Mesoscale Discussion 0166
   NWS Storm Prediction Center Norman OK
   0559 PM CST Tue Feb 27 2024

   Areas affected...Northern Illinois

   Concerning...Tornado Watch 25...

   Valid 272359Z - 280130Z

   The severe weather threat for Tornado Watch 25 continues.

   SUMMARY...Severe thunderstorm clusters, including supercells with
   the possibility for tornadoes, will spread/develop east toward
   southern Lake MI over the next several hours.

   DISCUSSION...Secondary surface low appears to be evolving along the
   front over southeast IA/northwest IL. A multifaceted corridor of
   low-level convergence arcs east from this feature across northern
   IL. Over the last few hours significant boundary-layer moistening
   has advanced as far north as Rockford where surface dew points are
   now in the lower 50s. Over the next few hours, low-level flow may
   back slightly downstream, in advance of the low. This should aid
   convergence along the warm front currently draped from Henry-La
   Salle-Iroquois County IL.

   Several maturing thunderstorm clusters are currently located from
   south of Davenport IA to DeKalb IL. Significant rotation is now
   observed with several supercells embedded along this corridor. Given
   the steep lapse rates observed, very large hail can be expected with
   this activity. Tornado threat is also increasing as environmental
   parameters become more favorable along the warm front. This activity
   should spread toward the southern portions of Lake MI, including the
   metro Chicago area.

   ..Darrow.. 02/27/2024

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

   ATTN...WFO...LOT...ILX...MKX...DVN...

   LAT...LON   42069020 42678699 41248699 40639022 42069020