textproduct: Duluth

KEY MESSAGES

- Temperatures trend colder the rest of this week. 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.

- More rain is possible early next week.

DISCUSSION

Issued at 1254 PM CDT Wed Sep 30 2026

Clouds continue to clear from west to east this afternoon as dry air filters in and a cold front will gradually pass through into tonight. Strong northwesterly cold air advection will develop with a tightening pressure gradient, leading to blustery conditions on Thursday. Temperatures won't get overly chilly tonight, but some lows around 40 are possible up around Koochiching county. The next cold night will be Thursday night into Friday as a surface high moves in from the west. This won't be a perfect radiational cooling night as we should have some winds still sticking around, but we should still have widespread temperatures in the 33 to 36 degree range and some areas falling to or below freezing, especially the usual cold spots and also more widespread in north-central Minnesota (40-60% chance for temperatures falling below freezing there). Widespread frost headlines will likely be needed, as well as some freeze headlines.

On Friday, look for a seasonably cool and dry day with highs in the 50s/60s. There will be at least localized concern for near freezing and freezing temperatures again Friday night, especially in northwest Wisconsin and the tip of the Arrowhead where the influence of departing high pressure will still be there. Warm air advection will develop with southerly flow starting Friday night, however, so expect increasing clouds in northeast Minnesota. A clipper is still looking like it will pass through on Saturday, with an axis of mainly light rain looking like it will target the Canadian border. Overall, rainfall amounts still look quite light from this. A few places could sneak up to a quarter of an inch total, but less for most places that see rain. The rain may be pretty limited in coverage to the Iron Range and points north.

Another cold front will pass through going into Sunday, resulting in another seasonably cool day and breezy northwest winds. High pressure moves in again Sunday night, and with this, we'll be looking at one of the coldest nights of the fall season so far. Widespread temperatures at or below freezing are likely (40-80% chance). Areas around Lake Superior may be spared from a freeze, but it will probably be only a few miles inland where freezing temperatures are found. This may be a season-ending freeze for many places. Probabilities of temperatures 28 degrees or lower are 10-30% at this time, so we will have to wait a few days and see how trends change.

There will be an upper-level trough just northeast into Ontario, producing a few rain/snow showers, and parts of the UP might see some of their first lake-effect rain/snow showers. We should remain dry into Monday with sunshine as high pressure passes through.

Southerly flow and an upper-level trough could bring more rain chances to the region early next week along with moderating temperatures.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 630 PM CDT Wed Sep 30 2026

Largely VFR conditions across the Northland to start the forecast period. A few pockets of MVFR ceilings can be found in NW WI but don't anticipate this impacting HYR until later this evening when cloud cover increases from a system moving across the Midwest. There is some potential for fog developing in NW WI as well, the probabilities elsewhere have really diminished with the latest forecast updates. Tomorrow will be widespread VFR again with wind gusts out of the northwest.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 1254 PM CDT Wed Sep 30 2026

A dense fog advisory continues this afternoon for parts of the North Shore this afternoon. The current headline from Taconite Harbor to Grand Portage runs into this evening. Webcam around Grand Marais shows greatly improving conditions, though satellite still suggests some fog further up the shore. Will hold the current headline as-is for a little while longer this afternoon to monitor trends while some moisture remains in place, but it's very possible that this headline may be allowed to expire several hours early if the clearing trend persists.

Tonight, a cold front will pass through, bringing a wind direction change to northwesterly. Conditions become breezy into Thursday with gusts in the 15 to 20 kt range, and perhaps locally higher along the North Shore with some downsloping. Right now, it looks like gusts will remain below Small Craft Advisory criteria or perhaps there could be a 1 to 3 hour period of gusts around 22 kt Thursday afternoon. No headlines will be issued now, but it's possible that a short-duration Small Craft Advisory may be needed for parts of the North Shore Thursday afternoon. This may extend into the outer Apostle Islands into Thursday night as northwest winds persist and colder air works its way over the lake. The next chance for any potentially hazardous conditions won't arrive until Saturday, when some breezy southerly winds may be possible.

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

FIRE WEATHER

Issued at 1254 PM CDT Wed Sep 30 2026

Drier air moves in this afternoon and tonight with a cold front passing through. Thursday, expect conditions to become pretty dry, especially in northwest Wisconsin where some 25 to 35 min RH values are expected. Winds will be a bit breezy Thursday as well, though the strongest winds gusting from 15 to 25 mph will be in northeast Minnesota (where RH will be a little higher, from around 35 to 50%) and gusts to around or just over 15 mph in northwest Wisconsin. Some elevated fire weather conditions may be possible, especially in northwest Wisconsin and possibly along the North Shore where downsloping may result in locally lower humidity and breezy conditions.

Another dry day is expected Friday with min RH falling to 35 to 45%, but with lighter winds. Expect more clouds and some rain Saturday into Saturday night, mainly Iron Range and north. Rainfall amounts will generally be less than a quarter inch where it does rain (most places in the region will remain dry). Expect another cold front going into Sunday, which may result in some blustery northwest winds and dry air with RH falling below 40% for many places Sunday into Monday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...None.