FZUS61 KBUF 190726 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 326 AM EDT Tue May 19 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...An area of low pressure at 29.7 inches over Wisconsin will track northeast to the Upper Great Lakes tonight into Tuesday morning, then to central Quebec Wednesday while strengthening to 29.4 inches. A cold front attendant to this low will cross the Lake late Tuesday night into Wednesday morning. A large 30.4 inch high will then build across the entire Great Lakes region Wednesday night through Thursday. High pressure will move to the east and weaken to 30.1 inches Friday. A 29.9 inch low will track across the Ohio Valley and near the lake Saturday. LOZ062-191500- Lake Ontario open waters from the Niagara River to Hamlin Beach- 326 AM EDT Tue May 19 2026 .TODAY...Southwest winds 10 to 15 knots increasing to 15 to 20 knots. A chance of showers early. Waves 1 to 3 feet building to 3 to 5 feet. .TONIGHT...Southwest winds 15 to 20 knots becoming west. Showers with a chance of thunderstorms in the evening, then showers likely after midnight. Waves 3 to 5 feet. .WEDNESDAY...Northwest winds 10 to 15 knots becoming west. A chance of showers in the morning. Waves 2 to 4 feet subsiding to 1 to 3 feet. .WEDNESDAY NIGHT...Northwest winds 10 to 15 knots becoming north. Waves 1 to 3 feet. .THURSDAY...Northeast winds 5 to 15 knots becoming east 10 knots or less. Waves 2 feet or less. .FRIDAY...East winds 10 to 15 knots increasing to 15 to 20 knots. Showers likely Friday night. Waves 2 feet or less building to 2 to 4 feet. .SATURDAY...East winds 15 to 25 knots diminishing to 10 to 15 knots. Showers likely. Waves 3 to 6 feet subsiding to 2 to 4 feet. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-191500- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 326 AM EDT Tue May 19 2026 .TODAY...Southwest winds 10 to 15 knots. A chance of showers early. Waves 1 to 3 feet building to 2 to 4 feet. .TONIGHT...Southwest winds 10 to 15 knots becoming west 15 to 20 knots. A chance of showers and thunderstorms early, then showers with a chance of thunderstorms. A chance of showers late. Waves 2 to 4 feet building to 3 to 5 feet. .WEDNESDAY...West winds 15 to 20 knots. A chance of showers in the morning. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .WEDNESDAY NIGHT...West winds 15 to 20 knots becoming north 10 to 15 knots. Waves 4 to 7 feet subsiding to 2 to 4 feet. Waves occasionally around 9 feet. .THURSDAY...Northeast winds 5 to 15 knots diminishing to less than 10 knots. Waves 1 to 3 feet subsiding to 1 foot or less. .FRIDAY...East winds 5 to 15 knots increasing to 15 to 20 knots. Showers likely Friday night. Waves 1 to 3 feet. .SATURDAY...East winds 15 to 25 knots becoming southeast. Showers. Waves 2 to 4 feet building to 3 to 5 feet, then subsiding to 1 to 3 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-191500- MAFOR 1909/ ONTARIO WEST 1/2 12510 13520 11526 11520 11620. A chance of thunderstorms this evening. Waves 1 to 3 feet building to 3 to 5 feet today. Waves 3 to 5 feet tonight. ONTARIO EAST 1/2 15510 11526 11520. A chance of thunderstorms this evening. Waves 1 to 3 feet today. Waves 2 to 4 feet building to 3 to 5 feet tonight. $$