Alert archive / Illinois / Tornado Warnings in 2026

Tornado Warning 55, NWS Chicago, IL

July 27, 2026Cook County, Illinois; Lake County, Indiana

NWS Chicago, IL issued this tornado warning at Jul 27, 2026, 12:55 PM CDT for Cook County, Illinois; Lake County, Indiana. It was in force for 38 min. 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 27, 2026, 12:55 PM CDT (17:55 UTC)
Expired: Jul 27, 2026, 1:33 PM CDT
In force: 38 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

Counties Cook County, IL, Lake County, IN

The radar

The Chicago radar (KLOT), 48 km from the middle of the area, began a volume at 17:54 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 27, 11:42 AM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 5.9 hours before the alert went out and 194 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: 3689 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 801 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 127 m²/s²
0-3 km storm-relative helicity: 158 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 4.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this tornado 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 tornado warning went out at Jul 27, 11:04 AM CDT, 1 hour 51 minutes earlier.

Area forecast discussion, Jul 27, 11:04 AM CDT, 1 hour 51 minutes before

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Hazardous weather outlook, Jul 27, 11:08 AM CDT, 1 hour 47 minutes before

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In the hours before

Local storm report, Jul 27, 12:04 PM CDT, 51 minutes before

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Local storm report, Jul 27, 12:07 PM CDT, 48 minutes before

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Local storm report, Jul 27, 12:34 PM CDT, 21 minutes before

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Local storm report, Jul 27, 12:49 PM CDT, 6 minutes before

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Local storm report, Jul 27, 12:51 PM CDT, 4 minutes before

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Local storm report, Jul 27, 12:53 PM CDT, 2 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 27, 2:10 AM CDT	Heat Advisory	LOT	Boone, Cook, DuPage, Iroquois, Kane, Kankakee and 4 more	14 hr
Jul 27, 2:10 AM CDT	Extreme Heat Warning	LOT	Boone, DeKalb, Ford, Grundy, Iroquois, Kane and 9 more	19 hr
Jul 27, 3:02 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Grundy, Kane, Kendall, LaSalle and 5 more	5 hr
Jul 27, 3:56 AM CDT	Small Craft Advisory	LOT		51 hr
Jul 27, 3:57 AM CDT	Beach Hazards Statement	LOT	Cook, Lake	54 hr
Jul 27, 10:42 AM CDT	Special Marine Warning	LOT		3 hr
Jul 27, 10:57 AM CDT	Severe Thunderstorm Warning	LOT	Cook, Kane, Lake, McHenry	78 min
Jul 27, 11:09 AM CDT	Severe Thunderstorm Warning	LOT	DuPage	51 min
Jul 27, 11:16 AM CDT	Special Marine Warning	LOT		119 min
Jul 27, 11:25 AM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Lake, McHenry	80 min
Jul 27, 11:39 AM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook, DuPage, Will	81 min
Jul 27, 11:55 AM CDT	Tornado Warning	LOT	DuPage	33 min
Jul 27, 12:02 PM CDT	Flash Flood Warning	LOT	Cook, DuPage	4 hr
Jul 27, 12:10 PM CDT	Tornado Warning	LOT	Cook, DuPage, Will	46 min
Jul 27, 12:14 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook	33 min
Jul 27, 12:15 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook, Will	75 min
Jul 27, 12:26 PM CDT	Areal Flood Advisory	LOT	Lake	114 min
Jul 27, 12:31 PM CDT	Tornado Warning	LOT	Will	13 min
Jul 27, 12:37 PM CDT	Severe Thunderstorm Warning	LOT	Cook	53 min
Jul 27, 12:41 PM CDT	Severe Thunderstorm Warning	LOT	Lake	11 min
Jul 27, 12:49 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Cook, Will	41 min
Jul 27, 12:50 PM CDT	Tornado Warning	LOT	Cook, Will	43 min
Jul 27, 1:01 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Kankakee	74 min
Jul 27, 1:05 PM CDT	Flash Flood Warning	LOT	Cook, Will	4 hr
Jul 27, 1:08 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Kankakee, Will	33 min
Jul 27, 1:28 PM CDT	Severe Thunderstorm Warning	LOT	Cook	20 min
Jul 27, 1:37 PM CDT	Severe Thunderstorm Warning	LOT	Cook	26 min
Jul 27, 1:39 PM CDT	Special Marine Warning	LOT		47 min
Jul 27, 1:40 PM CDT	Special Marine Warning	LOT		46 min
Jul 27, 2:56 PM CDT	Special Marine Warning	LOT		94 min
Jul 27, 3:09 PM CDT	River Flood Warning	LOT	Cook	11 hr
Jul 27, 3:13 PM CDT	Tornado Warning	LOT	Kendall, Will	47 min
Jul 27, 3:26 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kendall, Will	64 min
Jul 27, 3:35 PM CDT	Severe Thunderstorm Warning	LOT	Lake	40 min
Jul 27, 3:36 PM CDT	Flash Flood Warning	LOT	Kendall, Will	3 hr
Jul 27, 3:38 PM CDT	Special Marine Warning	LOT		114 min
Jul 27, 3:48 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Grundy, Kankakee, Livingston, Will	57 min
Jul 27, 4:08 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	82 min
Jul 27, 4:18 PM CDT	Tornado Warning	LOT	Iroquois, Kankakee	42 min
Jul 27, 4:32 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Iroquois	73 min
Jul 27, 4:45 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Kankakee	30 min
Jul 27, 4:53 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Will	67 min
Jul 27, 5:14 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Iroquois	76 min
Jul 27, 5:23 PM CDT	Tornado Warning	LOT	Iroquois	37 min
Jul 27, 5:28 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage	17 min
Jul 27, 6:05 PM CDT	Tornado Warning	LOT	Iroquois	16 min
Jul 27, 1:20 PM CDT	Tornado Warning	LOT	Porter	40 min
Jul 27, 1:26 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Jasper, Porter	49 min
Jul 27, 1:45 PM CDT	Severe Thunderstorm Warning	LOT	Benton, Jasper, Newton	45 min
Jul 27, 1:57 PM CDT	Flash Flood Warning	LOT	Lake	4 hr
Jul 27, 4:19 PM CDT	Severe Thunderstorm Warning	LOT	Lake, Porter	71 min
Jul 27, 5:30 PM CDT	Severe Thunderstorm Warning	LOT	Lake	45 min

Nearby

Tornado Warnings in Illinois, 2026 Tornado Warnings in Indiana, 2026 Every tornado warning in 2026 Tornadoes in 2026

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.