Convectively enhanced vorticity max lead to initiation of storms overnight Sunday across southern South Dakota. These initial storms grew upscale given concurrent downstream destabilization through northeast Nebraska and northwest Iowa. Widespread 80-100 mph winds developed through central/eastern Iowa as this derecho matured. Northern bookend and advection wing forcing led to some supercell structures across northern Illinois/southwest Wisconsin. Northern bookend turned northeast as it moved across Lake Michigan and tracked into western Michigan. As this occurred, attendant post convective wake low weakened as it crossed the lake. Thus the local area did not experience the 80 to 100 mph winds that N IL/E IA experienced. However the resultant slowing and breakup of the line as it moved across northwest Indiana/SW Michigan, yielded a LEWP and subsequent multiple small scale circulations developing along the line. These meso-vortices were associated with pockets of enhanced wind damage and brief tornado occurrences.

Seiche in BERRIEN, MICHIGAN
From 10-AUG-20 17:00:00 to 11-AUG-20 04:00:00 (EST-5)
Crop damage: 0.00K
Reported by: Emergency Manager

The initial gust front passed the Cook Buoy (45026) near Stevensville, MI around 5:55 pm when waves were reportedly one foot. By 6:20 pm, waves had climbed to four feet and a meteotsunami was reported by an off-duty NWS employee who was at Lion���s Park Beach. Water levels rose approximately one and one half foot above the mean levels by that time, and flooding was reported along Lion���s Park Drive through the evening. Wave heights at the Cook Buoy peaked at around five feet at 8:40 pm.
According to the Berrien County EMA, there was lakeshore flooding also reported in New Buffalo, MI, which lasted into the late evening hours. A seiche could be seen at various water level gauges across Lake Michigan into the next day (Tuesday August 11th, 2020), with the most extreme fluctuations extending from shortly after the storm passed until about 5 am EDT. Lesser fluctuations of up to one foot continued through around 10 am EDT.
No specific damage amounts were noted as near record high water levels and periodic high wave action continue to cause extensive erosion.

Thunderstorm Wind in ST. JOSEPH, MICHIGAN
From 10-AUG-20 05:30:00 to 10-AUG-20 05:31:00 (EST-5)
Location: EDWARDS CORNERS
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public reported a one to 2 foot diameter tree was blown down with several limbs up to one foot in diameter broken off along Wetherbee Rd.

Thunderstorm Wind in BERRIEN, MICHIGAN
From 10-AUG-20 17:06:00 to 10-AUG-20 17:07:00 (EST-5)
Location: GRAND BEACH
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency management officials reported a tree was blown down onto a power line.

Thunderstorm Wind in BERRIEN, MICHIGAN
From 10-AUG-20 17:12:00 to 10-AUG-20 17:13:00 (EST-5)
Location: BARODA
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public reported a transformer was blown down on Hollywood Rd and West Lemon Creek in Baroda township.

Thunderstorm Wind in BERRIEN, MICHIGAN
From 10-AUG-20 17:16:00 to 10-AUG-20 17:17:00 (EST-5)
Location: VINELAND
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public reported a large tree was blown down at Ansley and Lincoln.

Thunderstorm Wind in BERRIEN, MICHIGAN
From 10-AUG-20 17:18:00 to 10-AUG-20 17:19:00 (EST-5)
Location: BERRIEN SPGS
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public reported half a two foot diameter tree fell onto Mars Street.

Thunderstorm Wind in BERRIEN, MICHIGAN
From 10-AUG-20 17:21:00 to 10-AUG-20 17:22:00 (EST-5)
Location: BARODA
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency management officials reported several trees were blown down in Baroda township, Grand Beach, St. Joseph and surrounding areas.

Thunderstorm Wind in ST. JOSEPH, MICHIGAN
From 10-AUG-20 18:05:00 to 10-AUG-20 18:06:00 (EST-5)
Location: THREE RIVERS
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

The local fire department reported large trees blown down in the Three Rivers area.

Thunderstorm Wind in BERRIEN, MICHIGAN
From 10-AUG-20 17:25:00 to 10-AUG-20 17:26:00 (EST-5)
Location: (BEH)ROSS ARPT BNTN
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The ASOS at the Benton Harbor airport recorded a 67 mph wind gust.