027 FZUS63 KMQT 232001 GLFLS Open Lake Forecast for Lake Superior National Weather Service Marquette MI 400 PM EDT Sun Aug 23 2026 For waters beyond 5 nautical miles of shore on Lake Superior. 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... This afternoon, a 29.6 inch low is along the Quebec/Ontario line while 30.0 inch high pressure extends from Hudson Bay to Missouri. Little movement is expected with only a slight weakening of both pressure centers through tonight. By Monday night, the low weakens to 29.8 inches as it fully moves into Quebec, allowing the high to also weaken to 30.0 inches and settle over the Upper Great Lakes. Meanwhile, 29.8 inch low pressure moves over Lake Winnipeg. These systems all shift east slowly through Wednesday afternoon, when the weak high moves over New England as the 29.7 inch low moves over Lake Superior. By Thursday afternoon, the low will deepen to 29.6 inches over western Quebec as a 30.2 inch high moves over northern Manitoba. This high will extend 30.1 inch ridging over Lake Superior Friday into the weekend. LSZ162-240800- Lake Superior west of a line from Saxon Harbor WI to Grand Portage MN beyond 5NM- 400 PM EDT Sun Aug 23 2026 /300 PM CDT Sun Aug 23 2026/ .LATE THIS AFTERNOON...Southwest winds 5 to 15 knots. Waves calm to 2 feet. .TONIGHT...Southwest winds 5 to 15 knots veering north after midnight. Waves calm to 2 feet. .MONDAY...North winds 5 to 15 knots veering south in the afternoon. Waves calm to 2 feet. .MONDAY NIGHT...Southeast winds 5 to 15 knots diminishing to less than 10 knots after midnight, then backing east late. A slight chance of showers after midnight. Waves calm to 2 feet. .TUESDAY...South winds 5 to 15 knots backing east by mid afternoon. A slight chance of showers through early afternoon. A chance of thunderstorms. Showers likely by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...East winds 5 to 15 knots veering west after midnight. Showers through midnight. A chance of thunderstorms. A chance of showers after midnight. Waves calm to 2 feet. .WEDNESDAY...West winds 5 to 15 knots increasing to 10 to 20 knots by mid afternoon. Waves calm to 2 feet. .WEDNESDAY NIGHT...Northwest winds 10 to 20 knots. Waves calm to 2 feet. .THURSDAY...Northwest winds 5 to 15 knots veering north. Waves calm to 2 feet. .FRIDAY...Northeast winds 5 to 15 knots. Waves calm to 2 feet. $$ LSZ263-240800- Lake Superior from Saxon Harbor WI to Upper Entrance to Portage Canal MI 5NM off shore to the US/Canadian border including Isle Royale National Park- 400 PM EDT Sun Aug 23 2026 .LATE THIS AFTERNOON...West winds 5 to 15 knots. Waves calm to 2 feet. .TONIGHT...West winds 5 to 15 knots veering northwest after midnight. Waves calm to 2 feet. .MONDAY...North winds 5 to 15 knots backing southwest late. Waves calm to 2 feet. .MONDAY NIGHT...Southwest winds 5 to 15 knots backing south late. Waves calm to 2 feet. .TUESDAY...South winds 5 to 15 knots backing southeast by mid afternoon. Showers likely and a chance of thunderstorms by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 5 to 15 knots veering southwest after midnight. Showers and a chance of thunderstorms. Waves calm to 2 feet. .WEDNESDAY...West winds 10 to 20 knots. A chance of showers. Waves calm to 2 feet. .WEDNESDAY NIGHT...Northwest winds 10 to 20 knots. Waves calm to 2 feet. .THURSDAY...Northwest winds 10 to 20 knots becoming north 5 to 15 knots. Waves calm to 2 feet. .FRIDAY...North winds 5 to 15 knots veering south. Waves calm to 2 feet. $$ LSZ264-240800- Lake Superior from Upper Entrance to Portage Canal to Manitou Island MI 5NM off shore to the US/Canadian Border- 400 PM EDT Sun Aug 23 2026 .LATE THIS AFTERNOON...Northwest winds 10 to 20 knots. Waves 1 to 3 feet. .TONIGHT...Northwest winds 10 to 20 knots becoming north 5 to 15 knots late. Waves subsiding to calm to 2 feet. .MONDAY...North winds 5 to 15 knots backing west late. Waves building to 1 to 3 feet, then subsiding to calm to 2 feet. .MONDAY NIGHT...West winds 5 to 15 knots diminishing to less than 10 knots after midnight, then backing southwest late. Waves calm to 2 feet. .TUESDAY...South winds 5 to 15 knots backing southeast by mid afternoon. A chance of showers and a slight chance of thunderstorms by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 5 to 15 knots veering south after midnight. Showers and a chance of thunderstorms. Waves building to 1 to 3 feet. .WEDNESDAY...Southwest winds 10 to 20 knots veering west by mid afternoon. A chance of showers. Waves subsiding to calm to 2 feet. .WEDNESDAY NIGHT...Northwest winds 5 to 15 knots increasing to 10 to 20 knots after midnight. Waves calm to 2 feet. .THURSDAY...Northwest winds 10 to 20 knots becoming north 5 to 15 knots. Waves building to 1 to 3 feet, then subsiding to calm to 2 feet. .FRIDAY...North winds 5 to 15 knots backing southwest. Waves calm to 2 feet. $$ LSZ265-240800- Lake Superior West of Line from Manitou Island to Marquette MI Beyond 5NM from shore- 400 PM EDT Sun Aug 23 2026 .LATE THIS AFTERNOON...Northwest winds 20 to 30 knots. Waves 3 to 6 feet occasionally to 8 feet. .TONIGHT...Northwest winds 15 to 25 knots. Waves subsiding to 2 to 4 feet, then building to 3 to 5 feet occasionally to 7 feet. .MONDAY...North winds 15 to 25 knots diminishing to 5 to 15 knots. Waves subsiding to calm to 2 feet. .MONDAY NIGHT...Northwest winds 5 to 15 knots backing southwest late. Waves calm to 2 feet. .TUESDAY...South winds 5 to 15 knots becoming southeast 10 to 20 knots by mid afternoon. A chance of showers and a slight chance of thunderstorms by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...South winds 15 to 25 knots. Showers and a chance of thunderstorms. Waves building to 1 to 3 feet. .WEDNESDAY...Southwest winds 15 to 25 knots becoming west 10 to 20 knots by mid afternoon. Showers likely through early afternoon. A chance of showers by mid afternoon. Waves subsiding to calm to 2 feet. .WEDNESDAY NIGHT...Northwest winds 15 to 25 knots increasing to 20 to 30 knots after midnight. Waves building to 2 to 4 feet. .THURSDAY...Northwest winds 20 to 30 knots becoming north 10 to 20 knots. Waves building to 3 to 6 feet occasionally to 8 feet, then subsiding to calm to 2 feet. .FRIDAY...North winds 10 to 20 knots backing southwest. Waves calm to 2 feet. $$ LSZ266-240800- Lake Superior East of a line from Manitou Island to Marquette MI and West of a line from Grand Marais MI to the US/Canadian Border Beyond 5NM from shore- 400 PM EDT Sun Aug 23 2026 .LATE THIS AFTERNOON...Northwest winds 20 to 30 knots. A slight chance of showers. Waves 4 to 7 feet occasionally to 9 feet subsiding to 3 to 6 feet occasionally to 8 feet. .TONIGHT...Northwest winds 20 to 30 knots becoming north 15 to 25 knots after midnight. Waves 3 to 6 feet occasionally to 8 feet. .MONDAY...North winds 15 to 25 knots backing northwest in the afternoon, then diminishing to 10 to 20 knots late. Waves subsiding to 1 to 3 feet. .MONDAY NIGHT...Northwest winds 5 to 15 knots backing west late. Waves subsiding to calm to 2 feet. .TUESDAY...South winds 5 to 15 knots becoming southeast 10 to 20 knots by mid afternoon. A slight chance of showers by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 15 to 25 knots veering south after midnight. A chance of showers through midnight. A chance of thunderstorms. Showers after midnight. Waves building to 2 to 4 feet, then subsiding to 1 to 3 feet. .WEDNESDAY...South winds 10 to 20 knots veering west by mid afternoon. Showers through early afternoon. A chance of showers by mid afternoon. Waves subsiding to calm to 2 feet. .WEDNESDAY NIGHT...Northwest winds 15 to 25 knots increasing to 20 to 30 knots after midnight. Waves building to 2 to 4 feet. .THURSDAY...Northwest winds 20 to 30 knots becoming north 15 to 25 knots. Waves building to 4 to 7 feet occasionally to 9 feet, then subsiding to 1 to 3 feet. .FRIDAY...North winds 5 to 15 knots backing west. Waves subsiding to calm to 2 feet. $$ LSZ267-240800- Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off shore to the US/Canadian border- 400 PM EDT Sun Aug 23 2026 .LATE THIS AFTERNOON...Northwest winds 20 to 30 knots. A slight chance of showers. Waves 4 to 7 feet occasionally to 9 feet. .TONIGHT...Northwest winds 20 to 30 knots increasing to 30 knots with a few gale force gusts to 35 knots possible after midnight, then becoming north 20 to 30 knots late. A slight chance of showers through midnight. Waves subsiding to 3 to 6 feet occasionally to 8 feet. .MONDAY...North winds 20 to 30 knots becoming northwest 15 to 25 knots in the afternoon. Waves subsiding to 2 to 4 feet. .MONDAY NIGHT...Northwest winds 10 to 20 knots diminishing to 5 to 15 knots after midnight. Waves subsiding to calm to 2 feet. .TUESDAY...Southwest winds 5 to 15 knots backing east by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...South winds 10 to 20 knots increasing to 15 to 25 knots after midnight. A chance of showers through midnight. Showers after midnight. Waves building to 2 to 4 feet. .WEDNESDAY...South winds 15 to 25 knots diminishing to 10 to 20 knots by mid afternoon. Showers and a chance of thunderstorms. Waves subsiding to calm to 2 feet. .WEDNESDAY NIGHT...West winds 10 to 20 knots veering northwest after midnight. A chance of showers. Waves calm to 2 feet. .THURSDAY...Northwest winds 15 to 25 knots becoming north 10 to 20 knots. Waves building to 2 to 4 feet, then subsiding to 1 to 3 feet. .FRIDAY...Northwest winds 10 to 20 knots diminishing to 5 to 15 knots. Waves subsiding to calm to 2 feet. $$ LSZ261-240200- MAFOR 2321/ Superior West 11510 11500 11600 11700 12800 11100 11400. Waves 1 foot or less. Superior North Central 13720 11820 12810 12710. Waves 1 to 3 feet. Superior South Central 11730 12740 11730 11720 12830 11720. Waves 3 to 5 feet tonight. Waves 2 to 4 feet Monday. Superior East 11740 12730 13830 11730 11720. Waves 3 to 6 feet. $$ WFO MQT Experimental modernized open lake forecast is available online at weather.gov/mqt/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes  143 FZUS61 KBUF 232002 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 402 PM EDT Sun Aug 23 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 cold front continues to sweep eastward across Lake Ontario this evening. Behind the front, a trough averaging 29.8 inches lingers over Lake Ontario through Monday. On Tuesday through Wednesday, a ridge averaging 30.1 inches builds from the western and central Great Lakes. The ridge should begin to exit eastward on Thursday and allow a warm front to sweep northeastward across Lake Ontario. On Friday, a cold front should sweep eastward across the lake and be followed by a high pressure ridge averaging 30.0 inches and building from the Upper Midwest. LOZ062-240300- Lake Ontario open waters from the Niagara River to Hamlin Beach- 402 PM EDT Sun Aug 23 2026 .TONIGHT...West winds 15 to 25 knots. A chance of waterspouts. Showers with a chance of thunderstorms early, then a chance of showers from late evening on. Waves 3 to 6 feet. .MONDAY...Southwest winds 15 to 25 knots becoming west. A chance of waterspouts. A chance of showers early, then showers likely from late morning on. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY NIGHT...West winds 15 to 20 knots. A chance of waterspouts. Showers likely in the evening, then showers overnight. Waves 3 to 6 feet subsiding to 2 to 4 feet. .TUESDAY...Northwest winds 15 to 20 knots becoming west 10 to 15 knots. A chance of waterspouts. Showers. Waves 2 to 4 feet subsiding to 1 to 3 feet. .TUESDAY NIGHT...West winds 10 knots or less. Waves 2 feet or less. .WEDNESDAY...Southwest winds 10 knots or less becoming south. Waves 1 foot or less. .THURSDAY...South winds 10 to 15 knots becoming west. A chance of showers and thunderstorms. Waves 2 feet or less. .FRIDAY...West winds 5 to 15 knots becoming northwest. Waves 1 to 2 feet. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-240300- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 402 PM EDT Sun Aug 23 2026 .TONIGHT...West winds 15 to 25 knots becoming southwest. A chance of waterspouts. Showers with a chance of thunderstorms this evening, then showers after midnight. A chance of showers late. Waves 4 to 7 feet subsiding to 3 to 6 feet. Waves occasionally around 9 feet. .MONDAY...Southwest winds 15 to 20 knots. A chance of waterspouts. A chance of showers in the morning, then showers with a chance of thunderstorms in the afternoon. Waves 3 to 6 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY NIGHT...Southwest winds 15 to 20 knots becoming west. A chance of waterspouts. Showers with a chance of thunderstorms in the evening, then showers overnight. Waves 3 to 6 feet. .TUESDAY...Northwest winds 15 to 20 knots becoming west. A chance of waterspouts. Showers. Waves 3 to 5 feet subsiding to 2 to 4 feet. .TUESDAY NIGHT...West winds 5 to 15 knots. A chance of waterspouts in the evening. Waves 2 to 4 feet subsiding to 1 to 3 feet. .WEDNESDAY...Southwest winds 10 knots or less becoming south and increasing to 15 to 20 knots. Waves 1 foot or less building to 1 to 3 feet. .THURSDAY...South winds 15 to 20 knots becoming southwest 10 to 15 knots. A chance of showers and thunderstorms during the day, then showers likely with a chance of thunderstorms Thursday night. Waves 1 to 3 feet. .FRIDAY...West winds 5 to 15 knots becoming northwest. A chance of showers during the day. Waves 1 to 2 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-240300- MAFOR 2321/ ONTARIO WEST 1/2 11636 13620 12520 11536 11636. A chance of waterspouts. A chance of thunderstorms this evening. Waves 4 to 7 feet subsiding to 3 to 6 feet, and occasionally around 9 feet tonight. Waves 3 to 6 feet building to 4 to 7 feet, and occasionally around 9 feet Monday. ONTARIO EAST 1/2 12636 11626 14520 11526. A chance of waterspouts. A chance of thunderstorms this evening. Waves 4 to 7 feet subsiding to 3 to 6 feet, and occasionally around 9 feet tonight. Waves 3 to 6 feet Monday. $$  165 FZUS61 KBUF 232003 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 403 PM EDT Sun Aug 23 2026 SLZ022-024-240300- Saint Lawrence River from Cape Vincent to Saint Regis 403 PM EDT Sun Aug 23 2026 .TONIGHT...Southwest winds 5 to 15 knots. A chance of showers and thunderstorms early, then showers likely late this evening. Showers after midnight. .MONDAY...South winds 5 to 15 knots becoming southwest. Showers in the morning, then showers with a chance of thunderstorms in the afternoon. .MONDAY NIGHT...Southwest winds 5 to 10 knots. Showers with a chance of thunderstorms in the evening, then a chance of showers overnight. .TUESDAY...West winds 5 to 10 knots. A chance of showers in the morning, then showers likely in the afternoon. .TUESDAY NIGHT...West winds less than 10 knots. Showers likely in the evening. .WEDNESDAY...Southwest winds 10 knots or less becoming southeast. Partly cloudy. .THURSDAY...South winds 5 to 10 knots becoming southwest. A chance of showers during the day, then showers likely Thursday night. .FRIDAY...Southwest winds 10 knots or less becoming northwest. A chance of showers. Winds and waves higher in and near thunderstorms. $$