Marine Weather and Tide Forecast for Duluth, MN

DISCUSSION
Issued at 313 AM CDT Sat Apr 18 2026

The cold front that brought severe weather yesterday has moved well to our east, leaving the Northland in a much cooler and drier air mass. The mostly cloudy skies are expected to continue through much of the morning hours, but gradually give way to some sunshine by this afternoon as drier air moves into the area. Northwest winds will be the primary concern today, gusting between 25 and 35 mph across much of the region for several hours. High temperatures will struggle to reach the upper 30s or low 40s. A few flurries or light snow showers are possible this afternoon, mainly for the tip of the Arrowhead. The dry air moving into the region, along with the gusty northwest winds will create several hours of near critical fire weather conditions this afternoon for parts of the area.

Tonight, skies will continue to clear as the pressure gradient relaxes slightly. Low temperatures will drop into the upper teens and low 20s. Sunshine returns for Sunday as high pressure builds into the region and winds diminish. Temperatures will only be a few degrees warmer than today, though with the sunshine and lighter winds it will feel warmer.

We will see a significant warming trend through the middle part of the upcoming work week. Monday will see highs jump into the 50s as winds shift to the south and the high pressure ridge shifts to our east. This southerly flow, combined with deep mixing and low relative humidity, may create near-critical fire weather conditions for Monday. Tuesday through Thursday the warmup continues, with widespread highs in the 60s to low 70s by Wednesday. Dry conditions to persist through Wednesday as high pressure remains dominant over the Great Lakes region.

The pattern shifts late Wednesday night into Thursday as a new low pressure system approaches from the west. Rain chances increase significantly Wednesday night into Thursday, with a few embedded thunderstorms possible by Thursday afternoon and evening. While Thursday remains warm, temperatures will fall through Friday and Saturday as the system brings colder air back over the area. This system will also bring some more much- needed rainfall to the region. Scattered rain showers are expected to linger through Friday and into Saturday.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
Issued at 642 AM CDT Sat Apr 18 2026

An extensive area of MVFR/VFR stratus lingers over the area this morning, with a few flurries with VFR visibilities in the reports out there. This stratus will linger at least through the morning hours, before clearing moves in from the west for this afternoon and evening. Gradually improving ceiling heights are expected, with all sites becoming VFR no later than 17z this morning. While the lower ceilings linger, a few light snow showers may be possible. Northwest winds to remain gusty at 25 to around 30 knots through the afternoon hours, then slowly diminishing after 00z.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 313 AM CDT Sat Apr 18 2026

Strong and gusty northwest winds to continue through today, though we will be converting the Gale Warning for the North Shore over to a Small Craft Advisory here at 3 AM. The northwest winds to gust up to 30 knots in places through early evening.
Waves of 3 to 6 feet are expected today, particularly for the South Shore and the Apostle Islands. Conditions will gradually improve tonight through Sunday night. Winds will back into the south on Monday and increase once again, and conditions may become hazardous for Small Craft.

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

FIRE WEATHER
Issued at 313 AM CDT Sat Apr 18 2026

Gusty northwest winds are expected today with gusts of 25 to 35 mph. Relative humidity values will dip into the 25 to 35 percent range this afternoon. The strongest winds will be found along the North Shore, displaced from where conditions will be driest around the Brainerd Lakes region this afternoon. Much of the area got a wetting rainfall Friday afternoon, so am not as concerned for today. Some areas may get near critical fire weather conditions for a few hours this afternoon, but this should be limited in time and area affected. Sunday will be quite dry, with minimum RH values dropping into the 20 to 30 percent range over a large portion of the area. Winds will be much lighter reducing those concerns. Monday is the day we are most likely to see near-critical or even critical fire weather conditions due to a combination of warming temperatures, low humidity, and gusty southerly winds.

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 10 PM CDT this evening for LSZ121- 143-144-147-148.
Small Craft Advisory until 4 AM CDT Sunday for LSZ140>142-145- 146-150.