textproduct: Marquette

KEY MESSAGES

- Patchy dense fog is expected this morning, especially in the higher elevations of the central and western U.P.

- Above-average temperatures persist through Labor Day Weekend, with high temperatures in the mid 70s to low 80s.

- Dry conditions prevail Saturday and Sunday. Precipitation chances increase late on Labor Day, reaching 50% in the far west by the evening.

DISCUSSION

Issued at 230 AM EDT Sat Sep 5 2026

Early this morning GOES water vapor imagery and 500mb model height analysis showed an upper level ridge extending from the southern plains north into the Canadian Prairies, resulting in northwest flow aloft over the Great Lakes. At the surface troughing extended through much of the high plains, in the lee of the Rockies with high pressure over Ontario, resulting in light northeasterly flow over the U.P. GOES fog and microphysics products showed widespread low stratus and fog over the western and southern halves of the U.P. Dense fog had developed in some locations where fog was being enhanced by upslope flow, such as the higher elevations of Marquette County. Temperatures were in the upper 50s where skies had cleared in the east and far north (Keweenaw) with low to mid 60s elsewhere.

Not much change is expected in the pattern today into Sunday with an overall warm and pleasant Labor Day Weekend expected. Surface high pressure over Ontario will continue to extend a ridge south into the U.P. with a weak pressure gradient resulting in light northeasterly flow. Locally dense fog can be expected to start out the day over the western and southern halves of the U.P. Did not issue any headlines for the fog as it seems confined to favored upslope areas and not widespread. Expect fog and low clouds to diminish through mid-morning as diurnal heating mixes out the low levels. Temperatures will warm well into the 70s with abundant sunshine this afternoon over the north and east though scattered clouds will linger over parts of the western U.P. With clear skies and light winds expect good radiational cooling tonight with temperatures falling into the 40s away from the shorelines. Patchy fog may again develop tonight (30-50% chance), mainly in the central and eastern U.P. For the remainder of the Labor Day weekend expect highs in the upper 70s to low 80s along with partly cloudy skies Sunday, giving way to increasing cloud cover Monday afternoon as a system approaches the area.

Precip chances return Monday night from the west, continuing into Tuesday night as the upper level ridge moves east and flattens. This gives way to the deep western trough to lift northeast to Manitoba by the end of the day Tuesday, then tracking east to Quebec. A resulting sfc low from the northern Rockies lifts to Manitoba by Tuesday morning, then moves across far northern Ontario to Quebec through Wednesday. Showers and storms return to the UP ahead of the associated cold front, mainly on Tuesday. This does not look to bring much in the way of strong storms, but it does present the best rainfall chances as of recent. NBM probabilities of at least 1 inch of rain in 24 hours are between 30-50%. This system also yields breezy winds. Initially expecting south winds on Tuesday ahead of the cold front gusting between 15-30 mph, particulary in ideal southerly downslope flow. Behind the front, pressure rises and CAA support stronger westerly winds on Wednesday with frequent gusts of 20-30 mph. Probabilities for wind gusts exceeding 40 mph are between 30-60% in the Keweenaw.

There is a slight chance (15-24% chance) for additional showers late Wednesday into Thursday with a shortwave to the north and a secondary cold front pressing south. Otherwise temps return near normal in the mid 60s to mid 70s late next week.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 749 AM EDT Sat Sep 5 2026

High pressure will result in quiet weather across the U.P. with mainly clear skies and light winds through Sunday. Morning fog at SAW will result in VLIFR conditions at 12z but expect conditions to improve to VFR over the next few hours as diurnal heating mixes out the fog. MVFR conditions at IWD will also improve to VFR over the next few hours as satellite data shows the northern extent of the cloud deck approaching the TAF site. CMX will remain VFR. Additional fog is possible at SAW tonight with strong radiational cooling and light winds. Made mention of this with 1SM but would probabilities are increasing for dense fog (40-60% chance of VLIFR).

MARINE

Issued at 354 PM EDT Fri Sep 4 2026

Lake Superior: Lingering northeast wind gusts above 20 kts in the western waters falls below 20 kts this evening with high pressure building in from the north. This high pressure influence keeps winds below 20 kts through early Monday afternoon. A more prominent system lifting to the north of Lake Superior Monday night through mid week brings a prolonged period of 20 to 30 kt winds. Best chances for gales to 35 kts (30 to 60% chance) are Wednesday behind the cold front, supported by pressure rises. There is a low (15 to 25%) chance for southerly warm air advection gales on Tuesday and a 20 to 40% chance for high end gales (40 kts or higher) near the Keweenaw on Wednesday. Winds settle below 20 kts by late next week.

Northern Green Bay and northwestern Lake Michigan: Winds generally remain 15 kts or lower through Labor Day as high pressure slowly builds overhead. A more prominent system lifting north of the region early next week increases winds to around 15 kts with gusts up to 20 to 30 kts Tuesday afternoon through Wednesday.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... None. Lake Michigan... None.