Marine Weather and Tide Forecast for Copper Harbor, MI

DISCUSSION
Issued at 259 AM EDT Mon Oct 26 2026

Early morning GOES satellite imagery reveals cloudy skies overhead the Upper Great Lakes underneath the exit region of a departing upper jet and weak embedded mid-level shortwave. These features are touching off light rain showers across the western UP. Nothing more than like rain or sprinkles are expected considering the stout midlevel and surface dry layer hydrometeors have to fight through to reach the surface. Synoptic support must be adequate enough considering several ASOS stations are reporting light rain in northern WI despite sfc Td depressions 15-20F. Regardless, expecting these showers to graze the UP through morning before getting shunted south by incoming ridging and building surface high pressure.
Northerly winds ahead of the aforementioned building sfc high will keep temperatures near the climatological normal of 40s to low 50s for the first time in a while today. Seasonable temps will last for one whole day before being raised above normal again tonight as a shortwave lifts a weak surface low west of Lake Superior. Isentropic ascent ahead of this wave will force an area of light rain in the western UP through Tuesday while lifting temps back into the 50s.
Another more vigorous shortwave lifts into Ontario Wednesday, further pushing temps back into the 60s to near 70. This drags a cold front through the UP Wednesday night through Thursday morning, kicking off better chances for showers. Deterministic models and their ensemble counterparts generally agree on quiet weather dominating through much of the weekend, potentially keeping Halloween night dry, but diverge towards the end of the month as a more zonal/SW flow aloft pattern takes shape, sending shortwave activity back into the region. At this time, ensembles don't suggest any widespread meaningful rain across the area with 24hr prob of QPF >0.1" only reaching 60-80% on any given day for portions of the UP.
Additionally, above normal temperatures dominate through the rest of the month into early November with seemingly no end in sight as the CPC extended probabilities favor above normal temps through the 1-3 week and 3-4 week outlooks. All global ensembles highlight strong positive 850mb temp anomalies even into their extended 200+ hour range.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
Issued at 130 AM EDT Mon Oct 26 2026

Expect VFR conditions at all terminals through the period as mid and high level cloud cover streams across Upper Michigan today. Still seeing a radar echoes as of 06z Mon, but do not expect much if any precipitation to reach the ground given dry air in place in the lower levels of the atmosphere. Winds are generally light out of the north today, but could reach around 10 kt at KCMX and KSAW. Rain approaches the WI border region late in the period, resulting in lowering cigs at KIWD. Still expect VFR to prevail through 06z Tue.

MARINE
Issued at 259 AM EDT Mon Oct 26 2026

Lake Superior: Breezy northerlies 15-25kt gusts persist this morning, highest over the east-central waters, before falling back below 20 kts by the afternoon. A period of gustier E to S winds returns Tuesday-Thursday as a pair of surface lows lift west of Lake Superior. Ensembles have decreased the chance for gales to 35 kts through this period (25-50% chance), unsurprisingly considering over- lake stability inhibiting mixing into stronger winds aloft. Winds fall back below 20kts Thursday-Friday.

Northern Lake Michigan and northern Bay of Green Bay: Light winds mainly 15kts or less persist into early next week, turning northerly today and then southeast Tuesday. Winds begin to increase Tuesday night, with gusts of 20-25 kts through Wednesday, settling below 20 kts out of the west into Thursday.

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