textproduct: Duluth

KEY MESSAGES

- Showers will spread across the region today and linger into Saturday morning. The heaviest rainfall (30-50% of 1") will be south of a line from near Pine River to Sandstone to Hayward to near Phillips. - Dangerous swimming conditions expected for the beaches of the Twin Ports Friday and Saturday then again Sunday and Monday afternoons and evening. - Areas of frost are possible each night from Sunday through Wednesday night.

DISCUSSION

Issued at 357 AM CDT Fri Sep 18 2026

TODAY AND SATURDAY...

Early this morning surface high pressure was centered over northern Ontario with developing low pressure over northeast Colorado. Light rain and a few thunderstorms were observed on regional radar over eastern South Dakota, southwest Minnesota, and northwest Iowa. The precipitation was associated with a 700 mb trough and enhanced isentropic ascent ahead of the developing low pressure system. Areas of fog developed over portions of northeast Minnesota since about 9 PM. High stratus streaming northward ahead of the low pressure system is expected to limit additional cooling. Winds will also gradually increase through sunrise. The combination of these factors will allow fog to dissipate.

The rain will gradually spread northward through the day while combating northerly dry air advection aloft. The dry air associated with the anticyclonic circulation around the Ontario high pressure will limit the northward reach of rainfall today. Forecast rain totals in our area of responsibility haven't changed much from yesterday afternoon's forecast. There is still 40% chance or more of 0.5-1.0 inches of rain south of a line from near Pine River to Sandstone to Hayward to near Phillips. Meanwhile the 40% chance of a tenth of an inch of rain wasn't much farther north indicating the tight gradient of rainfall expected. That area was south of a line from near Park Rapids to near Cromwell to near Glidden to near Woodruff. The distance between the 40% chance of a tenth of an inch and the 40% chance of 1 inch of rain are separated by only 40 miles!

Winds over the southwest arm of Lake Superior will turn northeasterly and strengthen today. The wind direction and resultant waves will pose a high risk of rip currents for the beaches of the Twin Ports. A Beach Hazards Statement goes into effect at 1 PM. Rip current risk will diminish as winds relax this evening and should no longer be a concern by 1 AM Saturday. Winds and waves build again on Saturday and the rip current risk is expected to be high once again.

By 7 AM Saturday the high pressure over Ontario will propagate east into Quebec while the surface low over the Plains advances into the Midwest. Rain will taper off during the morning Saturday except for a small area generally along and south of WI-70 in northwest Wisconsin.

Temperatures today and Saturday will straddle normal. Highs will be in the upper 50s to middle to upper 60s.

SUNDAY THROUGH LATE NEXT WEEK...

The upper-level pattern will become less progressive Sunday through next week. A large area of high pressure will slowly migrate eastward across the Canadian Prairies and northern Ontario. Precipitation chances become negligible during the period. There are a few concerns with that evolution. Several days of strong northeast winds over western Lake Superior will keep a risk of rip currents in play for the beaches of the Twin Ports. Sunday appears to be the day with the highest waves. Areas of frost are possible each night through Wednesday. Monday night may be the coldest of the stretch and there are portions of northeast Minnesota and northwest Wisconsin with a 20% chance of temperatures less than 32 degrees. As of this morning the forecast included clouds Sunday night which would limit frost potential. High temperatures will generally be near normal with values in the upper 50s to the mid and upper 60s.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1231 AM CDT Fri Sep 18 2026

Fog has formed over much of the Northland and has affected HIB, BRD, and HYR. Visibilities are expected to rise and lower to IFR/LIFR throughout the morning before dissipating around or a couple hours after 12Z. Later on today, showers will move through the southern half of our area, leading to not only MVFR/IFR ceilings, but lowered visibilities with heaviest rainfall which is expected at times at BRD and HYR terminals. Showers will end this evening but lowered ceilings will linger for the TAF period.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 357 AM CDT Fri Sep 18 2026

Winds will become northeasterly early this morning. Wind speeds and gusts will increase. The strongest winds will be found over the southwest arm of Lake Superior near the Twin Ports. Gusts up to 25 knots are possible along portions of the North Shore from late this morning through this evening. A Small Craft Advisory is in effect from Grand Marais to Duluth to Port Wing. Winds and waves relax late tonight and will strengthen again during the late morning and early afternoon Saturday. Another Small Craft Advisory may be needed. Northeast winds weaken again Saturday evening and then increase quickly on Sunday. There is a 30% chance of a few hours of gales to 35 knots from Silver Bay to Duluth and over the eastern portions of the Apostle Islands to Saxon Harbor Sunday. Several more days of diurnal strengthening and weakening northeast winds are forecast Monday and Tuesday. Additional headlines will likely be needed.

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

FIRE WEATHER

Issued at 357 AM CDT Fri Sep 18 2026

No fire weather concerns. Min RHs through the forecast period remain above 35% throughout the next 7 days, with daily temperatures generally in the 60s to low 70s. Rain will spread in from the south today and depart Saturday morning, delivering up to 0.75" across our southern tier counties, with a sharp northern cut-off in totals. Drier conditions and light winds return for Sunday into early next week.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Beach Hazards Statement from 1 PM CDT this afternoon through late tonight for MNZ037. WI...Beach Hazards Statement from 1 PM CDT this afternoon through late tonight for WIZ001. MARINE...Small Craft Advisory from 10 AM this morning to 10 PM CDT this evening for LSZ141>145.