textproduct: Duluth

KEY MESSAGES

- Warm, dry conditions continue today before a dry cold front moves through tonight.

- High pressure behind the cold front will keep the warm and dry conditions in the region for most of the work week.

- Next chance (~40%) for precipitation will be Friday into the weekend.

DISCUSSION

Issued at 121 PM CDT Sun Oct 18 2026

For the rest of the day, a weak and moisture-starved cold front will slide southeastward across the Northland. While the boundary will bring a wind shift from the southwest to the northwest, no precipitation is expected due to dry air aloft. Deep mixing will maintain breezy conditions through the late afternoon before the pressure gradient relaxes this evening. Because the NBM guidance continues to have relative humidity values that are too high for today, forecast values have been lowered into the 25 to 40 percent range to align with observed trends over the past few days.

On Monday, broad surface high pressure builds across the Upper Midwest, leading to a quiet and sunny start to the work week. An exceptionally dry air mass aloft will remain settled overhead. NBM guidance again projects relative humidity values that are too high for Monday, so daytime minimum relative humidity has been lowered to between 25 and 45 percent to maintain consistency with recent dry trends. Winds will shift to the north and east at very light speeds, so critical fire weather conditions are not expected.

Heading into Tuesday and through the middle of the week, a stable omega blocking pattern becomes firmly established across the central United States. Under the influence of the upper-level ridge, unseasonably mild and dry conditions will prevail across the Northland. High temperatures will run well above mid-October climatological averages, reaching into the 60s and lower 70s inland. Afternoon lake breezes will develop along the Lake Superior shoreline at times, keeping immediate coastal areas noticeably cooler and closer to seasonal norms. This high pressure will remain in place for most of the week, which will ensure no precipitation concerns through at least Thursday night.

The soonest chance for more precipitation across the region still looks to be at least next Friday as the blocking ridge begins to break down. Global guidance indicates a closed upper-level low over the Great Basin will eject northeastward toward the Upper Midwest, phasing with a shortwave trough advancing across the Northern Rockies. While timing confidence remains somewhat limited due to the stubborn nature of omega blocks, moisture advection will increase cloud cover and introduce low shower chances Friday afternoon into Friday night. Temperatures will remain unseasonably warm ahead of the system, keeping all potential precipitation strictly in the form of liquid rain.

Showers may linger into Saturday as the trough axis crosses the Upper Great Lakes, but widespread or heavy accumulations are not anticipated. Dry conditions are currently expected to return afterwards as high pressure rebuilds behind the departing wave. Temperatures will trend back toward seasonal values for late October in the wake of the front, likely bringing an end to the extended unseasonably warm stretch.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 1158 AM CDT Sun Oct 18 2026

VFR conditions expected for the TAF period. Only ceilings expected will be high clouds higher than 25 kft. Southwest to west winds will lessen throughout the late afternoon and evening. Calm winds will last through the overnight and most terminals will have winds shift to primarily out of the east by morning. Wind speeds, however will remain light.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 121 PM CDT Sun Oct 18 2026

Gales along the North Shore and the Apostle Islands will ease early this afternoon as southwest winds subside. Small Craft Advisories remain in effect across the rest of the western Lake Superior nearshore zones through 7 PM CDT this evening for wind gusts up to 35 kt and waves between 3 and 8 ft. Winds will shift westerly and diminish under 15 kt tonight, allowing waves to fall below 3 ft. Light winds generally under 15 kt and waves of 1 to 2 ft or less are expected Monday through Wednesday, with no hazardous marine headlines anticipated for the remainder of the 72-hour forecast window.

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

FIRE WEATHER

Issued at 121 PM CDT Sun Oct 18 2026

Breezy conditions continue for the rest of the day with southwest winds shifting to the northwest behind a dry frontal passage, gusting between 25 and 35 mph. Because model guidance has been running too high, minimum relative humidity values this afternoon and Monday have been lowered into the 25 to 45 percent range. Winds on Monday will shift to the north and east at light speeds around 5 to 10 mph under high pressure, limiting fire weather concerns despite very dry air aloft. Light winds and low relative humidity values will maintain elevated fire weather awareness through midweek before humidity increases with shower chances late Friday into Saturday, followed by a return to dry weather.

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 until 7 PM CDT this evening for LSZ121- 141>148-150. Small Craft Advisory until 1 AM CDT Monday for LSZ140.