A cold front moving across a moist and unstable airmass generated severe thunderstorms over mainly the west half of Upper Michigan during the evening of the 27th.
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 across a moist and unstable airmass generated severe thunderstorms over mainly the west half of Upper Michigan during the evening of the 27th.
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 27, 4:46 PM CST, 6 minutes earlier.
Area Forecast Discussion National Weather Service Marquette MI 646 PM EDT Thu Jul 27 2023 .SHORT TERM...(This evening through Tonight) Issued at 326 PM EDT THU JUL 27 2023 Main forecast issues and notable hazardous weather threats continue to be hot, humid conditions this afternoon and potential strong to severe storms into the evening. Synoptic-scale pattern continues to be dominated by the heat dome encompassing the Desert Southwest with hot temperatures creeping into the Plains and Upper Midwest. Meanwhile, low-amplitude troughing is located over the Canadian Prairies. Juxtaposition of these features is promoting seasonably strong zonal midlevel flow (35-50 kt) over the northern tier of the US along with associated low-level baroclinic zone over northern/central MN. Troughing will tend to sag a bit southward through tonight, which will eventually end up pushing the baroclinic zone into our area, setting the stage for a potential convective episode. After a round of morning showers that held back temperatures into the late morning, skies have cleared out across most of the UP. There are some leftover midlevel clouds in the eastern UP, and some additional weak, widely scattered convection to the west. A cluster of storms is firing in northern WI (mainly southern Ashland and Iron counties) along an instability gradient, but these are almost stationary, quickly collapsing. Still, amid southerly flow, some convective debris and lighter showers are drifting towards Gogebic county. Otherwise, temperatures are reaching into the lower to mid 80s so far, and should continue to climb into the mid and upper 80s for most of the area with the interior-western UP still on track to peak near the 90 degree mark. With dewpoints in the upper 60s and lower 70s, it is feeling a bit soup-ey out there. Meanwhile, we continue to await convective initiation along the northern MN boundary. Some agitated cumulus is developing along the boundary northwest of Duluth, so some discrete cells may begin to pop over the next couple of hours. That more northerly initiation would prove more favorable for storms to track into our area, with simulated reflectivity continues to show discrete cells growing upscale into an MCS while dropping ESE towards the UP closer to 00Z. However, will note that some of the guidance still drops the feature more to our southwest, only grazing the UP with stronger convection. Convective parameters remain favorable. Here, midlevel lapse rates are steepening to 7-8 degc/km, with SBCAPE up to 2000-3000j/kg across the western half of the UP. Though some capping remains present in soundings, this is shown to erode heading into the evening hours in advance of the approaching convection. Deep layer shear is analyzed at around 30 to 45 knots, with some modest lower level SR helicity present. Would expect the main threats in storms to be wind and hail, but will not rule out some brief spinups with that weak lower level veering in soundings as well as potential lake breeze interactions. Heavy rain is also a concern, with plenty of moisture available (PWATs up to 1.6 inches). HREF ensemble mean indicates a general half to 0.75 inches by the time storms move out (around 06Z). However, ensemble max guidance shows some pockets of 1- 2in totals. That said, this is looking like a quick hit, with fast- moving storms and no indication for back building and training. So, flash flooding is not much of a concern. Rain and storms quickly wrap up from west to east tonight, moving out of the eastern UP around 06-09Z. As skies gradually clear out, some patchy fog will be possible, especially where we are able to pick up some decent rainfall. Otherwise, expect temperatures to fall back into the lower 60s and possibly upper 50s. .LONG TERM...(Friday through Thursday) Issued at 359 PM EDT THU JUL 27 2023 Reamplification of a western ridge and eastern trough pattern over North America will maintain a nw flow aloft over the Great Lakes region this weekend into early next week. What this means for Upper MI is after the very warm/hot, humid weather today, this pattern evolution will result in a trend back to normal to a little blo normal temps this weekend as nw flow returns under pattern reamplification. Sat will be the coolest day. Under general nw flow next week, temps likely won't stray too far from the end of July/early Aug normals. A couple of nw flow shortwaves moving through this weekend could bring increases in cloud cover, especially during the daytime with the aid of diurnal heating. Also, despite limited moisture isolated showers can't be completed ruled out either, especially Sun morning as a stronger shortwave moves across the area. The warmer days in the extended fcst will occur around the midweek period as mid-level flow