunderstorm Watch 422...

   Valid 301534Z - 301730Z

   The severe weather threat for Severe Thunderstorm Watch 422
   continues.

   SUMMARY...Isolated occurrences of large hail and locally damaging
   wind gusts remain possible across mainly the southern half of Severe
   Thunderstorm Watch 422. Some remnant of the ongoing storms could
   move into parts of northwest lower Michigan by early afternoon and
   pose a severe weather threat.

   DISCUSSION...Trends in visible satellite and radar data indicate
   periodic intensification-weakening cycles with the storms ongoing
   west through southwest of Green Bay. The storms are moving through a
   moist and moderate to strongly unstable environment with MLCAPE as
   high as 3000-3500 J/kg, per latest objective analysis. The storm
   behavior thus far suggests they may still be slightly elevated and
   are not fully realizing the available buoyancy. The current KGRB VWP
   is sampling largely westerly tropospheric winds with 40-50 kt speeds
   noted above 5-6 km.

   The environment described above is supportive of storm organization,
   assuming updrafts can become rooted in the boundary layer. Large
   hail is the primary concern in the short term, but the potential for
   damaging winds may increase with time owing to the unidirectional
   wind profiles and potential for downshear propagation along an
   organizing cold pool.

   Some convection-allowing model guidance indicates the WI storms
   moving across Lake MI into northwest lower MI by early afternoon
   with an associated damaging wind threat. However, considerable
   cloudiness currently exists across lower MI this morning, which is
   slowing the destabilization process.

   ..Mead.. 06/30/2026

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

   ATTN...WFO...APX...GRR...MQT...GRB...MKX...

   LAT...LON   44468939 45128908 45138734 44958580 44268563 43868626
               43878785 44108872 44228909 44468939 

   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN