FZUS61 KBUF 220203 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 1002 PM EDT Fri Aug 21 2026 SLZ022-024-220900- Saint Lawrence River from Cape Vincent to Saint Regis 1002 PM EDT Fri Aug 21 2026 .OVERNIGHT...East winds 5 to 10 knots. Mainly clear. .SATURDAY...Southeast winds 10 knots or less. Sunny. .SATURDAY NIGHT...Southeast winds 10 knots or less increasing to 10 to 15 knots. A chance of showers and thunderstorms in the evening, then showers likely with a chance of thunderstorms overnight. .SUNDAY...Southeast winds 5 to 15 knots becoming southwest. Showers with a chance of thunderstorms. .SUNDAY NIGHT...Southwest winds 5 to 15 knots. Showers with a chance of thunderstorms in the evening, then a chance of showers overnight. .MONDAY...Southwest winds 5 to 10 knots. Showers. .TUESDAY...West winds 10 knots or less becoming southwest. Mostly cloudy, then clearing. .WEDNESDAY...Southwest winds 10 knots or less becoming south. Partly to mostly cloudy. Winds and waves higher in and near thunderstorms. $$