textproduct: Duluth

KEY MESSAGES

- High pressure building into the area today and tonight will bring cooler than normal temperatures with highs in the upper 50s to mid 60s.

- Areas of frost are likely tonight into early Monday morning for portions of northwest WI and northeast MN. Frost Advisories are in effect.

- Widespread showers with embedded thunderstorms are expected Monday into Monday night. Rainfall amounts of 1" or greater are likely (60-80% chance) for areas south of the Iron Range.

UPDATE

Issued at 625 AM CDT Sun Sep 13 2026

Lowered forecast temps tonight by a few degrees. Opted for a Frost Advisory for portions of north-central MN and the Arrowhead along with most of NW WI. Main concern tonight remains how quickly the clouds will build into the area and whether temps will be able to plummet.

DISCUSSION

Issued at 134 AM CDT Sun Sep 13 2026

A weak cold front/trough axis is sliding across the Northland early this morning, which will be followed by a large high pressure ridge building into the area today and tonight. This high pressure will bring a couple days of pleasant early fall weather with cooler than normal temperatures. Highs today will only be in the upper 50s to mid 60s across the region. As the high pressure settles in tonight, skies will clear and winds will become light, setting the stage for good radiational cooling. Cirrus moving in from the west ahead of our next precipitation system could dampen the cooling effects as we get towards morning. Otherwise, temperatures should drop into the 30s across many inland areas, resulting in patchy frost development over parts of northern Minnesota and northwest Wisconsin 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. This system will bring a surge of moisture into the region and spread a round of widespread showers and embedded thunderstorms across our area Monday afternoon and continue Monday night. Rainfall amounts of one inch or greater are likely (60-80% chance) for areas south of the Iron Range and northwest Wisconsin. There is a marginal risk for elevated hail producing storms Monday evening for parts of Monday evening with a strong low level jet and some elevated instability, but at least some of this depends on how far north the surface boundary to our south can get, and how far north the elevated instability can be advected. We will also have a marginal risk of excessive rainfall. There will be PWAT values of 1-2", which would be in the 90th percentile or greater of climatology for the upper air site in International Falls. At this time, the ECMWF EFI is only showing QPF values in the 60-70th percentile, which decreases confidence in very heavy rainfall. The current QPF forecast maintains the NBM solution, which brings a broad 0.4 to 1.25" across the CWA on Monday through Monday night. Our forecast heaviest rainfall amounts are not co-located with the rainfall we got Friday night, reducing concerns for flooding.

The rainfall will come to an end by Tuesday, with a cold front bringing gusty westerly winds and another day of near to below normal high temperatures. Expect clearing skies as drier air filters into the area, leading to a mostly sunny Tuesday afternoon.

A relatively quiet and seasonable pattern takes hold for the remainder of the work week, with high pressure building in again for Wednesday. Chances for rain showers return Wednesday night into Thursday, and again on Friday and Friday night, as weak systems slide through the mostly zonal flow aloft. High temperatures Wednesday will be in the 60s for most locations, but should gradually moderate through the end of the week so highs on Friday and Saturday should be in the mid 60s to low 70s.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 625 AM CDT Sun Sep 13 2026

HIB and HYR both had brief periods of MVFR visibility during the early morning hours. Think HYR could see temporary MVFR visibility before 13Z. VFR conditions with gusty winds are forecast today. Cooler temperatures tonight with light winds will raise the potential for patchy fog. Greatest chance is at HIB and HYR. Probabilities are less than 20% so left VFR in place.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 625 AM CDT Sun Sep 13 2026

Small Craft Advisories are in effect for portions of the waters today. After a brief lull in wind speeds and gusts, expect wind and waves to build during the day. Winds will be northwest at less than 15 kts tonight.

Another period of hazardous marine conditions are anticipated to return Monday into Tuesday as a strong low pressure system moves through the region. Additional Small Craft Advisories are very likely. There is also a 30 to 60 percent chance for gale force wind gusts from the southwest to west, most likely to occur early Tuesday morning through Tuesday afternoon. A Gale Watch is in effect during that time.

Winds and waves relax again Tuesday night and hazardous conditions are not expected from that time through the end of the week.

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

FIRE WEATHER

Issued at 134 AM CDT Sun Sep 13 2026

Fire weather concerns will remain low through the forecast period. Minimum relative humidity values today will range from 35 to 55 percent across the area under mostly sunny skies. Winds will remain northwest, but gusts will remain 20 mph or less during the daytime today.

The sunshine will be overcome by incoming clouds and increasing precipitation chances on Monday into Tuesday as a strong low pressure system moves across the region. A widespread wetting rain is expected across most of the region, with rainfall amounts of 1 inch or greater likely (60-80% chance) for areas south of the Iron Range. Southeast winds will become strong and gusty on Monday, shifting to the west and remaining elevated on Tuesday behind a cold front.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Frost Advisory from midnight tonight to 8 AM CDT Monday for MNZ010>012-018-019. WI...Frost Advisory from midnight tonight to 8 AM CDT Monday for WIZ001>004-007>009. MARINE...Small Craft Advisory until 8 PM CDT this evening for LSZ140- 141. Gale Watch from late Monday night through Tuesday afternoon for LSZ140-141-144>147-150. Small Craft Advisory until 4 PM CDT this afternoon for LSZ146>148-150.