textproduct: Marquette

KEY MESSAGES

- A Gale Warning for the eastern open waters of Lake Superior remains in effect through 00Z tonight for southerly gusts of up to 35 knots.

- Gusty 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 a 60-80% chance for gusts up to 45 mph in the Keweenaw on Wednesday.

- A Gale Warning for most of Lake Superior is in effect Wednesday morning through the evening for westerly winds of 35-45 knots.

DISCUSSION

Issued at 422 PM EDT Tue Sep 8 2026

This afternoon, RAP13 surface analysis and GOES Channel 2 imagery show a 997 mb low pressure center over Lake Winnipeg with substantial cloud cover overspreading the UP. The stratiform precipitation that has worked its way across the UP throughout today has nearly exited to the southeast; MRMS estimates widespread 0.3- 0.7" has fallen (with locally higher spots) in the west, and less than 0.2" in the central and east. The dry slot following this precipitation is visible in satellite imagery, with a clearly defined airmass boundary currently lying just west of Duluth. With elevated southerly flow today, gusts at 15-20 mph are common, and some gusts are in the 25-30 mph range. For the most part, temperatures are warming into the mid 60s to low 70s.

As the low currently in Manitoba tracks ENE, it is projected to deepen, reaching toward 980 mb late tomorrow (Weds) night, sending a tight N-S pressure gradient over Lake Superior and the UP for much of Wednesday and into Thursday. Behind the trailing cold front, a core of higher lower-level westerlies will be able to mix to the surface as depressed lower-level temperatures allow for greater instability starting tomorrow morning. The LREF shows the core of the 700 mb jet at 45-50 knots (99th percent of climatology) over CWA early Wednesday morning through Wednesday evening; but given the lackluster temperature difference between the land (or water) surface temperature and the 850 mb, mixing is likely to be less than fully efficient. That said, the NBM shows 60-80% chance of 10m gusts greater than 45 mph and 30-60% chance of gusts greater than 40 mph in land areas near Lake Superior Wednesday afternoon. At this time, opted not to go with Wind Advisory for the Keweenaw due to uncertainty in how frequent higher gusts would be. Temperatures on Wednesday are expected to warm into the mid 70s for most of the UP, with lower temperatures (low 70s) in the west and warmer ones (low 80s) in the southeast (Menominee, Delta, and Schoolcraft Counties).

Elevated westerlies linger in the east into Thursday morning as the Canadian low departs toward the Canadian Maritimes and weakens; then ridging builds into the Upper Midwest for a benign weather day. High temperatures should be nearly exactly seasonable, with highs close to 70 and departures of only a few degrees.

This weekend sees another bout of unsettled weather as a second stout low tracks eastward across the Canadian Prairies, likely with a trailing, smaller low which scrapes across the northern tier of the US. Both systems (though not entirely unattached on one another) send tight pressure gradients across the CWA, hinting at the potential for higher winds at periods along with precipitation chances throughout 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 422 PM EDT Tue Sep 8 2026

Lake Superior: A Gale Warning remains in effect for the waters between Marquette and Grand Marais. Tonight, 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 gales aided by cold air advection and strong pressure rises. A Gale Warning has been issued for nearly all marine Superior zones on Wednesday (excepting LSZ262 in the far west), with 35-45 kt winds expected in the west through Wednesday evening and in the east through early Thursday morning. Wave heights continue to build to 6-11 ft in the west and 8-12 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 remain elevated into this evening with low pressure passing through Ontario. Southerly gusts to 20-30 kt and wave heights of 2-4 feet remain possible, with Small Craft Advisories remaining in place through early Wednesday morning. The extent of high winds is limited to regions north of Lake Michigan, so small craft headlines were not extended. TOmorrow, winds turn westerly and gust to 20 knots 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 Warning from 8 AM EDT /7 AM CDT/ to 10 PM EDT /9 PM CDT/ Wednesday for LSZ241>244-263-264.

Gale Warning from 8 AM Wednesday to midnight EDT Wednesday night for LSZ245>248-265-266.

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

Gale Warning from 3 PM Wednesday to 2 AM EDT Thursday for LSZ249>251-267.

Lake Michigan... None.