textproduct: Marquette

KEY MESSAGES

- A low pressure system tracking north of the area through midweek brings widespread wetting rain to the UP early this morning through the afternoon.

- Southerly winds turn gusty today, with frequent gusts of 15-25 mph expected. There is a 60-70% chance for gusts of 35+ mph near Lake Superior through this evening.

- Winds shift westerly tonight into Wednesday, with frequent gusts of 20 to 30 mph expected. There is a 30-60% chance for gusts up to 40 mph near Lake Superior and 70-90% chance for gusts up to 45 mph in the Keweenaw on Wednesday.

- A Gale Warning for southerly winds up to 35 knots is in effect for portions of east-central Lake Superior this afternoon and evening. A Gale Watch is in effect for westerly winds of 40-45 knots across the entire lake on Wednesday.

DISCUSSION

Issued at 306 AM EDT Tue Sep 8 2026

Early morning water vapor analysis shows quite nicely low pressure spinning over the Canadian Prairie, with persistent SSW flow into the Great Lakes out ahead of it advecting a moisture-rich airmass into the area. Polar satellite imagery indicates PWATs already near an inch over the UP, and higher values up to 1.75in over IA and MN. Meanwhile, spotty showers are already reaching the western UP so far, but a more widespread batch of showers (with embedded thunder) is moving northward into east-central MN on the nose of a stronger ~45kt LLJ core. This next batch looks to begin to spread into the western UP during the pre-dawn hours, continuing eastward through the morning and afternoon. Will note that CAMS continue to show shower activity becoming more spotty with eastward extent, then showers finally taper off in the eastern UP late tonight into early Wednesday morning as the cold front passes through.

Most of the area looks to receive at a wetting rainfall. The latest forecast reflects a widespread 0.10-0.25in over the eastern half of the UP, and 0.50-0.75in over the western half through this evening. However, NBM still shows a 50-60% chance for higher embedded totals in excess of an inch over the far western UP given the potential for thunderstorms and heavier downpours this morning. A good wind gust doesn't seem out of the question in any storms with such strong flow aloft, and will note that plenty of sites out in eastern MN are showing gusts to around 30mph in storms. However, we remain under a steep capping inversion given the WAA aloft, so confidence in the development of particularly strong to severe storms is low.

Gusty non-thunderstorm winds also remain a concern for today and Wednesday. The strongest gusts in this southerly warm advection regime will be in the areas favored by southerly downslope flow, particularly from the Huron Mountains eastward along the Lake Superior shoreline. These areas show a 60-70% chance for wind gusts of 35+ mph through this evening per latest HREF and NBM guidance. Winds shift westerly and strengthen further on Wednesday, aided by cold air advection and pressure rises behind the cold front. Expect widespread gusts of 20-30 mph through the day, with NBM probabilities now increasing to 30-60% for gusts to 40 mph near Lake Superior. A Wind Advisory for the Keweenaw continues to look like a strong consideration as the NBM probability for gusts of 45+ mph has increased to 70-90%. Meanwhile, will also have to watch areas to the east as there is a 25-40% probability for 45 mph gusts along the shoreline from east of Marquette to Whitefish Point.

Expect calmer weather to return to the region by Thursday as high pressure temporarily builds back over the UP behind the departing system, with highs on Thursday closer to seasonal norms in the mid 60s to low 70s. However, the overall pattern remains unsettled as another trough has the potential to bring additional rounds of precipitation and breezy conditions into the weekend.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 154 PM EDT Tue Sep 8 2026

VFR/MVFR cigs linger as rain departs through the east half of the UP this afternoon. Dry weather is favored through the forecast period with possible MVFR stratus/fog at SAW around sunrise. Otherwise, the main aviation hazard will be the winds. Gusty S to SW winds 15-25 kts will continue to be common before briefly falling overnight. Winds then pick back up from the west behind a cold front early tomorrow morning. West winds 20-30 kts at IWD and SAW are expected much of the day with gusts 30-40 kts at CMX.

MARINE

Issued at 306 AM EDT Tue Sep 8 2026

Lake Superior: Southerly winds starting off around 15-20 kt early this morning will increase to 20-30 kt across much of the lake later this morning with a tightening pressure gradient as low pressure moves towards Ontario. There is around a 50-60% chance for gales across east-central portions of Lake Superior this afternoon. A Gale Warning remains in effect for the waters between Marquette and Grand Marais as the bulk of guidance still suggests the possibility of frequent gusts to around 35 kt through this evening. Small craft headlines are in place for the remaining nearshore zones as wave heights build to 2-5 ft over the western half of the lake and 4-7 ft over the eastern half, with 20-30 kt southerly winds shifting southwesterly through tonight. Winds shift westerly behind a trailing cold front early Wednesday, bringing the likelihood of high end gales aided by cold air advection and strong pressure rises. A Gale Watch remains in effect for the entire lake on Wednesday, with 40-45 kt winds expected in the west through Wednesday evening and in the east through early Thursday morning. Wave heights continue to build to 6-10 ft in the west and 8-13 ft in the east on Wednesday. Winds briefly settle back below 20 kt under high pressure on Thursday, but another system traveling north of the lake brings additional strong wind potential Friday into the weekend. Confidence in specific details for late in the week is low at this time.

Northern Green Bay and northwestern Lake Michigan: Winds become elevated today with low pressure passing through Ontario. Southerly winds increase to 20-30 kt and wave heights to 2-4 ft later this morning, with Small Craft Advisories remaining in place through early Wednesday morning. Another round of small craft headlines is likely later Wednesday as winds turn westerly and continue to gust to 20-30 kt behind a trailing cold front. The return of high pressure brings calmer conditions for Thursday, with additional rounds of stronger winds possible Friday into the weekend. Confidence in specific details for late in the week is low at this time.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Beach Hazards Statement until 10 PM EDT this evening for MIZ014.

Lake Superior... Gale Watch from Wednesday morning through Wednesday afternoon for LSZ162.

Gale Watch from Wednesday morning through Wednesday evening for LSZ240>244-263-264.

Gale Watch from Wednesday morning through late Wednesday night for LSZ245>248-265.

Gale Warning until 8 PM EDT this evening for LSZ249-250-266.

Gale Watch from Wednesday afternoon through late Wednesday night for LSZ249>251-266-267.

Lake Michigan... None.