textproduct: Duluth

KEY MESSAGES

- Breezy west to northwest winds continue this afternoon with the potential for lake effect rain showers near the International Border tonight into early Tuesday morning.

- Patchy frost will be possible Sunday night into early Monday morning for portions of northwest WI and the MN Arrowhead.

- Widespread showers with embedded thunderstorms are expected on Monday into Monday night. Rainfall amounts of 1" or greater are likely (50-60% chance) for areas south of the Iron Range.

DISCUSSION

Issued at 150 PM CDT Sat Sep 12 2026

Northwest flow is occurring across the region this afternoon following a cold frontal passage that occurred earlier today. In this post-frontal environment, gusty winds have been ongoing and scattered to broken cloud cover has been occurring as lobes of vorticity at 500mb propagate through and low-level lapse rates remain moderately steep. An isolated sprinkle is not out of the question this afternoon, especially north of the Iron Range.

The strong winds being seen this afternoon are expected to ease overnight, as high pressure gradually builds in from the west and a weak, shallow nocturnal inversion develops. One thing of note overnight will be the potential for lake effect rain showers in the lee of large inland lakes near the International Border, such as Lake of the Woods and Rainy Lake. The ongoing northwest winds will provide CAA to the region into tonight, lowering 850mb temps to within a degree or two of 0 degC by early Sunday morning. With lake sfc temps still being in the 60s, hi-res model soundings suggest the potential for several hundred J/kg of lake induced CAPE to develop early Sunday morning. In addition, the arrival of a 500mb shortwave on early Sunday morning will help provide synoptic lift. This shortwave will aid in the development of lake effect rain showers, which was included in far northern MN where 850mb temps are expected to be coldest.

With the exception of lake effect rain showers on Sunday morning near the border, Sunday is shaping up to be a dry and sunny day across the CWA. Temperatures will certainly feel much more like fall, with highs in the upper 50s to mid 60s. Northwest winds remain breezy on Sunday, albeit a bit lighter than what is being observed today. On Sunday night, mostly clear to clear skies are expected to drop temperatures into the 30s across a large portion of the CWA. Patchy frost will be possible in inland northwest WI and in the MN Arrowhead. If forecast trends hold, Frost Advisories will likely be needed.

The fall-like pattern is anticipated to change on Monday, as deep low pressure propagates into the northern Great Plains and brings attendant sfc fronts through the CWA. With this weekend's high pressure propagating downstream into the lower Great Lakes, this will allow for southerly flow to advect Gulf moisture north into the CWA. PWATs of 1-2" are possible, 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 in the 60-70th percentile, which does decrease confidence in very heavy rainfall. The current QPF forecast maintains the NBM solution, which brings a broad 0.3 to 1.0" across the CWA on Monday into Monday night. Heaviest rainfall is forecast over northwest Wisconsin, where there is a Marginal risk for excessive rainfall and just a sliver of a Slight risk in southern Price County. Severe weather is unlikely as the better thermodynamic environment remains south of the area.

High pressure is favored to return following the early week low pressure system, with a trend of warmer temps for the latter half of the week. High temps from Tuesday into next weekend are forecast to be largely in the 60s to low 70s. Additional rain chances arrive both on Wednesday night into Thursday morning and again on Friday into Saturday as flow aloft remains relatively zonal, allowing shortwaves to propagate through the Upper Midwest.

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 150 PM CDT Sat Sep 12 2026

Small Craft Advisories remain in effect today into tonight, dropping off from west to east starting this evening. West to northwest winds with gusts of 20 to 30 knots are expected to continue through this afternoon with highest waves of 3-4 feet occurring in the outer Apostle Islands. Winds will begin easing overnight into Sunday as high pressure moves into the area.

Another period of hazardous marine conditions are anticipated to return on 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 on Tuesday morning into early Tuesday afternoon. A Gale Watch may be needed if trends persist.

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

FIRE WEATHER

Issued at 150 PM CDT Sat Sep 12 2026

Strong west to northwest winds continue this afternoon following a cold front that moved through earlier today. Partly cloudy to overcast skies are occurring in the wake of this front, with the potential for an isolated sprinkle this afternoon in far northern MN. There will be a chance for lake effect rain showers in the lee of Lake of the Woods and Rainy Lake tonight into Sunday morning, although precipitation amounts will likely be light. On Sunday, sunny skies are expected for most locations as high pressure gradually builds.

These sunny skies will not be persisting long, as widespread showers and thunderstorms arrive on Monday and linger into Monday night. At least 0.3" of rain is forecast across the region, with a 50 to 60% chance for rainfall amounts of 1" or greater for areas south of the Iron Range and in northwest Wisconsin. In addition to widespread rain, expect strong southeast winds on Monday, which will shift to westerly and remain elevated on Tuesday.

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.