textproduct: Duluth

KEY MESSAGES

- Cooler fall weather moves in today, then continues through the next week.

- Patchy frost is possible late Sunday night into early Monday morning across the typically colder locations of the Northland.

- Widespread rain and thunderstorms are likely Monday into early Tuesday, bringing a potential for heavy rainfall and soaking conditions. Severe weather is not expected.

UPDATE

Issued at 625 AM CDT Sat Sep 12 2026

Introduced sprinkles and maybe a shower north of the Iron Range today. Hi-res guidance persistently represented convective showers as colder air aloft passes overhead coincident with a surge of vorticity. Remainder of the forecast is on track.

DISCUSSION

Issued at 157 AM CDT Sat Sep 12 2026

The cold front that brought showers and thunderstorms to the Northland Friday evening is currently advancing out of the forecast area. Early this morning, only a few lingering showers remain behind the boundary. Winds are gradually turning out of the northwest during the overnight hours, bringing gusts in the 15 to 20 mph range. For today, expect a cooler and breezy day as high temperatures reach only into the 60s to lower 70s. Northwest winds will increase by mid morning, with gusts rising into the 20 to 25 mph range through the afternoon. Cyclonic flow aloft will bring some stratocumulus clouds to the Borderlands, while most other areas will see only passing high clouds.

Quiet and even cooler conditions settle in for Sunday as surface high pressure slides in to settle over Minnesota overnight. High temperatures on Sunday will generally stay in the 60s under mostly sunny skies. As winds become light and variable Sunday night under clear skies, temperatures will drop significantly. It's not the best night for radiational cooling, but I anticipate overnight lows cooler than the median of guidance. Low temps should fall into the mid 30s to low 40s. The typical cold spots could drop into the low 30s, which may support the development of patchy frost by early Monday morning.

A strong upper low pressure system moves from the northern Plains across the southern Canadian Prairies and into northern Ontario Monday through Tuesday of next week. This system will tap into a plume of rich moisture, spreading another round of widespread rain and scattered thunderstorms across the region from west to east starting Monday afternoon and continues Monday night. There is a risk for moderate to heavy soaking rainfall, with a 60 to 80 percent probability of getting at least a half inch of rain by 7 AM Tuesday. Severe weather is not anticipated. Showers will linger into Tuesday before the system departs to the east.

High pressure builds into the region beginning Tuesday night and Wednesday, allowing cooler air to filter into the Northland. High temperatures through the middle of the week will remain comfortably in the 60s with overnight lows in the 40s. A generally quiet weather pattern takes hold for Thursday and Friday, though there are some chances for showers and isolated storms. Temperatures will begin to slowly warm back into the 70s for Friday and Saturday as southerly return flow sets up ahead of the next potential system.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1222 PM CDT Sat Sep 12 2026

Scattered to broken MVFR cigs occurring across northern Minnesota have been continuing to lift early this afternoon. While cigs will predominately be VFR through the afternoon, occasional MVFR conditions may occur. West-northwest winds will continue to be strong this afternoon, easing overnight. With a surge of cooler air, lake effect rain showers are forecast in the lee of Lake of the Woods and Rainy Lake, which will bring a chance for rain showers to KINL early Sunday morning. Northwest winds once again increase on Sunday morning, albeit a bit lighter than what is being seen today.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 625 AM CDT Sat Sep 12 2026

Small Craft Advisories are in effect today into tonight. Winds are shifting to the west and northwest behind a cold front, with gusts of 20 to 30 knots expected through Saturday afternoon. Conditions will improve Sunday as high pressure moves into the area, producing diminishing winds and subsiding waves. However, hazardous conditions are expected to return for Monday and Tuesday as a strong low pressure system approaches, bringing a 30 to 60 percent chance for gale force wind gusts.

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

FIRE WEATHER

Issued at 157 AM CDT Sat Sep 12 2026

Fire weather concerns will remain low through the forecast period. A cooler and less humid airmass moves in today, with minimum relative humidity values dropping into the 35 to 50 percent range and breezy northwest winds gusting 20 to 25 mph. Similar humidity levels are expected on Sunday, but with lighter winds. A widespread wetting rain is increasingly likely across the region from Monday into Tuesday as a strong low pressure system moves through.

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 8 PM CDT this evening for LSZ121- 141>148. Small Craft Advisory until 4 AM CDT Sunday for LSZ140-150.