textproduct: Duluth

KEY MESSAGES

- A line of isolated to scattered strong to severe thunderstorms moves northeast through the Northland early to mid-morning today. Threats include damaging wind gusts to 60-70 mph, small hail, heavy rain rates, and perhaps an isolated tornado.

- A second round of storms develops this afternoon and evening, with numerous severe storms possible. All severe hazards are possible, including large to very large hail, damaging wind gusts, tornadoes, and locally heavy rainfall.

- Hot and humid conditions continue today away from Lake Superior, where high temperatures should be in the 80s with dew points in the 60s to low 70s. Northwest Wisconsin may need a Heat Advisory, but cloud cover and storms may mitigate this need.

- Additional, non-severe showers and storms on Thursday with cooling temperatures into the weekend.

UPDATE

Issued at 204 AM CDT Wed Jun 10 2026

The forecast continues to remain largely on track for two rounds of storms today, one early to mid-morning and another this afternoon and evening. Regional radar imagery shows a broken line of strong to severe storms extending from southeast Manitoba through the ND/SD/MN border and into southwest Minnesota. These storms have had several reports of 60-80 mph wind gusts and have access to an ample pool of instability and established cold pool should keep the line going near current strength for at least the next few hours. Timing of the current storm motion combined with high-resolution model depictions bring the SW MN portion of the line of storms into the Brainerd Lakes counties between 3 AM - 4 AM, then quickly moving northeast across the Northland through the 8 AM - 10 AM timeframe before exiting to our north and east. There is expectation for the line of storms to gradually weaken as it moves across the Northland as both effective shear and 0-3 km shear is fairly marginal (20-30 kt), but the threat remains for at least initial 60-70 mph wind gusts, isolated hail to quarter size, and perhaps an embedded tornado in any northeast oriented surge in the line.

There is some question as to how quickly the morning cloud cover and showers/storms can exit the Northland, which would play a factor regarding the amount of daytime heating to boost instability and location/coverage of storms. Hi-res model depictions still show some variation in exactly where and when storms will form in the Northland, but general agreement is for the best potential for the most intense storms to form in the I-35 corridor to NW WI in the afternoon, but eventually scattered storms form across the Northland as the capping inversion breaks and the strong forcing for ascent associated with the mid/upper-level trough moves overhead. MLCAPE of 1500-2500 J/kg, high downdraft CAPE, decent mid-level lapse rates of 6-7 C/km, and even a Significant Tornado Parameter of 1-2 will all be present in this environment. The best window of time for severe storms would be in the 2 PM - 8 PM timeframe, but strong to severe storms are possible in the 1 PM - 10 PM timeframe. Expect initial storm development to be on the discrete side with supercells that would be capable of producing very large hail (up to 2 inches), tornadoes (some strong tornado potential in northwest Wisconsin), and damaging wind gusts of 60-70 mph. Storms eventually grow upscale into a more linear mode in the evening, with the potential for localized 70-80 mph wind gusts with the line in the I-35 corridor, Twin Ports and NW WI. These storms will also be accompanied by high rain rates, with good potential for widespread 0.5-1" of rain, and pockets of 2-3" that could lead to some ponding of water. No widespread flooding or flash flooding is expected at this time. Showers and storms exit late this evening and overnight to our east.

Outside of storms, today will also see dense fog near Lake Superior during the morning, but the morning line of storms could act to reduce the fog scope over land. Hot and humid conditions also continue today, with high temperatures in the 80s away form Lake Superior, and dewpoints in the 60s to low 70s. Inland NW WI may need a Heat Advisory this afternoon, but morning cloud cover and showers/storms as well as afternoon convection may limit this risk.

DISCUSSION

Issued at 245 PM CDT Tue Jun 9 2026

THIS EVENING:

A warm front is slowly lifting over north-central to northwest MN this afternoon, allowing for very moist and hot air to overcome the Northland. Heat Advisories remain in effect for portions of the area where the worst of the heat and humidity is expected. While wind shear is lacking along this warm front, instability is plentiful with MUCAPE values of 3000-4500 J/kg. This has led to an agitated cumulus field with some convective attempts already early this afternoon. 12Z CAM guidance suggests that some showers and thunderstorms are possible for Koochiching County between now and 8pm. With that much instability, there is the potential than an isolated storm could produce severe hail or wind. However, there is also the potential that this warm front pushes further north and makes any storms Canada's problem.

Otherwise, expect dense fog over Lake Superior to push back inland this evening and overnight. A Dense Fog Advisory has been issued for areas along the North Shore and in the Twin Ports for the areas with the best chance of seeing visibilities drop below a quarter mile tonight.

TONIGHT-WEDNESDAY:

A strong upper level low and following troughing starts to move into our neck of the woods. The cold front associated with this low should traipse across the Dakotas today, expected to kick off a line of storms that accelerate away from the cold front and into the Northland sometime after midnight tonight. There is some significant variation on timing. We could see them getting in the Brainerd Lakes as early as 1-2am, or as late as 3-5am. Severe storm potential along this front is boosted by anomalous buoyancy and shear, and a strong mid level jet. There is the potential that this line could still be severe as it gets into our area, most likely an elevated wind and hail threat. If storms are able to stay surface based all the way into our area, there is a very slim tornado threat for the Brainerd Lakes to far NW Koochiching County.

Wednesday will see the cold front pushing smack across our area, buoyed by the same very unstable airmass that will affect the Dakotas the day before. This has the potential to lead to scattered to numerous severe storms in our area capable of producing all hazards as storms unzip along the cold front midday to early afternoon and then push east. However, there is some uncertainty with this setup, as lingering precipitation and convection Wednesday morning could have deleterious effects on an afternoon severe threat. High-res guidance is a bit of a mess when it comes to figuring out where and when storms might affect the area. The best chance for intense severe storms is over the I-35 corridor and into NW WI, but the entire area could see scattered severe storms at times with such a supportive environment. The best timing for severe storms to develop and push east is between 2-7pm on Wednesday, but there could be a stray storm possible outside of that range. Wednesday should be a decent rainmaker, with a decent chance for a widespread 0.5-1". There could be some locally higher amounts of 2- 4" that briefing lead to some ponding of water, but no widespread flooding is expected at this time.

Despite a very cold, stable airmass over Lake Superior, even those along the coastline should be prepared for severe storms tomorrow. First, the lake breeze is NOT expected to make it very far inland. While this could dampen the damaging wind threat if storms aren't too strong, large hail can crash through a the stable layer without any issue. Additionally, the lake breeze boundary can locally increase SRH which can intensify rotation and increase tornado potential.

Temperatures Wednesday ahead of any storms will be hot, but have trended down slightly. Expect afternoon highs to be in the 80s away from Lake Superior. Additionally, dew points in the 60s and 70s will make for a very sticky heat. Heat Advisories may be needed Wednesday for the I-35 corridor and east.

THURSDAY AND BEYOND:

Some additional wrap around precipitation may combine with a low pressure system to our south to produce additional showers and a few non-severe thunderstorms Thursday, along with relatively cooler temperatures. We stay in a zonal flow pattern into the weekend, stuck between a Hudson Bay low to our north and central Plains moisture to our south. This could make for some scattered showers at time, but nothing significant is expected.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 639 AM CDT Wed Jun 10 2026

Early morning showers and storms are quickly exiting the region as of 1130z with skies clearing and conditions improving to VFR in their wake for the rest of the morning into the early afternoon. This afternoon isolated to scattered showers and thunderstorms will develop ahead of a cold front, with strong to severe storms capable of producing large hail and wind gusts to 50 knots or stronger in spots. The timing of this development was adjusted slightly later with this set of TAFs but confidence in specific timing and location of storms is low, perhaps as early as 18z or as late as 21z. In most scenarios, though, the cold front will sweep west to east this evening resulting in clearing skies and the return of VFR conditions to all sites this evening with one major exception: KDLH. In the Twin Ports, fog is expected to return after storms roll through, and have made this set of TAFs very pessimistic for DLH visibility tonight. There is a possibility the dry air moving in from the west can overcome the marine fog, but for now am leaning towards an IFR to LIFR forecast based on our climatology for patterns like this in early June.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 204 AM CDT Wed Jun 10 2026

Northeast winds continue today. Some afternoon gusts of 10-15 knots are possible at the head of the lake today, as well as 15-20 knots in parts of the North Shore this afternoon.. Patchy to widespread areas of dense fog are likely to continue today, with a Marine Dense Fog Advisory remaining in effect. Expect showers and thunderstorms to return early this morning with scattered showers and thunderstorms again this afternoon and evening. Some storms could become severe, with damaging winds (best chance closest to shore), large hail, and frequent lightning. Overnight into Thursday, winds becoming southwesterly with some stronger gusts approaching 20-25 knots at times, mainly in the Outer Apostles and portions of the North Shore. Hazardous conditions for small craft may be possible, but confidence was not high enough to issue with this update. Additional rain showers are possible on Thursday.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.

FIRE WEATHER

Issued at 204 AM CDT Wed Jun 10 2026

More thunderstorms return early this morning and again this afternoon and evening along and ahead of a cold front moving from west to east. Scattered severe storms with 60-70 mph wind gusts and isolated 1 inch hail are possible with the morning round. Scattered to numerous severe storms are also possible this afternoon and evening, with all hazards possible in these severe storms, including large to very hail, damaging wind gusts, and a few tornadoes. Good rainfall is expected, with widespread rainfall accumulations of 0.5-1.0"+ likely. Scattered showers Thursday, and then slowly drying out into the weekend.

See the Fire Weather Forecast product for a more thorough breakdown of fire weather conditions.

DLH WATCHES/WARNINGS/ADVISORIES

MN...Dense Fog Advisory until 7 AM CDT this morning for MNZ020-021- 037. WI...Dense Fog Advisory until 7 AM CDT this morning for WIZ001>004. MARINE...Dense Fog Advisory until 1 PM CDT this afternoon for LSZ121- 140>148-150. Dense Fog Advisory until 7 AM CDT this morning for LSZ142.