FZUS61 KBUF 120205 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 1005 PM EDT Sat Apr 11 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 30.5 inch area of high pressure over the Lake this evening, will slip towards New England later tonight and Sunday and off the coast Sunday night. A 29.4 inch low will then move northeastward from the upper Midwest Sunday to near James Bay Sunday night, while pushing an attendant warm front across the Lake on Sunday. This low will strengthen to 29.2 inches while continuing to trek northeast into northern Quebec Monday, with a trailing cold front stalling near the Lake Monday through Tuesday. A 29.5 inch surface low advancing through the upper Great Lakes Wednesday will lift this frontal boundary northward into Canada. This 29.5 inch low will continue northeast into central Quebec on Thursday while dragging an attendant cold front across the Lake. A 30.2 inch high will then build over the lower Great Lakes Thursday night and Friday. LOZ062-120900- Lake Ontario open waters from the Niagara River to Hamlin Beach- 1005 PM EDT Sat Apr 11 2026 .OVERNIGHT...Northwest winds less than 10 knots becoming southeast. Waves 1 foot or less. .SUNDAY...Southeast winds 5 to 10 knots becoming east. A chance of rain showers late in the morning. Rain showers in the afternoon. Waves 2 feet or less. .SUNDAY NIGHT...Southeast winds 10 to 15 knots becoming southwest and increasing to 15 to 25 knots. Showers likely. Waves 1 to 2 feet building to 3 to 6 feet. .MONDAY...Southwest winds 20 to 25 knots. Showers. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY NIGHT...Southwest winds 15 to 20 knots diminishing to 10 to 15 knots. A chance of showers. Waves 3 to 6 feet subsiding to 1 to 2 feet. .TUESDAY...South winds 15 to 20 knots becoming southwest 10 to 15 knots. Showers likely. Waves 1 to 3 feet building to 2 to 4 feet. .WEDNESDAY...Southwest winds 15 to 20 knots. Showers likely during the day, then showers likely with a chance of thunderstorms Wednesday night. Waves 2 to 4 feet. .THURSDAY...Southwest winds 15 to 20 knots becoming west 5 to 15 knots. A chance of showers. Waves 2 to 4 feet subsiding to 1 to 2 feet. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-120900- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 1005 PM EDT Sat Apr 11 2026 .OVERNIGHT...Northwest winds 10 knots or less becoming southeast. Waves 2 feet or less. .SUNDAY...Southeast winds 5 to 15 knots. Rain showers in the afternoon. Waves 2 feet or less. .SUNDAY NIGHT...Southeast winds 15 to 25 knots becoming south. Showers likely. Waves 2 to 4 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY...Southwest winds 15 to 25 knots. Showers. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY NIGHT...Southwest winds 15 to 20 knots diminishing to 5 to 15 knots. Showers in the evening, then a chance of showers overnight. Waves 4 to 7 feet subsiding to 1 to 3 feet. Waves occasionally around 9 feet. .TUESDAY...South winds 5 to 15 knots becoming southwest. Showers likely with a chance of thunderstorms. Waves 1 to 3 feet. .WEDNESDAY...Southwest winds 10 to 15 knots increasing to 15 to 20 knots. Showers likely. Waves 1 to 3 feet building to 2 to 4 feet. .THURSDAY...Southwest winds 15 to 20 knots becoming west 10 to 15 knots. A chance of showers. Waves 3 to 5 feet subsiding to 1 to 2 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-120900- MAFOR 1203/ ONTARIO WEST 1/2 11800 11200 12300 11200 11206 11216 11326. Waves 2 feet or less overnight and Sunday. Waves 1 to 3 feet Sunday evening. ONTARIO EAST 1/2 11700 11200 13300 11316 11326 11436. Waves 2 feet or less overnight and Sunday. Waves 2 to 4 feet building to 3 to 5 feet Sunday evening. $$