On the evening of September 20th, a warm front was stretched west to east across southern Minnesota, and southern Wisconsin. The weather pattern, and associated boundaries were nearly stationary through early Thursday morning, September 22nd. The atmosphere was very moist which was evident in the soundings, as near record high Precipitable Water (PWAT) values were noted.
Although the most significant part of this weather event was flooding, some large hail reports and severe wind gusts were observed the evening of September 20th, and during the afternoon and evening of Wednesday, September 21st.
The evening of Tuesday, September 20th, an area of thunderstorms formed along and north of the warm front in southern Minnesota. This area of thunderstorms moved northeast into west central Wisconsin and caused torrential rainfall and a few reports of large hail. This rainfall event, although localized, created very wet antecedent conditions before the main heavy rainfall event developed during the afternoon and through the evening of Wednesday, September 21st.
A few thunderstorms develop Wednesday afternoon around Chippewa Falls and Eau Claire. However, once a line of storms developed during the afternoon and evening, training of these storms produced extreme rainfall rates and rainfall amounts of 5 to 8 inches.
The Wisconsin Department of Transportation reported numerous roads washed out or closed in Chippewa and Eau Claire Counties during the height of the storm. Some vehicles were swept into culverts and ditches as roadways became flooded. The Canadian National Railroad had 50 feet of track wash out in Stanley, and near Wheaton.
In Chippewa County, damage assessments found that three homes sustained major damage and 52 had minor damage. Total damages related to homes and businesses were estimated at $400,000.  Another $100,000 in damages occurred with railroad repairs. Damage to public infrastructure (roads, bridges, trails) were estimated at $382,000.
In Eau Claire County, damage assessments found that five homes sustained major damage and 45 had minor damage. Total damages related to homes and businesses were estimated at $300,000.  Damage to public infrastructure (roads, bridges, trails) were estimated at $360,000.
In Eau Claire County, the Red Cross assisted those displaced in the city of Eau Claire and surrounding communities.

Several roads were closed in Eau Claire county, that included; Highway DD, Q, XX, and G.
Due to the widespread and significant flood damage, there was an approved presidential disaster declaration for Chippewa County.

Hail in ST. CROIX, WISCONSIN
From 21-SEP-16 00:00:00 to 21-SEP-16 00:00:00 (CST-6)
Location: HAMMOND
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in CHIPPEWA, WISCONSIN
From 21-SEP-16 11:45:00 to 21-SEP-16 11:45:00 (CST-6)
Location: BLOOMER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in CHIPPEWA, WISCONSIN
From 21-SEP-16 12:10:00 to 21-SEP-16 12:10:00 (CST-6)
Location: JIM FALLS
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in DUNN, WISCONSIN
From 21-SEP-16 14:45:00 to 21-SEP-16 14:45:00 (CST-6)
Location: BOYCEVILLE
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in DUNN, WISCONSIN
From 21-SEP-16 16:28:00 to 21-SEP-16 16:28:00 (CST-6)
Location: COLFAX
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in EAU CLAIRE, WISCONSIN
From 21-SEP-16 16:30:00 to 21-SEP-16 16:30:00 (CST-6)
Location: AUGUSTA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A few trees were blown down near Highway 27 and Solie Road near Augusta.

Thunderstorm Wind in POLK, WISCONSIN
From 21-SEP-16 17:00:00 to 21-SEP-16 17:05:00 (CST-6)
Location: OSCEOLA MUNI ARPT
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A few trees were blown down between Osecola, St. Croix Falls and Amery, Wisconsin.

Hail in EAU CLAIRE, WISCONSIN
From 20-SEP-16 18:40:00 to 20-SEP-16 18:40:00 (CST-6)
Location: ALTOONA
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Flash Flood in CHIPPEWA, WISCONSIN
From 21-SEP-16 19:00:00 to 21-SEP-16 22:00:00 (CST-6)
Location: ALBERTVILLE
Flood cause: Heavy Rain
Property damage: 882.00K
Crop damage: 0.00K
Reported by: County Official

Widespread flash flooding occurred across southern Chippewa County due to extreme rainfall rates, and amounts of 5 to 8 inches fell in less than 6 hours. A 50 foot section of railroad was damaged near Stanley, and there was minor damage to 12 businesses and homes, and 3 more with major damage. Total damages were estimated at $400,000 in the private section, $100,000 in railroad expenses, and $382,000 in roads, bridges and trails infrastructure.

Flash Flood in EAU CLAIRE, WISCONSIN
From 21-SEP-16 19:00:00 to 21-SEP-16 22:00:00 (CST-6)
Location: EAU CLAIRE
Flood cause: Heavy Rain
Property damage: 660.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Widespread flooding occurred in the city of Eau Claire. 45 homes and businesses sustained minor damage, and 5 sustained major damage due to the flood waters. In addition, a mudslide occurred near Highway 53, on the north side of Eau Claire.  Total damages were estimated at $300,000 in the private sector, and $360,000 in the public sector for roads, bridges, and trails infrastructure.

Flash Flood in EAU CLAIRE, WISCONSIN
From 21-SEP-16 19:30:00 to 21-SEP-16 22:30:00 (CST-6)
Location: LUDINGTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Flood waters covered Highway 27 and County Highway X near Ludington.