ZCZC SPCSWOMCD ALL
ACUS11 KWNS 272359 
SPC MCD 272359 
INZ000-ILZ000-WIZ000-IAZ000-280130-

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 

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