A cold front moving through a moist and unstable air mass generated severe thunderstorms over portions of south central Upper Michigan on the afternoon of the 6th.
Every event with a place to put it. Tap one for its entry below.
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 cold front moving through a moist and unstable air mass generated severe thunderstorms over portions of south central Upper Michigan on the afternoon of the 6th.
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 Jul 6, 1:29 PM CST, 1 hour 16 minutes earlier.
Area Forecast Discussion National Weather Service Marquette MI 329 PM EDT Mon Jul 6 2020 .SHORT TERM...(This evening through Tuesday) Issued at 225 PM EDT MON JUL 6 2020 On the large scale, the pattern continues to be defined by broad ridging over much of the eastern half of the US and slight amplification to the ridge over Ontario and Quebec. A stronger upper- level disturbance exists well to the north of us over northern Manitoba west of Hudson Bay with a weak, ill-defined cold front stretched south and southwestward from it through northern Minnesota. After a weak warm front moved through early this morning, humidity is up from yesterday with dew points back in the mid 60s and temps in the mid 80s to lower 90s yet again. This heat and humidity has allowed 1000-2000 J/kg MLCAPE to build across the UP with no cap which means that weak forcing with the front to the west, plus lake breezes and remnant outflow boundaries are all combining to lead to widespread weak thunderstorms. These storms are expected to continue behaving the way they have for the past few hours with a lot of pulsing up and down but no sustained strong or severe storms since there continues to be little to no shear for these storms to work with. Expect that these storms will continue to fill in across the central UP along new outflow boundaries and the lake breezes. Still not sure exactly what happens this evening. Mesoanalysis shows a mid-level short wave near the ND/SD/MN triple point which will lift ENE into the UP by around 00z. This appears to be the feature that the NAM and other NMM-core models have keyed in on as the forcing for a larger and more significant bowing segment to develop and move into the western UP this evening. Mesoanalysis also shows a slight increase in effective shear to around 25-35 kts out ahead of this wave. The big question, however, will be how worked over the atmosphere is by that point by all of these earlier day storms that were not handled well at all by the 12z run of the CAMs. Have to think that the NAM, etc. are holding on to too much instability for too long and that this possible secant round of storms this evening won't materialize. Trended that way with POPs in keeping the highest values towards early evening, but then lingered lighter values through the evening just in case that does in fact materialize. Am very curious to see what the 18z NAM/NAM nest and CMC-Reg/CMC-hi-res show once they (hopefully) resolve the ongoing convection better. If they still show a strong storm signal at that point even after these storms today, may need to increase POPs and sky cover later on into the evening. Late tonight, the cold front will clear the area and become stationary oriented east-west through Wisconsin. Initially there will probably be lingering convective debris with low-level scattered clouds through midnight or early morning, but eventually the models show skies clearing towards dawn. The remnant moisture and scattered low clouds should keep overnight lows warm, in the mid to upper 60s. Behind the weak front, GEFS plumes show 850 mb temps cooling by about 1-2 C compared to today, and thus highs should be slightly cooler, although still in the mid 80s. Dew points should be just a few ticks lower as well. With lighter low-level winds behind the front, the Lake Superior lake breeze should make it farther inland tomorrow which will also help keep things cooler along the lakeshore where highs may not get out of the 70s. Depending on exactly where the front settles, there could be some scattered showers and storms again tomorrow afternoon over the south-central and along the Bay of Green Bay. The environment tomorrow looks to feature less heating and less moisture up here on the north side of the boundary, and thus MLCAPE only around 500-1000 J/kg, but stronger mid-level flow leading to 0-6 km bulk shear vectors of around 30-40 kts which could make for better storm organization should any form. .LONG TERM...(Tuesday night through Monday) Issued at 328 PM EDT MON JUL 6 2020 Ridging will move back into the upper Great Lakes into Wed. A 500 mb trough will move into the northern plains Wed night and then into the upper Great Lakes on Thu. Will still be unsettled for this forecast period and did not make too many changes to the going forecast. In the extended, the GFS and ECMWF show a 500 mb ridge in New England, another over the Rockies and a trough across the upper Great Lakes 12z Fri. Thu trough remains over the area into 12z Sat and then drops into the lower Great Lakes 12z Sun. Upper ridging then moves into the upper Great Lakes 12z Mon. Temperatures will remain at or above normal for this forecast period. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 143 PM EDT MON JUL 6 2020 Main story today will be scattered to numerous thunderstorms. Most have already moved through IWD but additional storms could develop next few hours so held on to a VCTS. Storms are just moving into CMX now. Most will stay south but they could get close enough for a brief vis reduction. Most storm coverage will be at SAW, beginning in about 2-3 hours and lasting through the evening with occasional MVFR vis possible. Once storms clear tonight, expecting low-level scattered clouds in their wake to linger through the evening, given that satellite shows a lot of that ongoing in Minnesota right now. They should finally clear late tonight. The W wind at CMX may push some marine fog onshore but models for the most part don't show it so only went as low as a 6SM BR for now. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 328 PM EDT MON JUL 6 2020 Light winds less than 20 kts are expected to continue throughout the forecast period. Areas of fog are likely to persist, especially over the east. Will still have to watch for dense fog at times with the moist humid airmass over the colder water. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && SHORT TERM...RJC LONG TERM...07 AVIATION...RJC MARINE...07
Hazardous Weather Outlook National Weather Service Marquette MI 358 PM EDT Mon Jul 6 2020 MIZ001>007-009>014-084-085-071200- Keweenaw-Ontonagon-Northern Houghton-Baraga-Marquette-Alger-Luce- Gogebic-Iron-Dickinson-Menominee-Delta-Southern Schoolcraft- Southern Houghton-Northern Schoolcraft- 358 PM EDT Mon Jul 6 2020 /258 PM CDT Mon Jul 6 2020/ This Hazardous Weather Outlook is for portions of western Upper Michigan and central Upper Michigan. .DAY ONE...Tonight Thunderstorms will persist into this evening, especially across the south central and east. Strong to severe storms will be capable of producing heavy rain, strong wind gusts and small hail. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Thunderstorms are possible Tuesday afternoon. By Wednesday afternoon, thunderstorms will be possible in the western half of Upper Michigan. During Wednesday evening into Thursday, thunderstorms will be likely across Upper Michigan. Some storms could be strong to severe at times and will be capable of producing heavy rainfall. The period of hot and humid weather is expected to continue through this week. Make sure you and your pets stay hydrated. Never leave pets or passengers unattended in hot vehicles! .SPOTTER INFORMATION STATEMENT... Spotters are encouraged to report any observed hail or wind damage from thunderstorms to the National Weather Service in Marquette. The public may also submit reports to the National Weather Service via phone, on our website, or through Facebook or Twitter. LSZ162-240>251-263>267-071200- 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- 358 PM EDT Mon Jul 6 2020 /258 PM CDT Mon Jul 6 2020/ This Hazardous Weather Outlook is for portions of Eastern Lake Superior...Central Lake Superior and Western Lake Superior. .DAY ONE...Tonight Thunderstorms will be possible over Lake Superior tonight...mainly in the east half. Areas of fog are expected tonight. Some locally dense areas will be possible. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Thunderstorms are possible over much of Lake Superior Wednesday afternoon through Thursday night. A few storms could be strong to severe with high wind gusts and some hail. .SPOTTER INFORMATION STATEMENT... The need for weather spotter reports is not anticipated at this time. LMZ221-248-250-071200- 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- 358 PM EDT Mon Jul 6 2020 This Hazardous Weather Outlook is for portions of Northern Lake Michigan. .DAY ONE...Tonight Thunderstorms will be possible tonight. Gusty winds and small hail may accompany stronger storms. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Thunderstorms are possible Tuesday, and Wednesday night through Friday. A few storms could be strong to severe at times. .SPOTTER INFORMATION STATEMENT... The need for weather spotter reports is not anticipated at this time. 07
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MARQUETTE MI
414 PM EDT MON JUL 6 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0300 PM HEAVY RAIN 3 ESE LAURIUM 47.23N 88.39W
07/06/2020 M1.46 INCH HOUGHTON MI CO-OP OBSERVER
CO-OP OBSERVER STATION TRRM4 2.5 NE LAKE
LINDEN. DURATION 24 HOURS, RADAR ESTIMATED.
&&
TAPSpecial Weather Statement National Weather Service Marquette MI 415 PM EDT Mon Jul 6 2020 MIZ006-062045- Alger MI- 415 PM EDT Mon Jul 6 2020 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL ALGER COUNTY UNTIL 445 PM EDT... At 415 PM EDT, Doppler radar was tracking a strong thunderstorm over Au Train, or 7 miles west of Munising, moving east at 10 mph. Wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Grand Island and Christmas. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Persons in campgrounds should consider seeking sturdy shelter until this storm passes. && LAT...LON 4640 8681 4645 8684 4654 8680 4644 8664 TIME...MOT...LOC 2015Z 257DEG 9KT 4644 8680 Ritzman
PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE MARQUETTE MI
418 PM EDT MON JUL 6 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0348 PM TSTM WND GST MUNISING 46.41N 86.65W
07/06/2020 M44 MPH ALGER MI ASOS
CORRECTS PREVIOUS NON-TSTM WND GST REPORT
FROM MUNISING. ASOS STATION KP53 MUNISING.
&&
TAPSpecial Weather Statement National Weather Service Marquette MI 420 PM EDT Mon Jul 6 2020 MIZ006-013-085-062045- Northern Schoolcraft MI-Delta MI-Alger MI- 420 PM EDT Mon Jul 6 2020 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN DELTA...WESTERN SCHOOLCRAFT AND SOUTHWESTERN ALGER COUNTIES UNTIL 445 PM EDT... At 420 PM EDT, Doppler radar was tracking strong thunderstorms along a line extending from near Au Train to Trenary. Movement was east at 20 mph. Half inch hail and wind gusts up to 50 mph will be possible with these storms. Locations impacted include... Munising, Miners Castle, Chapel Lake, Grand Island, Au Train, Chatham, Shingleton, Trenary, Christmas, Forest Lake, Diffin, Round Lake, Wetmore, Melstrand, Eben Junction, Van Meer and Traunik. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Persons in campgrounds should consider seeking sturdy shelter until these storms pass. && LAT...LON 4654 8638 4609 8651 4616 8706 4646 8694 TIME...MOT...LOC 2020Z 275DEG 16KT 4639 8687 4622 8696 Ritzman
Special Weather Statement
National Weather Service Marquette MI
437 PM EDT Mon Jul 6 2020
MIZ012-013-062130-
Delta MI-Menominee MI-
437 PM EDT Mon Jul 6 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN DELTA AND
NORTHEASTERN MENOMINEE COUNTIES UNTIL 530 PM EDT/430 PM CDT/...
At 437 PM EDT/337 PM CDT/, Doppler radar was tracking strong
thunderstorms along a line extending from U.S. 41 between Trenary and
Rapid River to Powers. Movement was north at 10 mph.
Half inch hail and winds in excess of 40 mph will be possible with
these storms.
Locations impacted include...
Escanaba, Gladstone, Rapid River, Powers, Rock, U.S. 41 between
Trenary and Rapid River, Wilson, Spalding, Bark River, Brampton,
Whitney, Cornell, St. Nicholas, Perkins, Hyde, Maplewood and
Schaeffer.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4562 8760 4580 8751 4599 8732 4599 8724
4606 8724 4616 8705 4612 8673 4595 8688
4567 8719
TIME...MOT...LOC 2037Z 201DEG 9KT 4615 8699 4569 8751
RJCSpecial Weather Statement National Weather Service Marquette MI 443 PM EDT Mon Jul 6 2020 MIZ006-013-014-085-062130- Northern Schoolcraft MI-Southern Schoolcraft MI-Delta MI-Alger MI- 443 PM EDT Mon Jul 6 2020 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN DELTA...NORTHWESTERN SCHOOLCRAFT AND CENTRAL ALGER COUNTIES UNTIL 530 PM EDT... At 443 PM EDT, Doppler radar was tracking strong thunderstorms along a line extending from near Chatham to near U.S. 41 between Trenary and Rapid River. Movement was east at 35 mph. Pea size hail and wind gusts up to 50 mph will be possible with these storms. Locations impacted include... Munising, Miners Castle, Chapel Lake, Grand Island, Shingleton, Steuben, Grand Sable Dunes, Christmas, Forest Lake, Cusino Lake, Beaver Lake, Grand Portal Point, Au Sable Point, Round Lake, Wetmore, Melstrand, Van Meer and Kingston Lake. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with these storms. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. Persons in campgrounds should consider seeking sturdy shelter until these storms pass. && LAT...LON 4674 8602 4607 8635 4615 8698 4642 8686 TIME...MOT...LOC 2043Z 252DEG 30KT 4636 8686 4616 8695 Ritzman
The Marquette radar (KMQT), 94 km away, was scanning. The volume nearest the first event began at 20:43 UTC.
4 thunderstorm wind. Local standard time, as filed.
A 10-foot by 20-foot horse shelter was blown down and tossed 50 feet near Wilson. Power was also knocked out in the area due to fallen trees on power lines.
There was a report of a car window smashed through with a tree and a silo leaning sideways due to thunderstorm winds near Wilson.
A tree and power lines were reported down near Hyde. Time of the report was estimated by radar.
Law enforcement reported multiple small trees down in north Escanaba. Time of report was estimated from radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2020Every state in 2020This day in weather historyWarnings in Michigan, July 2020
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: 902237, 902238, 902239, 902240.