946 FZUS63 KMQT 230801 GLFLS Open Lake Forecast for Lake Superior National Weather Service Marquette MI 400 AM 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... 30.1 inch ridging moves into Lake Superior early this week via a weakening 30.2 inch parent high from the Canadian Prairies that drops down into the Ohio River Valley by late Monday, weakening to 30.1 inches as it does so. A 29.7 inch Clipper over the Canadian Prairies Monday night then drops southeast towards Lake Superior, arriving early Wednesday morning. The low shifts east Wednesday night with weak ridging of 29.9 inches building over the lake on Thursday. LSZ162-232000- Lake Superior west of a line from Saxon Harbor WI to Grand Portage MN beyond 5NM- 400 AM EDT Sun Aug 23 2026 /300 AM CDT Sun Aug 23 2026/ .EARLY THIS MORNING...North winds 5 to 15 knots. Waves calm to 2 feet. .TODAY...North winds 5 to 15 knots backing southwest in the afternoon. Waves calm to 2 feet. .TONIGHT...Southwest winds 5 to 15 knots veering northwest after midnight, then veering north late. 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 becoming south less than 10 knots after midnight. 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 chance of showers through early afternoon, then showers likely by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...East winds 5 to 15 knots veering west after midnight. Showers likely through midnight. A chance of thunderstorms. A chance of showers after midnight. Waves calm to 2 feet. .WEDNESDAY...West winds 5 to 15 knots becoming northwest 10 to 20 knots. A chance of showers. Waves calm to 2 feet. .THURSDAY...Northwest winds 10 to 20 knots becoming north 5 to 15 knots. Waves calm to 2 feet. $$ LSZ263-232000- Lake Superior from Saxon Harbor WI to Upper Entrance to Portage Canal MI 5NM off shore to the US/Canadian border including Isle Royale National Park- 400 AM EDT Sun Aug 23 2026 .EARLY THIS MORNING...North winds 10 to 20 knots. Waves 1 to 3 feet. .TODAY...North winds 10 to 20 knots diminishing to 5 to 15 knots in the afternoon, then backing west late. Waves building to 2 to 4 feet, then subsiding to calm to 2 feet. .TONIGHT...West winds 5 to 15 knots veering north late. Waves calm to 2 feet. .MONDAY...North winds 5 to 15 knots backing northwest in the afternoon, then backing southwest late. Waves calm to 2 feet. .MONDAY NIGHT...Southwest winds 5 to 15 knots backing south after midnight. Waves calm to 2 feet. .TUESDAY...South winds 5 to 15 knots backing east by mid afternoon. Showers likely by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 5 to 15 knots veering south after midnight. Showers and a chance of thunderstorms. Waves calm to 2 feet. .WEDNESDAY...West winds 10 to 20 knots veering northwest. A chance of showers. Waves calm to 2 feet. .THURSDAY...Northwest winds 10 to 20 knots becoming north 5 to 15 knots. Waves calm to 2 feet. $$ LSZ264-232000- Lake Superior from Upper Entrance to Portage Canal to Manitou Island MI 5NM off shore to the US/Canadian Border- 400 AM EDT Sun Aug 23 2026 .EARLY THIS MORNING...North winds 10 to 20 knots. Waves 2 to 4 feet. .TODAY...North winds 10 to 20 knots backing northwest late. Waves building to 3 to 5 feet occasionally to 7 feet, then subsiding to 1 to 3 feet. .TONIGHT...Northwest winds 10 to 20 knots becoming north 5 to 15 knots late. Waves 1 to 3 feet. .MONDAY...North winds 5 to 15 knots backing west late. Waves subsiding to calm to 2 feet. .MONDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet. .TUESDAY...South winds 5 to 15 knots backing southeast by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 10 to 20 knots becoming south 5 to 15 knots after midnight. Showers and a chance of thunderstorms. Waves building to 1 to 3 feet. .WEDNESDAY...West winds 5 to 15 knots becoming northwest 10 to 20 knots. A chance of showers. Waves subsiding to calm to 2 feet. .THURSDAY...Northwest