Expires:202506190300;;967876 FZUS61 KBUF 182002 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 402 PM EDT Wed Jun 18 2025 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 29.4 inch low pressure passing well north of the Lake today will leave a cold front west of the Lake. Along this stalled front a deepening area of low pressure to 29.5 inches will advance from the Ohio Valley this morning to west of the Lake late tonight, and then north of the Lake Thursday, while dragging a cold front across the Lake midday Thursday. A 30.1 inch high builds northeast across the Lake Friday, and exits east of the Lake on Saturday. While a complex of thunderstorms may dive southeastward near or across the Lake Saturday night, this now 30.2 inch surface high pressure will remain anchored over the eastcoast Sunday. LOZ061-190300- MAFOR 1821/ ONTARIO WEST 1/2 11700 12400 11416 11420 12530 11630. A chance of thunderstorms early this evening. A chance of thunderstorms overnight. A chance of thunderstorms Thursday morning. Waves 1 foot or less building to 1 to 3 feet tonight. Waves 3 to 5 feet Thursday. ONTARIO EAST 1/2 11500 13400 12410 11526 11520. A chance of thunderstorms early this evening. Waves 1 foot or less tonight. Waves 1 to 3 feet building to 3 to 5 feet Thursday. $$