Duluth, MN 55806 Weather

Key Messages

- Above normal temperatures through Saturday.

- Next chance of rain (20-40%) is Friday afternoon into Saturday.

- Near-normal temperatures return Sunday.

Discussion

Issued at 121 PM CDT Tue Oct 20 2026

SYNOPTIC:

A complex split-flow regime was found aloft over the North American continent early this afternoon. A cutoff low was positioned off the coast of California with a broad relatively flat ridge farther east across the Canadian Prairies into Ontario. A northern jet stream with several troughs stretched across Canada. The first trough axis of note upstream from the Northland stretched from northwest Manitoba to southern Alberta. A southern jet stream was found over the southwest US along the southern periphery of the cutoff low. An area of low pressure ahead of the northern stream trough was centered over northern Manitoba with a cool front trailing to the southwest over southeast Saskatchewan into eastern Montana. Surface high pressure was situated over the Great Lakes and extended south into the Gulf Coast.

LATE THIS AFTERNOON THROUGH THURSDAY NIGHT:

The northern stream trough propagates eastward across the Canadian Prairies and into northwest Ontario by 12Z Wednesday morning. The surface low pressure and cold front will progress eastward across the Northland Wednesday. Winds will turn northerly and remain relatively light, around 5-10 mph. Temperatures will trend a few degrees cooler over the Borderlands, low 60s, while areas south of a line from Cass Lake to Duluth to Hurley will see temperatures in the upper 60s to low 70s.

Transient surface high pressure will drift eastward across the region Wednesday night and Thursday as an upper-level ridge builds over the northern Plains and Canadian Prairies. Temperatures will remain well above normal as winds turn southerly. Lows Thursday morning will range from the low 30s to around 40 degrees. Look for highs in the low 60s to low 70s, about 10-20 degrees above normal. Temps will be cooler for portions of the North Shore and Arrowhead due to on-shore flow. Those readings will be 5-10 degrees above normal with highs in the middle 50s to low 60s.

Aviation

Issued at 1230 AM CDT Wed Oct 21 2026

A weak cold front is advancing in from the northwest this morning. Radar is showing some weak echoes associated with this boundary but not expecting any precipitation at the surface. Mid and upper level clouds will clear out through the morning hours as high pressure builds in behind the boundary. Expect winds to be light and out of the north as the behind the front. Additionally, northern MN still has a few more hours under the influence of a low level wind shear at the start of the TAF period.

Marine

Issued at 1241 PM CDT Tue Oct 20 2026

High pressure will slowly drift to the east through Wednesday. A weak cool front will advance southeastward across western Lake Superior Wednesday and will be marked with a wind shift. Wind speeds will be in the 5 to 10 knot range for most locations. Waves will generally be less than 3 feet. Northeast winds strengthen Thursday. Wind speeds of 5-15 knots are expected. Gusts of 15-20 knots are possible in the southwest arm of Lake Superior near the Twin Ports. Small Craft Advisories may be needed if wind speeds and wave heights increase with later forecasts. A stronger system will move across the region Friday night and Saturday. Wind gusts and wave heights will become hazardous for smaller vessels as early as Friday evening and may remain strong through Saturday and into Sunday. Small Craft Advisories will likely be needed during that time.

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