Great Lakes Forecast
Issued by NWS
Issued by NWS
956 FZUS63 KMKX 171926 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 226 PM CDT Mon Aug 17 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... 30.1 inch low pressure is approaching Lake Michigan this afternoon, bringing light to variable winds to the open waters. The lighter winds will continue into this evening as the high continues east. A slow-moving cold front will approach from the northern Great Plains Tuesday into Wednesday, bringing increasing southwest winds and chances for thunderstorms. Tuesday evening and night appears most favored for storm potential, with storm chances expected to move well south of the waters on Wednesday. An isolated stronger storm with gusty winds and hail cant be ruled out in this activity, though widespread severe weather potential appears low at this time. Will continue to monitor trends through tomorrow. 30.0 inch high pressure will move through the western Great Lakes Wednesday through Thursday, with light and variable winds prevailing across the waters. The next thunderstorm chances arrive Friday afternoon and evening, when the next cold front is expected to move across Lake Michigan. LMZ261-362-364-366-563-565-567-868-180315- 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- 226 PM CDT Mon Aug 17 2026 SHEBOYGAN WI TO PENTWATER MI NORTH... .TONIGHT...South winds 10 to 20 kt becoming southwest. Waves 1 to 3 ft. .TUESDAY...Southwest winds 10 to 20 kt. Slight chance of showers and thunderstorms in the morning, then chance of showers and thunderstorms in the afternoon. Waves 2 to 4 ft. .TUESDAY NIGHT...Northwest winds 10 to 20 kt becoming north 10 to 15 kt. Chance of showers and thunderstorms in the evening. Waves 2 to 4 ft subsiding to 1 to 3 ft. .WEDNESDAY...Northwest winds 10 to 15 kt increasing to 10 to 20 kt. Waves 1 to 2 ft. .WEDNESDAY NIGHT...East winds 10 to 15 kt becoming northeast. Waves 1 to 2 ft. .THURSDAY...Northeast winds 5 to 10 kt veering to southeast 10 to 20 kt in the afternoon. Waves 1 ft or less. .THURSDAY NIGHT...South winds 10 to 20 kt increasing to 15 to 25 kt. Waves 1 to 2 ft. .FRIDAY...Southwest winds to 30 kt. Chance of showers. Waves 2 to 4 ft. .SATURDAY...Northwest winds 15 to 25 kt becoming north to 30 kt. Chance of showers. Waves 2 to 4 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-180315- Lake Michigan from Michigan City IN to St. Joseph MI 5 NM offshore to Mid Lake- Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore to Mid Lake- Lake Michigan from Port Washington to North Point Light WI 5 NM offshore to Mid Lake- Lake Michigan from North Point Light to Wind Point WI 5 NM offshore to Mid Lake- Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM offshore to Mid Lake- Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM offshore to Mid Lake- Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM offshore to Mid Lake- Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid Lake- Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to Mid Lake- Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid Lake- Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid Lake- Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to Mid Lake- 226 PM CDT Mon Aug 17 2026 SHEBOYGAN WI TO PENTWATER MI SOUTH... .TONIGHT...Southwest winds 10 to 15 kt becoming west 10 to 20 kt. Waves 2 to 4 ft. .TUESDAY...West winds 10 to 20 kt becoming southwest. Chance of showers and slight chance of thunderstorms in the afternoon. Waves 2 to 4 ft. .TUESDAY NIGHT...Southwest winds 10 to 20 kt veering to northwest 10 to 15 kt. Chance of showers and thunderstorms in the evening. Waves 2 to 4 ft. .WEDNESDAY...North winds 10 to 15 kt increasing to 10 to 20 kt. Waves 1 to 3 ft. .WEDNESDAY NIGHT...Northeast winds 10 to 20 kt diminishing to 5 to 10 kt overnight. Waves 1 to 2 ft. .THURSDAY...Northeast winds 5 to 10 kt increasing to 10 to 15 kt. Waves 1 to 2 ft. .THURSDAY NIGHT...Southeast winds 10 to 20 kt becoming south. Waves 1 to 2 ft. .FRIDAY...Southwest winds 10 to 20 kt increasing to 15 to 25 kt. Waves 1 to 2 ft building to 2 to 4 ft. .SATURDAY...West winds 15 to 25 kt becoming northwest. Waves 2 to 4 ft. $$ LMZ761-180315- MAFOR 1722/ MICHIGAN NORTH 12410 13520 11620 12520. A chance of showers and thunderstorms Tuesday afternoon. Waves 1 to 3 feet. MICHIGAN SOUTH 11610 11510 12520 11620 13520. A chance of showers Tuesday afternoon. Waves 1 to 3 feet. $$ Quigley Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes