Alert archive / Illinois / Flash Flood Warnings in 2026

Flash Flood Warning 8, NWS Chicago, IL

April 14, 2026Cook County, DuPage County, Illinois

NWS Chicago, IL issued this flash flood warning at Apr 14, 2026, 10:51 PM 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: Apr 14, 2026, 10:51 PM CDT (03:51 UTC)
Expired: Apr 15, 2026, 2:05 AM 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 03:54 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 3.9 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: 1575 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 1493 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 251 m²/s²
0-3 km storm-relative helicity: 371 m²/s²
Significant tornado parameter: 1.9
Supercell composite: 19.9

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 Apr 14, 6:36 PM CDT, 4 hours 15 minutes earlier.

Area forecast discussion, Apr 14, 6:36 PM CDT, 4 hours 15 minutes before

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Hazardous weather outlook, Apr 14, 4:04 PM CDT, 6 hours 47 minutes before

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
404 PM CDT Tue Apr 14 2026

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-152115-
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-
404 PM CDT Tue Apr 14 2026 /504 PM EDT Tue Apr 14 2026/

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

.DAY ONE...Tonight.

Weather hazards expected...

  Elevated Thunderstorm Risk...with an associated:
     Level 3 of 5 Tornado Risk.
     Level 3 of 5 Large Hail Risk...up to Tennis Ball size.
     Level 3 of 5 Damaging Wind Risk...up to 75 mph.
     Level 2 of 4 Flash Flood Risk.

DISCUSSION...

An all hazardous significant severe weather threat exists across
northern IL this evening, particularly along and north of I-88.

Multiple rounds of heavy rain producing storms moving over the
same areas may also result in areas of flash flooding tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wednesday...
  Elevated Thunderstorm Risk...with an associated:
     Level 2 of 5 Severe Thunderstorm Risk.
     Level 2 of 4 Flash Flood Risk.
Thursday...
  Limited Thunderstorm Risk southeast of Interstate-55.
Friday Night into Saturday morning...
  Limited Thunderstorm Risk...with an associated:
     Level 2 of 5 Severe Thunderstorm Risk.
     Level 1 of 4 Flash Flood Risk.
Sunday Night...
  Significant Frost Risk.

DISCUSSION...

Additional waves of storms are expected at times through the end
of the week, some of which could be severe and produce heavy rain
and localized flash flooding.

.SPOTTER INFORMATION STATEMENT...

  Spotters will likely be needed this evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the east northeast at 45 mph.

LMZ740>745-152115-
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-
404 PM CDT Tue Apr 14 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...

  Elevated Thunderstorm Risk...with an associated:
     Level 3 of 5 Thunderstorm Wind Gust Risk...up to 55 kt.
     Level 3 of 5 Hail Risk...up to Tennis Ball size.
     Level 3 of 5 Thunderstorm Waterspout Risk.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wednesday...
  Elevated Thunderstorm Risk...with an associated:
     Level 2 of 5 Severe Thunderstorm Risk.
Friday and Saturday...
  Hazardous conditions for small craft are likely.
  Limited Thunderstorm Risk.
Sunday...
  Hazardous conditions for small craft are likely.

KJB

Visit us at www.weather.gov/chicago

In the hours before

Local storm report, Apr 14, 10:03 PM CDT, 48 minutes before

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Local storm report, Apr 14, 10:08 PM CDT, 43 minutes before

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Local storm report, Apr 14, 10:10 PM CDT, 41 minutes before

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Local storm report, Apr 14, 10:27 PM CDT, 24 minutes before

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Local storm report, Apr 14, 10:28 PM CDT, 23 minutes before

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Local storm report, Apr 14, 10:45 PM CDT, 6 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
Apr 14, 7:11 PM CDT	Flood Watch	LOT	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 10 more	30 hr
Apr 14, 7:59 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Ogle, Winnebago	61 min
Apr 14, 8:12 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Boone, McHenry	78 min
Apr 14, 8:20 PM CDT	Tornado Warning	LOT	Winnebago	25 min
Apr 14, 8:29 PM CDT	Special Marine Warning	LOT		2 hr
Apr 14, 8:37 PM CDT	Flash Flood Warning	LOT	Boone, Winnebago	3 hr
Apr 14, 8:48 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Lake	57 min
Apr 14, 8:57 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Winnebago	48 min
Apr 14, 9:16 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	DeKalb, Kane	44 min
Apr 14, 9:28 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook, DuPage, Lake, McHenry	62 min
Apr 14, 9:33 PM CDT	Special Marine Warning	LOT		117 min
Apr 14, 9:42 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb	18 min
Apr 14, 9:53 PM CDT	Severe Thunderstorm Warning	LOT	Kane	37 min
Apr 14, 10:19 PM CDT	Areal Flood Advisory	LOT	Cook, DuPage	5 hr
Apr 14, 10:27 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Cook, DuPage	48 min
Apr 14, 10:33 PM CDT	River Flood Watch	LOT	Lake	6 hr
Apr 14, 10:37 PM CDT	River Flood Watch	LOT	Bureau, LaSalle, Putnam	21 days
Apr 14, 11:28 PM CDT	Special Marine Warning	LOT		2 hr
Apr 15, 12:24 AM CDT	River Flood Watch	LOT	Cook	21 days
Apr 15, 12:24 AM CDT	River Flood Watch	LOT	Cook, Lake	21 days
Apr 15, 12:24 AM CDT	River Flood Watch	LOT	Lake	6 hr
Apr 15, 2:48 AM CDT	Severe Thunderstorm Warning	LOT	Boone, McHenry	42 min
Apr 15, 3:51 AM CDT	Areal Flood Advisory	LOT	Lake	3 hr
Apr 15, 4:22 AM CDT	River Flood Warning	LOT	Lake	11 days
Apr 15, 6:19 AM CDT	River Flood Warning	LOT	Lake	10 days
Apr 15, 10:32 AM CDT	River Flood Watch	LOT	Cook	26 hr
Apr 15, 10:32 AM CDT	River Flood Watch	LOT	Cook	12 hr
Apr 15, 10:32 AM CDT	River Flood Warning	LOT	Cook	10 days
Apr 15, 10:32 AM CDT	River Flood Warning	LOT	Cook, Lake	10 days
Apr 15, 10:43 AM CDT	River Flood Watch	LOT	LaSalle	11 hr
Apr 15, 10:43 AM CDT	River Flood Warning	LOT	Kane, Kendall	11 hr
Apr 15, 11:42 AM CDT	River Flood Watch	LOT	Winnebago	20 hr
Apr 15, 11:42 AM CDT	River Flood Watch	LOT	Winnebago	23 hr
Apr 15, 11:42 AM CDT	River Flood Watch	LOT	Ogle, Winnebago	24 hr
Apr 15, 11:52 AM CDT	River Flood Watch	LOT	Winnebago	24 hr
Apr 15, 11:52 AM CDT	River Flood Watch	LOT	Boone, Winnebago	20 hr
Apr 15, 5:32 PM CDT	Tornado Warning	LOT	Ogle	26 min
Apr 14, 10:35 PM CDT	River Flood Watch	LOT	Lake, Newton	4 days

Nearby

Flash Flood Warnings in Illinois, 2026 Every flash flood warning 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.