Alert archive / Illinois / Flash Flood Warnings in 2025

Flash Flood Warning 8, NWS Chicago, IL

July 25, 2025Cook County, DuPage County, Illinois

NWS Chicago, IL issued this flash flood warning at Jul 25, 2025, 11:43 AM CDT for Cook County, DuPage County, Illinois. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 25, 2025, 11:43 AM CDT (16:43 UTC)
Expired: Jul 25, 2025, 2:45 PM CDT
In force: 3 hr
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Flood severity: None

Counties Cook County, IL, DuPage County, IL

The radar

The Chicago radar (KLOT), 35 km from the middle of the area, began a volume at 16:44 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 4.7 hours before the alert went out and 220 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 95 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 833 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before this flash flood warning went out at Jul 25, 10:47 AM CDT, 56 minutes earlier.

Area forecast discussion, Jul 25, 10:47 AM CDT, 56 minutes before

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Hazardous weather outlook, Jul 25, 11:38 AM CDT, 5 minutes before

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In the hours before

Special weather statement, Jul 25, 10:05 AM CDT, 1 hour 38 minutes before

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Local storm report, Jul 25, 10:16 AM CDT, 1 hour 27 minutes before

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Local storm report, Jul 25, 10:34 AM CDT, 1 hour 9 minutes before

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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 25, 11:31 AM CDT	Areal Flood Advisory	LOT	Cook, DuPage, Will	3 hr
Jul 25, 11:49 AM CDT	Flood Watch	LOT	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 8 more	27 hr
Jul 25, 1:50 PM CDT	Areal Flood Advisory	LOT	Cook, Will	115 min
Jul 25, 2:32 PM CDT	Areal Flood Warning	LOT	Cook, DuPage	3 hr

Nearby

Flash Flood Warnings in Illinois, 2025 Every flash flood warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.