FZUS61 KBUF 312011 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 410 PM EDT Tue Mar 31 2026 SLZ022-024-010300- Saint Lawrence River from Cape Vincent to Saint Regis 410 PM EDT Tue Mar 31 2026 .TONIGHT...Northeast winds 5 to 10 knots becoming north. Rain showers likely with a chance of thunderstorms early, then rain showers with a chance of thunderstorms late this evening. Rain showers likely with a chance of thunderstorms after midnight. Some thunderstorms may produce gusty winds through the early overnight. .WEDNESDAY...North winds 5 to 10 knots. Mostly cloudy. .WEDNESDAY NIGHT...North winds 5 to 10 knots becoming northeast. Mostly cloudy. .THURSDAY...Northeast winds 5 to 15 knots. Rain showers with a chance of snow showers. .THURSDAY NIGHT...East winds 5 to 15 knots becoming south 15 to 20 knots. Rain showers. .FRIDAY...South winds 15 to 20 knots becoming northwest and diminishing to 5 to 10 knots. Rain showers during the day. .SATURDAY...North winds 5 to 15 knots becoming south. A chance of rain showers during the day, then rain showers Saturday night. .SUNDAY...Southwest winds 10 to 15 knots becoming west. Rain showers during the day, then a chance of rain showers Sunday night. Winds and waves higher in and near thunderstorms. $$