A residual surface boundary that extended from eastern Iowa across northern Illinois was the focus for thunderstorm development as a moderate southwest 850 mb jet pushed it north as a warm front. Upper divergence from the right entrance region of an upper jet maxmum provided additional lift. Moderate deep layer wind shear produced sustained updrafts to form thunderstorm clusters that evolved into short line segments as they reached southern Wisconsin. The severe thunderstorm lines produced damaging wind gusts in a swath from Iowa County along and either side of the I-94 corridor to Milwaukee and Ozaukee counties.

Thunderstorm Wind in IOWA, WISCONSIN
From 03-SEP-11 01:40:00 to 03-SEP-11 01:45:00 (CST-6)
Location: LINDEN
Magnitude: 70.00 EG
Property damage: 50.00K
Reported by: Emergency Manager

The Iowa County Emergency manager reported damage from severe thunderstorm wind gusts estimated at 70 knots (80 mph) in a 5-mile wide swath from south of Linden to south-southwest of Dodgeville. The damaging winds blew the roof off of a cattle barn south of Dodgeville and knocked over a grain bin. Numerous trees and power lines were knocked down by the powerful winds.

Thunderstorm Wind in DANE, WISCONSIN
From 03-SEP-11 02:22:00 to 03-SEP-11 02:57:00 (CST-6)
Location: BLUE MOUNDS
Magnitude: 65.00 EG
Property damage: 15.00K
Reported by: Law Enforcement

Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 65 knots (75 mph) in an 8-mile wide swath from southwest of Blue Mounds to east of McFarland. The damaging winds downed numerous trees and power lines, with 1000 customers left without power in the Madison area.

Thunderstorm Wind in IOWA, WISCONSIN
From 03-SEP-11 02:05:00 to 03-SEP-11 02:15:00 (CST-6)
Location: DODGEVILLE
Magnitude: 70.00 EG
Property damage: 100.00K
Crop damage: 200.00K
Reported by: Law Enforcement

Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 70 knots (80 mph) in a 5-mile wide swath from southeast of Dodgeville to northeast of Hollandale. The damaging winds destroyed a cattle shed and caused minor damage to a barn. The winds damaged several corn fields on East Lawinger Road southeast of Dodgeville. A grain bin was knocked off its foundation and destroyed, and a corn field was flattened northeast of Hollandale. Numerous trees and power lines were knocked down by the powerful winds.

Thunderstorm Wind in JEFFERSON, WISCONSIN
From 03-SEP-11 03:20:00 to 03-SEP-11 03:40:00 (CST-6)
Location: WATERLOO
Magnitude: 65.00 EG
Property damage: 15.00K
Reported by: Law Enforcement

Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 65 knots (75 mph) in a 3-mile wide swath from Waterloo to northeast of Ixonia. The damaging winds downed numerous trees and power lines.

Thunderstorm Wind in WAUKESHA, WISCONSIN
From 03-SEP-11 03:40:00 to 03-SEP-11 03:40:00 (CST-6)
Location: MONTEREY
Magnitude: 56.00 EG
Property damage: 2.00K
Reported by: Law Enforcement

Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 56 knots (65 mph) that downed two trees and two power lines and numerous branches in the township of Oconomowoc.

Thunderstorm Wind in DODGE, WISCONSIN
From 03-SEP-11 03:55:00 to 03-SEP-11 03:55:00 (CST-6)
Location: ALDERLEY
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officials reported trees downed from damaging severe thunderstorm wind gusts estimated at 56 knots (65 mph).

Thunderstorm Wind in JEFFERSON, WISCONSIN
From 03-SEP-11 03:10:00 to 03-SEP-11 03:20:00 (CST-6)
Location: LAKE MILLS
Magnitude: 65.00 EG
Reported by: Trained Spotter

A trained spotter reported large tree branches blown down, an above ground pool blown into a neighbor's yard and lawn furniture tossed from severe thunderstorm wind gusts estimated at 65 knots (75 mph).

Hail in DANE, WISCONSIN
From 03-SEP-11 02:46:00 to 03-SEP-11 02:46:00 (CST-6)
Location: PAOLI
Magnitude: 0.75 
Reported by: Trained Spotter

A trained spotter reported hail near Paoli that was measured 3/4 of an inch in diameter that fell from strong to severe thunderstorms moving through Dane County during the early morning hours of of September 3rd.

Thunderstorm Wind in DANE, WISCONSIN
From 03-SEP-11 02:45:00 to 03-SEP-11 03:30:00 (CST-6)
Location: OREGON
Magnitude: 65.00 EG
Property damage: 15.00K
Reported by: Trained Spotter

A trained spotter reported numerous trees and power lines downed along a path from Oregon to northeast of Albion from damaging severe thunderstorm wind gusts estimated at 65 knots (75 mph). The winds tore some siding off a home in Oregon. Heavy rain caused ponding of water on area roadways, with water over the curb on some streets in Oregon.

Thunderstorm Wind in DODGE, WISCONSIN
From 03-SEP-11 03:20:00 to 03-SEP-11 03:45:00 (CST-6)
Location: PORTLAND
Magnitude: 65.00 EG
Property damage: 15.00K
Reported by: Law Enforcement

Law enforcement officials reported damage from severe thunderstorm wind gusts estimated at 65 knots (75 mph) in a 4-mile wide swath from north of Portland to north of Ashippun. The damaging winds downed numerous trees and power lines.

Thunderstorm Wind in DANE, WISCONSIN
From 03-SEP-11 03:11:00 to 03-SEP-11 03:11:00 (CST-6)
Location: MARSHALL
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officers reported trees downed from severe thunderstorm wind gusts estimated at 56 knots (65 mph).

Thunderstorm Wind in WASHINGTON, WISCONSIN
From 03-SEP-11 04:00:00 to 03-SEP-11 04:20:00 (CST-6)
Location: HARTFORD
Magnitude: 60.00 EG
Property damage: 3.00K
Reported by: Trained Spotter

A trained spotter reported numerous trees and power lines downed in a 6-mile wide swath from south of Hartford to southeast of Jackson from damaging severe thunderstorm wind gusts estimated at 60 knots (69 mph). The roof was blown off a silo, trees were downed and a hay wagon moved 20 feet by the severe wind gusts on a farm at the intersection of Western Avenue and CTH P south of Jackson.

Thunderstorm Wind in MILWAUKEE, WISCONSIN
From 03-SEP-11 04:10:00 to 03-SEP-11 04:30:00 (CST-6)
Location: TIMMERMAN ARPT
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officers reported numerous trees and power lines downed in a 4-mile wide swath from northwest of Timmerman Field to Bayside from damaging severe thunderstorm wind gusts estimated at 56 knots (65 mph).

Thunderstorm Wind in OZAUKEE, WISCONSIN
From 03-SEP-11 04:20:00 to 03-SEP-11 04:35:00 (CST-6)
Location: MEQUON
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officers reported numerous trees and power lines downed in a 5-mile wide swath from west of Mequon to Port Washington from damaging severe thunderstorm wind gusts estimated at 56 knots (65 mph).

Thunderstorm Wind in DANE, WISCONSIN
From 03-SEP-11 03:10:00 to 03-SEP-11 03:10:00 (CST-6)
Location: COTTAGE GROVE
Magnitude: 50.00 EG
Reported by: Trained Spotter

A trained spotter reported large tree branches downed from severe thunderstorm wind gusts estimated at 50 knots (58 mph).