Multiple rounds of storms were observed across northeastern Minnesota the afternoon of the 23rd into the early morning hours of the 24th. The first round developed in association with a warm front during the afternoon hours of the 23rd and produced damaging wind gusts leading to downed trees and power lines.
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.
Multiple rounds of storms were observed across northeastern Minnesota the afternoon of the 23rd into the early morning hours of the 24th. The first round developed in association with a warm front during the afternoon hours of the 23rd and produced damaging wind gusts leading to downed trees and power lines. The second round developed during the early morning hours of the 24th and led to a few isolated reports of tree damage and a measured gust to 62 mph at the Duluth Airport.
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, 11:43 AM CST, 3 hours 47 minutes earlier.
Area Forecast Discussion National Weather Service Duluth MN 1243 PM CDT Fri Jul 23 2021 .DISCUSSION...(Today through Thursday) Issued at 435 AM CDT Fri Jul 23 2021 Summary: Scattered strong to severe thunderstorms are expected late this afternoon into this evening and overnight. Hot and dry weather is expected this weekend, and this will bring near- critical fire weather conditions, especially on Saturday. Next week will feature warm and mainly dry weather with a few rain chances here and there. Mostly cloudy skies are common across the region this morning per satellite and observations. Some low- to mid-level clouds associated with warm air advection are building across the Arrowhead, and there could be some additional shower and perhaps thunderstorm development in the next several hours this morning. Otherwise, the two main stories for today are hot temperatures and potential for some severe thunderstorms this evening. With southerly to southwesterly warm air advection across the region today, temperatures will soar into the upper 80s to low and possibly mid 90s for most places. The North Shore will see slightly cooler temperatures with the onshore southerly winds while areas further south are most likely to see the warmest temperatures. A heat advisory is in effect this afternoon for Pine and Burnett counties, where temperatures in the low to mid 90s with heat indices around 100 degrees are expected. There is some potential that areas further west towards the Brainerd Lakes could see heat indices approaching 100 degrees today as well, but with clouds expected to be prevalent, there isn't high enough confidence to expand the heat advisory further west at this time. Attention then turns to severe weather potential late this afternoon, this evening, and overnight. Several upper level waves associated with previous convection over the Dakotas will move over the region today, and this will combine with the strong warm air advection to support lift for thunderstorm development. Lapse rates will be supportive, though not exactly ideal, for strong to severe thunderstorm development. The warm air advection at mid levels will keep mean lapse rates just below 7 C/km, and this will be the main inhibiting factor in severe weather potential, and may result in storms struggling to organize. This will be especially true during the day today, where some scattered showers and non- severe storms are likely to develop. The convection that develops today will likely play a role in how stronger convection evolves this evening along a cold front that will slide through from northwest to southeast. Around 1 to 2.5 kJ/kg of MUCAPE will combine with 30-40 kt of 0-6km vertical shear to support strong to low-end severe thunderstorms this evening. Storm initiation will depend on convective activity during the day, so some uncertainty still exists on timing. But, storms are most likely to develop near International Falls around 7 PM, then spread southeast towards the North Shore by around midnight, then northwest Wisconsin through the morning hours. The greatest chance for severe weather will be in northeastern Minnesota this evening with severe potential decreasing slightly as storms move southeast overnight. The main hazards will be potential for damaging winds up to 70 mph and large hail to quarter size in diameter. With dry air near the surface, damaging winds seem like the most likely hazard at this time, though coverage of all hazards is expected to be scattered. Some locally heavy rainfall will be possible as well, but storms will be moving fairly quickly such that flooding is not likely to be a concern. Storms will likely be exiting the region to the southeast around 8 AM. Saturday and Sunday will feature hot and dry weather, and there is potential for near-critical to critical fire weather conditions particularly on Saturday due to a combination of gusty post- frontal northwesterly winds as high as 20 to 25 mph and minimum relative humidity values between 20 and 30 percent. Looking forward into next week, a large upper level ridge over the Rockies and western Plains will keep the Northland under generally dry westerly flow. There are likely to be a few embedded waves passing through that may bring some chances for showers and thunderstorms. Widespread soaking rains are unlikely, so drought conditions are likely to persist with highs in the 80s to around 90 degrees each day. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1243 PM CDT Fri Jul 23 2021 VFR conditions continue across most of the region early this afternoon, with only some SCT to BKN high-level stratus overhead. The main focus for this TAF issuance will be on increasing chances of showers and thunderstorms, some of which could be strong to severe, late this afternoon and evening. There remains high uncertainty regarding the exact timing and location of this activity, per usual with these kinds of convective events. The most likely time frame for the strongest activity looks to be late this afternoon and evening along a cold front that will make its way eastward, although some high-res models are hinting at some earlier activity developing this afternoon across east-central Minnesota into northwest Wisconsin. We will need to watch closely for potential activity this afternoon. The main threats from the stronger storms tonight will be large hail and strong wind gusts. Conditions will improve late tonight through Saturday morning once the cold front departs the region. Gusty northwest winds under clear skies are expected for Saturday. && .MARINE... Issued at 435 AM CDT Fri Jul 23 2021 Breezy northeast winds will persist for much of the day today with wind speeds decreasing later this afternoon. Wave heights from 1 to 3 feet are expected, especially near the Twin Ports. Scattered thunderstorms are expected today and tonight as a cold front passes through with the best chances during the evening hours. Some storms may be strong to severe, containing locally strong wind gusts as high as 50 to 60 knots, large hail to quarter size, heavy rain, and cloud to water lightning. The North Shore has the best chances of seeing severe storms. Wind speeds will become westerly to southwesterly tonight and into Saturday. Wind speeds may become breezy on Saturday with speeds from 10 to 15 knots and gusts to 20 knots and slightly lesser wind speeds on Sunday. Wave heights will remain 2 feet or less tonight through Sunday. && .PRELIMINARY POINT TEMPS/POPS... DLH 83 65 87 60 / 20 70 10 0 INL 89 61 85 56 / 40 60 0 0 BRD 92 66 89 59 / 30 60 10 0 HYR 89 65 87 55 / 20 70 30 0 ASX 89 66 88 60 / 20 70 20 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...JDS AVIATION...JTS MARINE...JDS
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 338 PM CDT Fri Jul 23 2021 MNZ010>012-018>021-025-026-033>038-241000- Koochiching-North St. Louis-Northern Cook and Lake-North Itasca- Central St. Louis-Southern Lake-Southern Cook-North Cass- South Itasca-South Cass-Crow Wing-Northern Aitkin-South Aitkin- Carlton and South St. Louis-Pine- Including the cities of International Falls, Ely, Isabella, Bigfork, Hibbing, Two Harbors, Silver Bay, Grand Marais, Walker, Grand Rapids, Pine River, Brainerd, Hill City, Aitkin, Duluth, Pine City, and Hinckley 338 PM CDT Fri Jul 23 2021 ...NEAR-CRITICAL FIRE WEATHER CONDITIONS SATURDAY ACROSS NORTHEASTERN MINNESOTA FOR LOW RELATIVE HUMIDITIES... A combination of very dry conditions with minimum relative humidity dropping as low as 20 percent and northwesterly winds from 10 to 15 mph and gusts to 25 mph, will lead to near- critical fire weather conditions across northeastern Minnesota Saturday afternoon and early evening. Burning outdoors is not advised on Saturday. Please refer to fire officials for any outdoor burning restrictions. For more information on burning restrictions for Minnesota, see www.dnr.state.mn.us/forestry/fire/firerating_restrictions.html. JTS
Special Weather Statement
National Weather Service Duluth MN
344 PM CDT Fri Jul 23 2021
MNZ010-232100-
Koochiching-
344 PM CDT Fri Jul 23 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL KOOCHICHING
COUNTY...
At 343 PM CDT, a strong thunderstorm was over Manitou, or 26 miles
west of International Falls, moving east at 30 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 remain over mainly rural areas of north central
Koochiching County, including the following locations... Indus and
Franz Jevne State Park.
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.
This storm may intensify, please monitor local media outlets for
additional information and possible warnings from the National
Weather Service.
LAT...LON 4863 9393 4863 9384 4858 9381 4854 9381
4857 9411 4865 9409 4864 9402 4865 9401
TIME...MOT...LOC 2043Z 270DEG 25KT 4861 9399
Unruh/HuyckSpecial Weather Statement
National Weather Service Duluth MN
357 PM CDT Fri Jul 23 2021
MNZ010-232115-
Koochiching-
357 PM CDT Fri Jul 23 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL KOOCHICHING
COUNTY...
At 356 PM CDT, a strong thunderstorm was near Loman, or 22 miles west
of International Falls, moving southeast at 25 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...
Loman around 405 PM CDT.
Other locations impacted by this storm include Indus.
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.
This storm may intensify, please monitor local media outlets for
additional information and possible warnings from the National
Weather Service.
