FZUS63 KMKX 182335 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 635 PM 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... A Dense Fog Advisory is in effect tonight through Tuesday morning for the north half of the lake as relatively mild and humid air flows over the cold lake waters. Otherwise modest to breezy southerly winds will develop tonight and last into early Tuesday afternoon, then followed by the passage of a cold front. Winds will shift to northwesterly with the cold frontal passage and remain a bit breezy. Scattered thunderstorms can be expected over the central and southern portion of the lake late tonight into Tuesday. High pressure around 30.4 inches will push in behind the front with light and variable winds taking hold from late Wednesday into Thursday. LMZ261-362-364-366-563-565-567-868-190330- 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- 635 PM CDT Mon May 18 2026 SHEBOYGAN WI TO PENTWATER MI NORTH... ...DENSE FOG ADVISORY IN EFFECT UNTIL NOON CDT TUESDAY... .TONIGHT...South winds 10 to 20 kt increasing to 30 kt. Widespread dense fog. Slight chance of rain showers this evening, then chance of rain showers and thunderstorms overnight. Waves 3 to 5 ft building to 4 to 7 ft occasionally to 9 ft. .TUESDAY...South winds to 30 kt becoming west 15 to 25 kt. Widespread dense fog in the morning, then patchy fog in the afternoon. Slight chance of showers and thunderstorms in the morning, then chance of showers in the afternoon. Waves 4 to 7 ft occasionally to 9 ft subsiding to 4 to 6 ft occasionally to 8 ft. .TUESDAY NIGHT...Northwest winds 15 to 25 kt. Waves 3 to 5 ft subsiding to 2 to 4 ft. .WEDNESDAY...North winds 15 to 25 kt. Waves 2 to 4 ft. .WEDNESDAY NIGHT...Northeast winds 10 to 20 kt diminishing to 5 to 10 kt overnight. Waves 1 to 3 ft. .THURSDAY...East winds 5 to 10 kt becoming northeast 10 to 20 kt in the afternoon. Waves 1 to 2 ft. .THURSDAY NIGHT...Northeast winds 10 to 15 kt becoming east. Waves 1 to 3 ft. .FRIDAY...East winds 10 to 20 kt becoming northeast 15 to 25 kt. Waves 2 to 4 ft. .SATURDAY...Northeast winds 15 to 25 kt. Chance of rain showers. Waves 2 to 4 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-190330- 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- 635 PM CDT Mon May 18 2026 SHEBOYGAN WI TO PENTWATER MI SOUTH... .TONIGHT...South winds 10 to 20 kt increasing to 30 kt. Patchy fog. Slight chance of showers this evening, then chance of showers and thunderstorms overnight. Waves 3 to 5 ft building to 4 to 7 ft occasionally to 9 ft. .TUESDAY...South winds to 30 kt becoming west 15 to 25 kt. Patchy fog in the morning. Slight chance of showers and thunderstorms in the morning, then chance of showers and slight chance of thunderstorms in the afternoon. Waves 4 to 7 ft occasionally to 9 ft subsiding to 4 to 6 ft occasionally to 8 ft. .TUESDAY NIGHT...Northwest winds 10 to 20 kt becoming north. Waves 3 to 5 ft. .WEDNESDAY...North winds 10 to 20 kt increasing to 15 to 25 kt. Waves 4 to 6 ft occasionally to 8 ft. .WEDNESDAY NIGHT...Northeast winds 15 to 25 kt diminishing to 10 to 20 kt. Waves 4 to 6 ft occasionally to 8 ft. .THURSDAY...East winds 10 to 20 kt becoming northeast. Waves 2 to 4 ft. .THURSDAY NIGHT...Northeast winds 10 to 20 kt becoming east. Waves 2 to 4 ft. .FRIDAY...East winds 10 to 20 kt becoming northeast. Chance of showers. Waves 2 to 4 ft. .SATURDAY...Northeast winds 10 to 20 kt becoming north 10 to 15 kt. Waves 1 to 3 ft. $$ LMZ761-190330- MAFOR 1822 AMD/ MICHIGAN NORTH 12424 11434 11444 11446 19444 11444 12540. Waves 3 to 5 feet subsiding to 2 to 4 feet, then building to 4 to 7 feet tonight. Waves 4 to 7 feet subsiding to 3 to 6 feet Tuesday. MICHIGAN SOUTH 13430 12440 11430 12530. A chance of showers and thunderstorms overnight. A chance of showers Tuesday afternoon. Waves 2 to 4 feet building to 3 to 6 feet tonight. Waves 4 to 7 feet subsiding to 3 to 6 feet Tuesday. $$ Gehring Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes