FZUS61 KBUF 041402 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 1002 AM EDT Mon May 4 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 29.1 inch low over western Ontario Province will weaken to 29.3 inches as it moves to northern Quebec through Tuesday. Its trailing wavy cold front will slowly cross the lake Tuesday, then will drift across New England Wednesday and out to sea Thursday. A 30.1 inch high over the Tennessee and Ohio Valleys will then slide to the mid-Atlantic coastline Friday. LOZ062-042100- Lake Ontario open waters from the Niagara River to Hamlin Beach- 1002 AM EDT Mon May 4 2026 .THIS AFTERNOON...Southwest winds 15 to 20 knots. Waves 2 to 4 feet. .TONIGHT...Southwest winds 15 to 20 knots. A chance of showers from late evening on. Waves 2 to 4 feet building to 3 to 5 feet. .TUESDAY...Southwest winds 15 to 20 knots becoming west 10 to 15 knots. Showers likely. Waves 3 to 5 feet subsiding to 2 to 3 feet. .TUESDAY NIGHT...West winds 5 to 10 knots becoming north. Showers likely in the evening, then rain likely overnight. Waves 1 to 3 feet. .WEDNESDAY...North winds 5 to 15 knots becoming northwest. Rain likely during the day. Waves 2 feet or less. .THURSDAY...Northwest winds 5 to 10 knots becoming west. Waves 2 feet or less. .FRIDAY...West winds 5 to 15 knots. Waves 1 to 2 feet. $$ LOZ063>065-042100- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 1002 AM EDT Mon May 4 2026 .THIS AFTERNOON...Southwest winds 15 to 20 knots diminishing to 10 to 15 knots. Waves 2 to 4 feet subsiding to 1 to 3 feet. .TONIGHT...South winds 5 to 10 knots increasing to 15 to 20 knots. A chance of showers after midnight. Waves 1 to 3 feet building to 2 to 4 feet. .TUESDAY...Southwest winds 15 to 20 knots becoming west 10 to 15 knots. Showers likely in the morning, then showers with a chance of thunderstorms in the afternoon. Waves 2 to 4 feet. .TUESDAY NIGHT...West winds 5 to 15 knots becoming northwest. Showers with a chance of thunderstorms in the evening, then rain overnight. Waves 2 to 4 feet subsiding to 1 to 3 feet. .WEDNESDAY...North winds 5 to 10 knots becoming west. Rain during the day, then a chance of showers Wednesday night. Waves 1 to 2 feet. .THURSDAY...West winds 5 to 15 knots. Waves 1 to 3 feet. .FRIDAY...West winds 15 to 20 knots becoming southwest 10 to 15 knots. Waves 2 to 4 feet subsiding to 1 to 3 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-042100- MAFOR 0415/ ONTARIO WEST 1/2 13520 12420 13520. A chance of showers overnight and Tuesday morning. Waves 2 to 4 feet this afternoon. Waves 2 to 4 feet building to 3 to 5 feet tonight. Waves 3 to 5 feet Tuesday morning. ONTARIO EAST 1/2 12510 11500 11410 13420 11520. A chance of showers overnight and Tuesday morning. Waves 2 to 4 feet subsiding to 1 to 3 feet this afternoon. Waves 1 to 3 feet building to 2 to 4 feet tonight. Waves 2 to 4 feet Tuesday morning. $$