An upper level shortwave moved across the Northland instigating a few severe storms. The moderately unstable environment combined with high shear lead to several discrete cells moving southeast across northeast MN.
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 upper level shortwave moved across the Northland instigating a few severe storms. The moderately unstable environment combined with high shear lead to several discrete cells moving southeast across northeast MN. These cells produced large hail and damaging winds that damaged a few boat docks.
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 16, 2:56 PM CST, 1 hour 9 minutes earlier.
Area Forecast Discussion National Weather Service Duluth MN 356 PM CDT Thu Jul 16 2020 .SHORT TERM...(This evening through Friday night) Issued at 356 PM CDT Thu Jul 16 2020 Scattered showers and thunderstorms are expected to continue this afternoon and evening, primarily in northeast Minnesota. A few of these storms may be severe in the Arrowhead region this evening. A weak cold front and associated upper level shortwave will provide the necessary lifting, when combined with low level convergence associated with peak daytime heating. MLCAPE values of around 1500 J/kg in the western portion of the CWA should help to initiate an additional round of thunderstorms this evening. The current shear environment is favorable, with 40-50 knots of 0-6 km bulk shear. Storm motions are expected to remain quick, as 700mb winds from VWP have been increasing in the last hour to 50 knots from the southwest. Mode of convection this afternoon and evening will initially be discrete with the potential for damaging winds of 60 mph, large hail, and possibly an isolated tornado. The initial discrete convection is expected to transition to a more linear form of convection later this evening. Convection is expected to end after midnight as the shortwave trough exits the CWA to the east. Friday should remain mostly dry throughout the day. Temperatures will feel much warmer tomorrow with highs expected to be in the mid to upper 80s. The main weather concern for tomorrow will be in the evening and overnight. Showers and thunderstorms will form in association with an upper level shortwave. A few of these storms may be severe, particularly in Cass and Crow Wing counties. SPC currently has these counties under an enhanced risk, with damaging winds being the largest threat. MLCAPE from guidance suggest 1500-2500 J/kg, along with 30 kts of shear. Timing for tomorrow is expected to be after 00z, with the bulk of precipitation expected after 06z and continuing into early Saturday morning. Model guidance is suggesting a QLCS type system. This mode of convection has the potential to support damaging winds in excess of 60 mph and possible QLCS tornadoes. .LONG TERM...(Saturday through Thursday) Issued at 356 PM CDT Thu Jul 16 2020 An active pattern is expected on Saturday with showers and thunderstorms, some of which could be strong to severe. Remnants of Friday night's severe weather may linger early Saturday morning, though it will likely weaken and dissipate as an upper level short wave passes to the east, allowing for a mid-day break in convective activity. High temperatures will likely soar into the mid 80s to low 90s with some sunshine expected. However, warm and moist air will continue to advect into the area, with PWAT values around 1.5 to 2.0 inches Saturday afternoon and overnight. The atmosphere will initially be capped by a nose of warm air advection aloft, but quite a bit of instability will develop during the afternoon with long- range models suggesting SB and MU CAPE in excess of 3k J/kg developing primarily over northwest Wisconsin and east-central Minnesota. This will couple with deep layer shear around or just above 35 kt and an upper level trough / surface cold front to trigger showers and thunderstorms. Severe thunderstorms appear will be possible, with peak activity likely occurring in the late evening and overnight when instability and upper level / frontal forcing line up. The primary threats will include damaging winds, large hail, and heavy rainfall, but an isolated tornado can't be ruled out. After the cold front passes through Saturday night, cooler and less humid conditions will move into the region with a quasi-zonal upper level flow pattern. A shortwave may clip the International Border and bring a slight chance for scattered showers, but otherwise sunny and dry conditions are expected with highs in the low 80s. Going into next week, west to northwesterly flow will keep temperatures pretty seasonable with highs in the 70s to low 80s. There will be some on and off chances for showers and storms as short waves pass by, but any widespread strong to severe weather does not appear likely at this time with a lack of instability in the cooler air mass. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1259 PM CDT Thu Jul 16 2020 The main story this afternoon and early evening will be scattered showers and thunderstorms which may affect some of the terminals, particularly INL/HIB/DLH. The most recent short-range models suggest storms pushing through between 20Z and 01Z from northwest to southeast. Gusty winds and hail may accompany these storms. In addition, gusty southwesterly winds will continue at all terminals afternoon, with some gusts from 20 to near 25 kt at times. The storms will move out during the evening with winds becoming light and skies clearing. There may be some LLWS at HYR briefly this evening, as well as patchy fog late tonight. Left out the mention of fog for now as not all models are in agreement, but there will be a chance especially at HYR. && .MARINE... Issued at 356 PM CDT Thu Jul 16 2020 An approaching upper level disturbance will lead to developing showers and thunderstorms this afternoon and evening. A few of these storms may be severe with damaging winds and large hail. Winds this evening will be southwesterly at 10-15 knots. Wind gusts north of Two Harbors this afternoon and evening are expected to reach 25 knots. These gusts are expected to calm down later this evening. The first half of Friday should be dry with winds transitioning from the SW to NE in the late afternoon. Another chance for showers and thunderstorms are expected tomorrow night into early Saturday morning for most nearshore locations. A few of these storms may be severe producing damaging winds and large hail. Waves will generally be 2 feet or less. && .PRELIMINARY POINT TEMPS/POPS... DLH 58 85 65 87 / 60 0 90 60 INL 55 86 65 85 / 10 0 70 40 BRD 57 87 68 88 / 10 10 90 30 HYR 58 86 67 89 / 30 10 70 60 ASX 61 88 66 90 / 40 0 70 70 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...Small Craft Advisory until 8 PM CDT this evening for LSZ140>143. && SHORT TERM...Unruh/Wolfe LONG TERM...JDS AVIATION...JDS MARINE...Unruh/Wolfe
Hazardous Weather Outlook National Weather Service Duluth MN 1013 AM CDT Thu Jul 16 2020 MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-171515- 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- 1013 AM CDT Thu Jul 16 2020 This Hazardous Weather Outlook is for portions of northeast Minnesota and northwest Wisconsin. .DAY ONE...Today and Tonight Isolated to scattered thunderstorms are expected to develop today and move from west to east, reaching north central Wisconsin early this evening. A few storms could be severe over northern Minnesota into far northwest Wisconsin this afternoon and evening. The main threats will be hail to one inch and winds to 60 MPH. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Another chance for severe storms is expected Friday night into Saturday. Large hail, winds to 70 MPH, and very heavy rainfall will be the main threats. The severe storm threat will be greatest over east central Minnesota into northern Wisconsin on Saturday into Saturday evening. Periodic chances for more storms will occur Sunday into the middle of next week. Chances for severe storms is low during that time. .SPOTTER INFORMATION STATEMENT... Skywarn spotters may be needed this afternoon and evening. LSZ121-140>148-171515- 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- 1013 AM CDT Thu Jul 16 2020 This Hazardous Weather Outlook is for portions of the Nearshore waters of western Lake Superior. .DAY ONE...Today and Tonight Thunderstorms will be possible today into this evening. A few severe storms will be possible with large hail and strong winds around 50 knots possible. A small craft advisory is currently in effect until 8 PM CDT this evening for wind gusts up to 25 knots along the North Shore from Two Harbors to Grand Portage. Local wind gusts up to 25 knots are possible for locations from Two Harbors to Saxon Harbor. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Another chance for strong to severe storms will occur Friday night into Saturday. Strong winds, hail, and very heavy rainfall will be the main threats. Periodic chances for more storms will occur Sunday into early next week. Chances for severe storms are low during that time. Wolfe/Unruh 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
344 PM CDT Thu Jul 16 2020
MNZ010-011-162115-
Koochiching-North St. Louis-
344 PM CDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN KOOCHICHING AND
NORTHWESTERN ST. LOUIS COUNTIES...
At 344 PM CDT, a strong thunderstorm was 7 miles southeast of
International Falls, moving east at 30 mph.
Wind gusts up to 30 mph, penny size hail, heavy downpours, and
occasional cloud to ground lightning can be expected with this storm.
This storm will be near...
Voyageurs National Park around 400 PM CDT.
Kabetogama around 405 PM CDT.
Kabetogama Lake, Rainy Lake East and Rainy Lake West around 415 PM
CDT.
Other locations impacted by this storm include Ranier, Ericksburg and
Island View.
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 4862 9296 4861 9295 4855 9277 4836 9281
4845 9339 4861 9336 4863 9334
TIME...MOT...LOC 2044Z 276DEG 27KT 4854 9326
JTSSpecial Weather Statement
National Weather Service Duluth MN
358 PM CDT Thu Jul 16 2020
MNZ018-025-162130-
North Cass-North Itasca-
358 PM CDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL ITASCA AND NORTH
CENTRAL CASS COUNTIES...
At 358 PM CDT, a strong thunderstorm was 10 miles east of Lavinia, or
13 miles east of Bemidji, moving east at 35 mph.
Wind gusts up to 50 mph, penny size hail, heavy downpours, and
occasional cloud to ground lightning can be expected with this storm.
This storm will be near...
Bena around 430 PM CDT.
Other locations impacted by this storm include Portage Lake, Cass
Lake, Schley and Six Mile 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 4741 9442 4754 9441 4750 9407 4724 9417
4737 9467 4741 9467
TIME...MOT...LOC 2058Z 285DEG 29KT 4746 9460
JTSSpecial Weather Statement
National Weather Service Duluth MN
428 PM CDT Thu Jul 16 2020
MNZ025-026-162200-
North Cass-South Itasca-
428 PM CDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT CENTRAL ITASCA AND NORTHEASTERN
CASS COUNTIES...
At 428 PM CDT, a strong thunderstorm was near Bena, or 22 miles
northeast of Walker, moving east at 25 mph.
Wind gusts up to 50 mph, nickel size hail, heavy downpours, and
occasional cloud to ground lightning can be expected with this storm.
This storm will be near...
Federal Dam around 435 PM CDT.
Bena around 440 PM CDT.
Ball Club around 500 PM CDT.
Other locations impacted by this storm include Six Mile Lake, Ball
Club Lake, Portage Lake, Mud Lake and Goose 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 4743 9437 4743 9435 4741 9432 4744 9426
4739 9383 4714 9394 4728 9444
TIME...MOT...LOC 2128Z 286DEG 23KT 4735 9430
JTSSpecial Weather Statement
National Weather Service Duluth MN
431 PM CDT Thu Jul 16 2020
MNZ019-020-037-162200-
Central St. Louis-Southern Lake/North Shore-Carlton/South St. Louis-
431 PM CDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN ST. LOUIS AND
SOUTHWESTERN LAKE COUNTIES...
At 431 PM CDT, a strong thunderstorm was near Boulder Lake, or 18
miles north of Duluth, moving east at 30 mph.
Wind gusts up to 30 mph, half inch diameter hail, heavy downpours,
and occasional cloud to ground lightning can be expected with this
storm.
This storm will be near...
Two Harbors and Larsmont around 500 PM CDT.
Other locations impacted by this storm include Alger.
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 4700 9161 4694 9171 4693 9211 4711 9216
4719 9179 4715 9179 4720 9172 4722 9163
4702 9158
TIME...MOT...LOC 2131Z 259DEG 24KT 4704 9203
JTSSpecial Weather Statement National Weather Service Duluth MN 458 PM CDT Thu Jul 16 2020 MNZ025-026-035-162230- Northern Aitkin-North Cass-South Itasca- 458 PM CDT Thu Jul 16 2020 ...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL ITASCA...NORTHERN AITKIN AND NORTHEASTERN CASS COUNTIES... At 457 PM CDT, a strong thunderstorm was near Boy River, or 23 miles west of Grand Rapids, moving southeast at 35 mph. Wind gusts up to 40 mph, dime size hail, heavy downpours, and frequent cloud to ground lightning can be expected with this storm. This storm will be near... Days High Landing around 510 PM CDT. Remer around 515 PM CDT. Other locations impacted by this storm include Schoolcraft State Park, Mud Lake, Tobique, Goose Lake and Siseebakwet 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 4717 9418 4733 9405 4716 9349 4693 9369 TIME...MOT...LOC 2157Z 299DEG 29KT 4722 9402 JTS
Special Weather Statement
National Weather Service Duluth MN
502 PM CDT Thu Jul 16 2020
MNZ035>037-162230-
Northern Aitkin-Carlton/South St. Louis-South Aitkin-
502 PM CDT Thu Jul 16 2020
...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL AITKIN AND
SOUTHWESTERN CARLTON COUNTIES...
At 501 PM CDT, a strong thunderstorm was over McGregor, or 10 miles
south of Big Sandy Lake, moving east at 40 mph.
Wind gusts up to 35 mph, dime size hail, heavy downpours, and
occasional cloud to ground lightning can be expected with this storm.
This storm will be near...
McGregor around 505 PM CDT.
Tamarack around 520 PM CDT.
Kettle River around 530 PM CDT.
Other locations impacted by this storm include Flowage Lake, Ronald,
Kimberly, Wright, Lawler, Rice Lake Wildlife Refuge and Automba.
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 4671 9343 4667 9279 4642 9286 4642 9295
4654 9349
TIME...MOT...LOC 2201Z 281DEG 33KT 4661 9335
JTSThe Duluth radar (KDLH), 129 km away, was scanning. The volume nearest the first event began at 22:03 UTC.
3 hail, 1 thunderstorm wind, 1 funnel cloud. Local standard time, as filed.
Multiple docks were blown into Farm Island Lake. Trees 8-12 inches in diameter were also uprooted or snapped.
Photos and video were received from the public indicating a funnel cloud near Twin Lakes north of Island and Boulder Lakes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2020Every state in 2020This day in weather historyWarnings in Minnesota, July 2020
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: 904513, 904510, 904511, 904512, 904508.