deamplifies a bit in response to a shortwave cutting thru the western ridge and heading downstream. Depending on the strength of the wave, there could be a quick surge of much warmer air into the area midweek (most likely Wed) followed by the next best chc of pcpn late Wed into early Thu. Beginning Fri, the cold front moving across the area tonight will be situated just south of the fcst area and could provide the focus for some lingering isolated shra into south central and southeast portions of the cwa, mainly in the morning, although 12Z NAM and GFS soundings look pretty dry in low to mid-levels. Otherwise, look for max temps ranging from near 70F along Lake Superior to the lower 80s south central under decreasing cloud cover. The weekend into Mon should be pleasant with temps at or a little blo normal. Sat will be the coolest of the 3 days with high temps in the mid/upper 60s near Lake Superior to the mid 70s F s central. Although models indicate dry weather is mostly expected, the return of nw flow flow does bring some concern that some isolated -shra could occur, mainly Sat afternoon and Sunday as shortwaves move through while diurnal heating is taking place. Tue/Wed, shortwave that cuts thru the western ridge will track eastward vcnty of the U.S./Canada border, working to temporarily deamplify the flow as it forces some height rises downstream into the eastern mid-upper level trough. Models timing still is fairly good agreement suggesting Wed as the best chc of pcpn with maybe some lingering shra into Thu behind the fropa as a nw flow secondary shortwave moves across the region. Warmest day will likely be Wed with a WAA southwest flow ahead of the frontal boundary likely sending temps slightly above normal with lower to mid 80s readings. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 645 PM EDT THU JUL 27 2023 Showers and thunderstorms will quickly move through the area this evening and overnight and conditions in the thunderstorms will briefly be IFR/MVFR. Could be some hail early at IWD and then confidence in hail drops off quickly. Fog will develop tonight at SAW and last into Fri morning and will go MVFR in the fog. VFR conditions will mostly prevail at all sites with temporary reductions in visibility in the rain. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 359 PM EDT THU JUL 27 2023 Buildup of instability along an advancing cold front could cause strong to severe thunderstorms with damaging wind and hail over portions of Lake Superior late this afternoon into the early overnight hours tonight with the greatest risk of severe storms over far western Lake Superior into this evening where a Severe Thunderstorm Watch has been posted. In the wake of the cold front passing tonight, ne winds on Fri could gust to 20-25kt over portions of western Lake Superior. Otherwise, winds across Lake Superior should remain under 20kt into Tue as surface high pressure dominates. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && SHORT TERM...LC LONG TERM...Voss AVIATION...07 MARINE...Voss
Hazardous Weather Outlook National Weather Service Marquette MI 334 PM EDT Thu Jul 27 2023 MIZ001>007-009>014-084-085-281945- Keweenaw-Ontonagon-Northern Houghton-Baraga-Marquette-Alger-Luce- Gogebic-Iron-Dickinson-Menominee-Delta-Southern Schoolcraft- Southern Houghton-Northern Schoolcraft- 334 PM EDT Thu Jul 27 2023 /234 PM CDT Thu Jul 27 2023/ This Hazardous Weather Outlook is for portions of central Upper Michigan and western Upper Michigan. .DAY ONE...Tonight There is a chance of thunderstorms from this evening into the overnight hours. Some of the storms could be severe with strong winds, large hail, and heavy rainfall. .DAYS TWO THROUGH SEVEN...Friday through Wednesday No hazardous weather is expected at this time. .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>267-281945- 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- 334 PM EDT Thu Jul 27 2023 /234 PM CDT Thu Jul 27 2023/ This Hazardous Weather Outlook is for portions of Central Lake Superior...Eastern Lake Superior and Western Lake Superior. .DAY ONE...Tonight Areas of dense fog are expected at times through tonight. A round of thunderstorms is possible this evening into the overnight hours. Some of the storms could be severe with strong winds, large hail, and heavy rainfall. .DAYS TWO THROUGH SEVEN...Friday through Wednesday No hazardous weather is expected at this time. .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. LMZ221-248-250-281945- 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- 334 PM EDT Thu Jul 27 2023 This Hazardous Weather Outlook is for portions of Northern Lake Michigan. .DAY ONE...Tonight There is a chance of thunderstorms into the overnight hours. Some of the storms could be severe with strong winds, large hail, and heavy rainfall. .DAYS TWO THROUGH SEVEN...Friday through Wednesday There is a chance of thunderstorms on Friday. .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. LC
Preliminary Local Storm Report
National Weather Service Marquette MI
327 PM EDT Thu Jul 27 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0746 AM Tstm Wnd Gst Copper Harbor 47.47N 87.88W
07/27/2023 M43 MPH Keweenaw MI ASOS
ASOS station KP59 Copper Harbor.
