textproduct: Duluth

KEY MESSAGES

- Quiet conditions are expected today through tomorrow as high pressure builds. Expect areas of fog tonight, especially in northwest Wisconsin.

- Chances for rain arrive on Friday into the weekend. Rain chances on Friday will largely be in north-central Minnesota, becoming more widespread on Saturday into Sunday.

- Cooler temperatures are favored to arrive early next week.

DISCUSSION

Issued at 240 PM CDT Wed Oct 21 2026

Cloud cover has decreased this afternoon following a line of sprinkles that propagated through the area this morning ahead of a cold front. This cold front, and associated 500mb trough, are currently moving through the CWA this afternoon, with cooler and drier air from Canada already starting to filter in. Skies are expected to remain clear through tonight as high pressure builds over the Upper Great Lakes region. With low temps forecast to drop into the 30s tonight for most, this will likely lead to areas of fog. Patchy dense fog may also be possible, especially in northwest WI where the drier airmass will be arriving latest.

Thursday will see a continuation of the benign weather pattern that has dominated this past week as ridging aloft and sfc high pressure persists. Despite the ongoing cold fropa, high temps tomorrow will be unseasonably warm on Thursday in the mid 60s to low 70s. The exception will be locations near the North Shore, as northeast flow over the lake and southeast flow inland will advect cooler air from Lake Superior onshore.

A change in the dry pattern we've been seeing arrives on Friday as isentropic uplift associated with a warm frontal passage brings a chance for showers and potentially a rumble of thunder. Highest chances (50-65%) for rainfall will be in north-central MN, with the probability decreasing for locations farther to the east.

Additional rain chances begin to spread across the CWA this weekend as the low pressure associated with Friday's warm frontal passage continues to propagate north into northern Saskatchewan and Manitoba and a strong baroclinic zone becomes draped over the Northland. The 500mb trough that will be proving dynamic forcing to this low pressure is forecast to begin propagating downstream on Sunday, breaking down the omega block that has been keeping the recent pattern quiet.

An active synoptic pattern is favored to develop early next week with split flow aloft and additional troughs and areas of sfc low pressure move into the Upper Midwest. Whether or not these lows bring precipitation to the CWA remains uncertain, as they will be needing to overcome areas of high pressure and drier air, especially in the Borderlands, northern Ontario, and southern Manitoba. One of the biggest changes will be cooler temperatures. Highs on Monday and Tuesday are currently forecast to be in the mid 40s to low 50s with overnight lows dipping below freezing for a majority of the CWA.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1230 PM CDT Wed Oct 21 2026

The center of high pressure will slide from west to east over the international border through Thursday morning then push farther into the Great Lakes during the day Thursday. Clear skies will prevail today through tomorrow across all TAF sites, with winds diminishing to under 5 kts this afternoon and continuing to drop to near calm this evening through Thursday morning. Clear skies with light winds will promote at least patchy fog development during the early morning hours, with the most susceptible sites being DLH-HIB-HYR while also possible at BRD. Have brought conditions down to 1-3sm at this point, but LIFR conditions cannot be ruled out. Once past sunrise and deeper mixing allows for slightly stronger surface winds and scouring out of the low level moisture, VFR conditions return by late Thursday morning.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 240 PM CDT Wed Oct 21 2026

High pressure settling into the area this evening into tonight will keep conditions fairly quiet. Northeast flow developing tonight and continuing into Thursday is expected, although wind gusts are forecast to be 20 knots or less. If trends increase, a Small Craft Advisory may be needed especially around the Twin Ports. An increasing pressure gradient associated with arriving low pressure will likely create conditions hazardous to small craft late Friday into Saturday for most nearshore waters as southerly winds gust 25 to 30 knots. This low pressure will also bring a chance for rain showers.

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

FIRE WEATHER

Issued at 240 PM CDT Wed Oct 21 2026

With the exception of sprinkles this morning, a mostly dry cold front is currently passing through the area this afternoon with clear skies. Winds behind this front have been fairly light and are expected to ease further this evening into tonight as high pressure settle over the region. Areas of fog are expected tonight, especially in northwest Wisconsin where drier air behind the front will arrive the latest.

On Thursday, expect mostly clear to clear skies for most locations with min RH lowering into the low 40% range and unseasonably warm high temps. Northeast flow over Lake Superior tomorrow will likely result in an afternoon lake breeze moving inland after 1300. Chances for rain arrive Friday into the weekend as a more active pattern develops. Following these rain chances, much cooler temps are forecast to arrive early next week.

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.