Storms developed ahead of a warm front during the evening hours of the 23rd and ahead of a cold front during the early morning hours of the 24th across northeastern Minnesota. As the storms moved over Lake Superior, they produced strong winds with the highest gust being 57 mph that was recorded by a large lake vessel.
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 DLH wrote it up.
Storms developed ahead of a warm front during the evening hours of the 23rd and ahead of a cold front during the early morning hours of the 24th across northeastern Minnesota. As the storms moved over Lake Superior, they produced strong winds with the highest gust being 57 mph that was recorded by a large lake vessel.
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 Duluth, MN wrote its last area forecast discussion before the first event at Jul 23, 5:58 PM CST, 2 hours 26 minutes earlier.
Area Forecast Discussion National Weather Service Duluth MN 658 PM CDT Fri Jul 23 2021 .DISCUSSION...(This evening through Thursday) Issued at 359 PM CDT Fri Jul 23 2021 Summary: increasing chances of showers and storms are expected this afternoon and evening, some of which will be strong to severe. Then, drier conditions are expected for Saturday and Sunday, which will lead to dangerous fire weather conditions. The rest of the week will continue to be very warm, with off-and-on chances of showers and storms. This afternoon and evening: chances of showers and storms will increase from west to east as a mid-level shortwave impulse translates eastward. This shortwave is ahead of a cold front that will move eastward today through tonight, which could result in additional convection. Already, some showers and thunderstorms have formed over north-central Minnesota, with some gusts up to 60 mph already being reported near Birchdale. The environment continues to be conducive to large hail and damaging wind gusts, with strengthening upper-level flow, steepening low-level lapse rates, and mixed-layer CAPE between 1500-2500 J/kg. The threat for severe storms will continue through the evening hours, and perhaps into the overnight hours, although instability looks to diminish by then. Deep-layer shear will continue to be decent, generally around 30 to 40 knots. Some heavy rainfall will be possible with this activity as well, with total accumulations between 0.50" to 1.00" possible, especially over northwest Wisconsin where the activity is expected to become more widespread. The cold front will pass through the region late tonight into early Saturday morning, which will help usher in drier air behind it. Northwest winds look to strengthen, with gusts to around 20 to 25 mph. This, coupled with low relative humidities, will lead to near-critical fire weather conditions for Saturday afternoon and early evening. The severity of these fire weather conditions will be dependent on tonight's convection. If rainfall becomes widespread, this will help tamper down these conditions. Dry conditions will continue for Sunday, as well, so these near- critical fire weather conditions may continue into Sunday. For Monday through Friday next week: very warm conditions will continue as a broad upper-level ridge will be in place, centered over the Intermountain West states. Broad thermal ridging will result in high temperatures into the 80s and even some lower 90s as well. There will be some off-and-on chances of showers and thunderstorms for late Monday through Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 658 PM CDT Fri Jul 23 2021 A mix of mostly VFR, with some deteriorated flight conditions due to scattered showers and thunderstorms over far northern Minnesota, are anticipated. This storm activity is expected to continue through the evening hours, and generally make its way to the southeast. Flight conditions will deteriorate under these storms, with visibility reductions down to MVFR, and possibly IFR, under the strongest storms. These storms have already become severe at times, with wind gusts of up to 60 knots and possibly some large hail. There could be additional activity late tonight as a cold front makes its way eastward. Once the cold front passes through early Saturday morning, drier conditions are expected for Saturday, but gusty northwest winds are expected, with gusts to around 20 to 25 knots. && .MARINE... Issued at 500 PM CDT Fri Jul 23 2021 Increasing chances of showers and thunderstorms are anticipated across western Lake Superior this evening and overnight as a cold front makes its way eastward. Some of these storms could be strong to severe, with strong and erratic wind gusts as high as 50 to 60 knots, large hail the size of half-dollars, heavy rainfall, and cloud-to-water lightning. The North Shore has the best chances of seeing strong to severe storms. Before these storms move in this evening (around 8 to 10 PM or so), northeast winds will continue, with wave heights only around 2 feet or less. Winds will turn more westerly Saturday after the cold front passes through, sustained between 10 to 15 knots, with gusts up to 20 knots. Wave heights will continue to be around 2 feet or less. && .PRELIMINARY POINT TEMPS/POPS... DLH 66 87 60 87 / 70 10 0 0 INL 60 83 56 85 / 60 0 0 0 BRD 67 89 59 89 / 50 10 0 0 HYR 67 87 55 88 / 70 30 0 0 ASX 67 88 60 90 / 70 20 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...Heat Advisory until 7 PM CDT this evening for WIZ006. MN...Heat Advisory until 7 PM CDT this evening for MNZ038. LS...None. && DISCUSSION...JTS AVIATION...JTS MARINE...JTS
