251 FZUS61 KBUF 240802 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 402 AM EDT Mon Aug 24 2026 For waters beyond five nautical miles of shore on Lake Ontario Waves are the significant wave height - the average of the highest 1/3 of the wave spectrum. Occasional wave height is the average of the highest 1/10 of the wave spectrum. .SYNOPSIS...Behind a recently departed cold front, a trough averaging 29.8 inches will linger over the Lake today. On Tuesday through Wednesday, a ridge averaging 30.1 inches builds from the western and central Great Lakes. The ridge should begin to exit eastward on Thursday and allow a warm front to sweep northeastward across Lake Ontario. On Friday, a cold front should sweep eastward across the lake and be followed by a high pressure ridge averaging 30.0 inches and building from the Upper Midwest. LOZ062-241500- Lake Ontario open waters from the Niagara River to Hamlin Beach- 402 AM EDT Mon Aug 24 2026 .TODAY...Southwest winds 15 to 25 knots becoming west. A chance of waterspouts. Showers. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .TONIGHT...West winds 15 to 20 knots becoming northwest. A chance of waterspouts. Showers likely early, then a chance of showers from late evening on. Waves 3 to 6 feet subsiding to 2 to 4 feet. .TUESDAY...Northwest winds 10 to 15 knots becoming west. A chance of waterspouts in the morning. A chance of showers. Waves 1 to 3 feet. .TUESDAY NIGHT...West winds 10 knots or less becoming southwest. Waves 2 feet or less. .WEDNESDAY...Southwest winds 10 knots or less becoming south. A chance of showers and thunderstorms Wednesday night. Waves 1 foot or less. .THURSDAY...Southwest winds 5 to 15 knots becoming west. Showers likely with a chance of thunderstorms during the day, then a chance of showers and thunderstorms Thursday night. Waves 1 to 2 feet. .FRIDAY...Northwest winds 5 to 10 knots becoming north. Waves 1 foot or less. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-241500- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 402 AM EDT Mon Aug 24 2026 .TODAY...Southwest winds 15 to 25 knots. A chance of waterspouts. A chance of showers early, then showers likely late this morning. Showers with a chance of thunderstorms this afternoon. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .TONIGHT...Southwest winds 15 to 20 knots becoming west. A chance of waterspouts. Showers with a chance of thunderstorms in the evening, then showers after midnight. Showers likely late. Waves 3 to 6 feet. .TUESDAY...Northwest winds 15 to 20 knots becoming west 10 to 15 knots. A chance of waterspouts in the morning. Showers likely in the morning, then a chance of showers in the afternoon. Waves 3 to 5 feet subsiding to 1 to 3 feet. .TUESDAY NIGHT...West winds 5 to 15 knots. A chance of showers in the evening. Waves 1 to 3 feet subsiding to 1 foot or less. .WEDNESDAY...Southwest winds 5 to 10 knots becoming south and increasing to 15 to 20 knots. Waves 1 foot or less building to 1 to 3 feet. .THURSDAY...South winds 15 to 20 knots becoming southwest 5 to 15 knots. A chance of showers and thunderstorms during the day, then showers likely with a chance of thunderstorms Thursday night. Waves 1 to 3 feet. .FRIDAY...West winds 5 to 10 knots becoming northwest. A chance of showers during the day. Waves 2 feet or less. Winds and waves higher in and near thunderstorms. $$ LOZ061-241500- MAFOR 2409/ ONTARIO WEST 1/2 11520 12536 11636 11626 12620 11720. A chance of waterspouts. Waves 3 to 6 feet building to 4 to 7 feet, and occasionally around 9 feet today. Waves 3 to 6 feet subsiding to 2 to 4 feet tonight. ONTARIO EAST 1/2 12520 12536 11526 13626. A chance of waterspouts. Waves 3 to 6 feet. $$  268 FZUS61 KBUF 240803 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 403 AM EDT Mon Aug 24 2026 SLZ022-024-241500- Saint Lawrence River from Cape Vincent to Saint Regis 403 AM EDT Mon Aug 24 2026 .TODAY...South winds 5 to 15 knots becoming southwest. Showers this morning, then showers with a chance of thunderstorms this afternoon. .TONIGHT...Southwest winds 5 to 15 knots becoming west. Showers with a chance of thunderstorms early, then showers likely. A chance of showers late. .TUESDAY...West winds less than 10 knots. A chance of showers. .TUESDAY NIGHT...West winds less than 10 knots. A chance of showers in the evening. .WEDNESDAY...Southwest winds 10 knots or less becoming south. Partly cloudy. .THURSDAY...South winds 5 to 15 knots becoming southwest. A chance of showers and thunderstorms