Mesoscale Discussion 1490
NWS Storm Prediction Center Norman OK
1124 AM CDT Sat Jul 04 2026
Areas affected...north-central Illinois into Indiana
Concerning...Severe potential...Watch possible
Valid 041624Z - 041930Z
Probability of Watch Issuance...60 percent
SUMMARY...A cluster of strong to severe storms is expected to
develop after 18Z over central and north-central Illinois, moving
into Indiana later this afternoon. Damaging gusts will be possible.
DISCUSSION...Visible satellite and surface observations show a low
and MCV moving out of eastern IA into northern IL. Analyzed
streamlines show substantial convergence into northwest IL
currently, with modest southerly winds ahead of this feature aiding
warming/destabilization. Cooler air exists over southeast WI and
northeast IL, but areas of heating and gradual warm advection may
allow destabilization close to parts of the Chicago metro area.
The 12Z ILX sounding shows high PWAT over 1.75", along with 25-35 kt
midlevel westerlies. Overall storm motions will be toward the east,
with a tendency for southeastward propagation. This could bring wind
potential toward the Indianapolis area during the early evening.
..Jewell/Hart.. 07/04/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...IND...LOT...ILX...DVN...
LAT...LON 40118965 40489010 41258940 41948909 41818777 41698682
40928653 40398654 39788684 39608762 39618768 40118965
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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