Thunderstorms began developing during the late morning hours of July 1st across northern Illinois and continued into the early afternoon hours.  Some of these thunderstorms organized into a powerful line that produced widespread wind damage across parts of north central Dupage County with wind speeds between 75 mph and 90 mph.  Power outages in these areas lasted several days.

Thunderstorm Wind in LEE, ILLINOIS
From 01-JUL-12 10:12:00 to 01-JUL-12 10:12:00 (CST-6)
Location: STEWARD
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated wind gusts to 60 mph.

Hail in GRUNDY, ILLINOIS
From 01-JUL-12 10:25:00 to 01-JUL-12 10:26:00 (CST-6)
Location: MORRIS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Nickel size hail was reported at Route 47 and Route 6.

Hail in GRUNDY, ILLINOIS
From 01-JUL-12 10:27:00 to 01-JUL-12 10:28:00 (CST-6)
Location: COAL CITY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in WILL, ILLINOIS
From 01-JUL-12 10:37:00 to 01-JUL-12 10:38:00 (CST-6)
Location: BRAIDWOOD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Nickel size hail was reported in Diamond.

Thunderstorm Wind in KANE, ILLINOIS
From 01-JUL-12 11:03:00 to 01-JUL-12 11:03:00 (CST-6)
Location: GENEVA
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A four foot diameter tree was blown down.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:03:00 to 01-JUL-12 11:03:00 (CST-6)
Location: (DPA)DUPAGE CO ARPT
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in KANE, ILLINOIS
From 01-JUL-12 11:08:00 to 01-JUL-12 11:09:00 (CST-6)
Location: ST CHARLES
Magnitude: 52.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Newspaper

Tents were blown down and shredded at the Kane County Fair Grounds.  Some of the tent poles were twisted.

Hail in WILL, ILLINOIS
From 01-JUL-12 11:17:00 to 01-JUL-12 11:18:00 (CST-6)
Location: PLAINFIELD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:17:00 to 01-JUL-12 11:17:00 (CST-6)
Location: (DPA)DUPAGE CO ARPT
Magnitude: 65.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:18:00 to 01-JUL-12 11:18:00 (CST-6)
Location: CAROL STREAM
Magnitude: 70.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A roof was blown off a Walgreens store.  Shingles were blown off other roofs and a light pole was blown down.  Wind gusts were estimated to 80 mph.

Thunderstorm Wind in KANE, ILLINOIS
From 01-JUL-12 11:18:00 to 01-JUL-12 11:18:00 (CST-6)
Location: ST CHARLES
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated wind gusts to 70 mph.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:20:00 to 01-JUL-12 11:20:00 (CST-6)
Location: ROSELLE
Magnitude: 61.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Trained Spotter

A large pine tree was uprooted and multiple tree limbs were snapped off trees.  Shingles were blown off a roof.

Hail in DU PAGE, ILLINOIS
From 01-JUL-12 11:22:00 to 01-JUL-12 11:25:00 (CST-6)
Location: WHEATON
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in KANE, ILLINOIS
From 01-JUL-12 11:25:00 to 01-JUL-12 11:26:00 (CST-6)
Location: AURORA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:25:00 to 01-JUL-12 11:25:00 (CST-6)
Location: WHEATON
Magnitude: 61.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees and power lines were blown down near County Farm Road and Route 38.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:25:00 to 01-JUL-12 11:25:00 (CST-6)
Location: GLEN ELLYN
Magnitude: 70.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Extensive tree damage resulted in damage to houses in the 500 block of Forest Avenue.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:25:00 to 01-JUL-12 11:25:00 (CST-6)
Location: WHEATON
Magnitude: 70.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A large tree fell onto two cars.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:26:00 to 01-JUL-12 11:26:00 (CST-6)
Location: WINFIELD
Magnitude: 78.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees were blown down and roofs were damaged.  Wind gusts were estimated to 90 mph.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:27:00 to 01-JUL-12 11:27:00 (CST-6)
Location: GLEN ELLYN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six to ten inch diameter tree limbs were blown down.

Hail in DU PAGE, ILLINOIS
From 01-JUL-12 11:27:00 to 01-JUL-12 11:30:00 (CST-6)
Location: GLEN ELLYN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DU PAGE, ILLINOIS
From 01-JUL-12 11:30:00 to 01-JUL-12 11:31:00 (CST-6)
Location: WHEATON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DU PAGE, ILLINOIS
From 01-JUL-12 11:32:00 to 01-JUL-12 11:33:00 (CST-6)
Location: VILLA PARK
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:32:00 to 01-JUL-12 11:35:00 (CST-6)
Location: VILLA PARK
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Eight to ten inch diameter trees were blown down.  One house was damaged by a tree.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:35:00 to 01-JUL-12 11:35:00 (CST-6)
Location: ADDISON
Magnitude: 71.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in COOK, ILLINOIS
From 01-JUL-12 11:41:00 to 01-JUL-12 11:41:00 (CST-6)
Location: RIVER GROVE
Magnitude: 67.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in COOK, ILLINOIS
From 01-JUL-12 11:43:00 to 01-JUL-12 11:43:00 (CST-6)
Location: (ORD)O'HARE INTL ARP
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Hail in COOK, ILLINOIS
From 01-JUL-12 11:45:00 to 01-JUL-12 11:46:00 (CST-6)
Location: WESTCHESTER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Penny size hail was reported at Cermack and La Grange Roads.

Hail in COOK, ILLINOIS
From 01-JUL-12 11:45:00 to 01-JUL-12 11:46:00 (CST-6)
Location: BROOKFIELD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WILL, ILLINOIS
From 01-JUL-12 11:46:00 to 01-JUL-12 11:47:00 (CST-6)
Location: BEECHER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in COOK, ILLINOIS
From 01-JUL-12 12:05:00 to 01-JUL-12 12:05:00 (CST-6)
Location: WINNETKA
Magnitude: 65.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Windows were blown out of buildings in downtown Winnetka.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:45:00 to 01-JUL-12 11:45:00 (CST-6)
Location: OAK BROOK
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

An eight inch diameter tree limb was blown down.

Thunderstorm Wind in COOK, ILLINOIS
From 01-JUL-12 11:50:00 to 01-JUL-12 11:50:00 (CST-6)
Location: EDGEBROOK
Magnitude: 55.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Newspaper

A tree fell onto a car trapping one person inside the car in the 6600 block of North Kostner Avenue but the person did not need medical treatment.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 01-JUL-12 11:38:00 to 01-JUL-12 11:38:00 (CST-6)
Location: ELMHURST
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large trees were blown down.  Wind gusts were estimated to 80 mph.

Thunderstorm Wind in COOK, ILLINOIS
From 01-JUL-12 11:50:00 to 01-JUL-12 11:50:00 (CST-6)
Location: MANNHEIM
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A shed was flipped over in the parking lot of a home improvement center.