Hazardous Weather Outlook National Weather Service Duluth MN 407 PM CDT Fri Jul 23 2021 MNZ010>012-018>021-025-026-033>037-242115- Koochiching-North St. Louis-Northern Cook/Northern Lake- North Itasca-Central St. Louis-Southern Lake/North Shore- Southern Cook/North Shore-North Cass-South Itasca-South Cass- Crow Wing-Northern Aitkin-South Aitkin-Carlton/South St. Louis- 407 PM CDT Fri Jul 23 2021 This Hazardous Weather Outlook is for portions of northeast Minnesota. .DAY ONE...Tonight Thunderstorms are expected this evening and some may be strong to severe. The strongest storms will be capable of hail up to quarter size and gusts up to 70 mph. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Very low relative humidity values and breezy northwest winds will lead to near-critical fire weather conditions Saturday afternoon across much of the Northland. There is a chance for thunderstorms Monday through Thursday next week. .SPOTTER INFORMATION STATEMENT... Skywarn spotters may be needed this evening. WIZ001>004-007>009-242115- Douglas-Bayfield-Ashland-Iron-Washburn-Sawyer-Price- 407 PM CDT Fri Jul 23 2021 This Hazardous Weather Outlook is for portions of northwest Wisconsin. .DAY ONE...Tonight Thunderstorms are expected this evening and overnight and some of the storms may be strong to severe. The strongest storms will be capable of gusts up to 60 mph. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Very low relative humidity values and breezy northwest winds will lead to near-critical fire weather conditions Saturday afternoon across much of the Northland. There is a chance for thunderstorms Monday through Thursday next week. .SPOTTER INFORMATION STATEMENT... Skywarn spotters may be needed the evening. MNZ038-WIZ006-242115- Pine-Burnett- 407 PM CDT Fri Jul 23 2021 This Hazardous Weather Outlook is for portions of northeast Minnesota and northwest Wisconsin. .DAY ONE...Tonight Hot and humid conditions will result in heat index values near 100 degrees in parts of Pine and Burnett counties where a Heat Advisory is in effect through 7PM. Thunderstorms are expected this evening and overnight and some of the storms may be strong to severe. The strongest storms will be capable of gusts up to 60 mph. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Very low relative humidity values and breezy northwest winds will lead to near-critical fire weather conditions Saturday afternoon across much of the Northland. There is a chance for thunderstorms Monday through Thursday next week. .SPOTTER INFORMATION STATEMENT... Skywarn spotters may be needed this evening. LSZ121-140>148-150-242115- Bayfield to Oak Point WI-Grand Portage to Grand Marais MN- Grand Marais to Taconite Harbor MN- Taconite Harbor to Silver Bay Harbor MN- Silver Bay Harbor to Two Harbors MN-Two Harbors to Duluth MN- Duluth MN to Port Wing WI-Port Wing to Sand Island WI- Sand Island to Bayfield WI-Oak Point to Saxon Harbor WI- Outer Apostle Islands Beyond 5 NM from Mainland- 407 PM CDT Fri Jul 23 2021 This Hazardous Weather Outlook is for portions of Lake Superior and the Nearshore waters of western Lake Superior. .DAY ONE...Tonight There is a slight risk for a few strong to severe storms across western Lake Superior this evening and into tonight. The strongest storms capable of large hail, strong winds up to 40 knots, heavy rainfall which my reduce visibility and frequent cloud-to-water lightning. .DAYS TWO THROUGH SEVEN...Saturday through Thursday There is chance for thunderstorms most of next week from Monday to Thursday. BJH More information may be obtained at the following web address: http://www.weather.gov/duluth (all lower case)
Special Weather Statement
National Weather Service Duluth MN
812 PM CDT Fri Jul 23 2021
MNZ019-037-240130-
Central St. Louis-Carlton/South St. Louis-
812 PM CDT Fri Jul 23 2021
...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN ST. LOUIS COUNTY...
At 812 PM CDT, a strong thunderstorm was near Floodwood, or 24 miles
northwest of Cloquet, moving southeast at 35 mph.
Wind gusts up to 45 mph, dime size hail, heavy downpours, and
frequent cloud to ground lightning can be expected with this storm.
