Alert archive / Illinois / Red Flag Warnings in 2025

Red Flag Warning 3, NWS Chicago, IL

May 16, 20256 counties in Illinois

NWS Chicago, IL issued this red flag warning at May 16, 2025, 9:31 AM CDT for 6 counties in Illinois. It took effect at May 16, 2025, 10:00 AM CDT. It was in force for 9 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: May 16, 2025, 9:31 AM CDT (14:31 UTC)
In effect from: May 16, 2025, 10:00 AM CDT
Expired: May 16, 2025, 7:00 PM CDT
In force: 9 hr
Issued by: NWS Chicago, IL

Counties DeKalb County, IL, Grundy County, IL, Kane County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL

The radar

The Chicago radar (KLOT), 52 km from the middle of the area, began a volume at 14:35 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

Lincoln, IL (KILX), launched 12:00Z, 2.5 hours before the alert went out and 165 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2325 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: -13 m²/s²
0-3 km storm-relative helicity: -15 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 red flag 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 red flag warning went out at May 16, 6:24 AM CDT, 3 hours 7 minutes earlier.

Area forecast discussion, May 16, 6:24 AM CDT, 3 hours 7 minutes before

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Hazardous weather outlook, May 16, 4:23 AM CDT, 5 hours 8 minutes before

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In the hours before

Local storm report, May 16, 8:44 AM CDT, 47 minutes before

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Local storm report, May 16, 8:47 AM CDT, 44 minutes before

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Local storm report, May 16, 9:02 AM CDT, 29 minutes before

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Special weather statement, May 16, 9:31 AM CDT, 0 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
May 15, 7:08 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Ford, Livingston	54 min
May 15, 7:27 PM CDT	Special Marine Warning	LOT		93 min
May 15, 7:29 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Lake	46 min
May 15, 7:35 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kankakee, Livingston, Will	28 min
May 15, 7:45 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Ford, Grundy, Kankakee, Livingston, Will	60 min
May 15, 7:48 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Will	57 min
May 15, 7:54 PM CDT	Special Marine Warning	LOT		81 min
May 15, 8:01 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Cook, Will	29 min
May 16, 3:22 AM CDT	Small Craft Advisory	LOT		40 hr
May 16, 10:56 AM CDT	Wind Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	10 hr
May 16, 3:52 PM CDT	Blowing Dust Advisory	LOT	Boone, DeKalb, Ford, Grundy, Iroquois, Kane and 9 more	5 hr
May 16, 4:48 PM CDT	Dust Storm Warning	LOT	Ford, Iroquois, Livingston	117 min
May 16, 5:00 PM CDT	Severe Thunderstorm Warning	LOT	Ford, Iroquois	65 min
May 16, 5:32 PM CDT	Dust Storm Warning	LOT	Grundy, Kankakee, Kendall, LaSalle, Will	94 min
May 16, 6:00 PM CDT	Dust Storm Warning	LOT	Cook, DeKalb, Kendall, LaSalle, Will	75 min
May 16, 6:22 PM CDT	Special Marine Warning	LOT		113 min
May 16, 6:23 PM CDT	Dust Storm Warning	LOT	Cook, DeKalb, DuPage, Kane	79 min
May 16, 6:43 PM CDT	Severe Thunderstorm Warning	LOT	Boone, Winnebago	35 min
May 15, 8:13 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Lake, Porter	62 min

Nearby

Red Flag Warnings in Illinois, 2025 Every red flag 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.