during the day, then showers likely with a chance of thunderstorms Thursday night. .FRIDAY...Southwest winds 10 knots or less becoming northwest. A chance of showers. Winds and waves higher in and near thunderstorms. $$  440 FZUS63 KMKX 240806 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 306 AM CDT Mon Aug 24 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... Low pressure around 29.6 inches in eastern Ontario will linger through this evening, resulting in breezy northwest winds across the northern third of Lake Michigan. High pressure around 30.1 inches drift across Wisconsin and Lake Michigan through Tuesday afternoon and winds will diminish and become light and variable. Look for south to southwest winds to develop over the lake Tuesday afternoon as the high shifts into Ontario and 29.7 inch low pressure approaches from the northern Great Plains Tuesday night into Wednesday. The low will cross Lake Michigan Wednesday afternoon, bringing a breezy northwest wind shift, but gales are not expected as this occurs. Showers and thunderstorms will accompany the approaching/passing surface low Tuesday night into Wednesday afternoon, but they are not expected to be severe. The next area of 30.1 inch high pressure will gradually build toward Lake Michigan from the northern Great Plains Wednesday night through Friday. LMZ261-362-364-366-563-565-567-868-241530- 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- 306 AM CDT Mon Aug 24 2026 SHEBOYGAN WI TO PENTWATER MI NORTH... .TODAY...Northwest winds to 30 kt becoming north 15 to 25 kt. Waves 4 to 6 ft occasionally to 8 ft subsiding to 2 to 4 ft. .TONIGHT...North winds 10 to 20 kt diminishing to 5 to 10 kt. Waves 1 to 3 ft subsiding to 1 to 2 ft. .TUESDAY...South winds 5 to 10 kt increasing to 15 to 25 kt. Waves 1 to 3 ft building to 3 to 5 ft. .TUESDAY NIGHT...South winds 15 to 25 kt. Chance of showers overnight. Waves 4 to 7 ft occasionally to 9 ft. .WEDNESDAY...South winds to 30 kt becoming southwest. Chance of showers. Waves 4 to 7 ft occasionally to 9 ft. .WEDNESDAY NIGHT...West winds 15 to 25 kt becoming northwest 10 to 20 kt. Waves 3 to 5 ft subsiding to 1 to 3 ft. .THURSDAY...Northwest winds 15 to 25 kt increasing to 30 kt. Waves 1 to 3 ft. .FRIDAY...North winds 10 to 15 kt increasing to 10 to 20 kt. Waves 1 to 2 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-241530- Lake Michigan from Michigan City IN to St. Joseph MI 5 NM offshore to Mid Lake- Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore to Mid Lake- Lake Michigan from Port Washington to North Point Light WI 5 NM offshore to Mid Lake- Lake Michigan from North Point Light to Wind Point WI 5 NM offshore to Mid Lake- Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM offshore to Mid Lake- Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM offshore to Mid Lake- Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM offshore to Mid Lake- Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid Lake- Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to Mid Lake- Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid Lake- Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid Lake- Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to Mid Lake- 306 AM CDT Mon Aug 24 2026 SHEBOYGAN WI TO PENTWATER MI SOUTH... .TODAY...Northwest winds 10 to 20 kt becoming north. Waves 3 to 5 ft. .TONIGHT...North winds 10 to 20 kt diminishing to 5 to 10 kt late in the evening, then becoming west after midnight becoming west 5 to 10 kt late. Waves 2 to 4 ft subsiding to 1 to 2 ft. .TUESDAY...Southwest winds 5 to 10 kt increasing to 10 to 15 kt late in the morning, then becoming south 10 to 20 kt in the afternoon. Waves 1 to 3 ft building to 3 to 5 ft. .TUESDAY NIGHT...South winds 10 to 20 kt increasing to 15 to 25 kt. Waves 4 to 6 ft occasionally to 8 ft. .WEDNESDAY...Southwest winds to 30 kt. Chance of showers in the afternoon. Waves 4 to 7 ft occasionally to 9 ft. .WEDNESDAY NIGHT...Southwest winds 15 to 25 kt becoming west 10 to 20 kt. Waves 3 to 5 ft subsiding to 1 to 3 ft. .THURSDAY...Northwest winds 10 to 20 kt. Waves 2 to 4 ft. .FRIDAY...North winds 10 to 15 kt. Waves 1 to 2 ft. $$ LMZ761-241530- MAFOR 2410/ MICHIGAN NORTH 11740 12730 12830 11810 12800. Waves 3 to 5 feet subsiding to 1 to 3 feet today. Waves 2 feet or less tonight. MICHIGAN SOUTH 13720 12820 11810 12600. Waves 2 to 4 feet today. Waves 1 to 3 feet subsiding to 1 foot or less tonight. $$ Cronce Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes