textproduct: Duluth

KEY MESSAGES

- Isolated severe thunderstorms are possible this afternoon and evening from the Brainerd Lakes area eastward across the Interstate 35 corridor and northwest Wisconsin.

- Near critical to possible critical fire weather conditions for areas north of the Iron Range in far northern Minnesota Sunday afternoon and evening.

- Another period of severe weather potential sets up Monday, especially for north central Minnesota.

- Heat dome next week brings high confidence in at least Moderate (Level 2 of 4) heat-related impacts to entire region away from Lake Superior shorelines. Areas of Major (Level 3 of 4) impacts north-central Minnesota and inland northwest Wisconsin.

DISCUSSION

Issued at 110 PM CDT Fri Jun 5 2026

A weak boundary is pushing across the Northland this afternoon and is accompanied by a moderately unstable environment. Thunderstorms moving through the MN/WI stateline area will continue eastward over the next few hours. Another round back into western Minnesota present is being monitored for another round in the Brainerd Lakes later this evening. In general, expect continued chances of storms through sunset today for areas south of the Iron Range in Minnesota and across northwest Wisconsin. The strongest deep-layer wind shear around 30 knots will support passably organized storm structures south of MN 210 in northern MN and south of US Hwy 2 in NW WI. Isolated severe storms will be capable of producing damaging wind gusts up to 60 mph and large hail up to an inch in diameter before the convective activity tracks south and east out of the region tonight.

As the storms depart later tonight, skies will clear and winds will become light and variable. This setup will promote the development of fog and mist after midnight, which will linger into early Saturday morning. On Lake Superior, marine fog is anticipated to form and may bring limited visibilities to around 1 mile for immediate mainland shoreline areas along the North and South Shores.

High pressure builds across the Upper Midwest on Saturday, bringing a period of sunny skies and dry conditions. Attention will quickly shift to fire weather concerns north of the Iron Range in far northern Minnesota, including Koochiching, North Itasca, and Northern St. Louis counties. Unseasonably warm temperatures climbing into the mid to upper 80s combined with very low low- level moisture will cause relative humidity values to drop to 25 to 30 percent on Saturday afternoon. While winds remain light under 10 mph, these low humidities over dry fuels may create near-critical fire weather conditions. The potential for a Special Weather Statement will need to be assessed in time.

On Sunday, an upper-level ridge moves eastward through the central U.S., tightening the pressure gradient as low pressure deepens in Canada. Southerly to southeasterly winds will increase substantially across the Northland, gusting 25 to 30 mph. These breezy winds, still dry airmass over areas north of the Iron Range and hot temperatures into the lower 90s combining with still-dry fuels per land management agencies has prompted a Fire Weather Watch for Sunday afternoon and evening.

The weekend heat breaks briefly on Monday as a shortwave trough tracks through southern Canada. This system pulls a warm front across the region Sunday night, drawing deep Gulf moisture northward and triggering widespread wetting rainfall chances between 50 and 90 percent on Monday. Saturated profiles will support efficient rainfall producers, but we are also monitoring the potential for severe weather conditions in northern Minnesota Monday afternoon as the better forcing aligns with diurnal instability.

By Tuesday, the brief heat reprieve clears out as period of even more hot establishes itself firmly over the Great Lakes region through the middle of next week. Multiple days of consecutive, intense heat are forecast for interior portions of the Northland away from the immediate Lake Superior shorelines. High temperatures on Wednesday and Thursday are forecast into the low to mid-90s, while southerly winds keep dew points elevated in the upper 60s and 70s. This prolonged pattern brings high confidence in widespread Moderate HeatRisk impacts, with Major HeatRisk impacts likely across north-central Minnesota and inland northwest Wisconsin, where heat index values may eclipse 100 degrees. Heat headlines may be needed in time.

Active southwest flow aloft on the periphery of the ridge will maintain moderate (30-60% chance), diurnally-driven showers and thunderstorms Tuesday through Thursday.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1229 PM CDT Fri Jun 5 2026

A few different rounds of thunderstorms, isolated severe, are expected through 06Z this evening for terminals south of the Iron Range. Erratic, damaging wind gusts to 50 knots and large hail around an inch in size are the primary hazards from any isolated severe thunderstorms. After the storms depart, fog and mist is again expected after 06Z tonight and to linger through 13Z...producing IFR to MVFR visibilities under mostly clear skies. Terminals along the North and South Shore though could see lake-enhanced dense fog though tomorrow morning so will be monitoring those TAFs. Quiet VFR conditions Saturday daytime.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 106 PM CDT Fri Jun 5 2026

Scattered thunderstorms, some strong with higher gusts and small hail, are expected this afternoon and evening across western Lake Superior. Winds will remain out of the southwest at 5 to 10 knots this afternoon and become light and variable on Saturday, keeping waves at 1 to 2 feet or less. Marine fog is forecast to develop late tonight and persist into Saturday morning. Winds shift easterly Saturday evening and then northeast on Sunday, increasing to 10 to 15 knots with building waves in the southwestern arm that may at times become hazardous to small craft.

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

FIRE WEATHER

Issued at 104 PM CDT Fri Jun 5 2026

Isolated severe thunderstorms are forecast south of the Iron Range through this evening as a weak cold front departs tonight. Erratic, damaging wind gusts to 60 mph and large hail around an inch in size are the primary hazards through this evening.

High pressure moves in late tonight into Saturday with winds becoming light and variable. No rainfall is expected this weekend as that high pressure sets up over the Great Lakes this weekend. Minimum relative humidity values will drop to 25 to 30 percent north of the Iron Range Saturday PM, creating possible near- critical conditions Saturday afternoon...a Special Weather Statement may be needed in time for Saturday afternoon in those locations.

On Sunday, hot temperatures in the 90s arrive as breezy southeast winds gusting up to 25 to 30 mph develop. Due to very low humidity values around 25 percent and dry fuels, a Fire Weather Watch is in effect for Sunday afternoon and evening for Northern Itasca, Koochiching and Northern St Louis Counties in far northern Minnesota. Wetting rain returns Monday afternoon.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Fire Weather Watch from Sunday afternoon through Sunday evening for MNZ010-011-018. WI...None. MARINE...None.