A convective complex from the Northern Plains brought strong to severe thunderstorms across mainly west half portions of Lake Superior on the morning of the 8th.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MQT wrote it up.
A convective complex from the Northern Plains brought strong to severe thunderstorms across mainly west half portions of Lake Superior on the morning of the 8th.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Marquette, MI wrote its last area forecast discussion before the first event at Jun 8, 5:22 AM EST, 28 minutes earlier.
Area Forecast Discussion National Weather Service Marquette MI 622 AM EDT Tue Jun 8 2021 .SHORT TERM...(Today and tonight) Issued at 311 AM EDT TUE JUN 8 2021 Upper air pattern consists of a 500 mb trough on the west coast and a low in the mid Mississippi Valley. There is also a ridge across the ern half of the U.S. The ridge remains stationary and the upper Great Lakes remains on the northern edge of it. This will mean continued above normal temperatures through this forecast period. It will also mean there will be some lake breezes with some localized cooling and with convergence of lake breezes, possibilities of lake breeze convection in the late morning into the evening as well. .LONG TERM...(Wednesday through Monday) Issued at 440 AM EDT TUE JUN 8 2021 An amplified upper level longwave trough will continue to be anomalously deep over the Pacific NW portion of the CONUS to start off this extended forecast period for Wednesday. Conversely, with the anomalous longwave trough further to the Pacific NW, an amplified upper level ridge will persist over the Central CONUS through the end of the week. EPS/GEPS/GEFS Ensemble members trending toward this solution from Wednesday through early Friday before the longwave trough begins to get absorbed into the jet energy flow and propagate to the east as a shortwave, and ultimately near the Great Lakes by this weekend. The overall trend will continue to be above average temperatures for the interior of Upper Michigan, and slightly cooler temperatures near the lake shorelines. Wednesday and Thursday afternoon will result in possible weak to scattered convective initiation after the lake breeze moves inland. Total rainfall QPF still remains on the low threshold however. Some of the model guidance has guidance in decent agreement on some precipitation arriving late Thursday evening into early Friday ahead of an approaching shortwave. Bumped up PoPs for the west half because of this for the time being. On Friday, the longwave trough over the Pacific NW will move east as a potent shortwave, becoming negatively tilted at 500mb over the northern Plains area. This shortwave will propagate northward into Manitoba and far NW Ontario. An attendant surface low associated with the upper level shortwave is likely to remain to the north of the cwa for Friday, but thundershowers will possible across Upper Michigan. A weak cold front will arrive Saturday with widespread rain showers through Saturday night. Surface High pressure will move toward the Great Lakes on Sunday as the upper level flow returns to a weak zonal to ridging signal. Next week will start with model guidance continuing the trend of a building upper level ridge over the Intermountain West, and another shortwave potentially affecting the Great Lakes with more precipitation. BW && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 622 AM EDT TUE JUN 8 2021 VFR conditions should prevail at KIWD/KCMX/KSAW thru most of this fcst period. Isold to sct shra/tsra should develop during the aftn, but confidence is low on whether any of the terminals may be affected. Of the 3 terminals, KSAW has the best chc of possibly seeing some pcpn. VCSH/VCTS was included in fcst for now. Fog looks likely at KCMX and KSAW tonight and will go down to IFR/LIFR at both sites. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 311 AM EDT TUE JUN 8 2021 Marine fog has started to make an appearance as airmass going across the cold waters has started to condense out some fog...especially over Lake Michigan and beginning to do so over Lake Superior as well. With lighter winds, this will come increasingly into play. Expect wind speeds less than 20 knots through the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... Dense Fog Advisory until 11 AM EDT this morning for LMZ248-250. && SHORT TERM...07 LONG TERM...BW AVIATION...07 MARINE...07
Hazardous Weather Outlook National Weather Service Marquette MI 429 AM EDT Tue Jun 8 2021 MIZ001>007-009>014-084-085-090830- Keweenaw-Ontonagon-Northern Houghton-Baraga-Marquette-Alger-Luce- Gogebic-Iron-Dickinson-Menominee-Delta-Southern Schoolcraft- Southern Houghton-Northern Schoolcraft- 429 AM EDT Tue Jun 8 2021 /329 AM CDT Tue Jun 8 2021/ This Hazardous Weather Outlook is for portions of western Upper Michigan and central Upper Michigan. .DAY ONE...Today and Tonight Scattered thunderstorms are possible today, mainly this afternoon. Hot weather is expected today. Take steps to prevent heat exhaustion when outdoors, and never leave children or pets in a hot car! .DAYS TWO THROUGH SEVEN...Wednesday through Monday Hot weather is expected to last through at least the middle of this week. Take steps to prevent heat exhaustion when outdoors, and never leave children or pets in a hot car! Thunderstorms are possible every day this week, mainly in the afternoon. Best chance is on Friday. .SPOTTER INFORMATION STATEMENT... The need for weather spotter reports is not anticipated at this time. LSZ162-240>251-263>267-090830- Lake Superior west of a line from Saxon Harbor WI to Grand Portage MN beyond 5NM-Saxon Harbor WI to Black River MI- Black River to Ontonagon MI- Ontonagon to Upper Entrance of Portage Canal MI- Upper Entrance of Portage Canal to Eagle River MI- Eagle River to Manitou Island MI- Manitou Island to Point Isabelle MI- Point Isabelle to Lower Entrance of Portage Canal MI- Lower Entrance of Portage Canal To Huron Islands MI Including Keweenaw and Huron Bays-Huron Islands to Marquette MI- Marquette to Munising MI-Munising to Grand Marais MI- Grand Marais to Whitefish Point MI- Lake Superior from Saxon Harbor WI to Upper Entrance to Portage Canal MI 5NM off shore to the US/Canadian border including Isle Royale National Park- Lake Superior from Upper Entrance to Portage Canal to Manitou Island MI 5NM off shore to the US/Canadian Border- Lake Superior West of Line from Manitou Island to Marquette MI Beyond 5NM from shore- Lake Superior East of a line from Manitou Island to Marquette MI and West of a line from Grand Marais MI to the US/Canadian Border Beyond 5NM from shore- Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off shore to the US/Canadian border- 429 AM EDT Tue Jun 8 2021 /329 AM CDT Tue Jun 8 2021/ This Hazardous Weather Outlook is for portions of Eastern Lake Superior...Central Lake Superior and Western Lake Superior. .DAY ONE...Today and Tonight There is a slight chance for thunderstorms across the southern third of the lake today. .DAYS TWO THROUGH SEVEN...Wednesday through Monday There is a slight chance for thunderstorms across the southern third of the lake on Thursday. Scattered thunderstorms expected for Friday. .SPOTTER INFORMATION STATEMENT... The need for weather spotter reports is not anticipated at this time. LMZ221-248-250-090830- Green Bay North of line from Cedar River MI to Rock Island Passage-Seul Choix Point to Point Detour MI- 5NM East of a line from Fairport MI to Rock Island Passage- 429 AM EDT Tue Jun 8 2021 This Hazardous Weather Outlook is for portions of Northern Lake Michigan. .DAY ONE...Today and Tonight Locally dense fog is possible across northern Lake Michigan outside of the Bay of Green Bay. See the latest Marine Weather Message for further details .DAYS TWO THROUGH SEVEN...Wednesday through Monday There is a chance of thunderstorms for Friday, mainly in the afternoon. .SPOTTER INFORMATION STATEMENT... The need for weather spotter reports is not anticipated at this time. BW
The Duluth radar (KDLH), 192 km away, was scanning. The volume nearest the first event began at 10:50 UTC.
4 marine thunderstorm wind. Local standard time, as filed.
The western Lake Superior buoy 45006 measured a peak thunderstorm wind gust of 45 mph.
Measured peak thunderstorm wind gust at Rock of Ages Light C-MAN station.
Measured peak thunderstorm wind gust at Passage Island Light C-MAN station.
Peak thunderstorm wind gust at Stannard Rock Light C-MAN station.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Lake Superior in 2021Every state in 2021This day in weather history
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 960003, 960004, 960005, 960006.