Mesoscale Discussion 0685
   NWS Storm Prediction Center Norman OK
   0251 PM CDT Sat May 23 2020

   Areas affected...northern Illinois...southern Wisconsin...eastern
   Iowa...and far northwestern Indiana

   Concerning...Tornado Watch 207...

   Valid 231951Z - 232115Z

   The severe weather threat for Tornado Watch 207 continues.

   SUMMARY...The severe threat continues across WW 207.  Severe storms
   are expected to impact that Chicago Metro area over the next 1-2
   hours or so.

   DISCUSSION...Scattered supercells have evolved across much of WW 207
   over the past couple of hours.  A few of these storms have a history
   of producing tornadoes (particularly in eastern Iowa and near
   Whiteside, Woodford and Livingston Counties in Illinois).  The
   storms are in an environment that has become increasingly conducive
   for tornadoes, with low-level warming and moistening contributing to
   around 2000 J/kg MUCAPE.  Shear appears to be maximized near the
   warm front across northwestern and north-central Illinois, and
   supercells in that region may continue to produce tornadoes,
   damaging wind gusts, and occasional 1-inch hail stones over the next
   couple hours. 

   A separate cell over Kendall and northern Grundy counties in
   Illinois has had occasionally strong cyclonic wind signatures at
   times and may pose a damaging wind/isolated tornado threat as it
   approaches the southern Chicago Metro area over the next 1-2 hours.

   Farther south, newer cells are attempting to organize across central
   Illinois, and these trends may continue given sustained surface
   covergence along an axis from near MLI to BMI.  West of this axis,
   surface winds have veered to more of a westerly component in tandem
   with drying aloft and subsidence.  These areas have been suggested
   for clearing from WW 207 (see the most recent Watch Status product
   for more information).

   ..Cook/Hart.. 05/23/2020

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

   ATTN...WFO...IWX...IND...LOT...ILX...MKX...DVN...ARX...DMX...

   LAT...LON   43109217 43269127 43348977 43268820 42948754 42398734
               41798695 41048682 40488676 40208729 40118837 40008919
               40118988 40359010 40919035 41399061 41589119 41639169
               41999207 42519226 42799226 43109217