Storm Prediction Center Mesoscale Discussion 1066

   Mesoscale Discussion 1066
   NWS Storm Prediction Center Norman OK
   0100 PM CDT Wed Jun 10 2026

   Areas affected...southern Wisconsin and northern Illinois

   Concerning...Severe Thunderstorm Watch 301...

   Valid 101800Z - 102000Z

   The severe weather threat for Severe Thunderstorm Watch 301
   continues.

   SUMMARY...An arcing line of thunderstorms has organized in eastern
   Iowa and will move northeastward for the next few hours through WW
   301. The threat for severe wind gusts is greatest in the delineated
   area as the system moves through.

   DISCUSSION...A line of severe thunderstorms has developed in eastern
   IA and is moving northeastward into southern WI and northern IL. A
   64-kt wind gust was reported at 1740z in Dubuque, IA associated with
   this convection. Difluence aloft and low-level convergence along the
   leading edge of a ~10-F-deficit cold pool have likely contributed to
   storm strengthening during the last hour or so. Per current
   mesoanalysis, the line of storms is moving into a CAPE axis
   stretching from central IN northwestward into southeastern MN,
   featuring 2500+ J/kg along the WI/IL border. Bulk shear magnitudes
   are around 40 kts and southwesterly, oriented perpendicular to the
   convective line. This environment will support a threat for
   continued severe wind gusts as the system moves northeast for the
   next few hours.

   ..Flournoy.. 06/10/2026

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

   ATTN...WFO...GRB...LOT...MKX...DVN...ARX...

   LAT...LON   42909185 43639117 44029026 44198911 43798795 42698784
               42008854 41379002 42289068 42909185 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN