As a significant ridge was over the southeastern US, hot and unstable air was over Michigan's Upper Peninsula by the 30th. This warm and moist air caused unseasonable heat impacts, and forcing from an approaching upper level disturbance over the Canadian Prairie initiated thunderstorms that caused multiple forms of severe weather, including the first confirmed tornado for the Upper Peninsula…
Every event with a place to put it; 7 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
As a significant ridge was over the southeastern US, hot and unstable air was over Michigan's Upper Peninsula by the 30th. This warm and moist air caused unseasonable heat impacts, and forcing from an approaching upper level disturbance over the Canadian Prairie initiated thunderstorms that caused multiple forms of severe weather, including the first confirmed tornado for the Upper Peninsula since 2020.
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 30, 6:36 AM EST, 3 hours 24 minutes earlier. Its key messages:
Area Forecast Discussion
National Weather Service Marquette MI
736 AM EDT Tue Jun 30 2026
.KEY MESSAGES...
- Hot and humid weather is expected through much of the week, with
the hottest temperatures today and tomorrow. The heat index will
reach the low 100s today. Therefore, heat advisories remain in
effect over the entire CWA.
-There is a slight risk (15% chance) for severe thunderstorms today,
mainly during the afternoon and evening. The main threat will be
damaging winds though a few storms with large hail cannot be ruled
out.
- There will be the chance for thunderstorms every day/night this
week along with the potential for strong to severe thunderstorms.
&&
.UPDATE...
Issued at 343 AM EDT Tue Jun 30 2026
RAP analysis/GOES water vapor imagery early this morning shows upper
level low pressure over southern Manitoba with its associated warm
front extending southeastward across southern Ontario and into the
Keweenaw and eastern UP. With temperatures and dew points south of
the boundary still in the 60s/70s and MUCAPE values around 1000
J/kg, instability has been sufficient enough to trigger a few
isolated showers and embedded thunderstorms. Reflectivities on
current radar mosaic are lighting up across portions of the Keweenaw
and north-central Wisconsin, drifting northeastward. But, the most
intense activity remains just to the west of Lake Superior where the
jet streak is providing the best dynamics. This will be area of
focus through daybreak, but cannot rule out some of the inland
showers/storms intensifying a bit at times as well with some gusty
winds and small hail through the early morning hours. Otherwise,
main event is still progged for later this afternoon as low-level
jet strengthens over north-central Wisconsin and combines with upper-
level trough. Meanwhile, forecast soundings highlight deep layer
shear conducive to damaging winds and large hail. As a result, the
entire UP remains under a Slight Risk from SPC. Further additional
development also cannot be ruled out this evening into tonight
dependent on upstream MCS evolution.
&&
.DISCUSSION...
Issued at 314 PM EDT Mon Jun 29 2026
Ridging was building over the area today ahead of an upper level low
pressure over eastern MT. Thunderstorm formed early this morning as
a warm from lifted north through the region. Thunderstorms lingered
through the early afternoon hours over the eastern UP, northern Lake
Michigan and parts of Lake Superior. Low level moisture advecting
into the area and clouds shearing off of the anvils of storms to the
west helped keep ample cloud cover over the region, putting a hamper
on the expected heating today. At 130pm this afternoon temperatures
were only in the 60s east and 70s south and west. Some patches of
broken cloud cover were beginning to show up in the western UP and
north central WI, lifting northwards. It is still likely that the
sun will make an appearance in the western UP late this afternoon
and evening and it will quickly feel quite muggy. That being said,
knocked the expected highs down into the mid to upper 80s over the
west. A line of severe thunderstorms was over north-cental MN moving
eastwards.
Steepening mid-level lapse rates and deep moisture will bring
increasing instability to the area through tonight, reaching upwards
of 3000-4000 J/kg. While instability and shear will create a
favorable environment for strong thunderstorms the best lift will
remain closer to a jet streak and diffluent flow over northern MN.
Models are in decent agreement that convection west of the region
will push into western Lake Superior tonight, weakening as it moves
into the central part of the lake, where the LLJ will be weaker.
There is uncertainty as to how far south the storms will extend and
can't rule out a stronger thunderstorm over the western UP this
evening into the late night hours. The CAMs are not handling the
ongoing bow echo over MN very well, if at all, but with loss of
support as it moves east the southern part of the complex will
likely dissipate. It will be warm and muggy overnight with lows in
the mid 60s east to the low 70s west.
The upper level low will very slowly make its way to northern
Manitoba through Wednesday night with ridging over the Upper Great
Lakes. On Wednesday the ridge will begin to flatten out some with
several shortwaves pushing through into early next week. 850mb temps
of 22-24C are expected on Tuesday with highs well into the 80s and
mid 90s. This, combined with dewpoints in the 60s to near 70 will
bring the heat index to the low 100s over much of the UP. Expanded
heat advisories to the rest of the CWA for Tuesday. Those who will
be exposed to the heat for prolonged periods and those who are
sensitive to the heat should have a plan to stay cool and hydrated.
850mb temps will remain warm but a bit cooler, 18-20C through the
rest of the week into next weekend. This will likely keep the heat
below advisory levels but very warm and muggy conditions will
continue.
Extreme instability will develop through the day, with mucape at an
impressive 5000+ J/kg along with 40+ kt bulk shear. A capping
inversion should hold for much of the morning and early afternoon
but will weaken in the late afternoon. At this time it appears a
boundary (moisture gradient) will set up over western Lake Superior
and UP, providing a focus for convection with the weakening cap.
Confidence is fairly high that we will see thunderstorms in the
region, some of which will be strong to severe. However, the
location of the boundary could be highly influenced by the
convection this afternoon and tonight to the north and west. Should
severe storms develop they will likely grow upscale into an MSC with
the main threat being strong, damaging winds up to 80mph. Secondary
threats being large hail and an isolated tornado.
The chance for thunderstorms (possibly strong to severe) will
continue through the week as multiple shortwaves round the
flattening ridge. Predictability is low on timing and placement of
thunderstorm activity, which will be highly dependent on the
evolution of MCSs and resultant outflow boundaries.
&&
.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 735 AM EDT Tue Jun 30 2026
With the exception of airport mins at SAW for a few more hours, VFR
conditions are prevailing at all other TAF sites. Once VFR returns
to SAW by mid-morning, it will be the predominant flight category
there, too, for the TAF period. However, forecast is still on track
for scattered severe thunderstorms later this afternoon and evening,
which are best highlighted with PROB30s at this point. Winds will
have a primarily southerly component throughout the period, but may
fluctuate between southwest and southeast around 10 kt with
gusts up to 20 kt, except in the immediate vicinity of a
thunderstorm. Will carry LLWS mention at CMX through mid-
morning.
&&
.MARINE...
Issued at 314 PM EDT Mon Jun 29 2026
The weather will remain active across the Upper Great Lakes through
the week with multiple rounds of thunderstorms, some of which could
be strong to severe. Southerly winds will increase to 30kt tonight
before falling back to 20kt or less on Tuesday. As a very humid
airmass spreads across the lake areas of dense fog will continue to
develop, especially anywhere rainfall is occuring. Issued dense fog
advisories for the mid-lake through tonight but there is the
potential for fog to increase in coverage tonight, lingering into
the day tomorrow. Some of the thunderstorms this week could be
strong to severe. For this evening and Tuesday strong winds will be
the main threat with any of the stronger storms. There is a
potential for winds up to 70kt should severe thunderstorms for
Tuesday afternoon and evening.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Heat Advisory until 8 PM EDT /7 PM CDT/ this evening for
MIZ002>007-009>014-084-085.
Beach Hazards Statement through this evening for MIZ014.
Lake Superior...
Dense Fog Advisory until 2 PM EDT /1 PM CDT/ this afternoon
for LSZ162-240>251-263>267.
Lake Michigan...
None.
&&
UPDATE...TDUD
DISCUSSION...NL
AVIATION...TDUD
MARINE...NLPreliminary Local Storm Report
National Weather Service Marquette MI
1031 AM EDT Tue Jun 30 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0519 PM Tstm Wnd Gst 1 NW Ontonagon 46.87N 89.32W
06/29/2026 M45 MPH Ontonagon MI Public
Public weather station KMIONTON26 measured a
45mph along the Ontonagon River. Delayed
report.
&&
JSSPreliminary Local Storm Report
National Weather Service Marquette MI
1048 AM EDT Tue Jun 30 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0611 PM Tstm Wnd Gst Houghton Co Airport 47.17N 88.48W
06/29/2026 M39 MPH Houghton MI ASOS
ASOS station KCMX Houghton Co. Airport.
&&
JSSPreliminary Local Storm Report
National Weather Service Marquette MI
1049 AM EDT Tue Jun 30 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0718 PM Tstm Wnd Gst 4 NE Negaunee 46.53N 87.55W
06/29/2026 M46 MPH Marquette MI Mesonet
Mesonet station CW4331 WFO-Negaunee
Township.
&&
JSSPreliminary Local Storm Report
National Weather Service Marquette MI
1050 AM EDT Tue Jun 30 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0753 PM Tstm Wnd Gst 1 NW Kingsford 45.82N 88.12W
06/29/2026 M40 MPH Dickinson MI ASOS
ASOS station KIMT Ford Airport.
&&
JSSPreliminary Local Storm Report
National Weather Service Marquette MI
1058 AM EDT Tue Jun 30 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0613 PM Tstm Wnd Gst 3 SSW Pelkie 46.78N 88.66W
06/29/2026 M41 MPH Baraga MI Mesonet
Mesonet station PIEM4 Pelkie RAWS.
&&
JSSPreliminary Local Storm Report
National Weather Service Marquette MI
1059 AM EDT Tue Jun 30 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1010 PM Tstm Wnd Gst 10 SE Ford River 45.58N 87.00W
06/29/2026 M35 MPH LMZ221 MI Mesonet
Mesonet station XMAPV Minneapolis Shoal.
&&
JSSThe Marquette radar (KMQT), 64 km away, was scanning. The volume nearest the first event began at 23:08 UTC.
4 heat, 3 excessive heat, 3 hail, 2 tornado, 1 thunderstorm wind. Local standard time, as filed.
The Pelkie RAWS site PIEM4 reported heat index values in excess of 100 degrees from 10 AM EST through 2 PM, with a peak heat index of 105 at 2 PM.
The ASOS site at KIMT Ford Airport in Iron Mountain recorded heat indices in excess of 100 degrees for all but 1 hour from 9:54 CST to 3:54 CST, including 4 contiguous hours of heat index exceeding 100 and a peak heat index value of 107 at 2:54.
The High Bridge RAWS site HBRM4 reported heat index values in excess of 105 degrees from 11 AM EST through 3 PM with a peak value of 110 at 1 PM.
Additionally, the AWOS site KESC at the Delta County Airport and STOM4, the Stonington RAWS site, reached a peak heat index in excess of 105 degrees despite close proximity to the cooling influence of Lake Michigan.
The RAWS site DOEM4 at Doe Lake reported heat index values from 107 to 109 degrees from noon EST through 4 PM with heat index in excess of 100 degrees in the 1 hour preceding and 2 hours following that time period. Additionally, the ASOS site KP53 at the Munising Lakeshore reached a peak heat index of 105 degrees at 3:56 PM despite the close proximity to the cooling influence of Lake Superior.
The Spincich Lake RAWS site SPCM4 reported heat index values of 100-101 degrees beginning around noon and falling below 100 at 3 PM.
The AWOS site KMNM at the Menominee Marinette Twin County Airport reported heat index values exceeding 100 degrees from 12:57 PM to 4:47 PM with a peak heat index of 108 degrees at 2:57.
Additionally, the La Branche RAWS site, LBRM4, reported heat index values in excess of 100 from 11 AM through 3 PM, peaking at 105 at 3 PM.
The RAWS site GINM4 at Gwinn reported a 3 hour period of 105 to 106 degree heat index from 3 PM to 6 PM EST, including heat index values over 100 in the 2 hours preceding that period and 1 hour following.
A public observation of ping pong ball size hail was reported 1.5 miles south of Trenary on social media. The time was estimated by radar.
A public report of a picture from social media showed ping pong ball sized hailstone. The time was estimated via radar.
A public report from social media indicated tree damage on Stone Road. The time was estimated via radar.
A thunderstorm initiating in southern Marquette County continued to develop into a supercell thunderstorm as it moved east into Delta and Alger County. As the thunderstorm began splitting, the southern segment intensified and produced a weak, EF-0 tornado south of Trenary, MI in Delta County. The tornado crossed Alger Delta 43rd road and proceeded northeast before dissipating.
A public report from social media indicated nickel size hail. A picture was not included with the observation.
A thunderstorm initiating in southern Marquette County continued to develop into a supercell thunderstorm as it moved east into Delta and Alger County. As the thunderstorm began splitting, the southern segment intensified and produced a weak, EF-0 tornado south of Trenary, MI in Delta County. The tornado crossed Alger Delta 43rd road and proceeded northeast before dissipating.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2026Every state in 2026This day in weather historyThe tornado archive for Michigan, 2026Warnings in Michigan, June 2026
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: 1345601, 1345536, 1345569, 1345546, 1345570, 1345537, 1345543, 1347166, 1347167, 1347169, 1345526, 1347170, 1345527.