&&
TAPSpecial Weather Statement
National Weather Service Marquette MI
536 PM CDT Thu Jul 27 2023
MIZ009-272300-
Gogebic MI-
536 PM CDT Thu Jul 27 2023
...Strong thunderstorms will impact portions of Gogebic County
through 600 PM CDT...
At 536 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Saxon to near Marenisco. Movement was east
at 40 mph.
HAZARD...Winds in excess of 40 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Strong thunderstorms will be near...
Marenisco around 545 PM CDT.
Ironwood around 555 PM CDT.
Other locations in the path of these storms include Bessemer and
Wakefield.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
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.
A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
western Upper Michigan.
&&
LAT...LON 4666 8998 4650 8972 4651 8940 4620 8940
4634 9010 4650 9022 4650 9027 4652 9028
4651 9032 4654 9031 4656 9034 4654 9035
4654 9040 4656 9042
TIME...MOT...LOC 2236Z 267DEG 34KT 4649 9037 4640 8981
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH
TAPThe Duluth radar (KDLH), 170 km away, was scanning. The volume nearest the first event began at 22:52 UTC.
16 thunderstorm wind. Local standard time, as filed.
The Gogebic County Dispatch reported power lines down in Bessemer. Wind gusts at the Ironwood ASOS were measured at 50 mph, but were probably higher in Bessemer where wind damage occurred.
The Ontonagon County Dispatch reported a few trees of unknown size down on power lines in Ewen.
There was a picture posted on social media of a large tree and power line down across a road in Ewen.
Three large maple trees were observed down in Sidnaw.
The U.S. Forest Service reported a wide variety of scattered multiple trees and large branches down throughout the Sylvania Wilderness Area in eastern Gogebic County during an onsite survey by USFS personnel in the Ottawa National Forest. The time of the delayed report was based on radar. Estimated wind gusts were between 50 and 70 mph.
The U.S. Forest Service reported multiple trees and large branches downed of maple and fir trees along Crystal Lake Road and Birch Lake Road in eastern Gogebic County just north of the Wisconsin State line. The delayed report was estimated from radar. Winds were estimated between 50 and 70 mph.
A large diameter maple tree was observed snapped off around five feet above the trunk in Tilden Township along Marquette County Road 581. A section of the tree landed in the driveway of a NWS Employee. The time of the delayed report was estimated from radar. Winds were estimated around 50 mph.
A social media report of a pavilion blown over and a large spruce tree snapped. Time of the report was estimated from radar.
The Marquette County Central Dispatch reported a tree down on power lines off Midway Drive in Negaunee Township. The max wind gust at NWS Marquette was 47 mph just a few minutes prior to this damage report.
The Marquette County Central Dispatch reported trees and power lines downed on Wilkinson Street on the north side of Marquette.
Marquette County Central Dispatch reported a downed tree on a vehicle on Altamont Street in Marquette.
Marquette County Central Dispatch reported trees and power lines downed along Reservoir Street and Quarry Road in Harvey.
There was a delayed public report of a large maple tree limb downed in south Marquette. Winds were estimated between 40 and 50 mph.
Social media report from south Marquette of three trees down in very close proximity to each other, all blocking the driveway.
There was a social media report and picture of a downed tree at Shot Point.
Report from social media included description of damage and posted image. Observer stated that he came home and found large storage shed/carport thrown and wrapped around trees. The frame of the shed was destroyed and it was anchored down. Not much damage elsewhere aside from some downed tree limbs. Time of the report was estimated from radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2023Every state in 2023This day in weather historyWarnings in Michigan, July 2023
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: 1119181, 1119199, 1119255, 1119309, 1119267, 1119264, 1119262, 1119319, 1119218, 1119223, 1119231, 1119241, 1119263, 1119314, 1119317, 1119305.