Storm Prediction Center Mesoscale Discussion 1101

   Mesoscale Discussion 1101
   NWS Storm Prediction Center Norman OK
   0638 PM CDT Thu Jun 11 2026

   Areas affected...Southwest Lower Michigan...central and northern
   Indiana...far western Ohio and eastern Illinois.

   Concerning...Severe potential...Watch needed soon 

   Valid 112338Z - 120115Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A tornado watch will be issued within the hour east of
   tornado watch 313.

   DISCUSSION...Instability continues to increase across northern
   Indiana and into southern Michigan as the outflow boundary from
   earlier convection continues to modify/lift northward. South of this
   boundary, an environment similar to the 21Z ILX RAOB is present with
   near 4000 J/kg MLCAPE. Along and north of the boundary instability
   is more limited, but shear is very strong with 250 m2/s2 0-1 km SRH
   and strong low-level clockwise curvature per an 22Z RAOB launched by
   the Valparaiso University Meteorological Department in Valparaiso,
   Indiana. Along and south of this boundary, widespread damaging winds
   are likely along a squall line this evening. In addition, embedded
   QLCS tornadoes and occasional embedded supercell tornadoes will be
   possible through the evening given the presence of strong low-level
   shear.

   The last few runs of the HRRR hint at some pre-frontal convection
   ahead of the line across central/northern Indiana later this
   evening, likely in response to the strengthening low-level jet. It
   is uncertain whether this will occur, or have sufficient time to
   mature before being caught by the main squall line, but these storms
   could pose an additional supercell tornado threat later this
   evening.

   ..Bentley/Smith.. 06/11/2026

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

   ATTN...WFO...ILN...DTX...IWX...GRR...IND...LOT...ILX...

   LAT...LON   39568995 40378866 40948771 41958718 42708671 43028575
               43028496 42878447 42168429 41088455 40078471 39638548
               39258687 39568995 

   MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
   MOST PROBABLE PEAK WIND GUST...75-90 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN