673 FZUS61 KBUF 240202 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 1002 PM EDT Sun Aug 23 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...A cold front continues to sweep eastward across Lake Ontario this evening. Behind the front, a trough averaging 29.8 inches lingers over Lake Ontario through Monday. 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. LOZ062-240900- Lake Ontario open waters from the Niagara River to Hamlin Beach- 1002 PM EDT Sun Aug 23 2026 .REST OF TONIGHT...West winds 15 to 20 knots. A chance of waterspouts. A chance of showers. Waves 3 to 5 feet. .MONDAY...Southwest winds 15 to 25 knots becoming west. A chance of waterspouts. A chance of showers early, then showers likely from late morning on. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY NIGHT...West winds 15 to 20 knots. A chance of waterspouts. Showers likely in the evening, then showers overnight. Waves 3 to 6 feet subsiding to 2 to 4 feet. .TUESDAY...Northwest winds 15 to 20 knots becoming west 10 to 15 knots. A chance of waterspouts. Showers. Waves 2 to 4 feet subsiding to 1 to 3 feet. .TUESDAY NIGHT...West winds 10 knots or less. Waves 2 feet or less. .WEDNESDAY...Southwest winds 10 knots or less becoming south. Waves 1 foot or less. .THURSDAY...South winds 10 to 15 knots becoming west. A chance of showers and thunderstorms. Waves 2 feet or less. .FRIDAY...West winds 5 to 15 knots becoming northwest. Waves 1 to 2 feet. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-240900- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 1002 PM EDT Sun Aug 23 2026 .REST OF TONIGHT...West winds 15 to 20 knots becoming southwest. A chance of waterspouts. Showers with a chance of thunderstorms late this evening, then showers after midnight. A chance of showers late. Waves 4 to 7 feet subsiding to 3 to 6 feet. Waves occasionally around 9 feet. .MONDAY...Southwest winds 15 to 20 knots. A chance of waterspouts. A chance of showers in the morning, then showers with a chance of thunderstorms in the afternoon. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY NIGHT...Southwest winds 15 to 20 knots becoming west. A chance of waterspouts. Showers with a chance of thunderstorms in the evening, then showers overnight. Waves 3 to 6 feet. .TUESDAY...Northwest winds 15 to 20 knots becoming west. A chance of waterspouts. Showers. Waves 3 to 5 feet subsiding to 2 to 4 feet. .TUESDAY NIGHT...West winds 5 to 15 knots. A chance of waterspouts in the evening. Waves 2 to 4 feet subsiding to 1 to 3 feet. .WEDNESDAY...Southwest winds 10 knots or less becoming south and increasing to 15 to 20 knots. Waves 1 foot or less building to 1 to 3 feet. .THURSDAY...South winds 15 to 20 knots becoming southwest 10 to 15 knots. A chance of showers and thunderstorms during the day, then showers likely with a chance of thunderstorms Thursday night. Waves 1 to 3 feet. .FRIDAY...West winds 5 to 15 knots becoming northwest. A chance of showers during the day. Waves 1 to 2 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-240900- MAFOR 2403/ ONTARIO WEST 1/2 12620 12520 11536 11636 11626 11620. A chance of waterspouts. Waves 3 to 5 feet overnight. Waves 3 to 6 feet building to 4 to 7 feet, and occasionally around 9 feet Monday. Waves 3 to 6 feet Monday evening. ONTARIO EAST 1/2 11626 14520 12526 11626. A chance of waterspouts. Waves 3 to 6 feet. $$  705 FZUS61 KBUF 240203 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 1003 PM EDT Sun Aug 23 2026 SLZ022-024-240900- Saint Lawrence River from Cape Vincent to Saint Regis 1003 PM EDT Sun Aug 23 2026 .REST OF TONIGHT...Southwest winds 5 to 10 knots. Showers likely late this evening, then showers after midnight. .MONDAY...South winds 5 to 15 knots becoming southwest. Showers in the morning, then showers with a chance of thunderstorms in the afternoon. .MONDAY NIGHT...Southwest winds 5 to 10 knots. Showers with a chance of thunderstorms in the evening, then a chance of showers overnight. .TUESDAY...West winds 5 to 10 knots. A chance of showers in the morning, then showers likely in the afternoon. .TUESDAY NIGHT...West winds less than 10 knots. Showers likely in the evening. .WEDNESDAY...Southwest winds 10 knots or less becoming southeast. Partly cloudy. .THURSDAY...South winds 5 to 10 knots becoming southwest. A chance of showers during the day, then showers likely Thursday night. .FRIDAY...Southwest winds 10 knots or less becoming northwest. A chance of showers. Winds and waves higher in and near thunderstorms. $$  652 FZUS63 KMKX 240202 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 902 PM CDT Sun Aug 23 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 29.7 inches in eastern Ontario linger through Monday, resulting in breezy northwest wind across the northern third of the Lake. Gusts are expected to approach gales at times. High pressure around 30.1 inches high pressure will build into the Upper Mississippi Valley, reaching the waters by Monday afternoon. Winds will diminish across the Lake as the high moves overhead becoming light and variable. The high will shift east into Ontario by Tuesday, resulting in a south-southwest wind shift across the waters. 29.7 inch low pressure will approach from the northern Great Plains Tuesday night into Wednesday, reinforcing the south-southwesterly wind pattern. The low will cross Lake Michigan during the second half of the day Wednesday, bringing a breezy northwest wind shift. Gales are not expected as this occurs. Showers and thunderstorms will accompany the approaching/passing surface low Tuesday night into Wednesday afternoon. It remains too early to tell if any of these storms could be severe, with trends being monitored through the beginning of this week. The next area of 30.1 inch high pressure will gradually build toward Lake Michigan from the northern Great Plains Wednesday night through Friday, bringing slowly decreasing winds. LMZ261-362-364-366-563-565-567-868-240930- 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- 902 PM CDT Sun Aug 23 2026 SHEBOYGAN WI TO PENTWATER MI NORTH... .REST OF TONIGHT...North winds to 30 kt becoming northwest. Waves 4 to 6 ft occasionally to 8 ft. .MONDAY...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. .MONDAY NIGHT...North winds 10 to 20 kt diminishing to 5 to 10 kt. Waves 1 to 3 ft subsiding to 1 to 2 ft. .TUESDAY...Southwest winds 10 to 15 kt increasing to 15 to 25 kt in the afternoon. Waves 1 to 2 ft building to 2 to 4 ft. .TUESDAY NIGHT...South winds 15 to 25 kt. Chance of showers overnight. Waves 3 to 5 ft. .WEDNESDAY...South winds to 30 kt becoming southwest. Showers in the morning, then showers likely with a chance of thunderstorms in the afternoon. Waves 4 to 7 ft occasionally to 9 ft. .WEDNESDAY NIGHT...West winds 15 to 25 kt becoming northwest 10 to 20 kt. Waves 4 to 6 ft occasionally to 8 ft subsiding to 2 to 4 ft. .THURSDAY...Northwest winds 15 to 25 kt increasing to 30 kt. Waves 2 to 4 ft. .FRIDAY...North winds 10 to 20 kt. Waves 1 to 2 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-240930- 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- 902 PM CDT Sun Aug 23 2026 SHEBOYGAN WI TO PENTWATER MI SOUTH... .REST OF TONIGHT...North winds 10 to 20 kt becoming northwest. Waves 3 to 5 ft. .MONDAY...Northwest winds 10 to 20 kt becoming north. Waves 2 to 4 ft. .MONDAY NIGHT...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 10 to 15 kt becoming south 10 to 20 kt. Waves 1 to 2 ft building to 2 to 4 ft. .TUESDAY NIGHT...South winds 10 to 20 kt increasing to 15 to 25 kt. Waves 3 to 5 ft. .WEDNESDAY...Southwest winds to 30 kt. Chance of showers in the morning, then chance of showers and thunderstorms 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 4 to 6 ft occasionally to 8 ft subsiding to 2 to 4 ft. .THURSDAY...Northwest winds 10 to 20 kt. Waves 2 to 4 ft. .FRIDAY...North winds 10 to 15 kt becoming northeast 10 to 20 kt. Waves 1 to 2 ft. $$ LMZ761-240930- MAFOR 2404/ MICHIGAN NORTH 12740 13730 12830 11810. Waves 3 to 6 feet overnight. Waves 3 to 5 feet subsiding to 1 to 3 feet Monday. Waves 1 to 3 feet Monday evening. MICHIGAN SOUTH 11820 11710 13720 12820 11810. Waves 2 to 4 feet overnight. Waves 1 to 3 feet building to 2 to 4 feet Monday. Waves 1 to 3 feet Monday evening. $$ Patterson Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes