The combination of a cold front, unstable air and an upper level disturbance produced severe thunderstorms that caused extensive damage across the Fox Valley.  A small cluster of intense thunderstorms produced wind gusts in excess of 70 mph, causing widespread damage across central and east central Wisconsin.  Thousands of trees and power lines were blown down by the thunderstorm cluster.  Numerous buildings were damaged by fallen trees and high winds.  Power was knocked out to 60,000 people at the height of the storm.
Some of the highest measured thunderstorm wind gusts included 81 mph at Sherwood (Calumet Co.), 78 mph at Wrightstown (Brown Co.), 74 mph at Oshkosh (Winnebago Co.), 72 mph at Appleton (Outagamie Co.), and 65 mph at Point Beach State Forest (Manitowoc Co.).
One of the hardest hit areas during the storm was Appleton (Outagamie Co.).  Widespread 70 to 75 mph wind gusts were experienced in the city, with isolated winds estimated at around 95 mph.

Thunderstorm Wind in CALUMET, WISCONSIN
From 02-SEP-11 09:52:00 to 02-SEP-11 09:52:00 (CST-6)
Location: BRILLION
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds caused power outages in Brillion.

Thunderstorm Wind in WINNEBAGO, WISCONSIN
From 02-SEP-11 08:55:00 to 02-SEP-11 08:55:00 (CST-6)
Location: MENASHA
Magnitude: 55.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds snapped trees, downed power lines and tore 2 sections from a dock on the north side of Lake Winnebago.

Thunderstorm Wind in WINNEBAGO, WISCONSIN
From 02-SEP-11 08:05:00 to 02-SEP-11 08:05:00 (CST-6)
Location: EUREKA
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds snapped numerous 6 inch diameter tree limbs in Eureka.

Thunderstorm Wind in BROWN, WISCONSIN
From 02-SEP-11 09:15:00 to 02-SEP-11 09:20:00 (CST-6)
Location: CORMIER
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: NWS Employee

Thunderstorm winds knocked a large tree onto a house on the west side of Green Bay and downed numerous trees and tree limbs near Preble Park.

Thunderstorm Wind in WAUSHARA, WISCONSIN
From 02-SEP-11 07:45:00 to 02-SEP-11 07:45:00 (CST-6)
Location: COLOMA
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds downed trees and power lines in Coloma.

Thunderstorm Wind in BROWN, WISCONSIN
From 02-SEP-11 09:15:00 to 02-SEP-11 09:15:00 (CST-6)
Location: KUNESH
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Public

Thunderstorm winds snapped 1 to 2 foot diameter trees, blocking roads near Pittsfield.

Thunderstorm Wind in CALUMET, WISCONSIN
From 02-SEP-11 08:40:00 to 02-SEP-11 08:40:00 (CST-6)
Location: HIGH CLIFF
Magnitude: 70.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm wind gust of 78 mph was measured 40 feet above a bluff on the east side of Lake Winnebago.

Thunderstorm Wind in WAUSHARA, WISCONSIN
From 02-SEP-11 07:56:00 to 02-SEP-11 07:56:00 (CST-6)
Location: WAUTOMA
Magnitude: 61.00 EG
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds, with gusts to 70 mph, downed power lines and snapped the limbs of or uprooted thousands of trees throughout the county.

Thunderstorm Wind in CALUMET, WISCONSIN
From 02-SEP-11 08:49:00 to 02-SEP-11 08:49:00 (CST-6)
Location: CHILTON
Magnitude: 55.00 EG
Property damage: 70.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds uprooted large trees at the county fair grounds and damaged several vehicles and campers.  The high winds also caused scattered power outages.

Thunderstorm Wind in WOOD, WISCONSIN
From 02-SEP-11 07:45:00 to 02-SEP-11 07:45:00 (CST-6)
Location: NEKOOSA
Magnitude: 50.00 EG
Reported by: Law Enforcement

Thunderstorm winds downed power lines in Nekoosa.

Thunderstorm Wind in MANITOWOC, WISCONSIN
From 02-SEP-11 09:40:00 to 02-SEP-11 09:40:00 (CST-6)
Location: EASTWIN
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm wind gust to 65 mph was measured at Point Beach State Forest.

Thunderstorm Wind in MANITOWOC, WISCONSIN
From 02-SEP-11 09:00:00 to 02-SEP-11 09:00:00 (CST-6)
Location: BRANCH
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds overturned a semi-trailer into the the median near Interstate Highway 43 at exit 154.

Thunderstorm Wind in MANITOWOC, WISCONSIN
From 02-SEP-11 09:03:00 to 02-SEP-11 09:03:00 (CST-6)
Location: MANITOWOC
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds downed many trees and power lines in the City of Manitowoc.

Thunderstorm Wind in OUTAGAMIE, WISCONSIN
From 02-SEP-11 08:45:00 to 02-SEP-11 08:45:00 (CST-6)
Location: LITTLE CHUTE
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds downed many trees and power lines in Little Chute.

Thunderstorm Wind in DOOR, WISCONSIN
From 02-SEP-11 09:52:00 to 02-SEP-11 09:52:00 (CST-6)
Location: FORESTVILLE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds downed trees and power lines in Forestville.

Thunderstorm Wind in BROWN, WISCONSIN
From 02-SEP-11 09:22:00 to 02-SEP-11 09:22:00 (CST-6)
Location: FLINTVILLE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm winds downed trees and large branches at the NEW Zoo, near Suamico.

Thunderstorm Wind in WAUPACA, WISCONSIN
From 02-SEP-11 08:26:00 to 02-SEP-11 08:26:00 (CST-6)
Location: NEW LONDON
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds produced a measured 60 mph gust at New London.

Thunderstorm Wind in OUTAGAMIE, WISCONSIN
From 02-SEP-11 08:33:00 to 02-SEP-11 08:38:00 (CST-6)
Location: GREENVILLE
Magnitude: 70.00 EG
Property damage: 5.30M
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds, with gusts estimated to 80 mph, downed thousands of trees and knocked out power to 20,000 customers in Appleton alone.  Around 200 homes sustained at least minor damage, including one that was destroyed.  More than 60 businesses also sustained damage.  A semi-trailer was blown over near US-41 and US-10.

Thunderstorm Wind in MANITOWOC, WISCONSIN
From 02-SEP-11 09:15:00 to 02-SEP-11 09:15:00 (CST-6)
Location: (MTW)MANITOWOC ARPT
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorms produced a 63 mph wind gust at Manitowoc County Airport.

Thunderstorm Wind in BROWN, WISCONSIN
From 02-SEP-11 08:45:00 to 02-SEP-11 08:45:00 (CST-6)
Location: WRIGHTSTOWN
Magnitude: 68.00 MG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds, gusting to 78 mph, overturned a semi-trailer near Wrightstown, on CR-U and US-41, and damaged dugouts at a baseball field.

Thunderstorm Wind in OUTAGAMIE, WISCONSIN
From 02-SEP-11 08:55:00 to 02-SEP-11 08:55:00 (CST-6)
Location: LITTLE CHUTE
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorms wind gust to 65 mph was measured near SR-55 and US-41.  The winds downed tree branches.

Thunderstorm Wind in WINNEBAGO, WISCONSIN
From 02-SEP-11 08:36:00 to 02-SEP-11 08:36:00 (CST-6)
Location: (OSH)WITTMAN FLD OSH
Magnitude: 64.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

Thunderstorms produced a wind gust measured at 74 mph at the EAA fair grounds in Oshkosh.

Thunderstorm Wind in OUTAGAMIE, WISCONSIN
From 02-SEP-11 08:30:00 to 02-SEP-11 08:30:00 (CST-6)
Location: HORTONVILLE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorms produced a wind gust of 60 mph that was measured at Hortonville High School.  Winds from the storm knocked out power at the school.

Thunderstorm Wind in WAUPACA, WISCONSIN
From 02-SEP-11 09:13:00 to 02-SEP-11 09:13:00 (CST-6)
Location: FREMONT
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds downed trees, snapped a light pole, and knocked out power in Fremont.