FZUS61 KBUF 122003 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 403 PM EDT Thu Mar 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 30.1 inch high will build into the Ohio Valley and lower Great Lakes this evening before drifting to the eastern seaboard Friday. A 29.0 inch low will then move from the upper Great Lakes Friday morning to the Ottawa Valley Friday night while weakening to 29.4 inches. This low will continue east to the Canadian Maritimes Saturday as a 30.3 inch high builds into the lower Great Lakes. A 30.3 inch high will then ridge across the lake Saturday night, before moving east of the lake Sunday. Meanwhile, a 29.5 inch surface low over the mid Mississippi Valley Sunday morning will track northeastward and deepen to 28.9 inches just to the west of the lake Monday morning, before pushing northeastward across Quebec through the remainder of Monday and Tuesday. This low will sweep a strong cold front across the lake Monday afternoon, with a 30.3 inch high then building across the Great Lakes and Ohio Valley Tuesday. LOZ062-130300- Lake Ontario open waters from the Niagara River to Hamlin Beach- 403 PM EDT Thu Mar 12 2026 ...GALE WARNING IN EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY MORNING... .TONIGHT...Northwest winds 15 to 20 knots becoming southwest 5 to 15 knots. Waves 3 to 6 feet subsiding to 1 to 2 feet. .FRIDAY...Southeast winds 10 to 15 knots becoming southwest and increasing to 35 knot gales in the afternoon. Snow in the morning, then rain and snow in the afternoon. Waves 1 to 2 feet building to 8 to 11 feet. Waves occasionally around 14 feet. .FRIDAY NIGHT...Southwest gales to 40 knots becoming west to 35 knots. A chance of rain and snow showers. Waves 11 to 16 feet subsiding to 10 to 15 feet. Waves occasionally around 20 feet. .SATURDAY...West gales to 35 knots diminishing to 15 to 25 knots. A chance of snow showers in the morning. Waves 11 to 15 feet subsiding to 4 to 7 feet. Waves occasionally around 19 feet. .SATURDAY NIGHT...West winds 15 to 20 knots becoming east 5 to 15 knots. A chance of snow showers overnight. Waves 3 to 5 feet subsiding to 1 to 3 feet. .SUNDAY...East winds 15 to 25 knots becoming southeast to 30 knots. Snow showers with a chance of rain showers during the day, then a chance of rain and snow showers Sunday night. Waves 3 to 5 feet building to 5 to 9 feet. Waves occasionally around 11 feet. .MONDAY...South winds to 30 knots becoming west and increasing to 40 knot gales. Rain showers during the day, then rain showers with a chance of snow showers Monday night. Waves 5 to 8 feet building to 12 to 17 feet. Waves occasionally around 22 feet. .TUESDAY...West gales to 35 knots diminishing to 15 to 25 knots. A chance of snow showers. Waves 10 to 15 feet subsiding to 6 to 9 feet. Waves occasionally around 19 feet. $$ LOZ063>065-130300- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 403 PM EDT Thu Mar 12 2026 ...GALE WARNING IN EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON... .TONIGHT...Northwest winds to 30 knots becoming west and diminishing to 5 to 10 knots. Waves 6 to 10 feet subsiding to 2 to 4 feet. Waves occasionally around 13 feet. .FRIDAY...South winds 10 to 15 knots increasing to 30 knots in the afternoon. Snow. Rain and snow late. Waves 2 feet or less building to 5 to 8 feet. Waves occasionally around 10 feet. .FRIDAY NIGHT...Southwest gales to 35 knots becoming west. Rain and snow. Waves 9 to 13 feet building to 12 to 16 feet. Waves occasionally around 20 feet. .SATURDAY...West gales to 40 knots diminishing to 30 knots. Snow likely in the morning, then a chance of snow showers in the afternoon. Waves 14 to 18 feet subsiding to 9 to 12 feet. Waves occasionally around 23 feet. .SATURDAY NIGHT...West winds 15 to 25 knots becoming northeast and diminishing to 5 to 15 knots. Waves 7 to 10 feet subsiding to 2 feet or less. Waves occasionally around 13 feet. .SUNDAY...East winds 15 to 25 knots becoming southeast and increasing to 40 knot gales. Snow showers with a chance of rain showers. Waves 2 to 4 feet building to 7 to 11 feet. Waves occasionally around 14 feet. .MONDAY...Southeast gales to 40 knots becoming west to 35 knots. Rain showers during the day, then rain showers with a chance of snow showers Monday night. Waves 7 to 11 feet building to 12 to 17 feet. Waves occasionally around 22 feet. .TUESDAY...West gales to 35 knots diminishing to 30 knots. Waves 11 to 16 feet subsiding to 9 to 12 feet. Waves occasionally around 20 feet. $$ LOZ061-130300- MAFOR 1221/ ONTARIO WEST 1/2...GALE WARNING IN EFFECT...11730 11720 11710 11600 11410 11337 11447 11457. Waves 4 to 7 feet subsiding to 1 to 3 feet, and occasionally around 9 feet tonight. Waves 1 to 2 feet building to 7 to 10 feet, and occasionally around 13 feet Friday. ONTARIO EAST 1/2 11740 11730 11720 11710 11510 11320 11337 11447. Waves 6 to 10 feet subsiding to 2 to 4 feet, and occasionally around 13 feet tonight. Waves 2 feet or less building to 3 to 6 feet Friday. $$