Storm Prediction Center Mesoscale Discussion 1345

   Mesoscale Discussion 1345
   NWS Storm Prediction Center Norman OK
   1057 AM CDT Wed Jun 18 2025

   Areas affected...eastern IL...western/northern IN...far southwest
   Lower MI

   Concerning...Tornado Watch 432...

   Valid 181557Z - 181800Z

   The severe weather threat for Tornado Watch 432 continues.

   SUMMARY...Severe threat should increase substantially through
   mid-afternoon as an arc of storms intensifies to the east-northeast
   from central Illinois. A few tornadoes, scattered damaging winds,
   and isolated severe hail will remain possible. Downstream tornado
   watch issuance is anticipated to the northeast of Ww 432.

   DISCUSSION...While the primary surface cyclone and attendant MCV are
   centered near the northeast MO/west-central IL border area, a
   downstream arc of increasing deep convection is expected to
   strengthen across central IL. With mid 70s surface dew points common
   across southern IL/IN, a pronounced MLCAPE gradient is setting up
   from south to north. A compact belt of strong 700-500 mb
   southwesterlies in the LSX VWP, recently sampled by the ILX VWP as
   well, should support a broken band of supercells within this leading
   arc as it spreads northeast. The potential for tornadoes has
   increased and a 10 percent tornado probability will be added in the
   1630Z D1 Outlook. The LSX VWP also indicates low-level SRH
   diminishing behind this leading arc, but some tornado threat should
   linger near the immediate MCV/surface low.

   ..Grams/Hart.. 06/18/2025

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

   ATTN...WFO...IWX...GRR...IND...LOT...ILX...LSX...DVN...

   LAT...LON   38828765 38718868 38918905 39628955 39998986 40269003
               40668975 41248906 41698817 42238631 42058597 41788572
               41378574 40628592 40218623 39618689 38828765 

   MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN