A cold front moving through a moist and unstable air mass generated strong to severe thunderstorms across Lake Superior on the afternoon and evening of the 27th.

Marine Thunderstorm Wind in HURON ISLANDS TO MARQUETTE MI, LAKE SUPERIOR
From 27-AUG-19 14:50:00 to 27-AUG-19 14:55:00 (EST-5)
Location: GRANITE ISLAND LIGHT
Magnitude: 38.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Peak thunderstorm wind gust at the Granite Light GLOS station.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI BEYOND 5NM FROM SHORE, LAKE SUPERIOR
From 27-AUG-19 14:50:00 to 27-AUG-19 14:55:00 (EST-5)
Location: MARQUETTE
Magnitude: 38.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Peak thunderstorm wind gust at the Granite Light GLOS station.

Waterspout in HURON ISLANDS TO MARQUETTE MI, LAKE SUPERIOR
From 27-AUG-19 14:31:00 to 27-AUG-19 14:35:00 (EST-5)
Location: BIG BAY POINT LIGHT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A waterspout was observed from the Big Bay Lighthouse.

Marine Thunderstorm Wind in HURON ISLANDS TO MARQUETTE MI, LAKE SUPERIOR
From 27-AUG-19 14:33:00 to 27-AUG-19 14:38:00 (EST-5)
Location: MARQUETTE LIGHTHOUSE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

There was an estimated thunderstorm wind gust of 60 mph in Marquette.

Marine Thunderstorm Wind in MARQUETTE TO MUNISING MI, LAKE SUPERIOR
From 27-AUG-19 14:33:00 to 27-AUG-19 14:38:00 (EST-5)
Location: MARQUETTE LIGHTHOUSE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

There was an estimated thunderstorm wind gust of 60 mph in Marquette.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI BEYOND 5NM FROM SHORE, LAKE SUPERIOR
From 27-AUG-19 14:33:00 to 27-AUG-19 14:38:00 (EST-5)
Location: MARQUETTE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

There was an estimated thunderstorm wind gust of 60 mph in Marquette.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI AND W OF GRAND MARAIS MI TO US/CANADIAN BORDER BEYOND 5NM OF SHORE, LAKE SUPERIOR
From 27-AUG-19 14:33:00 to 27-AUG-19 14:38:00 (EST-5)
Location: MARQUETTE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

There was an estimated thunderstorm wind gust of 60 mph in Marquette.

Marine Thunderstorm Wind in MARQUETTE TO MUNISING MI, LAKE SUPERIOR
From 27-AUG-19 15:25:00 to 27-AUG-19 15:30:00 (EST-5)
Location: MUNISING
Magnitude: 39.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Munising ASOS measured a thunderstorm wind gust of 45 mph.

Marine Thunderstorm Wind in MUNISING TO GRAND MARAIS MI, LAKE SUPERIOR
From 27-AUG-19 15:25:00 to 27-AUG-19 15:30:00 (EST-5)
Location: GRAND ISLAND HARBOR LIGHT
Magnitude: 39.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Munising ASOS measured a thunderstorm wind gust of 45 mph.

Marine Thunderstorm Wind in MUNISING TO GRAND MARAIS MI, LAKE SUPERIOR
From 27-AUG-19 15:50:00 to 27-AUG-19 15:55:00 (EST-5)
Location: GRAND MARAIS LIGHT
Magnitude: 44.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 51 mph.

Marine Thunderstorm Wind in GRAND MARAIS TO WHITEFISH POINT MI, LAKE SUPERIOR
From 27-AUG-19 15:50:00 to 27-AUG-19 15:55:00 (EST-5)
Location: GRAND MARAIS LIGHT
Magnitude: 44.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 51 mph.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI AND W OF GRAND MARAIS MI TO US/CANADIAN BORDER BEYOND 5NM OF SHORE, LAKE SUPERIOR
From 27-AUG-19 15:50:00 to 27-AUG-19 15:55:00 (EST-5)
Location: GRAND MARAIS
Magnitude: 44.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 51 mph.

Marine Thunderstorm Wind in MUNISING TO GRAND MARAIS MI, LAKE SUPERIOR
From 27-AUG-19 16:20:00 to 27-AUG-19 16:25:00 (EST-5)
Location: GRAND MARAIS LIGHT
Magnitude: 37.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 43 mph.

Marine Thunderstorm Wind in GRAND MARAIS TO WHITEFISH POINT MI, LAKE SUPERIOR
From 27-AUG-19 16:20:00 to 27-AUG-19 16:25:00 (EST-5)
Location: GRAND MARAIS LIGHT
Magnitude: 37.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 43 mph.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI AND W OF GRAND MARAIS MI TO US/CANADIAN BORDER BEYOND 5NM OF SHORE, LAKE SUPERIOR
From 27-AUG-19 16:20:00 to 27-AUG-19 16:25:00 (EST-5)
Location: GRAND MARAIS
Magnitude: 37.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 43 mph.

