Scattered thunderstorms lifted across northern Illinois during the afternoon and evening hours producing large hail.  A squall line moved across the region later in the evening producing strong winds, hail, and heavy rain that resulted in flooding.

Hail in LA SALLE, ILLINOIS
From 12-MAY-14 17:01:00 to 12-MAY-14 17:03:00 (CST-6)
Location: LA SALLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in COOK, ILLINOIS
From 12-MAY-14 17:30:00 to 12-MAY-14 17:30:00 (CST-6)
Location: ARLINGTON HGTS
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 12-MAY-14 17:41:00 to 12-MAY-14 17:43:00 (CST-6)
Location: NORTHBROOK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in COOK, ILLINOIS
From 12-MAY-14 18:13:00 to 12-MAY-14 18:14:00 (CST-6)
Location: PALATINE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 12-MAY-14 18:20:00 to 12-MAY-14 18:22:00 (CST-6)
Location: NORTHBROOK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flash Flood in KANE, ILLINOIS
From 12-MAY-14 18:25:00 to 12-MAY-14 23:00:00 (CST-6)
Location: ELGIN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Approximately four to eight inches of flowing water was reported over the intersection of Route 25 and Route 19.

Flash Flood in COOK, ILLINOIS
From 12-MAY-14 18:30:00 to 13-MAY-14 00:00:00 (CST-6)
Location: HUBBARD WOODS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

One to two feet of flowing water was reported on Asbury Avenue.

Hail in LEE, ILLINOIS
From 12-MAY-14 18:32:00 to 12-MAY-14 18:33:00 (CST-6)
Location: FRANKLIN GROVE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCHENRY, ILLINOIS
From 12-MAY-14 19:00:00 to 12-MAY-14 19:02:00 (CST-6)
Location: MARENGO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flash Flood in LAKE, ILLINOIS
From 12-MAY-14 19:30:00 to 13-MAY-14 00:00:00 (CST-6)
Location: GURNEE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Grand Avenue was closed at 1st Street.  High water was reported under a railroad overpass just west of 1st Street.

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 12-MAY-14 19:47:00 to 12-MAY-14 19:47:00 (CST-6)
Location: RCKFRD COTTONWOOD AR
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 12-MAY-14 20:00:00 to 12-MAY-14 20:00:00 (CST-6)
Location: ROCKTON WGN WHEEL AR
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Healthy tree branches 6 to 8 inches in diameter and power lines were blown down near the intersection of Roscoe Road and Route 2.

Flood in LAKE, ILLINOIS
From 12-MAY-14 20:10:00 to 13-MAY-14 00:00:00 (CST-6)
Location: NORTH CHICAGO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Standing water approximately 6 to 12 inches deep was reported on streets and parking lots across Great Lakes Naval Station.

Flash Flood in LAKE, ILLINOIS
From 12-MAY-14 21:46:00 to 13-MAY-14 00:00:00 (CST-6)
Location: KNOLLWOOD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Approximately 10 feet of water was reported under the railroad underpass on Route 41 just north of Route 176.  An observer reported 4.06 inches of rain near Lake Bluff.

Flash Flood in LAKE, ILLINOIS
From 12-MAY-14 19:30:00 to 13-MAY-14 00:00:00 (CST-6)
Location: PARK CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Route 41 was closed near Route 120 due to flooding.

Hail in WINNEBAGO, ILLINOIS
From 12-MAY-14 14:17:00 to 12-MAY-14 14:20:00 (CST-6)
Location: BELOIT
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail one to two inches in diameter was reported across portions of South Beloit, including two inch diameter hail near Route 2 and Prairie Road.

Flash Flood in LAKE, ILLINOIS
From 12-MAY-14 18:45:00 to 13-MAY-14 00:00:00 (CST-6)
Location: RONDOUT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

On southbound Interstate 90, the two right lanes were blocked due to flood waters at the Lake Forest Oasis.  A nearby CoCoRaHS observer approximately a mile west of Lake Bluff measured 4.06 inches of rain.