Marine Weather and Tide Forecast for Marquette, MI

DISCUSSION
Issued at 301 AM EDT Tue Oct 14 2025

Early morning RAP analysis and GOES satellite imagery reveal a deep trough encompassing much of the western CONUS as a closed upper low digs south down the California coastline. This is working to amplify upstream height rises across the Upper Midwest and Great Lakes where incoming sfc high pressure in the Canadian Prairies is providing mostly clear skies and chilly NW flow. Temps across the UP this morning range from the mid 30s in the interior west where light winds have allowed efficient radiational cooling to around 50 in the Keweenaw, being somewhat modified by NW flow off of Lake Superior.
Elsewhere, temps have dipped into the 40s. Weak embedded shortwaves within the broad troughing further S and W is beginning to usher in high to midlevel cloud cover.

Aforementioned sfc high pressure builds over the Upper Great Lakes on today, becoming centered overhead on Wednesday as it weakens slightly. Mid level ridging builds over the central CONUS with a ridge riding shortwave tonight into Wednesday. Meanwhile, the deep trough upstream sets up over the Rockies and a series of troughs moves over eastern Canada. Cooler northerly flow keeps temps slightly colder than normal with highs only expected in the upper 40s to upper 50s under partly to mostly cloudy skies. Latest guidance suite is still rather unimpressed with measurable (>0.01")
rain chances late tonight into early Wednesday, with global ensembles displaying a 10-40% chance along the MI/WI border.
HRRR/NBM are a bit more optimistic, suggesting a ~40-70% chance for measurable rain by Wednesday morning. Regardless, if any rain can be squeezed out, it will be rather low impact. That said, if a drier solution pans out, less clouds could help cooler temps resolve.
Quiet and calm weather returns on Wednesday with the high pressure now centered overhead. Highs will be in the 50s across the UP.
Expect similar lows Wednesday night, but with clouds increasing from the southwest, coldest temps will be interior east instead.

Attention then turns to the deep trough upstream. The mid level ridge begins to migrate east as the trough lifts out over the Northern Plains, developing surface low Wednesday night. The high pressure quickly gives way to the east on Thursday, allowing for a warm front to re-introduce PoPs to the forecast as the low to the west lifts toward the Dakotas. The trough begins to quickly pivot northeast Thursday night through Friday, deepening the surface low as it lifts to near Lake Winnipeg. Guidance begins to diverge on the mid level pattern as the shortwave/surface low pair continue northeast this weekend, but persistent troughing over the region keeps rain chances in the forecast this weekend (supported also by marginally cold enough lake surface-850mb delta-Ts for lake effect precip Saturday night and Sunday). That said, impactful amounts of rain are unlikely given probabilities of 0.5" struggle to reach 25%.
Otherwise, temps warm back above normal for the first half of the weekend with spots possibly reaching back into the low to mid 70s on Friday.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
Issued at 724 AM EDT Tue Oct 14 2025

VFR conditions expected across Upper Michigan through the period as high pressure moves overhead today. Winds NW ~10 kt at CMX and N ~10 kt at SAW today, becoming light this evening into tonight. A weak disturbance crossing northern WI will bring a 15-30% chance of rain showers across the UP tonight, with the best chances along the WI border 00-06z Wed.

MARINE
Issued at 301 AM EDT Tue Oct 14 2025

North-northwest winds settle below 25 kts across the west half of Lake Superior this morning with winds over the east half following suit this evening as high pressure builds in. Winds settle below 15 kts across the lake Tuesday night, holding through Thursday morning. High pressure quickly gives way on Thursday, reintroducing 20-30 kt winds to the lake for Thursday night and next weekend.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.