FZUS63 KMKX 180821 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 321 AM CDT Mon May 18 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... No major changes to the going synopsis at this time. A warm front will move from southern Lake Michigan to northern Lake Michigan throughout the night. East to northeast winds will become breezy out of the south. Areas of dense fog may occur at times until the front passes. Breezy south winds will then continue through Monday and into Tuesday followed by a wind shift to the northwest late Tuesday afternoon and evening with the passage of a cold front. High pressure and light and variable winds will then take hold from late Wednesday into Thursday. LMZ261-362-364-366-563-565-567-868-181515- 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- 321 AM CDT Mon May 18 2026 SHEBOYGAN WI TO PENTWATER MI NORTH... .TODAY...South winds to 30 kt diminishing to 15 to 25 kt. Patchy fog. Chance of rain showers and thunderstorms. Waves 4 to 7 ft occasionally to 9 ft. .TONIGHT...South winds 15 to 25 kt increasing to 30 kt. Patchy fog in the evening, then areas of fog overnight. Chance of showers and thunderstorms in the evening, then showers with a chance of thunderstorms overnight. Waves 4 to 7 ft occasionally to 9 ft building to 5 to 8 ft occasionally to 10 ft. .TUESDAY...South winds to 30 kt veering to west. Showers with a chance of thunderstorms in the morning, then chance of showers and thunderstorms in the afternoon. Waves 7 to 10 ft occasionally to 13 ft. .TUESDAY NIGHT...Northwest winds 15 to 25 kt. Waves 4 to 7 ft occasionally to 9 ft subsiding to 3 to 5 ft. .WEDNESDAY...North winds 15 to 25 kt diminishing to 10 to 20 kt. Waves 2 to 4 ft. .WEDNESDAY NIGHT...Northeast winds 10 to 20 kt diminishing to 5 to 10 kt. Waves 1 to 3 ft. .THURSDAY...East winds 5 to 10 kt becoming northeast 10 to 20 kt. Waves 1 to 2 ft. .FRIDAY...Southeast winds 10 to 20 kt becoming east. Waves 1 to 3 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-181515- 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- 321 AM CDT Mon May 18 2026 SHEBOYGAN WI TO PENTWATER MI SOUTH... .TODAY...South winds to 30 kt diminishing to 15 to 25 kt. Chance of showers and thunderstorms. Waves 4 to 7 ft occasionally to 9 ft. .TONIGHT...South winds 10 to 20 kt increasing to 30 kt. Chance of showers and thunderstorms. Waves 4 to 7 ft occasionally to 9 ft building to 5 to 8 ft occasionally to 10 ft. .TUESDAY...South winds to 30 kt becoming west 15 to 25 kt. Showers likely with a chance of thunderstorms in the morning, then chance of showers and thunderstorms in the afternoon. Waves 6 to 9 ft occasionally to 12 ft. .TUESDAY NIGHT...Northwest winds 10 to 20 kt becoming north. Chance of rain showers and thunderstorms in the evening. Waves 4 to 7 ft occasionally to 9 ft subsiding to 3 to 5 ft. .WEDNESDAY...North winds 10 to 20 kt increasing to 15 to 25 kt. Waves 3 to 5 ft. .WEDNESDAY NIGHT...Northeast winds 10 to 20 kt. Waves 3 to 5 ft subsiding to 2 to 4 ft. .THURSDAY...East winds 10 to 20 kt becoming northeast. Waves 2 to 4 ft. .FRIDAY...East winds 10 to 20 kt diminishing to 10 to 15 kt. Waves 2 to 4 ft. $$ LMZ761-181515- MAFOR 1810/ MICHIGAN NORTH 13440 13430 11433 11446. A chance of thunderstorms. Waves 3 to 6 feet today. Waves 3 to 6 feet building to 4 to 7 feet tonight. MICHIGAN SOUTH 12440 15430. A chance of showers and thunderstorms. Waves 3 to 6 feet today. Waves 3 to 6 feet building to 4 to 7 feet tonight. $$ CMiller Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes