National Weather Service Marine Forecast FZUS63 KMKX

FZUS63 KMKX 191940
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
240 PM CDT Wed Aug 19 2026

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 winds are expected tonight into Thursday, as high pressure around 30.0 inches tracks through the western Great Lakes region. As the high exits to the southeast later Thursday into Thursday night, south to southwest winds will develop. Gusty southwest winds, as well as shower and thunderstorm chances, return Friday into Friday night, as low pressure around 29.8 inches moves across the region and drags a cold front through. Gusty winds will shift to the northwest later Friday night into Saturday after the front moves through. High pressure around 30.2 inches moving toward the region later in the weekend may help maintain gusty north winds.

LMZ261-362-364-366-563-565-567-868-200315
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
240 PM CDT Wed Aug 19 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

TONIGHT
East winds 10 to 15 kt becoming southeast. Waves 1 to 2 ft subsiding to nearly calm.

THURSDAY
South winds 5 to 10 kt becoming southwest 10 to 15 kt early in the afternoon, then becoming south 10 to 20 kt late. Waves 1 ft or less building to 1 to 3 ft.

THURSDAY NIGHT
South winds 10 to 20 kt. Chance of showers overnight. Waves 1 to 3 ft.

FRIDAY
South winds 15 to 25 kt. Chance of showers. Waves 3 to 5 ft.

FRIDAY NIGHT
Southwest winds 10 to 20 kt veering to northwest 10 to 15 kt. Chance of showers. Waves 3 to 5 ft subsiding to 2 to 4 ft.

SATURDAY
Northwest winds 10 to 20 kt increasing to 30 kt in the afternoon. Waves 1 to 3 ft.

SATURDAY NIGHT
North winds to 30 kt diminishing to 15 to 25 kt. Waves 2 to 4 ft.

SUNDAY
Northwest winds to 30 kt becoming north gales to 35 kt. Waves 3 to 5 ft.

MONDAY
North winds 10 to 20 kt becoming northwest. Waves 1 to 2 ft.

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LMZ080-669-671-673-675-777-779-870-872-874-876-878-200315
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
240 PM CDT Wed Aug 19 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

TONIGHT
Northeast winds 10 to 15 kt diminishing to 5 to 10 kt. Waves 1 to 3 ft.

THURSDAY
Northeast winds 5 to 10 kt becoming east late in the morning, then becoming northeast early in the afternoon becoming southwest 10 to 20 kt late. Waves 1 to 2 ft.

THURSDAY NIGHT
Southeast winds 10 to 20 kt becoming south. Waves 1 to 3 ft.

FRIDAY
South winds 10 to 20 kt increasing to 15 to 25 kt. Chance of showers. Waves 3 to 5 ft.

FRIDAY NIGHT
Southwest winds 10 to 20 kt becoming west 10 to 15 kt. Chance of showers. Waves 2 to 4 ft subsiding to 1 to 3 ft.

SATURDAY
Northwest winds 10 to 20 kt increasing to 15 to 25 kt. Waves 2 to 4 ft.

SATURDAY NIGHT
North winds 10 to 20 kt. Waves 1 to 3 ft building to 3 to 5 ft.

SUNDAY
North winds 15 to 25 kt increasing to 30 kt. Waves 4 to 6 ft occasionally to 8 ft.

MONDAY
Northeast winds 10 to 15 kt. Waves 1 to 2 ft.

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LMZ761-200315
MAFOR 1922/ MICHIGAN NORTH 11210 13200 11300 11400 11510 11420. Waves 2 feet or less.

MICHIGAN SOUTH 13110 13100 11210 11820. Waves 2 feet or less.

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Wood

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

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