This storm will remain over mainly rural areas of southwestern
Central St. Louis and northwestern Carlton/South St. Louis Counties,
including the following locations... Gowan, Elmer, Island, Prosit,
Alborn and Floodwood Lake.
Seek shelter inside a sturdy building and away from windows until
this storm passes. Get off area lakes and seek shelter on shore in a
sturdy shelter or a hard topped vehicle.
LAT...LON 4718 9303 4701 9246 4677 9279 4698 9306
4714 9306
TIME...MOT...LOC 0112Z 299DEG 32KT 4698 9286
Unruh/HuyckPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
819 PM CDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0647 PM TSTM WND DMG ELY 47.90N 91.86W
07/23/2021 ST. LOUIS MN TRAINED SPOTTER
PHOTOS AND MEASUREMENTS WERE RECEIVED FROM
THE DAMAGED TREES IN WHITESIDE PARK. THE TWO
LARGEST TREES WERE ELMS. ONE WAS UPROOTED
AND HAD A DIAMETER OF 1 FOOT AT THE BASE OF
THE TRUNK. THE SECOND TREE WAS 27 INCHES IN
DIAMETER AND WAS COMPLETELY SNAPPED OFF
ABOUT 8 FEET UP. THIS PARK IS ALSO THE
LOCATION OF THE BLUEBERRY/ARTS FEST WHICH
SUSTAINED SIGNIFICANT DAMAGE TO TEMPORARY
TENTS AND BOOTHS.
&&
BJHSpecial Weather Statement
National Weather Service Duluth MN
831 PM CDT Fri Jul 23 2021
MNZ037-240145-
Carlton/South St. Louis-
831 PM CDT Fri Jul 23 2021
...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN ST. LOUIS COUNTY...
At 830 PM CDT, a strong thunderstorm was near Meadowlands, or 21
miles northwest of Cloquet, moving east at 40 mph.
Wind gusts up to 45 mph, nickel size hail, heavy downpours, and
frequent cloud to ground lightning can be expected with this storm.
This storm will be near...
Brookston and Canyon around 845 PM CDT.
Other locations impacted by this storm include Culver, Burnett,
Prosit and Alborn.
Seek shelter inside a sturdy building and away from windows until
this storm passes. Get off area lakes and seek shelter on shore in a
sturdy shelter or a hard topped vehicle.
LAT...LON 4703 9282 4704 9246 4703 9242 4680 9256
4694 9288
TIME...MOT...LOC 0130Z 291DEG 34KT 4699 9274
Unruh/HuyckPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
901 PM CDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0745 PM TSTM WND DMG 5 WNW ISABELLA 47.65N 91.46W
07/23/2021 LAKE MN LAW ENFORCEMENT
POWER LINES WERE REPORTED DOWN ON TREES
ALONG MITAWAN LAKE ROAD NORTHWEST OF
ISABELLA. TIME ESTIMATED BY RADAR.
&&
BJHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
905 PM CDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0842 PM TSTM WND DMG 1 SSE CULVER 46.92N 92.55W
07/23/2021 ST. LOUIS MN LAW ENFORCEMENT
THREE TREES WERE DOWNED 1 MILE SOUTH OF
HIGHWAY 8 ALONG HIGHWAY 7 WITH ONE TREE
COMPLETELY BLOCKING THE ROAD. TIME ESTIMATED
BY RADAR.
&&
BJHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
912 PM CDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0840 PM TSTM WND DMG 1 NNE CULVER 46.94N 92.55W
07/23/2021 ST. LOUIS MN LAW ENFORCEMENT
TWO TREES WERE REPORTED DOWN NORTH OF
HIGHWAY 8 ALONG HIGHWAY 7. TIME ESTIMATED BY
RADAR.
&&
BJHThe Duluth radar (KDLH), 14 km away, was scanning. The volume nearest the first event began at 02:25 UTC.
4 marine thunderstorm wind. Local standard time, as filed.
A personal weather station in the Lester Park neighborhood recorded a gust of 40 mph with the storm.
The 1000-ft ship American Century reported a maxiumum wind gust of 57 mph off the Duluth Entry. The strong winds varied in intensity for about 20 minutes before subsiding.
The National Ocean Service's Water Level Observation Network station DULM5 recorded a gust to 49 mph during the storm.
CWOP Station DW6222 at the Madeline Island Ferry Dock recorded a gust of 42 mph.
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: 973074, 970355, 973073, 970357.