textproduct: Duluth

KEY MESSAGES

- Widespread rainfall today ends early tonight.

- Warm temperatures through Wednesday, then cooling down Thursday and into the weekend.

- Frost and freezing low temperatures are expected starting Thursday night and lasting into the weekend.

DISCUSSION

Issued at 217 AM CDT Tue Sep 29 2026

Early this morning, radar and satellite imagery shows the ongoing band of moderate to pockets of heavy rainfall over the Red River Valley terminating into far north-cental Minnesota. This band will slowly move eastward over the rest of the Northland later today and bring a tenth to a half-inch of rain. Once this band exits inland northwest Wisconsin early tonight, the trends for rainfall on Wednesday rainfall have trended downward notably over the last 24 hours. What was once looking like two different rounds of rainfall for northwest Wisconsin is now more of just a round one event through this evening. Tonight, fog may develop across much of the region and we will monitor for any Dense Fog Advisory needs if it looks to be trending more dense over the next few forecast updates.

The fog tonight into Wednesday clears later Wednesday morning as daytime temperatures quickly spike and peak in the low to mid-70s, and a few spots in northwest Wisconsin may peak into the upper-70s. Any lingering precipitation will be limited to spotty and light rain showers for inland northwest Wisconsin. This warmth quickly passes though with a cold frontal passage early Thursday morning.

A cool down of 10 to 15 degrees will occur on Thursday compared to Wednesday, but temperatures will still remain fairly seasonable given the very warm day Wednesday. Expect breezy conditions Thursday as winds gust 20 to 30 mph. A generally drier airmass sets up behind the front, so dewpoints will be much lower into the rest of the forecast period, dropping into the 30s and 40s versus the 50s and low-60s observed recently. We will expect much lower relative humidity each day from Thursday onward.

High pressure will dominate the late week and early next week weather pattern. From Thursday night onward, there is potential each night for frost somewhere in the region. Minimum temperatures for Thursday night into early Friday morning have trended downward, and frost or freeze headlines are very likely Thursday night and maybe each night into the weekend for at least some parts of the area.

Friday night a Northern U.S. Rockies shortwave trough with Pacific moisture deepens along the MT/ND/MB border area and helps to create scattered light rain showers for Saturday daytime as it passes through the Upper Midwest. Following this quick system, a generally minimal to no precipitation pattern is forecast into early next week.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 612 AM CDT Tue Sep 29 2026

Rainfall over the Iron Range and Borderlands continues today while entering the rest of northern Minnesota over the next six hours. Expect a few hour period at least of that rain for those TAF sites not seeing rain right now later today. The rainfall ends this evening in northwest Wisconsin. Southerly winds today gust to 20 knots during the daytime hours and decrease this evening while shifting southwesterly. Fairly widespread IFR to LIFR ceilings are forecast for Tuesday night and lasting into Wednesday morning. Will have to watch for how limited visibilities can drop tonight for further reductions that could be needed to the TAF visibilities.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 218 AM CDT Tue Sep 29 2026

A Small Craft Advisory remains in effect from late this morning through this evening from Grand Portage to Grand Marais due to gusty southerly winds up to 25 knots and building waves. Rain showers will move across western Lake Superior today. By Wednesday night and into Thursday, a cold front will sweep across the lake, shifting winds to the west and increasing gusts up to 30 knots along the North Shore, which may need additional Small Craft Advisories.

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

FIRE WEATHER

Issued at 221 AM CDT Tue Sep 29 2026

A band of rainfall will bring a tenth to a half-inch of wetting rain to the region today. Minimum relative humidity will remain high today and Wednesday, generally above 50 percent. Southerly winds around 10 to 15 mph are expected today. A cold front passes late Wednesday night into early Thursday, shifting winds to the northwest with gusts of 20 to 30 mph. A drier airmass will drop dewpoints into the 30s and 40s, leading to much lower relative humidity from Thursday onward. This setup for late this weekend onward begins to look more like the beginning of a pattern shift favoring the fall fire weather season looking into early October.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Small Craft Advisory from 10 AM this morning to 10 PM CDT this evening for LSZ140.