286
ACUS11 KWNS 241345
SWOMCD
SPC MCD 241344
ILZ000-WIZ000-IAZ000-241545-

Mesoscale Discussion 0927
NWS Storm Prediction Center Norman OK
0844 AM CDT Fri May 24 2024

Areas affected...far southern WI...northern IL

Concerning...Severe Thunderstorm Watch 301...

Valid 241344Z - 241545Z

The severe weather threat for Severe Thunderstorm Watch 301
continues.

SUMMARY...A severe bow echo will continue moving east at 40 mph
across far southern WI and northern IL through 1030 am CDT.  Severe
gusts 60-75 mph are likely with the more intense bowing segments of
the squall line and a couple of mesovortex tornadoes are possible.

DISCUSSION...A long-lived bow echo is currently moving across the MS
River this morning.  The airmass downstream of the squall line
continues to destabilize despite an anvil-level cloud shield
spreading east.  Surface analysis indicates a warm front is
advancing northward from north-central IN through far northeast IL
and into southern WI.  South of the boundary, surface dewpoints are
rising into the lower to mid 60s deg F and temperatures are in the
upper 60s.  Further heating will likely result in temperatures
rising into the mid-upper 60s over far southern WI and into the
low-mid 70s across northern IL prior to squall line passage.

Water-vapor imagery shows a progressive negatively tilted mid-level
shortwave trough/mid-level low over the Upper Midwest.  The very
mature character of the Rear Inflow Jet sampled via the Des Moines
and Davenport WSR-88Ds VADs suggest the strongly dynamic nature of
the squall line and destabilizing boundary layer ahead of it, will
combine to support a likely continuation of severe-gust risk into
the greater Chicago metro during the 1030am to 1200pm timeframe.
Severe gusts primarily in the 60-75 mph are likely in the next 1-2
hours as this activity moves east across northern IL/far southern
WI.  A couple of mesovortices capable of severe gusts and/or brief
tornadoes are possible.

..Smith.. 05/24/2024

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

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

LAT...LON   42689028 42848860 42218837 41538832 41158851 41158935
            41189010 41659008 41989014 42099036 42359024 42689028