textproduct: Marquette

KEY MESSAGES

- Gusty winds shift westerly for today, with frequent gusts of 20 to 30 mph expected. There is a 40-60% chance for gusts up to 40 mph near Lake Superior and a 60-80% chance for gusts up to 45 mph in the Keweenaw.

- A Gale Warning is in effect for most of Lake Superior later this morning through this evening for gales to 35-45kts.

DISCUSSION

Issued at 310 AM EDT Wed Sep 9 2026

Early this morning, ~990mb low pressure is moving towards Hudson Bay, with a trailing cold front extending into the Great Lakes and already reaching the western UP. Water vapor imagery reveals drier midlevel air and clearing skies over most of the area, with the exception of the south-central and eastern UP. There, SSW flow keeps us connected to a more moisture-rich airmass, and is even advecting in mid and upper level cloud cover from convection over the Central Plains. Some spotty shower activity is also evident over Lake Michigan, though cloud cover and convection should dwindle closer to daybreak as the cold front makes its way eastward. Of greater concern will be wind speeds, as steepening lapse rates and deeper mixing allow us to tap into stronger wind speeds aloft through the daytime hours. The latest RAP analysis shows a core of 40-50kt flow at around the 800-700mb level over MN and pointing towards Lake Superior and the UP. Given the lackluster temperature difference between the land (or water) surface temperature and the 850 mb level, mixing is likely to be less than fully efficient. That said, the NBM still shows 60-80% chance of 10m gusts greater than 45 mph in the Keweenaw, and 40-60% chance of gusts greater than 40 mph elsewhere near the Superior shoreline behind the cold front. Still, will hold off on a Wind Advisory over the Keweenaw given uncertainty in the frequency of those higher-end wind gusts.

Otherwise, expect temperatures to warm into the lower to mid 70s for most of the UP, and the upper 70s to lower 80s ahead of the cold front in the eastern UP. Temperatures fall back into the 40s to lower 50s under mostly clear skies tonight.

Elevated westerlies linger in the eastern UP 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 and towards Hudson Bay, eventually dragging a cold front through the Great Lakes. Some of the guidance does feature a secondary low developing along the boundary over the Dakotas and heading towards the UP by early Saturday. Both systems (though not entirely unattached on one another) send tight pressure gradients across the CWA, hinting at the potential for higher winds at times along with precipitation chances from late Friday through Saturday. Much of the guidance favors a brief period of ridging to finish out the weekend before deepening low pressure ejects out of the Plains early next week, bringing in another period of active weather and blustery winds.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 109 AM EDT Wed Sep 9 2026

Despite possible MVFR fog at CMX/SAW early this morning, VFR will be the main flight category. Therefore, the main threat will be an uptick in the S to SW winds (15 to 25kts) again early this morning before veering to the west in the wake of a cold front. West winds 20 to 30 kts at IWD and SAW are then expected much of the day with gusts of 30 to 40 kts at CMX.

MARINE

Issued at 310 AM EDT Wed Sep 9 2026

Lake Superior: Winds shift westerly behind a cold front this morning, bringing the likelihood of gales aided by cold air advection and strong pressure rises. A Gale Warning is in effect for all of the open waters of Lake Superior, with 35-45 kt winds expected in the west through this evening and in the east late tonight. Wave heights continue to build to 6-11 ft in the west and 8- 12 ft in the east by early afternoon. 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, with a potential for southerly gales over the east-central waters Friday evening into early Saturday morning.

Northern Green Bay and northwestern Lake Michigan: Southerly winds remain elevated over northern Lake Michigan, with gusts to 20-25kts, while winds within the Bay are largely falling below 20kts. Later this morning, a passing cold front causes winds to shift over to the west, with gusts to near 20kts becoming common. 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... None. Lake Superior... Gale Warning from 8 AM EDT /7 AM CDT/ this morning to 6 PM EDT /5 PM CDT/ this evening for LSZ162.

Gale Warning from 8 AM EDT /7 AM CDT/ this morning to 10 PM EDT /9 PM CDT/ this evening for LSZ241>244-263-264.

Gale Warning from 8 AM this morning to midnight EDT tonight for LSZ245>248-265-266.

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

Lake Michigan... None.