An area of low pressure lifted a warm front into the Northland during the day on the 26th. Behind this warm front was a moist and unstable airmass and daytime heating led to the development of strong to severe storms over northern Minnesota that moved to the southeast during the evening hours.
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.
An area of low pressure lifted a warm front into the Northland during the day on the 26th. Behind this warm front was a moist and unstable airmass and daytime heating led to the development of strong to severe storms over northern Minnesota that moved to the southeast during the evening hours. One of the first storms was a supercell that produced hail 3 inches in diameter. Later storms continued to produce hail and damage to trees as they moved across the region. The Grand Rapids area in particular was hit hard in this event with widespread tree damage across the city. The KDLH radar was inoperable for this event but a high level of service was maintained by utilizing the KMVX and KMPX radars and one minute GOES-16 satellite data.
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 26, 3:27 PM CST, 1 hour 33 minutes earlier.
Area Forecast Discussion National Weather Service Duluth MN 427 PM CDT Mon Jul 26 2021 .DISCUSSION...(This evening through Sunday) Issued at 426 PM CDT Mon Jul 26 2021 Summary...The main concern this forecast is this evening's convection with the Enhanced risk of severe storms we have. After that, we have warm weather continuing with chance for more showers and thunderstorms on Wednesday, and again on Friday. The convection this evening is an unusual Enhanced risk for this area, which we do not typically see more than a couple of days a summer around here. There is a low pressure system over central North Dakota this afternoon, with a warm front draped east into our area, generally from the Brainerd Lakes region east into northwest Wisconsin. Along and south of this boundary the airmass is strongly unstable, with surface based CAPE values already over 2k j/Kg, with models indicating it may get up over 3k j/Kg at some point this evening. Sounding from this morning show an Elevated Mixed Layer that should be over our area this evening that is also showing as a drier area on satellite imagery. This EML will produce steep lapse rates in the mid levels, even as it also produces the capping that we are seeing at the lower levels this afternoon. Model soundings show that we should have a long hodograph this evening with moderate to strong winds aloft to help lengthen it, despite the weaker winds in the boundary layer. This all shows that if we can get convection to fire, severe storms are likely, with very large hail and strong winds, as already depicted in the SPC day one severe outlook. We may have a very weak shortwave moving along the North Dakota/Manitoba line this afternoon which has been generating an area of accas and -tsra over northwest Minnesota this afternoon. This is likely based in the 700-600mb Warm air advection region, and we do not expect this area to grow significantly or become rooted in the surface based instability, at least in part due to its position relative to the surface boundary. However, ahead of the surface low over eastern North Dakota we have some decent pressure falls over northwest Minnesota and would expect some new development in this area sometime in the next few hours. Models have been wildly inconsistent in depicting this event, with the NAMNest and FV3SAR showing development over NW MN and eastern ND by 01z, then sliding southeast across the forecast area, but the HRRR not developing anything until after 03z, and with much less coverage than either of the other models. Uncertainty in timing and evolution is still pretty high, even as of late afternoon. Unfortunately, we are in the wait and see mode, and we will have to see how things evolve this evening. There may be some lingering showers into early Tuesday morning, but otherwise expect the bulk of the convection to be out of the forecast area shortly after midnight. Tuesday should be relatively quiet with the boundary having shifted south of the forecast area and weak ridging over the area. Highs to get back into the 80s for the day, though slightly cooler than today. We have another chance for showers and thunderstorms on Wednesday, and while we have a small threat for severe weather, am not as concerned about it as I am for this evening. Should it shift a little later in the day and allow instability to build before the convection moves into the area, that would be a different story. Highs to creep back up into the low 90s for the Brainerd Lakes region. After another quiet day on Thursday, another shortwave should bring another chance for showers and thunderstorms Friday night and early Saturday, but it is too soon to determine the severe weather potential with this. This should usher in a bubble of cooler temperatures aloft with cooler high temperatures through the weekend, with highs back in the 70s to low 80s for both days. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1246 PM CDT Mon Jul 26 2021 Main concern this forecast time range is for the convection that is expected to develop later this afternoon and last through the evening hours, with showers lingering overnight. Have included a tempo group for KDLH and KHYR with MVFR conditions and thunder, the sites that appear most likely to be affected by thunderstorms. Have with VCTS groups for KHIB and KBRD, and have kept them VFR. Some MVFR/IFR fog and stratus is expected during the early morning hours where the heavy rainfall occurs, and for now have included these only for KDLH, KHIB and KHYR. Once the fog clears, expect VFR conditions through remainder of TAF period. && .MARINE... Issued at 426 PM CDT Mon Jul 26 2021 Thunderstorm development this evening is also expected to affect western Lake Superior, and may bring damaging winds and large hail, especially right after it moves off land areas. There may also be a period of increased winds in the hours after any convection moves through the area, and we may need a short term Small Craft Advisory for a few hours overnight. After tonight wind stay out of the northeast for Tuesday at 10 to 15 knots, then diminish Tuesday night and become westerly for Wednesday. Waves to generally stay less than 2 ft. && .PRELIMINARY POINT TEMPS/POPS... DLH 61 78 60 82 / 60 0 40 60 INL 56 85 62 85 / 20 10 60 70 BRD 63 86 66 92 / 50 10 30 50 HYR 61 84 61 86 / 70 0 30 60 ASX 61 79 59 87 / 70 10 40 60 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && DISCUSSION...LE AVIATION...LE MARINE...LE
Hazardous Weather Outlook National Weather Service Duluth MN 401 PM CDT Mon Jul 26 2021 MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-272115- 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- Pine-Douglas-Bayfield-Ashland-Iron-Burnett-Washburn-Sawyer-Price- 401 PM CDT Mon Jul 26 2021 This Hazardous Weather Outlook is for portions of northeast Minnesota and northwest Wisconsin. .DAY ONE...This afternoon and Tonight Strong to severe thunderstorms are likely this evening and tonight. Storms may develop any time this afternoon, but are most likely to develop this evening around 7 to 8 PM in northeastern Minnesota, then spreading into northwest Wisconsin around 10 to 11 PM. The primary threat with these storms is large hail up to baseball size. Gusty winds to 70 mph, isolated tornadoes, and torrential rainfall that may lead to localized flash flooding are also possible. Later tonight the risk of large hail and tornadoes will decrease and the potential for heavy rain and damaging winds will become the main threats. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday A strong thunderstorm or two may be ongoing early Tuesday morning. The chance of thunderstorms returns late Tuesday night and continues through Wednesday night. A few storms may be strong to severe mainly along and south of US Highway 2 in Minnesota and Wisconsin. Large hail and damaging winds are the main threats with the strongest storms. There is a slight chance of isolated thunderstorms Friday afternoon and evening over portions of northern Minnesota, and Saturday afternoon and evening over portions of northwest Wisconsin. .SPOTTER INFORMATION STATEMENT... SKYWARN spotters are encouraged to report hail of any size, wind damage, and rainfall amounts to the National Weather Service. LSZ121-140>148-150-272115- 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- 401 PM CDT Mon Jul 26 2021 This Hazardous Weather Outlook is for portions of Lake Superior and the Nearshore waters of western Lake Superior. .DAY ONE...This afternoon and Tonight Thunderstorms are likely this evening and overnight, and some may be strong to severe with hail to baseball ball size, wind gusts to 60 knots, frequent cloud- to- water lightning, and torrential rainfall which may reduce visibility to less than one- quarter mile. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday There is another chance of thunderstorms Wednesday and Wednesday night. A few storms may be strong to severe once again. JDS 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
541 PM CDT Mon Jul 26 2021
MNZ010-018-262300-
Koochiching-North Itasca-
541 PM CDT Mon Jul 26 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL ITASCA AND SOUTH
CENTRAL KOOCHICHING COUNTIES...
At 540 PM CDT, a strong thunderstorm was 11 miles southeast of
Gemmell, moving east at 50 mph.
Wind gusts up to 50 mph, penny size hail, and frequent cloud to
ground lightning can be expected with this storm.
This storm will be near...
Effie around 555 PM CDT.
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 4791 9428 4803 9409 4799 9360 4783 9363
4770 9374
TIME...MOT...LOC 2240Z 288DEG 44KT 4789 9391
KossenSpecial Weather Statement National Weather Service Duluth MN 600 PM CDT Mon Jul 26 2021 MNZ018-262315- North Itasca- 600 PM CDT Mon Jul 26 2021 ...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL ITASCA COUNTY... At 559 PM CDT, a strong thunderstorm was 9 miles northeast of Oslund, or 37 miles northwest of Grand Rapids, moving southeast at 40 mph. Wind gusts up to 50 mph, nickel size hail, and frequent cloud to ground lightning can be expected with this storm. This storm will be near... Marcell around 615 PM CDT. Other locations impacted by this storm include Jessie Lake, Spring Lake, Whitefish Lake, North Star Lake, Talmoon, Bowstring, Wirt, Scenic State Park and Coon 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. This storm may intensify, please monitor local media outlets for additional information and possible warnings from the National Weather Service. LAT...LON 4783 9383 4766 9345 4746 9372 4770 9401 TIME...MOT...LOC 2259Z 324DEG 35KT 4772 9386 Kossen
The national radar mosaic for the moment the first event began.
16 hail, 13 thunderstorm wind. Local standard time, as filed.
A photo was received of a power pole that was snapped in Wirt.
Photos were received of damage to trees and docks around Side Lake.
Photos and video were received of damage along the shore of Jessie Lake. A dock was overturned along with a boat lift. A pontoon boat that was on the boat lift was also overturned.
A tree was reported down in Bassett Township.
A few trees were downed in Deer River.
A large pine tree was uprooted in Cohasset.
A tree 16 inches in diameter was uprooted in Zim.
Large tree branches were broken off and a flag pole was snapped in half by the winds.
A few small branches were downed as well.
Numerous reports of extensive tree damage were received from Grand Rapids including nine 80 foot tall Norway pine trees that were uprooted.
The top part of a healthy pine tree was knocked over by the wind and punctured a garage roof.
Trees and power lines were reported down in Jacobson by the storm.
A power line taken down due to a 50 to 60 foot tall tree snapping.
Half of a tree fell onto a house in the Endion neighborhood.
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: 970052, 970053, 970054, 970055, 970056, 970057, 970058, 970059, 970060, 970061, 970062, 970063, 970064, 970065, 970066, 970067, 973085, 970069, 970070, 970071, 973087, 973088, 973089, 970072, 970073, 970074, 970075, 973091, 970076.