A strong cold front moved into northwest Illinois during the early to mid afternoon hours on August 4th with a line of severe thunderstorms moving into the area from eastern Iowa. This line of thunderstorms produced straight-line winds with gusts as high as 80 mph along and north of Interstate 80. In addition to the straight-line winds, these thunderstorms produced heavy rainfall; a trained spotter reported 2.05 inches near Council Hill, 1.30 inches near Fulton, 1.50 inches at Rock Falls in 30 minutes.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 04-AUG-12 13:09:00 to 04-AUG-12 13:09:00 (CST-6)
Location: USTICK
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter estimated thunderstorm wind speeds of 60 to 70 mph bringing down 3 inch tree branches.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 04-AUG-12 12:57:00 to 04-AUG-12 12:57:00 (CST-6)
Location: ALBANY
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported tree limbs down that were approximately 3 inches in diameter. Heavy rain was falling at the time of the report.

Thunderstorm Wind in CARROLL, ILLINOIS
From 04-AUG-12 13:25:00 to 04-AUG-12 13:25:00 (CST-6)
Location: MILLEDGEVILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The Emergency Manager estimated wind speeds of 40 to 60 MPH along with a report of two buildings down at the Fairgrounds.

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 04-AUG-12 13:25:00 to 04-AUG-12 13:25:00 (CST-6)
Location: LENA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency Manager estimated winds speeds of 60 mph.

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 04-AUG-12 13:57:00 to 04-AUG-12 13:57:00 (CST-6)
Location: FREEPORT
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Chicago Avenue was reported closed due to an estimated 1 to 1.5 foot tree down across the road.

Thunderstorm Wind in CARROLL, ILLINOIS
From 04-AUG-12 13:45:00 to 04-AUG-12 13:45:00 (CST-6)
Location: SAVANNA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency Manager reported power lines down across Carroll County.

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 04-AUG-12 13:49:00 to 04-AUG-12 13:49:00 (CST-6)
Location: FREEPORT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 04-AUG-12 13:25:00 to 04-AUG-12 13:25:00 (CST-6)
Location: STERLING
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A few large diameter tree limbs down.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 04-AUG-12 13:10:00 to 04-AUG-12 13:10:00 (CST-6)
Location: MALVERN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public report of several large tree limbs down.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 04-AUG-12 13:05:00 to 04-AUG-12 13:05:00 (CST-6)
Location: GARDEN PLAIN
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind speeds were estimated and relayed via ESPOTTER.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 04-AUG-12 13:15:00 to 04-AUG-12 13:15:00 (CST-6)
Location: MALVERN
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A report received via ESPOTTER estimated sustained thunderstorms wind speeds of 60 MPH and gusts over 70 MPH. A huge oak tree was down along with numerous large tree limbs down estimated at approximately 4 to 6 inches.