Official

SPC MD 299

MD 0299 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR PORTIONS OF NORTHEAST ILLINOIS…NORTHERN INDIANA…SOUTHWEST LOWER MICHIGAN


Mesoscale Discussion 0299
NWS Storm Prediction Center Norman OK
1243 PM CDT Sun Mar 30 2025

Areas affected...Portions of northeast Illinois...northern
Indiana...southwest Lower Michigan

Concerning...Severe potential...Watch likely 

Valid 301743Z - 301945Z

Probability of Watch Issuance...80 percent

SUMMARY...Damaging winds will be the primary hazard with storms this
afternoon. Isolated large hail may also occur. The tornado threat is
less certain, but a few line-embedded circulations do appear
possible.

DISCUSSION...Temperatures in northeast Illinois into northern
Indiana have risen into the low/mid 70s F. Cumulus along the cold
front has deepened in northeast Illinois and storms appear likely to
initiate as the shortwave trough moves through the region. In
addition, some portion of the activity in central Illinois will move
northeastward into parts of northern Indiana.

Destabilization should continue through the afternoon, particularly
in northern Indiana into southern Lower Michigan. MLCAPE in
northeast Illinois is 500-750 J/kg and it is not clear how much more
buoyancy will develop before the fast moving storms move through.
The greatest risk will be strong/damaging wind gusts with what is
expected to be one or more linear segments. Large hail is possible,
but should be more spatially limited given storm mode. The tornado
threat is less clear this far north. Low-level winds are veered and
effective SRH values from objective mesoanalysis and regional VAD
profiles is not large. However, the QLCS tornado threat is nonzero
as line-embedded circulations are certainly possible. A watch is
likely this afternoon.

..Wendt/Smith.. 03/30/2025

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

ATTN...WFO...IWX...GRR...LOT...ILX...

LAT...LON   40848645 40448774 40378826 40878876 41708893 41928887
            42328804 42768640 42598582 41918550 40948614 40848645 

MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN

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