textproduct: Marquette

KEY MESSAGES

- Above-average temperatures and dry weather persist through Labor Day, with high temperatures in the mid 70s to low 80s again on Monday.

- A low pressure system tracking north of the area early next week brings likely rain on Tuesday and breezy winds Tuesday and Wednesday.

- Frequent westerly wind gusts of 20 to 30 mph are expected on Wednesday. There is a 25-50% chance for gusts up to 40 mph near Lake Superior and 60-80% chance for gusts up to 45 mph in the Keweenaw.

- A Gale Watch for southerly winds up to 35 knots has been issued for east-central Lake Superior on Tuesday. Westerly gales of potentially 40+ knots are becoming increasingly likely across the entire lake on Wednesday.

DISCUSSION

Issued at 304 PM EDT Sun Sep 6 2026

Afternoon RAP analysis continues to show a stout upper level ridge of high pressure encompassing the central CONUS and extending into the Canadian Prairie, with surface high pressure extending over the Upper Great Lakes from eastern Ontario and Quebec. This is resulting in another pleasant day across the Upper Peninsula, with mostly sunny skies and temperatures in the mid 70s to low 80s away from the lakeshores as of mid afternoon. Increased high level cloud cover emanating from an upstream disturbance over ND and MN tonight will keep overnight temps a bit warmer than last night, with lows generally in the mid 50s to low 60s across the area. This will also help to limit fog development relative to last night, though the southcentral and eastern UP still show a 15-25% chance for some patchy fog through early Monday morning. High pressure remains in control through Monday, resulting in another warm and dry, albeit somewhat cloudier, day with 850 mb temps around 14-15C continuing to support high temps in the upper 70s to low 80s across the area. Any precipitation should hold off over the western UP until Monday night with the approach of the next system.

The upper level pattern begins to shift Monday night into Tuesday as the central CONUS ridge is flattened out by a deep trough lifting out of the Pacific Northwest into the Canadian Prairie. This will induce surface cyclogenesis in the lee of the northern Rockies on Monday, with a strong low then tracking to the southern shores of Hudson Bay by Wednesday morning and driving a strong cold front across the UP late Tuesday into early Wednesday. Rain and embedded thunderstorms will precede the front on Tuesday. Limited instability on the order of 500 J/kg or less MUCAPE should help to preclude a greater threat for strong/severe storms, but SPC does include the western third of the UP in a marginal risk for Day 3 as bulk shear increases above 40 kt. Expect most of the area to receive a wetting rainfall from this event as latest NBM has a 65% or greater chance to receive at least a quarter inch for a but the far southcentral UP (closer to 50%) through Tuesday night. The western UP from the Keweenaw to the Porcupines has a 40-60% chance to receive an inch or more of rain on Tuesday, but those probabilities quickly drop off to 10-25% over the central and eastern UP. Rain should depart the eastern UP behind the front by Wednesday morning.

This system will also make for breezy conditions from Tuesday into Wednesday, with southerly winds increasing to 15-30 mph across a wide swath of the area on Tuesday ahead of the front. The strongest gusts on Tuesday will be in the areas favored by southerly downslope flow, particularly from the Huron Mountains eastward along the Lake Superior shoreline. Winds will shift westerly on Wednesday, aided by cold air advection and pressure rises behind the front. Expect widespread gusts of 20-30 mph through the day, with stronger gusts to 40 mph possible near Lake Superior. Will need to consider an eventual Wind Advisory for the Keweenaw as NBM now shows a 60-80% chance for gusts of 45+ mph there. Meanwhile, there is also a 25-35% 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 from Friday into the weekend.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 119 AM EDT Mon Sep 7 2026

VFR conditions will prevail for the duration of the TAF period and will continue to leave out mention of fog early this morning. Focus will then turn to rain showers late in the TAF period at IWD as the next low pressure system approaches Upper Michigan. For now, will not lower flight conditions, but will continue to monitor. In addition, southerly winds will become strong aghead of the system by this evening at IWD with gusts up to 25 kts.

MARINE

Issued at 304 PM EDT Sun Sep 6 2026

Lake Superior: 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 Wednesday brings a prolonged period of widespread 20 to 30 kt winds. Have hoisted a Gale Watch for east-central parts of the lake on Tuesday as southerly winds increase ahead of the system. Most likely area to see 35+ kt gusts on Tuesday will be over the open waters between Marquette and Grand Marais, but also could see a few low end gales westward into Keweenaw Bay. Also expect some gales around Isle Royale with southerly flow on Tuesday, but do not see enough coverage to justify a Gale Watch over the western lake at this time. Would anticipate eventually needing small craft headlines for most of the nearshore zones as the event draws closer. A potential high end gale event (40-45 kt) will follow on Wednesday as winds shift westerly behind the front aided by cold air advection and pressure rises. Winds settle below 20 kts by Thursday afternoon. Another system traveling north of Lake Superior brings stronger wind potential into early next weekend, but significant model discrepancies leave confidence low.

Northern Green Bay and northwestern Lake Michigan: Winds remain 15 kts or lower through Labor Day as high pressure remains 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. Anticipate an eventual need for multiple periods of small craft headlines for southerly winds on Tuesday and then west-southwest winds on Wednesday. Winds settle below 20 kts by Thursday morning, holding below 20 kts into Friday. Another system traveling north of Lake Superior brings stronger wind potential into early next weekend, but significant model discrepancies leave confidence low.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Watch from Tuesday morning through Tuesday evening for LSZ248>250-265-266.

Lake Michigan... None.