textproduct: Duluth

KEY MESSAGES

- Persistent northeasterly winds will keep the threat for rip currents in place at Twin Port beaches this afternoon and Monday and may linger into mid-week as well.

- Chances for frost tonight before widespread frost and perhaps some areas of freeze for Monday night into Tuesday morning.

- Low chances for rainfall through the forecast period.

DISCUSSION

Issued at 1246 PM CDT Sun Sep 20 2026

Strong low pressure was located over northwestern Ontario early this afternoon with low pressure across the Mid-Mississippi Valley. Between these features was a tight pressure gradient across the Northland leading to breezy northeasterly winds, especially across western Lake Superior. A weak cold front also stretched across lower Michigan into Wisconsin with lingering low stratus behind the front. Another area of low stratus was observed in areas along and north of the Iron Range with a swath of clear skies from northern Cass County into northern Aitkin County. The area of high pressure to our north will drift southeast this afternoon into tonight and become centered just to the north of Lake Superior. This will lead to diminishing winds into tonight, but areas of low stratus are expected to linger. Lows tonight will still be able to cool into the middle 30s to lower 40s and may lead to some patchy frost for areas along and north of the Iron Range.

High pressure will remain in place for Monday with skies becoming mostly sunny. Clear skies and light winds Monday night will allow lows to cool into the 30s away from Lake Superior with 40s near the lake. Some areas along and north of the Iron Range may cool to around freezing, or perhaps just at bit below. A Frost Advisory will likely be needed for most of the Northland for Monday night into Tuesday morning with the potential for a Freeze Warning for Koochiching and northern St. Louis counties.

Heading into Tuesday, the area of high pressure north of Lake Superior will start to move to the east with southeasterly to southerly flow setting up across the Northland. This will signal the start of a slow warming trend across the region through the remainder of the week and into the weekend. Highs Tuesday will be in the 60s with some upper 50s along the North Shore with some onshore flow expected. Lows Tuesday night will again be in the 30s away from Lake Superior and another round of Frost Advisories may be possible.

Upper ridging will build in for the remainder of the week before shifting to the east on Saturday. A shortwave will bring some shower chances to the area on Thursday, but it will be running into high pressure to the east and possibly dry air at the low levels. Additional rainfall chances, albeit low, will be seen over the weekend. Temperatures will reach into the 60s and lower 70s for Friday into the weekend.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 637 PM CDT Sun Sep 20 2026

VFR conditions are expected for the TAF period. Elevated winds will continue to decrease overnight. East to northeast winds will increase again tomorrow for DLH off Lake Superior.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 1246 PM CDT Sun Sep 20 2026

Northeast winds will diminish this evening to around 5 to 15 knots with gusts to 20 knots lingering at the head of the lake. Waves of 2 to 4 feet may linger through the night, however. Small Craft Advisories remain in effect into this evening. Easterly to northeasterly winds persist for tomorrow, but will not be as strong. Winds will be sustained at 5 to 15 knots with gusts to 20 to 25 knots, highest in the western arm. Additional Small Craft Advisories may be need for Monday afternoon into early Monday evening. Tuesday will be nearly a repeat of Monday with northeasterly winds at 5 to 15 knots, gusting to 20 to 25 knots, highest in the western arm.

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

FIRE WEATHER

Issued at 1246 PM CDT Sun Sep 20 2026

Winds will remain the main concern this afternoon, especially near Lake Superior. Gusts to 25 mph will be possible early this afternoon before diminishing late this afternoon and evening. Minimum RH values are expected to remain above 50%. Afternoon RH values of 40-50% are expected for Monday and Tuesday. Values may fall into the 30-40% range Tuesday afternoon across the Wisconsin Pine Barrens. The next chance for rainfall will be Wednesday night into Thursday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Frost Advisory from 1 AM to 8 AM CDT Monday for MNZ010>012. Beach Hazards Statement until 10 PM CDT this evening for MNZ037. WI...Beach Hazards Statement until 10 PM CDT this evening for WIZ001. MARINE...Small Craft Advisory until 10 PM CDT this evening for LSZ121- 143>148-150.