FZUS61 KBUF 120803 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 403 AM EDT Sun Apr 12 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 will drift east into New England today, before sliding off the coast tonight. A 29.4 inch low over the upper Midwest today, will move quickly northeastward to near James Bay tonight, while pushing an attendant warm front across the Lake this afternoon. 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 southern 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 on Friday. LOZ062-121500- Lake Ontario open waters from the Niagara River to Hamlin Beach- 403 AM EDT Sun Apr 12 2026 .TODAY...Southeast winds 5 to 15 knots becoming east. Rain showers this afternoon. Waves 2 feet or less. .TONIGHT...East winds 10 to 15 knots becoming southwest and increasing to 15 to 25 knots. A chance of showers in the evening. A chance of showers late. Waves 1 to 3 feet building to 3 to 5 feet. .MONDAY...Southwest winds 15 to 25 knots. Showers. Waves 3 to 6 feet. .MONDAY NIGHT...Southwest winds 15 to 20 knots diminishing to 10 to 15 knots. Showers likely overnight. Waves 3 to 5 feet subsiding to 1 to 3 feet. .TUESDAY...South winds 15 to 20 knots becoming southwest 10 to 15 knots. Showers likely with a chance of thunderstorms. Waves 1 to 3 feet building to 3 to 5 feet, then subsiding to 1 to 3 feet. .WEDNESDAY...Southwest winds 10 to 15 knots. Showers likely with a chance of thunderstorms during the day, then showers likely Wednesday night. Waves 1 to 2 feet. .THURSDAY...South winds 15 to 20 knots becoming west 10 to 15 knots. Showers likely. Waves 1 to 3 feet building to 2 to 4 feet. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-121500- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 403 AM EDT Sun Apr 12 2026 .TODAY...Southeast winds 5 to 15 knots. A chance of rain showers early this afternoon. Rain showers late. Waves 2 feet or less. .TONIGHT...Southeast winds 15 to 25 knots becoming south. Showers likely early, then a chance of showers late in the evening. A chance of showers late. Waves 1 to 3 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY...Southwest winds 15 to 25 knots. Showers. Waves 3 to 6 feet. .MONDAY NIGHT...Southwest winds 15 to 20 knots becoming south 5 to 15 knots. A chance of showers. Waves 3 to 5 feet subsiding to 1 to 3 feet. .TUESDAY...South winds 10 to 15 knots becoming southwest. Showers with a chance of thunderstorms. Waves 1 to 2 feet building to 2 to 4 feet, then subsiding to 1 to 3 feet. .WEDNESDAY...Southwest winds 5 to 15 knots. Showers likely. Waves 2 feet or less. .THURSDAY...South winds 15 to 20 knots becoming west. Showers likely. Waves 1 to 3 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-121500- MAFOR 1209/ ONTARIO WEST 1/2 12300 11200 11216 11210 11310 12520. Waves 2 feet or less today. Waves 1 to 3 feet building to 2 to 4 feet tonight. ONTARIO EAST 1/2 12300 12310 11326 11330 12430. Waves 2 feet or less today. Waves 1 to 3 feet building to 4 to 7 feet, and occasionally around 9 feet tonight. $$