A strong cold front swept through eastern Iowa in the early afternoon of August 4th generating severe thunderstorms that moved along and to the north of Interstate 80.  These thunderstorms produced strong straight-line winds as high as 75 mph across this area. In addition to the strong straight-line winds these thunderstorms produced very heavy rainfall in a short period of time; Vinton in Benton County received 1.28 inches of rain in 40 minutes, 1.60 inches was recorded at the Davenport ASOS in 15 minutes, 2.45 inches was reported by storm spotter in Princeton in 40 minutes, 1.80 inches in 25 minutes at the Cedar Rapids ASOS.

Thunderstorm Wind in JOHNSON, IOWA
From 04-AUG-12 11:36:00 to 04-AUG-12 11:36:00 (CST-6)
Location: CORALVILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms wind gusts were estimated between 50 and 60 mph.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:47:00 to 04-AUG-12 11:47:00 (CST-6)
Location: CEDAR RAPIDS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated thunderstorm wind gusts near 60 mph.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:38:00 to 04-AUG-12 11:38:00 (CST-6)
Location: (CID)CEDAR RAPIDS AR
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in CEDAR, IOWA
From 04-AUG-12 12:14:00 to 04-AUG-12 12:14:00 (CST-6)
Location: BENNETT
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated thunderstorm wind gusts of 60 to 65 mph.

Thunderstorm Wind in DELAWARE, IOWA
From 04-AUG-12 12:16:00 to 04-AUG-12 12:16:00 (CST-6)
Location: BUCK CREEK
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The Delaware County Sheriffs Office relayed a report from the Emergency Manager of thunderstorm wind gusts estimated to be between 60 and 70 mph.

Thunderstorm Wind in CEDAR, IOWA
From 04-AUG-12 12:17:00 to 04-AUG-12 12:17:00 (CST-6)
Location: TIPTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public report received via ESPOTTER estimated thunderstorm wind gusts near 60 mph.

Thunderstorm Wind in JOHNSON, IOWA
From 04-AUG-12 11:25:00 to 04-AUG-12 11:25:00 (CST-6)
Location: WILLIAMSTOWN
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Trees were blown down and the windows were blown out at a residence. A grain bin is also reported to have been blown over.

Thunderstorm Wind in SCOTT, IOWA
From 04-AUG-12 12:54:00 to 04-AUG-12 12:54:00 (CST-6)
Location: DAVENPORT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Received a public report of thunderstorm wind gusts estimated at 60 mph.

Thunderstorm Wind in CLINTON, IOWA
From 04-AUG-12 12:35:00 to 04-AUG-12 12:35:00 (CST-6)
Location: CLINTON MUNI ARPT
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio relayed a report of a fruit tree down from thunderstorm winds.

Thunderstorm Wind in CLINTON, IOWA
From 04-AUG-12 13:01:00 to 04-AUG-12 13:01:00 (CST-6)
Location: CLINTON
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported that an 18 to 24 inch tree was down across north 3rd Street in the City of Clinton.

Thunderstorm Wind in CLINTON, IOWA
From 04-AUG-12 12:12:00 to 04-AUG-12 12:12:00 (CST-6)
Location: DEWITT
Magnitude: 54.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported a 5 inch tree was down.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:40:00 to 04-AUG-12 11:40:00 (CST-6)
Location: CEDAR RAPIDS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated thunderstorm wind speeds of 50 to 60 mph.

Thunderstorm Wind in BENTON, IOWA
From 04-AUG-12 11:28:00 to 04-AUG-12 11:28:00 (CST-6)
Location: NORWAY
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds were estimated at 60 to 65 mph. Heavy rain was falling at the time and was limiting visibility to a quarter of a mile or less.

Thunderstorm Wind in JOHNSON, IOWA
From 04-AUG-12 11:48:00 to 04-AUG-12 11:48:00 (CST-6)
Location: NORTH LIBERTY
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm wind gusts snapped an aluminum flag pole and damaged several trees.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:55:00 to 04-AUG-12 11:55:00 (CST-6)
Location: CEDAR RAPIDS
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A 12 inch tree was reported down.

Thunderstorm Wind in JOHNSON, IOWA
From 04-AUG-12 11:48:00 to 04-AUG-12 11:48:00 (CST-6)
Location: NORTH LIBERTY
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm wind gusts were estimated between  60 and 65 mph.

Thunderstorm Wind in JOHNSON, IOWA
From 04-AUG-12 11:35:00 to 04-AUG-12 11:35:00 (CST-6)
Location: OAKDALE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A 3 inch diameter tree branch was down on a home along with numerous other smaller branches down.

Flash Flood in LINN, IOWA
From 04-AUG-12 12:05:00 to 04-AUG-12 12:05:00 (CST-6)
Location: CEDAR RAPIDS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Reports were received that cars were floating on J Street in Cedar Rapids.  The ASOS at Cedar Rapids reported 1.81 inches of rain fell in 25 minutes.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:48:00 to 04-AUG-12 11:48:00 (CST-6)
Location: CEDAR RAPIDS
Magnitude: 64.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm wind gusts knocked down 3 to 4 inch tree limbs. The wind gusts were estimated to be between 70 and 75 mph.

Thunderstorm Wind in JOHNSON, IOWA
From 04-AUG-12 11:35:00 to 04-AUG-12 11:35:00 (CST-6)
Location: OAKDALE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm wind gusts were estimated to be between 50 and 60 mph.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:47:00 to 04-AUG-12 11:47:00 (CST-6)
Location: HIAWATHA
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated thunderstorm wind speeds of 60 to 65 mph.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:47:00 to 04-AUG-12 11:47:00 (CST-6)
Location: (CID)CEDAR RAPIDS AR
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:48:00 to 04-AUG-12 11:48:00 (CST-6)
Location: ELY
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A public report estimated thunderstorm wind gusts between 60 and 70 mph. Heavy rain was helping to reduce visibility.

Thunderstorm Wind in CEDAR, IOWA
From 04-AUG-12 12:14:00 to 04-AUG-12 12:14:00 (CST-6)
Location: CLARENCE
Magnitude: 63.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A report received via ESPOTTER estimated thunderstorm wind gusts around 72 mph.

Thunderstorm Wind in BENTON, IOWA
From 04-AUG-12 11:25:00 to 04-AUG-12 11:25:00 (CST-6)
Location: NORWAY
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter estimated sustained winds of 40 mph with gusts of 60 to 70 mph.

Thunderstorm Wind in SCOTT, IOWA
From 04-AUG-12 12:45:00 to 04-AUG-12 12:45:00 (CST-6)
Location: PANORAMA PARK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

An off duty NWS employee reported several 3 to 4 inch tree branches down at Middle Road and 29th Street. Time of the event was estimated from radar.

Thunderstorm Wind in LINN, IOWA
From 04-AUG-12 11:45:00 to 04-AUG-12 11:45:00 (CST-6)
Location: CEDAR RAPIDS
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Reports that numerous tree limbs were down with some of them as large as three inches in diameter. The time of the event was estimated from radar.

Thunderstorm Wind in CLINTON, IOWA
From 04-AUG-12 12:20:00 to 04-AUG-12 12:20:00 (CST-6)
Location: WHEATLAND
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio reported a thunderstorm wind gust around 70 mph.