Marine Thunderstorm Wind in GRAND MARAIS MI TO WHITEFISH POINT MI 5NM OFFSHORE TO THE US/CANADIAN BORDER, LAKE SUPERIOR
From 27-AUG-19 16:20:00 to 27-AUG-19 16:25:00 (EST-5)
Location: GRAND MARAIS
Magnitude: 37.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 43 mph.

Marine Thunderstorm Wind in GRAND MARAIS MI TO WHITEFISH POINT MI 5NM OFFSHORE TO THE US/CANADIAN BORDER, LAKE SUPERIOR
From 27-AUG-19 15:50:00 to 27-AUG-19 15:55:00 (EST-5)
Location: GRAND MARAIS
Magnitude: 44.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Grand Marais GLOS station measured a thunderstorm wind gust of 51 mph.

Marine Thunderstorm Wind in GRAND MARAIS TO WHITEFISH POINT MI, LAKE SUPERIOR
From 27-AUG-19 16:58:00 to 27-AUG-19 17:05:00 (EST-5)
Location: WHITEFISH POINT LIGHT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mariner

There was a ship report just north of Whitefish Point of a thunderstorm wind gust of 60 mph.  Waterspouts were also sighted.  The report was relayed via NWS Gaylord and the Sault Ste. Marie Coast Guard.

Marine Thunderstorm Wind in GRAND MARAIS MI TO WHITEFISH POINT MI 5NM OFFSHORE TO THE US/CANADIAN BORDER, LAKE SUPERIOR
From 27-AUG-19 16:58:00 to 27-AUG-19 17:05:00 (EST-5)
Location: WHITEFISH POINT LIGHT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mariner

There was a ship report just north of Whitefish Point of a thunderstorm wind gust of 60 mph.  Waterspouts were also sighted.  The report was relayed via NWS Gaylord and the Sault Ste. Marie Coast Guard.

Marine Hail in MARQUETTE TO MUNISING MI, LAKE SUPERIOR
From 27-AUG-19 20:01:00 to 27-AUG-19 20:06:00 (EST-5)
Location: SHOT POINT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Nickel-sized hail was reported just west of the Marquette-Alger county line.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI AND W OF GRAND MARAIS MI TO US/CANADIAN BORDER BEYOND 5NM OF SHORE, LAKE SUPERIOR
From 27-AUG-19 20:00:00 to 27-AUG-19 20:05:00 (EST-5)
Location: STANNARD ROCK LIGHT
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: C-MAN Station

The Stannard Rock Light station measured a peak thunderstorm wind gust of 59 mph.

Marine Thunderstorm Wind in HURON ISLANDS TO MARQUETTE MI, LAKE SUPERIOR
From 27-AUG-19 19:20:00 to 27-AUG-19 19:25:00 (EST-5)
Location: GRANITE ISLAND LIGHT
Magnitude: 43.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Granite Island Light GLOS station measured a peak thunderstorm wind gust of 49  mph.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI BEYOND 5NM FROM SHORE, LAKE SUPERIOR
From 27-AUG-19 19:20:00 to 27-AUG-19 19:25:00 (EST-5)
Location: MARQUETTE
Magnitude: 43.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Granite Island Light GLOS station measured a peak thunderstorm wind gust of 49  mph.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI AND W OF GRAND MARAIS MI TO US/CANADIAN BORDER BEYOND 5NM OF SHORE, LAKE SUPERIOR
From 27-AUG-19 19:20:00 to 27-AUG-19 19:25:00 (EST-5)
Location: MARQUETTE
Magnitude: 43.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Granite Island Light GLOS station measured a peak thunderstorm wind gust of 49  mph.

Marine Thunderstorm Wind in MANITOU ISLAND TO MARQUETTE MI AND W OF GRAND MARAIS MI TO US/CANADIAN BORDER BEYOND 5NM OF SHORE, LAKE SUPERIOR
From 27-AUG-19 20:40:00 to 27-AUG-19 20:45:00 (EST-5)
Location: STANNARD ROCK LIGHT
Magnitude: 37.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Buoy

The eastern Lake Superior buoy measured a peak thunderstorm wind gust of 43 mph.

Marine Thunderstorm Wind in GRAND MARAIS MI TO WHITEFISH POINT MI 5NM OFFSHORE TO THE US/CANADIAN BORDER, LAKE SUPERIOR
From 27-AUG-19 20:40:00 to 27-AUG-19 20:45:00 (EST-5)
Location: CARIBOU ISLAND
Magnitude: 37.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Buoy

The eastern Lake Superior buoy measured a peak thunderstorm wind gust of 43 mph.