A strengthening low-level jet pushed over a stalled frontal boundary over southern Wisconsin with a very warm, moist and unstable air mass under very steep lapse rates provided the focus for strong to severe thunderstorms during the pre-dawn hours of July 24th. The severe thunderstorms produced a discontinous swath of damaging wind gusts that downed trees and power lines from near Darlington in Lafayette County, eastward across Green and Rock counties to Lake Geneva in Walworth County.

Thunderstorm Wind in IOWA, WISCONSIN
From 24-JUL-12 02:45:00 to 24-JUL-12 02:45:00 (CST-6)
Location: AVOCA
Magnitude: 56.00 EG
Property damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported trees were blown down by severe thunderstorm wind gusts estimated at 56 knots (64 mph).

Thunderstorm Wind in IOWA, WISCONSIN
From 24-JUL-12 03:05:00 to 24-JUL-12 03:05:00 (CST-6)
Location: MINERAL PT
Magnitude: 56.00 EG
Property damage: 10.00K
Reported by: Law Enforcement

Law enforcement reported trees and power lines were blown down by severe thunderstorm wind gusts estimated at 56 knots (64 mph).

Thunderstorm Wind in LAFAYETTE, WISCONSIN
From 24-JUL-12 03:05:00 to 24-JUL-12 03:05:00 (CST-6)
Location: DARLINGTON
Magnitude: 56.00 EG
Property damage: 10.00K
Reported by: Law Enforcement

Law enforcement reported trees and power lines were blown down by severe thunderstorm wind gusts estimated at 56 knots (64 mph).

Thunderstorm Wind in GREEN, WISCONSIN
From 24-JUL-12 03:16:00 to 24-JUL-12 03:16:00 (CST-6)
Location: NEW GLARUS
Magnitude: 56.00 EG
Reported by: Emergency Manager

Emergency management officials reported trees and numerous power lines were blown down throughout the county by severe thunderstorm wind gusts estimated at 56 knots (64 mph). A window at a car dealership in Monroe was blown out by the damaging winds.

Thunderstorm Wind in GREEN, WISCONSIN
From 24-JUL-12 03:20:00 to 24-JUL-12 03:20:00 (CST-6)
Location: MONROE
Magnitude: 56.00 EG
Reported by: Trained Spotter

A trained spotter reported trees and power lines were blown down by severe thunderstorm wind gusts estimated at 56 knots (64 mph). Heavy rains also caused a rain gutter to back up with water covering State Highway 69 in Monroe.

Thunderstorm Wind in LAFAYETTE, WISCONSIN
From 24-JUL-12 03:18:00 to 24-JUL-12 03:25:00 (CST-6)
Location: GRATIOT
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officials reported trees and power lines were blown down in a swath from Gratiot to South Wayne by severe thunderstorm wind gusts estimated at 56 knots (64 mph).

Thunderstorm Wind in GREEN, WISCONSIN
From 24-JUL-12 03:42:00 to 24-JUL-12 03:42:00 (CST-6)
Location: MONROE
Magnitude: 52.00 MG
Reported by: Trained Spotter

A trained spotter measured a severe thunderstorm wind gust estimated at 52 knots (60 mph).

Thunderstorm Wind in ROCK, WISCONSIN
From 24-JUL-12 03:45:00 to 24-JUL-12 03:55:00 (CST-6)
Location: EVANSVILLE
Magnitude: 61.00 EG
Reported by: Law Enforcement

Law enforcement officials reported trees and power lines were blown down by severe thunderstorm wind gusts estimated at 61 knots (70 mph).

Thunderstorm Wind in WALWORTH, WISCONSIN
From 24-JUL-12 04:16:00 to 24-JUL-12 04:16:00 (CST-6)
Location: SHARON
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officials reported trees were blown down by severe thunderstorm wind gusts estimated at 56 knots (65 mph).

Thunderstorm Wind in ROCK, WISCONSIN
From 24-JUL-12 04:00:00 to 24-JUL-12 04:00:00 (CST-6)
Location: BELOIT
Magnitude: 65.00 EG
Reported by: Newspaper

A local newspaper reported trees and power lines were blown down all over the county by severe thunderstorm wind gusts estimated at 65 knots (75 mph). The fallen trees blocked roads in residential neighborhoods on the west side of Beloit, as well as on State Highway 213 between Luther Valley Road and Yahara Road. Homes and vehicles were damaged by storm debris.  It was estimated 7,000 people were without power. A residential fire on Lincoln Avenue in Beloit was possibly started by lightning.

Thunderstorm Wind in WALWORTH, WISCONSIN
From 24-JUL-12 04:23:00 to 24-JUL-12 04:30:00 (CST-6)
Location: LAKE GENEVA
Magnitude: 56.00 EG
Reported by: Law Enforcement

Law enforcement officials reported scattered trees and a power pole were blown down by severe thunderstorm wind gusts estimated at 56 knots (65 mph) in a swath from 3 miles southwest of Lake Geneva to Lake Geneva.