


Great Lakes Forecast
Issued by NWS
Issued by NWS
450 FZUS63 KMKX 171423 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 923 AM CDT Fri Oct 17 2025 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... Southerly winds will increase today as high pressure of 30.1 inches moves across the eastern US, and low pressure of 29.3 inches deepens over Alberta. Winds over most of the lake will be be between 20 and 30 knots, but occasional gusts to gale force will be possible for a short time this afternoon over the northern third of the lake. These gales will be marginal in nature and confined to a small area of the lake for a short period of time, so no gale warning is planned at this time. A weak cold front will move across the lake tonight and early Saturday, with winds turning westerly behind the front. Low pressure is then expected to rapidly develop over northern Indiana late Saturday night, and lift through Lower Michigan Sunday morning, reaching the vicinity of Lake Huron by mid day, at 29.1 inches. This will drag a much stronger cold front across the lake, with gales looking increasingly likely Sunday morning through Sunday afternoon. Additional gales are possible on Tuesday as another low moves through the region. LMZ261-362-364-366-563-565-567-868-172115- 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- 923 AM CDT Fri Oct 17 2025 SHEBOYGAN WI TO PENTWATER MI NORTH... .REST OF TODAY...South winds to 30 kt. Slight chance of showers late this morning. Waves 7 to 10 ft occasionally to 13 ft. .TONIGHT...South winds to 30 kt becoming southwest. Slight chance of showers and thunderstorms in the evening, then showers with a chance of thunderstorms overnight. Waves 7 to 10 ft occasionally to 13 ft subsiding to 6 to 9 ft occasionally to 12 ft. .SATURDAY...Southwest winds 15 to 25 kt diminishing to 10 to 20 kt. Showers likely in the morning, then chance of showers in the afternoon. Waves 5 to 8 ft occasionally to 10 ft subsiding to 4 to 6 ft occasionally to 8 ft. .SATURDAY NIGHT...South winds 10 to 15 kt veering to north 15 to 25 kt overnight. Chance of showers in the evening, then showers likely overnight. Waves 3 to 5 ft. .SUNDAY...North gales to 35 kt becoming northwest. Showers likely in the morning, then chance of showers in the afternoon. Waves 8 to 11 ft occasionally to 14 ft. .SUNDAY NIGHT...Northwest gales to 35 kt diminishing to 15 to 25 kt. Waves 7 to 10 ft occasionally to 13 ft subsiding to 4 to 7 ft occasionally to 9 ft. .MONDAY...Southwest winds 15 to 25 kt becoming south gales to 35 kt. Waves 3 to 5 ft building to 8 to 11 ft occasionally to 14 ft. .TUESDAY...West winds to 30 kt increasing to gales to 40 kt. Chance of showers. Waves 7 to 10 ft occasionally to 13 ft building to 8 to 11 ft occasionally to 14 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-172115- 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- 923 AM CDT Fri Oct 17 2025 SHEBOYGAN WI TO PENTWATER MI SOUTH... .REST OF TODAY...South winds to 30 kt. Slight chance of showers late this morning. Waves 6 to 9 ft occasionally to 12 ft. .TONIGHT...South winds to 30 kt. Slight chance of showers in the evening, then chance of showers and thunderstorms overnight. Waves 6 to 9 ft occasionally to 12 ft. .SATURDAY...Southwest winds 15 to 25 kt diminishing to 10 to 20 kt. Showers with a chance of thunderstorms. Waves 5 to 8 ft occasionally to 10 ft subsiding to 4 to 6 ft occasionally to 8 ft. .SATURDAY NIGHT...Southwest winds 10 to 20 kt becoming west to 30 kt overnight. Showers with a chance of thunderstorms in the evening, then showers overnight. Waves 4 to 6 ft occasionally to 8 ft. .SUNDAY...Northwest gales to 40 kt increasing to gales to 45 kt. Showers in the morning, then chance of showers in the afternoon. Waves 14 to 18 ft occasionally to 23 ft. .SUNDAY NIGHT...Northwest gales to 35 kt diminishing to 15 to 25 kt. Waves 12 to 16 ft occasionally to 21 ft subsiding to 7 to 10 ft occasionally to 13 ft. .MONDAY...Southwest winds to 30 kt becoming south gales to 35 kt. Waves 4 to 6 ft occasionally to 8 ft building to 8 to 12 ft occasionally to 16 ft. .TUESDAY...West gales to 35 kt increasing to gales to 40 kt. Chance of showers. Waves 12 to 16 ft occasionally to 21 ft. $$ LMZ761-172115- MAFOR 1716/ MICHIGAN NORTH 14440 11446 11546 11536 11526. A chance of thunderstorms overnight. Waves 5 to 9 feet building to 7 to 10 feet this afternoon. Waves 6 to 10 feet subsiding to 5 to 8 feet tonight. Waves 4 to 7 feet subsiding to 3 to 6 feet Saturday morning. MICHIGAN SOUTH 14440 11440 11436 12536. A chance of thunderstorms overnight and Saturday morning. Waves 5 to 8 feet building to 6 to 9 feet this afternoon. Waves 5 to 9 feet tonight. Waves 4 to 7 feet Saturday morning. $$ Wagner Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes