FZUS63 KMKX 181939
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
239 PM CDT Thu Sep 18 2025

FOR WATERS BEYOND FIVE NAUTICAL MILES OF SHORE ON Lake Michigan.

Waves are provided as a range of significant wave heights, which is the average of the highest 1/3 of the wave, along with the average height of the highest 10% of the waves which will occasionally be encountered.

SYNOPSIS

Light to modest northeast winds over the northern half of the lake will gradually expand into the southern half of the lake this afternoon with the passage of a weak backdoor cold front. Light to modest northeast winds are then expected tonight becoming easterly on Friday. Breezy east to southeast winds will then prevail Friday night through Saturday morning as Canadian high pressure strengthens to around 30.4 inches as it moves into the Lower Great Lakes and southern Quebec, and as low pressure around 29.9 inches moves from the eastern Dakotas into Minnesota. Intermittent showers and thunderstorms are expected Friday night through Sunday.

LMZ261-362-364-366-563-565-567-868-190315
Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM offshore to Mid Lake
Lake Michigan South of a line from Seul Choix Point to the Mackinac Bridge and north of a line from Charlevoix MI to South Fox Island 5 NM offshore
Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to Mid Lake
Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to Mid Lake
Lake Michigan from Rock Island Passage to Sturgeon Bay WI
Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to Mid Lake
Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to Mid Lake
Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid Lake
239 PM CDT Thu Sep 18 2025

SHEBOYGAN WI TO PENTWATER MI NORTH...

TONIGHT
North winds 10 to 15 kt becoming east. Waves 1 to 3 ft.

FRIDAY
East winds 10 to 20 kt becoming northeast. Waves 2 to 4 ft.

FRIDAY NIGHT
East winds 15 to 25 kt becoming southeast. Waves 4 to 6 ft occasionally to 8 ft.

SATURDAY
Southeast winds 15 to 25 kt. Chance of showers. Waves 4 to 6 ft occasionally to 8 ft.

SATURDAY NIGHT
Southeast winds 15 to 25 kt becoming south 10 to 20 kt. Chance of showers in the evening, then chance of showers and thunderstorms overnight. Waves 2 to 4 ft.

SUNDAY
South winds 10 to 20 kt. Chance of showers. Waves 2 to 4 ft.

SUNDAY NIGHT
South winds 10 to 15 kt becoming southwest. Chance of showers. Waves 2 to 4 ft.

MONDAY
Southwest winds 10 to 15 kt. Chance of showers. Waves 1 to 3 ft.

TUESDAY
Northeast winds 10 to 15 kt. Waves 1 to 3 ft.

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LMZ080-669-671-673-675-777-779-870-872-874-876-878-190315
Lake Michigan from Michigan City IN to St. Joseph MI 5 NM offshore to Mid Lake
Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore to Mid Lake
Lake Michigan from Port Washington to North Point Light WI 5 NM offshore to Mid Lake
Lake Michigan from North Point Light to Wind Point WI 5 NM offshore to Mid Lake
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM offshore to Mid Lake
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM offshore to Mid Lake
Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM offshore to Mid Lake
Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid Lake
Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to Mid Lake
Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid Lake
Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid Lake
Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to Mid Lake
239 PM CDT Thu Sep 18 2025

SHEBOYGAN WI TO PENTWATER MI SOUTH...

TONIGHT
Northeast winds 10 to 15 kt becoming east. Waves 1 to 3 ft.

FRIDAY
East winds 10 to 15 kt becoming northeast. Waves 1 to 3 ft.

FRIDAY NIGHT
Northeast winds 10 to 15 kt becoming east 15 to 25 kt late in the evening, then becoming southeast after midnight becoming southeast 15 to 25 kt late. Chance of showers overnight. Waves 1 to 3 ft building to 4 to 6 ft occasionally to 8 ft.

SATURDAY
Southeast winds 10 to 20 kt. Chance of showers. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft.

SATURDAY NIGHT
Southeast winds 10 to 15 kt increasing to 10 to 20 kt. Chance of showers. Waves 2 to 4 ft.

SUNDAY
South winds 10 to 20 kt. Chance of showers in the morning, then chance of showers and thunderstorms in the afternoon. Waves 2 to 4 ft.

SUNDAY NIGHT
South winds 10 to 15 kt becoming southwest. Showers likely. Waves 2 to 4 ft.

MONDAY
Southwest winds 10 to 15 kt becoming south. Chance of showers and thunderstorms. Waves 1 to 3 ft.

TUESDAY
South winds 10 to 15 kt backing to east. Waves 1 to 3 ft.

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LMZ761-190315
MAFOR 1822/ MICHIGAN NORTH 11810 13110 13220 11120. Waves 1 to 3 feet.

MICHIGAN SOUTH 13110 14210 11110. Waves 1 to 3 feet.

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Gehring

Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable

Graphical marine forecasts are available online at: weather.gov/greatlakes