LAT...LON 4863 9389 4863 9383 4858 9381 4852 9381
4852 9365 4836 9385 4852 9405 4864 9391
TIME...MOT...LOC 2056Z 307DEG 23KT 4854 9389
Unruh/HuyckSpecial Weather Statement National Weather Service Duluth MN 402 PM CDT Fri Jul 23 2021 MNZ011-012-019-240115- North St. Louis-Northern Cook and Lake-Central St. Louis- Including the cities of Ely, Isabella, and Hibbing 402 PM CDT Fri Jul 23 2021 ...STRONG TO SEVERE THUNDERSTORMS WILL AFFECT THE BOUNDARY WATERS CANOE AREA WILDERNESS THIS AFTERNOON AND TONIGHT... Strong to severe thunderstorms will affect the Boundary Waters Canoe Area Wilderness this afternoon and tonight. The storms will be capable of erratic and gusty winds of 30 to 70 mph, hail up to half-dollar size, frequent cloud-to-ground lightning, and locally heavy rainfall, which may lead to localized minor flooding of creeks, streams, and low-lying areas. Campers should take extra precautions in order to secure campsites and make a plan in case of severe weather. Check campsites for possible hazards, including standing dead trees or limbs, as well as low spots where water can pool. Move tents away from creeks and rivers in case of flash flooding. Prepare to protect yourself from large hail using sleeping bags or other padded Monitor NOAA Weather Radio for updates and possible warnings. Huyck
Special Weather Statement
National Weather Service Duluth MN
411 PM CDT Fri Jul 23 2021
MNZ010-232130-
Koochiching-
411 PM CDT Fri Jul 23 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN KOOCHICHING
COUNTY...
At 410 PM CDT, a strong thunderstorm was near Pelland, or near
International Falls, moving east at 20 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 be near...
International Falls around 425 PM CDT.
Other locations impacted by this storm include Ranier and Ericksburg.
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.
This storm may intensify, please monitor local media outlets for
additional information and possible warnings from the National
Weather Service.
LAT...LON 4864 9326 4844 9333 4851 9365 4853 9363
4852 9357 4854 9347 4856 9345 4859 9346
4861 9340 4860 9338 4863 9334
TIME...MOT...LOC 2110Z 275DEG 17KT 4858 9352
Unruh/HuyckPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
429 PM CDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0427 PM HAIL INTERNATIONAL FALLS 48.59N 93.41W
07/23/2021 M0.25 INCH KOOCHICHING MN TRAINED SPOTTER
HAIL FELL FOR ABOUT 5 MINUTES.
&&
BJHThe Duluth radar (KDLH), 212 km away, was scanning. The volume nearest the first event began at 21:28 UTC.
17 thunderstorm wind. Local standard time, as filed.
A tree was reported down on a power line along County Road 2 near the International Falls Airport.
A spotter reported a tree down on power lines about two miles west of the their home.
A few trees were downed at the spotter's location and the power was out.
A report was received via mPING of trees uprooted or snapped.
Photos were received showing an uprooted red pine tree along with a with pine that was broken about halfway up. The trees were estimated to be about 80 feet tall.
Photos were received showing several large aspen trees that were downed by the storm.
Multiple canoes were flipped over from thunderstorm wind gusts on Trout Lake. The occupants of one canoe unaccounted for at the time of the report. There were later found safe. Additional water emergencies were ongoing in other portions of the Boundary Waters Canoe Area Wilderness due to the storm.
Numerous reports were received of downed trees and blocked streets in Ely from the storm.
Photos and measurements were received of the downed trees in Whiteside Park. The two largest trees were elms with one uprooted that was 1 foot in diameter with the second being 27 inches in diameter and was completely snapped about 8 feet up. The Blueberry/Arts Fest was ongoing in the park at the time of the storm and the storm caused significant damage to temporary tents and booths along with the items for sale in the tents/booths. The remainder of the festival was subsequently canceled due to the damage.
Trees were reported down on power lines along Mitawan Lake Road northwest of Isabella.
Multiple downed trees were observed along Minnesota Highway 200 east of Hill City.
Two trees were reported down north of County Highway 8 along Highway 7.
Three trees were downed one mile south of County Highway 8 along County Highway 7 with one tree completely blocking the road.
A large tree was down along State Highway 200 approximately 6 miles west of Hill City.
A tree branch about a foot in diameter was snapped off an ash tree at the NWS office.
A gust to 64 mph was measured with the storm at the KDLH ASOS station at the Duluth International Airport.
Large trees were down along Arrowhead Road east of the Rice Lake Road intersection.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2021Every state in 2021This day in weather historyWarnings in Minnesota, July 2021
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: 969146, 969148, 969149, 973075, 969151, 969152, 969153, 969157, 969155, 969159, 969161, 969162, 969163, 973078, 973079, 973080, 973081.