National Weather Service Marine Forecast FZUS63 KMKX

FZUS63 KMKX 151949
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
249 PM CDT Sat Aug 15 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

30.2 inch high pressure is centered near the Saint Lawrence River this afternoon, resulting in generally light easterly winds across the open waters. The high will progress into the northeastern United States tonight as a cold front approaches from the northern Great Plains, resulting in a brief period of south
southeasterly winds this afternoon and tonight. The aforementioned surface front will move across Lake Michigan early Sunday morning, with northwest winds becoming established by Sunday afternoon across the entirety of the lake. Periods of scattered showers and thunderstorms continue today into Sunday morning ahead of the front. Severe weather is not anticipated.

A new area of 30.1 inch high pressure will build in from the northern Great Plains late Sunday night into Monday, bringing light and variable winds to the waters through the majority of Monday and Monday evening. A slow-moving cold front will approach from the northern Great Plains Tuesday into Wednesday, bringing increasing southwest winds and chances for thunderstorms. Precise timing details will continue to be refined over coming forecasts, though it does appear that a few stronger storms could be possible over the southern half of the waters Tuesday afternoon & night. Winds will trend light and variable behind the front from Wednesday night through the end of next week.

LMZ261-362-364-366-563-565-567-868-160315
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
249 PM CDT Sat Aug 15 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

TONIGHT
East winds 10 to 20 kt veering to south. Slight chance of showers and thunderstorms overnight. Waves 1 to 3 ft.

SUNDAY
Southwest winds 10 to 15 kt increasing to 10 to 20 kt late in the morning, then becoming west early in the afternoon becoming north 15 to 25 kt late. Chance of showers and slight chance of thunderstorms in the morning, then slight chance of showers in the afternoon. Waves 1 to 2 ft building to 2 to 4 ft.

SUNDAY NIGHT
North winds 15 to 25 kt becoming northwest 10 to 15 kt. Waves 2 to 4 ft subsiding to 1 to 3 ft.

MONDAY
Northwest winds 10 to 15 kt backing to southwest 10 to 20 kt. Waves 1 to 3 ft.

MONDAY NIGHT
South winds 10 to 20 kt becoming southwest. Waves 1 to 3 ft.

TUESDAY
Southwest winds 15 to 25 kt. Chance of showers and thunderstorms in the afternoon. Waves 2 to 4 ft.

TUESDAY NIGHT
Northwest winds 10 to 20 kt becoming north. Chance of showers. Waves 2 to 4 ft.

WEDNESDAY
North winds 10 to 20 kt increasing to 15 to 25 kt. Waves 1 to 3 ft.

THURSDAY
North winds 10 to 15 kt backing to southwest 10 to 20 kt. Waves 1 to 2 ft.

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LMZ080-669-671-673-675-777-779-870-872-874-876-878-160315
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
249 PM CDT Sat Aug 15 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

TONIGHT
Southeast winds 5 to 10 kt becoming south. Chance of showers and slight chance of thunderstorms overnight. Waves 2 to 4 ft subsiding to 1 to 2 ft.

SUNDAY
Southwest winds 10 to 15 kt becoming northwest 10 to 20 kt. Chance of showers and slight chance of thunderstorms in the morning, then slight chance of showers and thunderstorms in the afternoon. Waves 1 to 2 ft.

SUNDAY NIGHT
Northwest winds 10 to 20 kt becoming north. Waves 2 to 4 ft.

MONDAY
North winds 10 to 15 kt becoming northwest 10 to 20 kt. Waves 2 to 4 ft.

MONDAY NIGHT
Southwest winds 10 to 20 kt. Waves 1 to 2 ft building to 2 to 4 ft.

TUESDAY
Southwest winds 10 to 20 kt. Waves 2 to 4 ft.

TUESDAY NIGHT
Southwest winds 10 to 20 kt becoming northwest. Showers likely with a chance of thunderstorms. Waves 2 to 4 ft.

WEDNESDAY
North winds 10 to 20 kt increasing to 30 kt. Chance of showers. Waves 2 to 4 ft.

THURSDAY
Northeast winds 10 to 15 kt becoming east 10 to 20 kt. Waves 1 to 3 ft.

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LMZ761-160315
MAFOR 1522/ MICHIGAN NORTH 12220 11320 11420 11410 11510 11620 11730. A chance of showers Sunday morning. Waves 1 to 3 feet.

MICHIGAN SOUTH 11310 11300 11400 11410 11510 13610. A chance of showers overnight and Sunday morning. Waves 1 to 3 feet subsiding to 1 foot or less tonight. Waves 2 feet or less Sunday.

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Quigley

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

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