Mesoscale Discussion 1114
   NWS Storm Prediction Center Norman OK
   0608 PM CDT Sat Jun 26 2021

   Areas affected...east-central Illinois...northwest Indiana...and
   much of Lower Michigan

   Concerning...Tornado Watch 321...322...

   Valid 262308Z - 270015Z

   The severe weather threat for Tornado Watch 321, 322 continues.

   SUMMARY...Thunderstorms continue to occur across Illinois northeast
   into Lower Michigan. The overall environment will continue to
   support strong, gusty thunderstorm winds and a couple of tornadoes
   for a few more hours likely requiring a local extension to Tornado
   Watch #321. The need for additional watches downstream, however,
   remain uncertain.

   DISCUSSION...Two main bands of convection remain ongoing across the
   region, with one moving out of west-central Illinois into northwest
   Indiana, and another moving across Lower Michigan. Although both
   bands of thunderstorms have trended more linear in nature the last
   hour, supercellular-like structures remain embedded within the line
   -- especially across Lower Michigan. 

   Across Lower Michigan, the kinematic environment ahead of the line
   remains favorable for low-level rotation, as the KDTX VAD indicates
   strong low-level shear (greater than 30 knots in the surface to 1km
   layer) within a veering-with-height wind profile (0-1KM SRH 220
   m2/s2). This favorable wind field will support at least transient
   low-level circulations for the next couple of hours.

   Farther south, thunderstorms continue to move east-northeast out of
   Illinois into northwest Indiana. Although low-level wind fields are
   less favorable than farther north, deep-layer wind shear remains
   sufficient to support thunderstorm updraft organization and the
   organizational low-level circulation. Over the next few hours, these
   thunderstorms should move east of the better deep-layer shear and a
   transition to a more outflow dominant/wind threat. However, given
   the very moist airmass in place and low LCLs, a couple of tornadoes
   will still be possible. Areas downstream of Tornado Watch 321 will
   continue to be monitored for future watch needs.

   ..Marsh.. 06/26/2021

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

   ATTN...WFO...CLE...DTX...APX...IWX...GRR...IND...LOT...ILX...

   LAT...LON   41648738 43858548 44888309 44618210 43278211 41808332
               41018457 39708684 39238811 39278855 39588914 40728831
               41648738