A disturbance moving through northwest flow aloft brought several rounds of thunderstorms to northwest Illinois from the early afternoon through the early evening hours. The initial round of thunderstorms developed in eastern Iowa during the late morning hours and moved into northwest Illinois where heavy rains were the main threat. Another round of thunderstorms developed in the late afternoon and early evening as the disturbance approached the Mississippi River with wind, hail, and heavy rain being the main threats.

Hail in BUREAU, ILLINOIS
From 08-AUG-11 12:49:00 to 08-AUG-11 12:51:00 (CST-6)
Location: YORKTOWN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Mutliple reports of pennt to quarter sized hail.

Heavy Rain in STEPHENSON, ILLINOIS
From 08-AUG-11 16:45:00 to 08-AUG-11 16:45:00 (CST-6)
Location: FREEPORT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

This is a 30 minute total.

Thunderstorm Wind in BUREAU, ILLINOIS
From 08-AUG-11 12:51:00 to 08-AUG-11 12:51:00 (CST-6)
Location: YORKTOWN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Six to 7 inch tree limbs were reported down. Time is estimated from radar.

Thunderstorm Wind in HENRY, ILLINOIS
From 08-AUG-11 16:23:00 to 08-AUG-11 16:23:00 (CST-6)
Location: KEWANEE
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Wind speeds were estimated by the public and lasted approximately ten minutes. Power is out in the town of Kewanee. Several large 8 inch tree limbs were also down in Kewanee.

Heavy Rain in STEPHENSON, ILLINOIS
From 08-AUG-11 16:50:00 to 08-AUG-11 16:50:00 (CST-6)
Location: LENA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm total rainfall from 500 pm cdt to 545 pm cdt.

Heavy Rain in STEPHENSON, ILLINOIS
From 08-AUG-11 17:04:00 to 08-AUG-11 17:04:00 (CST-6)
Location: WINNESHIEK
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rain fell in less than one hour.

Heavy Rain in STEPHENSON, ILLINOIS
From 08-AUG-11 16:59:00 to 08-AUG-11 16:59:00 (CST-6)
Location: CEDARVILLE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Report relayed by media and reported to have fallen in 30 minutes.

Heavy Rain in STEPHENSON, ILLINOIS
From 08-AUG-11 17:27:00 to 08-AUG-11 17:27:00 (CST-6)
Location: WINNESHIEK
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rain fell over a 90 minute period and ponding of water has been reported in fields.

Thunderstorm Wind in CARROLL, ILLINOIS
From 08-AUG-11 13:02:00 to 08-AUG-11 13:02:00 (CST-6)
Location: THOMSON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Pine trees approximately 12 inches in diameter snapped off near the base on Main Street and West street.  This tree fell on power lines causing power outages in the town of Thomson.

Heavy Rain in CARROLL, ILLINOIS
From 08-AUG-11 13:52:00 to 08-AUG-11 13:52:00 (CST-6)
Location: CHADWICK
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Rain fell over a 40 minute period.

Hail in BUREAU, ILLINOIS
From 08-AUG-11 13:08:00 to 08-AUG-11 13:08:00 (CST-6)
Location: WALNUT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Dime to nickel sized hail was reported.

Heavy Rain in WHITESIDE, ILLINOIS
From 08-AUG-11 12:45:00 to 08-AUG-11 12:45:00 (CST-6)
Location: MORRISON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rain fell over a 10 to 15 minute period.

Heavy Rain in WHITESIDE, ILLINOIS
From 08-AUG-11 14:27:00 to 08-AUG-11 14:27:00 (CST-6)
Location: MORRISON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm total precipitation as of 15:27 CDT.

Heavy Rain in ROCK ISLAND, ILLINOIS
From 08-AUG-11 15:35:00 to 08-AUG-11 15:35:00 (CST-6)
Location: ROCK IS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rain fell over the course of a 30 minute period.

Heavy Rain in ROCK ISLAND, ILLINOIS
From 08-AUG-11 15:59:00 to 08-AUG-11 15:59:00 (CST-6)
Location: (MLI) QUAD CITY ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Rain began at 424 pm cdt and ended at 450 pm cdt.

Heavy Rain in JO DAVIESS, ILLINOIS
From 08-AUG-11 16:05:00 to 08-AUG-11 16:05:00 (CST-6)
Location: STOCKTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The rain fell over a period of 25 minutes.

Hail in WHITESIDE, ILLINOIS
From 08-AUG-11 13:23:00 to 08-AUG-11 13:23:00 (CST-6)
Location: STERLING
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail fell for 1 to 2 minutes with hailstones varying in size from pea to quarter sized.

Heavy Rain in STEPHENSON, ILLINOIS
From 08-AUG-11 16:11:00 to 08-AUG-11 16:11:00 (CST-6)
Location: LENA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Heavy rain fell in a period of 30 minutes. Rain continues to fall in Lena.