Marine Weather and Tide Forecast for Copper City, MI

DISCUSSION
Issued at 213 PM EDT Sun Mar 8 2026

GOES visible imagery shows mostly clear skies across the region early this afternoon. Its been this way for most of the day so far behind this morning's shortwave, save for morning cloud cover over the Michigamme Highlands and Spine north of Mass City early. Under these mostly clear skies, daytime temperatures have soared into the 40s and 50s across all of the forecast area, with a few locations even climbing into the 50s in the south-central, interior west, and by Lake Superior in Marquette County. Breezy southwest to westerly winds have been observed in many locations through the day as well with KCMX winning gold with its peak wind of 43 mph at 0830 ET.
Outside of the Keweenaw, which has experienced gusts above 30 mph for most of the day so far, gusty winds have generally been observed in the 20s. Given that we've a few more hours of higher sun angle sunshine this afternoon, I wouldn't be surprised if observations climb a few more degrees before beginning their downward nighttime trek. Breezy westerly winds are expected to continue, but lighten for a few hours after sunset.

Tonight, a surface low will push through the Northern Tier, passing near or just north of Thunder Bay by Monday morning. This will support continued above normal temperatures and reignition of the winds through Monday. Overnight lows will likely bottom out in the mid to upper 30s for most locations, and the low 40s in the south- central. These abnormal conditions are on the order of 20 to 30 degrees above normal for early March. Monday, another day of widespread mid to upper 40s and 50s is also expected. The strongest winds are expected tonight into Monday morning from the southwest, likely peaking near 35 mph in the Keweenaw and by Lake Superior.
Winds will lighten Monday as they become more westerly behind the aforementioned low's parent shortwave, but still likely blow 20-30 mph for most of the morning in the Keweenaw and by Lake Superior.
CAMs do suggest a non-zero chance for rain along the low's weak warm frontal boundary as it moves through Monday morning, but a majority of guidance packages suggest only light rainfall amounts, if it all.

The past 24 hours hasn't shown much change in expectations for the Tuesday to Thursday period, save for maybe an earlier start to snow in the west half Tuesday and better agreement on when the post system lake effect snow ends Wednesday night. It should be noted that the 06z and 12z EC trended southeastward, which then results in a less northward extent of the QPF shield into our forecast area.
This trend will need to be monitored. However, favoring all other guidance for now, the overall progression in the period will begin with a surface high transiting northern Ontario Monday night while a weakening surface low moves through the Northern Plains and a second surface low organizes and lifts out of the Southern Plains on Tuesday. Preceding swath of isentropically forced snow associated with the fizzling northern stream's surface low will stretch across the region Tuesday morning into Tuesday night as the two features begin phasing. By Wednesday, the remaining surface low will lift northeast through southeastern lower Michigan, with its inverted trough/deformation axis stretching northwestward into the Upper Great Lakes under the support of left exit jet dynamics tied to a 150kt jet streak near 300mb. The 850mb airmass looks to slowly cool through this transition, reaching near -7C Wednesday morning, with additional cooling to near -13C Wednesday night. This will help reinforce snowfall Wednesday with a possible lake enhanced component, under northerly flow, before transitioning to lake effect overnight downwind of Lake Superior into the traditional northwest wind snowbelts.

Hazards with this event will include the potential for light to moderate, wet snow, becoming fluffier through the day Wednesday, when the greater synoptic forcing is present and better snowfall rates are expected. There has been a slight increase in probabilities of >2 inches per 6 hours central and east Wednesday afternoon and evening (now 40-55%) and 30-50% chance for the storm total of at least 6 inches for most areas outside of the region touching Wisconsin Tuesday morning through Thursday morning.

Attention then turns to another potentially impactful clipper working through the region late Thursday into Friday. Between yesterday and today's guidance, there is better agreement on a deepening low moving quickly across the Northern Plains through the Upper Great Lakes. GEFS and EC ensemble means are in better agreement on the low moving through Upper Michigan or Lake Superior.
While there are still outlier ensemble members, the mean agreement and general clustering of the surface lows do point to growing confidence in a potential widespread snowfall and windier event.
There isn't much confidence though on the depth/strength of the system though given 6z GFS and EC deterministic solutions differ by 10+mb and their ensemble counterparts by 10-20+mb, nor snowfall amounts. For what its worth though, both the 6z GEFS and EC suggest 40-60% probabilities of exceeding 3 inches in 24 hours during the event and a 30-50% chance of exceeding 40 mph.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/
Issued at 719 PM EDT Sun Mar 8 2026

VFR conditions prevail at all sites throughout this period. Besides a 20-30% chances of rain this evening at CMX, dry conditions are expected. Winds will be quite gusty at IWD (up to 25 kt) and CMX (up to 30 kt), first out of the SW tonight becoming W Monday morning and NW for Monday PM. A LLJ will lead to a LLWS threat at all sites tonight.

MARINE
Issued at 213 PM EDT Sun Mar 8 2026

Gale conditions lighten this afternoon, but increase again from the southwest tonight. Through the night, expecting the winds to steadily increase, likely peaking at or near gale Monday morning north and east of the Keweenaw, and 20-30kts elsewhere. Opted to go ahead and hoist a Gale Warning for where gales would be most likely to occur. Winds lighten through the day Monday, likely falling below 20kts lake-wide by evening.

Tuesday evening into Wednesday night, another period of elevated winds is expected, with potential for gales Wednesday and Wednesday night. Best chances for gales are mainly east of the Keweenaw Wednesday night. Another stronger system looks to move through the Upper Great Lakes late Thursday, potentially resulting in high end gales and storms Thursday night and Friday. Afterwards, winds lighten to near or below 20kts lake-wide Saturday.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
None.
Lake Superior...
Gale Warning from 5 AM to 2 PM EDT Monday for LSZ244-245- 264>266.

Lake Michigan...
None.