Very warm and humid conditions ahead of a cold front moving into the Northland on the afternoon of the 31st led to the development of thunderstorms. These storms went on to produce damaging wind gusts that led to widespread reports of trees and power lines down across northeastern Minnesota during the late afternoon and early evening hours.
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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.
Very warm and humid conditions ahead of a cold front moving into the Northland on the afternoon of the 31st led to the development of thunderstorms. These storms went on to produce damaging wind gusts that led to widespread reports of trees and power lines down across northeastern Minnesota during the late afternoon and early evening hours. The storms were not as prolific or damaging across northwest Wisconsin with only one tree being downed in Superior from one of the storms.
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 31, 3:02 PM CST, 1 hour 19 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Duluth MN 402 PM CDT Wed Jul 31 2024 .KEY MESSAGES... - Storms tonight may be strong to severe. Wind gusts to 70 mph, hail to 2 inches in diameter, and heavy rainfall are possible with the storms. - Areas of dense fog are possible once again tonight. - Another chance of storms Thursday, although severe weather is unlikely. - A little cooler Thursday, then hot and humid again Friday and most of Saturday. Cooler Sunday into next week. && .DISCUSSION... Issued at 401 PM CDT Wed Jul 31 2024 Convection foreshortened discussion this afternoon. No major changes to the ongoing forecast. MCS over central and western Minnesota should gradually weaken and become less organized through 01.00Z. SPC RAP mesoanalysis indicates the storms were moving into a less favorable environment and should outrun the best MLCAPE by 01.00Z. Will continue to monitor as the evening progresses. CAMs have been really struggling to handle the ongoing convection today and have offered surprisingly little help. Locally heavy rainfall, hail up to 2 inches in diameter, and wind gusts to 70 mph are the main threats from the storms this evening. Showers and storms will persist through tonight and there may be redevelopment on Thursday as an upper-level trough and cool air advection passes over the Northland. Temperatures will trend a little cooler for Thursday with the cold air advection aloft and partly to mostly cloudy skies. Warmer weather on tap again Friday with hot and humid conditions returning. Another cooling trend arrives late Saturday and really takes hold on Sunday pushing temps near to below normal. PREV DISCUSSION Issued at 438 AM CDT Wed Jul 31 2024 Conditions are fairly quiet early this morning as weak ridging and high pressure occur over the CWA. Patchy dense fog development has occurred early this morning, primarily over northwest WI. A Dense Fog Advisory remains in effect for the northwest WI portion of the CWA, excluding Burnett, until 9 AM today. While not included within the Dense Fog Advisory, the MN side of the CWA is still expected to see patches of dense fog reducing visibility to 1/2 mile or less. Cloud cover from a decaying MCS in western MN advecting into the area from the west is expected to limit the extent of dense fog development in northern Minnesota. Expect fog to dissipate shortly after sunrise as diurnal heating begins. Temperatures today are expected to be very warm as southerly winds ahead of an approaching shortwave results in strong WAA. High temps today will be in the upper 80s to low 90s for most locations. Decided against issuing a Heat Advisory for today in Pine and Burnett Counties, as HREF grand ensemble probability of exceeding 100 degrees is only around 10%. Despite not having a Heat Advisory in place today, it will still be an uncomfortably hot day, with heat indices in the 90s for the vast majority of the CWA. These warm temps, when combined with strong moisture advection, is expected to result in high instability across the CWA by this afternoon and evening with MLCAPE values reaching as high as the 2000-3000 J/kg range. This large amount of instability is likely (60% chance) to initiate thunderstorms this afternoon and evening as the shortwave trough propagates into the area along with an associated weak cool front. In recent runs, CAMs have been coming into better agreement regarding the spatial coverage of thunderstorms today. The general consensus is that scattered discrete cells will form in north-central MN and move into the Arrowhead this afternoon and evening. In addition, a line of storms will be diving south of the CWA late this afternoon through the evening along the CAPE gradient towards southern MN. A few of these storms could become strong to severe. Steep mid-level lapse rates in excess of 8 degC/km keep large hail up to 2" as a hazard for today, especially in the southwestern portion of the CWA where CAPE will be maximized. In addition to large hail, damaging winds up to 70 mph will also be possible this afternoon and evening as DCAPE increases to around 1000 J/kg. Expect the potential for severe convection to come to an end tonight as instability decreases and the shear environment weakens. Thursday will see additional chances for scattered showers and thunderstorms as the CWA sits under a pattern of cyclonic flow aloft. Highs tomorrow will be slightly cooler than today, with temps in the low to mid 80s. This slight reprieve from the heat will be short-lived though, as high pressure and ridging return on Friday. Hot temps will accompany this ridge, increasing highs on Friday into the upper 80s to low 90s once again. Relief from the heat does appear on the horizon late this weekend into early next week as cooler air advects into the region from Canada. Looking even further, the Northland is likely to see a pattern change with below- normal temps filtering in for the second week of August per the latest outlook from the Climate Prediction Center. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1238 PM CDT Wed Jul 31 2024 VFR conditions are expected to prevail through much of the afternoon before chances for showers and thunderstorms increase heading into this evening and tonight. Overall confidence on timing and location of storms remains low with models not having a good handle on what is currently occurring. BRD should be the first to see activity by/after 5PM this afternoon with activity spreading north and east overnight. Activity may not reach HYR until closer to daybreak Thursday. Storms will bring gusty and erratic winds along with MVFR or lower ceilings and visibilities. Additional updates will be needed this afternoon as activity develops. Some guidance hints at the development of fog and low ceilings overnight, but this will likely be dependent on whether rainfall is received or not. Have kept out with this update aside from BRD which is the most likely to receive rainfall. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 401 PM CDT Wed Jul 31 2024 Main concerns tonight are fog potentially redeveloping and a risk of thunderstorms, some possibly strong to severe. As of 330 PM CDT, a line of storms was located over central and western Minnesota moving toward Lake Superior. These storms should weaken somewhat before reaching the lake. There will still be a possibility of wind gusts to 30 to 40 knots with the strongest storms. Fog may redevelop tonight and could become dense with visibility less than 1 mile possible. Outside of thunderstorms, winds will be relatively light over the next few days. Additional storm chances Thursday. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...None. && DISCUSSION...Huyck PREV DISCUSSION...Unruh AVIATION...BJH MARINE...Huyck
Hazardous Weather Outlook National Weather Service Duluth MN 1242 PM CDT Wed Jul 31 2024 MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-011745- 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- 1242 PM CDT Wed Jul 31 2024 This Hazardous Weather Outlook is for portions of northeast Minnesota and northwest Wisconsin. .DAY ONE...This afternoon and Tonight Hot and muggy with heat index values reaching the upper 80s and 90s are expected this afternoon. Severe storms will be possible this afternoon and evening, with the greatest risk around the Brainerd Lakes area, with a lower risk over the remainder of the Northland. The main risk this evening will be for large hail up to 2 inches and winds up to 70 mph. Locally heavy rain leading to minor flooding will also be possible. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Thunderstorm chances will continue for Thursday and then again into the weekend and early next week. Friday will be another hot and muggy day with heat index values rising into the upper 80s to mid 90s. .SPOTTER INFORMATION STATEMENT... Skywarn spotters may be needed late this afternoon and evening. LSZ121-140>148-150-011745- 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- 1242 PM CDT Wed Jul 31 2024 This Hazardous Weather Outlook is for portions of Lake Superior and the Nearshore waters of western Lake Superior. .DAY ONE...This afternoon and Tonight Isolated strong to severe storms will be possible this evening over the lake. Storms may be capable of producing storm force wind gusts, cloud- to- water lightning, and hail. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Thunderstorm chances will continue for Thursday and then again into the weekend and early next week. BJH More information may be obtained at the following web address: http://www.weather.gov/duluth
Preliminary Local Storm Report
National Weather Service Duluth MN
456 PM CDT Wed Jul 31 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0455 PM Hail 1 W Coleraine 47.28N 93.44W
07/31/2024 M0.50 Inch Itasca MN Public
Report from mPING Half-inch (0.50 in.).
&&
BJHPreliminary Local Storm Report
National Weather Service Duluth MN
459 PM CDT Wed Jul 31 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0439 PM Tstm Wnd Dmg 1 N Kettle River 46.50N 92.88W
07/31/2024 Carlton MN Trained Spotter
Reports of branches down with a mature pine
tree down across the road on the north side
of town.
&&
BJHPreliminary Local Storm Report
National Weather Service Duluth MN
502 PM CDT Wed Jul 31 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0445 PM Tstm Wnd Dmg 1 NNW Grand Rapids 47.24N 93.53W
07/31/2024 Itasca MN Park/Forest Srvc
Multiple mature pine trees down along US2 in
Grand Rapids. Time estimated by radar.
&&
BJHSpecial Weather Statement
National Weather Service Duluth MN
503 PM CDT Wed Jul 31 2024
MNZ011-018-019-026-312230-
Central St. Louis MN-North St. Louis MN-North Itasca MN-
South Itasca MN-
503 PM CDT Wed Jul 31 2024
...STRONG THUNDERSTORMS WILL IMPACT EASTERN ITASCA AND WEST CENTRAL
ST. LOUIS COUNTIES THROUGH 530 PM CDT...
At 502 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 13 miles southeast of Scenic State Park to
Warba. Movement was northeast at 35 mph.
HAZARD...Wind gusts up to 50 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Hibbing, Grand Rapids, Chisholm, Coleraine, Keewatin, Buhl, Nashwauk,
Taconite, Meadow Brook, Hill Annex Mine State Park, Togo, Gunn,
McCarthy Beach State Park, Pengilly, Perch Lake, Blackberry, Bovey,
Marble, La Prairie, and Hart Lake.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
north central and northeastern Minnesota.
&&
LAT...LON 4798 9293 4771 9276 4729 9282 4708 9352
4762 9354
TIME...MOT...LOC 2202Z 229DEG 29KT 4761 9334 4716 9328
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
KMLPreliminary Local Storm Report
National Weather Service Duluth MN
509 PM CDT Wed Jul 31 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0448 PM Tstm Wnd Dmg 5 S Grand Rapids 47.16N 93.52W
07/31/2024 Itasca MN Trained Spotter
A small pine tree was downed onto a power
line and started a small fire.
&&
BJHPreliminary Local Storm Report
National Weather Service Duluth MN
511 PM CDT Wed Jul 31 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0508 PM Tstm Wnd Dmg 2 SE Warba 47.11N 93.24W
07/31/2024 Itasca MN Public
Report from mPING of 3-inch tree limbs
broken.
&&
BJHThe Duluth radar (KDLH), 15 km away, was scanning. The volume nearest the first event began at 22:23 UTC.
1 thunderstorm wind. Local standard time, as filed.
An 18 to 24 inch diameter silver maple tree was snapped about 8 feet up in front of the old library.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2024Every state in 2024This day in weather historyWarnings in Wisconsin, July 2024
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: 1199725.