Alert archive / Illinois / Tornado Warnings in 2026

Tornado Warning 47, NWS Chicago, IL

June 17, 2026Lake County, Illinois

NWS Chicago, IL issued this tornado warning at Jun 17, 2026, 9:36 PM CDT for Lake County, Illinois. It was in force for 13 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
Jun 17, 2026, 9:36 PM CDT (02:36 UTC)
Expired
Jun 17, 2026, 9:49 PM CDT
In force
13 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Lake County, IL

The radar

The Chicago radar (KLOT), 85 km from the middle of the area, began a volume at 02:36 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 00:00Z, 2.6 hours before the alert went out and 233 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-pSkew-T log-p diagram, Davenport, at 00:00Z on 2026-06-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 183 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2026-06-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -108 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
183 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
867 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
-108 m²/s²
0-3 km storm-relative helicity
-24 m²/s²
Significant tornado parameter
-0.1
Supercell composite
-1.6

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 Jun 17, 6:28 PM CDT, 3 hours 8 minutes earlier.

Area forecast discussion, Jun 17, 6:28 PM CDT, 3 hours 8 minutes before
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Hazardous weather outlook, Jun 17, 2:19 PM CDT, 7 hours 17 minutes before
Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
219 PM CDT Wed Jun 17 2026

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-181930-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-
La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-
Northern Cook-Central Cook-Southern Cook-Northern Will-
Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton-
219 PM CDT Wed Jun 17 2026 /319 PM EDT Wed Jun 17 2026/

This Hazardous Weather Outlook is for portions of north central
Illinois...northeast Illinois and northwest Indiana.

.DAY ONE...Tonight.

Weather hazards expected...

  Significant Thunderstorm Risk...with an associated:
     Level 3 of 5 Tornado Risk mainly south of the Kankakee River.
     Level 3 of 5 Damaging Wind Risk...up to 65 mph.
     Level 3 of 5 Large Hail Risk...up to half dollar size.
  Significant Flooding Risk mainly near and south of I-80.
  High Swim Risk Illinois Lake Michigan Beaches.

DISCUSSION...

Thunderstorms are expected this afternoon and early evening. The
strongest storms, currently favored south of the Kankakee River,
will be capable of producing large hail, damaging winds, and
potentially strong tornadoes. Farther north, damaging winds will
be the biggest concern with afternoon storms.

Thunderstorms today will also be capable of producing torrential
rainfall which could lead to localized flash flooding and sudden
river/stream rises.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...
  High Swim Risk Porter County Lake Michigan Beaches.
Saturday...
  Limited Thunderstorm Risk.
Sunday...
  Limited Flooding Risk.
  Limited Thunderstorm Risk.
Monday and Tuesday...
  Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

  Spotters will likely be needed this afternoon and evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the east at 50 to 60 mph.

LMZ740>745-181930-
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
219 PM CDT Wed Jun 17 2026

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...Tonight.

Weather hazards expected...

  Gale force winds and or very hazardous waves.
  Significant Thunderstorm Risk...with an associated:
     Thunderstorm Waterspout Risk
     Level 3 of 5 Thunderstorm Wind Gust Risk...up to 50 knots.
     Level 2 of 5 Hail Risk...up to quarter size.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday morning...
  Hazardous conditions for small craft are likely.
Saturday...
  Limited Thunderstorm Risk.
Sunday...
  Hazardous conditions for small craft are likely.
  Limited Thunderstorm Risk.
Monday...
  Hazardous conditions for small craft are likely.
Tuesday...
  Limited Thunderstorm Risk.

Doom

Visit us at www.weather.gov/chicago

In the hours before

Local storm report, Jun 17, 4:16 PM CDT, 5 hours 20 minutes before
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Local storm report, Jun 17, 4:23 PM CDT, 5 hours 13 minutes before
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Local storm report, Jun 17, 4:24 PM CDT, 5 hours 12 minutes before
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Local storm report, Jun 17, 4:34 PM CDT, 5 hours 2 minutes before
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Local storm report, Jun 17, 4:37 PM CDT, 4 hours 59 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 17, 7:02 PM CDTAreal Flood AdvisoryLOTCook5 hr
Jun 17, 8:31 PM CDTSevere Thunderstorm WarningLOTBoone, McHenry44 min
Jun 17, 8:58 PM CDTSpecial Marine WarningLOT108 min

Nearby

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