textproduct: Duluth

KEY MESSAGES

- Widespread frost/freeze conditions are expected Thursday night into Friday morning.

- A chance for rain on Saturday, especially along the International Border.

- Another widespread frost/freeze is likely Sunday night into Monday morning.

DISCUSSION

Issued at 220 AM CDT Thu Oct 1 2026

A cold front is dropping southeastward through northeast Minnesota early this morning, bringing in a much drier airmass with dewpoints falling into the upper 40s. Patchy dense fog across inland northwest Wisconsin will last through 5 AM before the front clears it out. Behind the front, northwest winds will increase to around 10 mph and gust 20 to 25 mph today. This will allow cooler temperatures to filter in, returning closer to normal, though still remaining slightly above normal for northwest Wisconsin. A weak disturbance passing through northwest Ontario later this afternoon and evening will create an area of clouds over the Minnesota Borderlands. Any rain showers associated with this feature look to remain north of the International Border.

A colder airmass aloft and building surface high pressure into north-central Minnesota tonight will create conditions for widespread frost and limited pockets of sub-freezing temperatures into early Friday morning. The lingering cloud cover towards midnight may delay cooling late this evening for the Minnesota Borderlands, but temperatures are expected to drop quickly as those clouds from the passing Ontario disturbance move eastward overnight. A Freeze Warning is in effect for the Iron Range and Minnesota Borderlands for late tonight into Friday morning. Frost Advisories also cover much of northwest Wisconsin and other parts of northern Minnesota. Friday will feature dry and seasonable temperatures across the region. Another period of frost and pockets of sub-freezing temperatures is expected into early Saturday morning, though more limited in areal coverage. Frost headlines may be needed again Friday night for the Arrowhead and much of northwest Wisconsin.

An incoming shortwave trough passing along the International Border late Friday night will bring increasing scattered rain showers for north-central Minnesota early Saturday morning. These showers will spread eastward into the Arrowhead by daylight Saturday morning. This Saturday rainfall has continued to trend northward over the last 24 hours, with mainly areas of far northern Minnesota north of US Highway 2 being affected by light and spotty rain showers through Saturday afternoon. A few isolated showers cannot be completely ruled out further south into northwest Wisconsin that late afternoon and evening though.

The rain showers will end by Saturday evening as dry weather sets up once again. The next round of even colder air will move in behind an incoming cold front on Sunday. Sunday night into Monday morning features an even more likely chance of sub-freezing temperatures across the Northland, and freeze headlines will very likely be needed to start the next work week. Finally, a warmer air mass moves back into the region from Tuesday through the middle of next week. This will bring a return of areawide above normal temperatures, even reaching around 70 degrees by Wednesday, alongside only a 10 percent chance of rainfall.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 624 AM CDT Thu Oct 1 2026

VFR conditions prevail today under breezy daytime winds gusting 20 to 25 knots. A passing weak system in northwest Ontario later today creates low-end VFR cumulus for the Borderlands this afternoon and evening hours before clearing after 03Z Fri from west to east. All rain showers remain north of the International Border though with that weak system.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 218 AM CDT Thu Oct 1 2026

A cold front will sweep across Western Lake Superior early this morning, causing winds to shift to the west-northwest. Wind speeds will increase through the day, with gusts reaching 20 to 25 knots by the afternoon. Small Craft Advisories are in effect from this afternoon through this evening for most nearshore zones due to these gusty winds and building waves of 1 to 2 feet. Winds will diminish by Friday mid to late morning tonight as high pressure builds in, keeping conditions quiet through Friday before southerly winds increase on Saturday.

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

FIRE WEATHER

Issued at 216 AM CDT Thu Oct 1 2026

A drier airmass is moving into the region today behind a passing cold front. Minimum relative humidity values will drop into the 28 to 38 percent range across northwest Wisconsin, and 35 to 50 percent in northeast Minnesota. Northwest winds will be breezy, gusting 15 to 25 mph. Friday will see lighter winds but similarly dry humidity. A weak disturbance moves through northern Minnesota Saturday and brings light and spotty rain showers during the daytime Saturday; also expect a notable gradient in minimum relative humidity for far eastern Minnesota where a drier airmass will be lingering into northwest Wisconsin that day. A cold front brings another day of breezy northwest winds and dry air on Sunday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Freeze Warning from midnight tonight to 9 AM CDT Friday for MNZ010-011-019. Frost Advisory from midnight tonight to 9 AM CDT Friday for MNZ012-018-026-035. WI...Frost Advisory from midnight tonight to 9 AM CDT Friday for WIZ001>004-007-008. MARINE...Small Craft Advisory from 1 PM this afternoon to 7 PM CDT this evening for LSZ140>147. Small Craft Advisory from 1 PM this afternoon to 10 PM CDT this evening for LSZ150.