Marine Weather and Tide Forecast for Munising, MI

DISCUSSION
Issued at 346 AM EST Sat Nov 29 2025

Early this morning satellite and model analysis showed an upper level in the lee of the Rockies with a 1004mb surface low near the Oklahoma Panhandle and southwest Kansas. Downstream of the trough, over the U.P, winds were becoming light with a very weak pressure gradient over the area under a somewhat diffluent flow. Lake effect snow showers continued to push off Lake Superior, especially over the eastern U.P. Temperatures had fallen into the teens away from the Lake Superior shoreline.

The main forecast concern through the weekend is an approaching storm system that will bring heavy snow to parts of WI, with light to moderate snow over the U.P. For the U.P generally light snow is expected with moderate snow at times for locations along Lake Michigan in higher terrain of the central and western U.P where upslope flow and lake effect will help boost snow amounts. The most likely scenario is 2-4" of snowfall for much of the U.P with 4-7" over the higher terrain and along Lake Michigan. Have expanded the winter headlines to cover the western U.P through Sunday morning.

Through this morning expecting the winds to become easterly across the area. As this happens lake effect snow showers will push offshore with CAMs showing banding orientating itself east to west with embedded mesolow features. As we get into the afternoon lake effect snow showers will begin to push across the Keweenaw from the east and off Lake Michigan into Menominee and Delta counties.
Isentropic ascent will also increase as a mid level warm front pushes into the area resulting in widespread light snow spreading from south to north through the afternoon.

Snow will increase in intensity for Menominee and Delta counties this evening with moderate snowfall rates of 0.5 in/hr where lake enhancement is expected. Lake enhancement is also expected late tonight over the western U.P with 0.5 in/hr snowfall rates as a shoreline parallel lake effect snow band will push onshore. Lake enhancement with a period of moderate snowfall rates will also develop late tonight over the higher elevations of the central U.P as winds turn northeasterly resulting in upslope flow. By morning winds will start a transition to the northwest from west to east.
Strong convergence over the central portion of the lake could bring a period of moderate to briefly heavy lake effect snow into Marquette and Alger Counties during the early to mid morning hours.
By afternoon lake effect snow shifts into the northwest wind snowbelts but should progressively become lighter as moisture profiles become drier. Light lake effect snow showers will continue through Sunday night.

Uncertainty grows into next week as high pressure skirts around the Great Lakes in the wake of the low and then one or more clipper lows pass near the area next week, though ensembles are highly spread on the track, intensity, and timing of such a feature. With Lake Superior around 5 C, 850mb temperatures of around -10 C should all but guarantee at least some presence of LES, and the LREF suggests 50-90% chances of that temperature or cooler, even with periods of SW flow next week. Cooler than normal temperatures will prevail at the surface as well, especially overnight, where the NBM calls for single-digit lows for many interior UP locations, including some lows near 0 (though raw, un-"bias corrected" model guidance would suggest warmer temperatures).

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
Issued at 1253 PM EST Sat Nov 29 2025

Mainly VFR conditions continue to prevail across Upper Michigan as of 18z Sat, but look to trend down to MVFR later this afternoon as snow spread into U.P. terminals from the south 21-00z. Expect further deterioration to IFR 00-03z as heaviest snow moves into the area tonight. Snow transitions to more of a lake effect regime on Sunday, with variable IFR/MVFR conditions and increasing north winds gusting to 20-25 kt through the end of the TAF period.

MARINE
Issued at 346 AM EST Sat Nov 29 2025

A low pressure will move from the Southern Plains this morning to the southern Lake Michigan by early Sunday morning. This will result in a tightening pressure gradient and winds becoming easterly this afternoon up to around 20kt. As the low gets closer this evening into tonight northeast winds will pick up to 25-30 kt in the west and up to 25kt in the east. Winds will turn northerly on Sunday morning with gales to 35kt developing in the central part of the lake. Winds become northwesterly by Sunday afternoon with gales to 40kt over the eastern half of the lake, generally along and east of the Keweenaw. From there, uncertainty grows as high pressure to the south of the lake is contrasted by weaker low pressures to the north, with each potential feature bringing the potential for gusty winds and perhaps gales (up to 30 percent chance, highest Monday and Wednesday PM), but predictability is low at this time.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
Winter Weather Advisory from 7 PM EST /6 PM CST/ this evening to 1 PM EST /noon CST/ Sunday for MIZ001>006-009-084.

Winter Weather Advisory from 4 PM this afternoon to 1 PM EST Sunday for MIZ007-014-085.

Winter Weather Advisory until 7 AM EST /6 AM CST/ Sunday for MIZ010>013.

Lake Superior...
Gale Watch from late tonight through Sunday afternoon for LSZ243-244-264.

Gale Watch from late tonight through Sunday evening for LSZ245>248-265.

Gale Watch from Sunday morning through Sunday evening for LSZ249-250-266.

Gale Watch from Sunday afternoon through Sunday evening for LSZ251-267.

Lake Michigan...
None.