winds 15 to 25 knots becoming north 5 to 15 knots. Waves building to 1 to 3 feet, then subsiding to calm to 2 feet. $$ LSZ265-232000- Lake Superior West of Line from Manitou Island to Marquette MI Beyond 5NM from shore- 400 AM EDT Sun Aug 23 2026 .EARLY THIS MORNING...North winds 20 to 30 knots. Waves 3 to 5 feet occasionally to 7 feet. .TODAY...North winds 20 to 30 knots backing northwest late. Isolated showers. Waves building to 3 to 6 feet occasionally to 8 feet. .TONIGHT...Northwest winds 15 to 25 knots. Waves subsiding to 2 to 4 feet. .MONDAY...North winds 10 to 20 knots backing northwest in the afternoon, then diminishing to 5 to 15 knots late. Waves subsiding to 1 to 3 feet. .MONDAY NIGHT...West winds 5 to 15 knots. Waves subsiding to calm to 2 feet. .TUESDAY...South winds 5 to 15 knots becoming southeast 10 to 20 knots by mid afternoon. A chance of showers by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 15 to 25 knots veering south after midnight. Showers and a chance of thunderstorms. Waves building to 1 to 3 feet. .WEDNESDAY...West winds 10 to 20 knots becoming northwest 15 to 25 knots. Showers likely. Waves subsiding to calm to 2 feet, then building to 2 to 4 feet. .THURSDAY...Northwest gales to 35 knots diminishing to 15 to 25 knots. Waves building to 3 to 6 feet occasionally to 8 feet, then subsiding to calm to 2 feet. $$ LSZ266-232000- 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 AM EDT Sun Aug 23 2026 .EARLY THIS MORNING...North winds 20 to 30 knots. Waves 3 to 6 feet occasionally to 8 feet. .TODAY...North winds 20 to 30 knots backing northwest late. Isolated showers. Waves building to 4 to 7 feet occasionally to 9 feet. .TONIGHT...Northwest winds 20 to 30 knots diminishing to 15 to 25 knots after midnight, then veering north late. Waves subsiding to 3 to 6 feet occasionally to 8 feet, then building to 4 to 7 feet occasionally to 9 feet. .MONDAY...North winds 15 to 25 knots backing northwest in the afternoon, then diminishing to 10 to 20 knots late. Waves subsiding to 2 to 4 feet. .MONDAY NIGHT...Northwest winds 10 to 20 knots becoming west 5 to 15 knots after midnight. Waves subsiding to calm to 2 feet. .TUESDAY...South winds 5 to 15 knots becoming southeast 10 to 20 knots 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 becoming northwest 15 to 25 knots. Showers likely. Waves subsiding to calm to 2 feet, then building to 2 to 4 feet. .THURSDAY...Northwest gales to 35 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. $$ LSZ267-232000- Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off shore to the US/Canadian border- 400 AM EDT Sun Aug 23 2026 .EARLY THIS MORNING...North winds 20 to 30 knots. Waves 3 to 6 feet occasionally to 8 feet. .TODAY...North winds 20 to 30 knots becoming northwest to 30 knots with a few gale force gusts to 35 knots possible in the afternoon. Isolated showers. Waves building to 4 to 7 feet occasionally to 9 feet. .TONIGHT...Northwest winds to 30 knots with a few gale force gusts to 35 knots possible becoming north 20 to 30 knots late. Waves building to 4 to 8 feet occasionally to 10 feet. .MONDAY...North winds 20 to 30 knots becoming northwest 15 to 25 knots in the afternoon. Waves subsiding to 2 to 4 feet. .MONDAY NIGHT...Northwest winds 10 to 20 knots diminishing to 5 to 15 knots after midnight. Waves subsiding to calm to 2 feet. .TUESDAY...West winds 5 to 15 knots backing east by mid afternoon. Waves calm to 2 feet. .TUESDAY NIGHT...Southeast winds 5 to 15 knots becoming south 15 to 25 knots after midnight. A chance of thunderstorms. Showers likely after midnight. Waves building to 2 to 4 feet. .WEDNESDAY...South winds 10 to 20 knots veering west. Showers. A chance of thunderstorms. A chance of showers. Waves subsiding to calm to 2 feet. .THURSDAY...Northwest winds 15 to 25 knots. Waves building to 2 to 4 feet, then subsiding to 1 to 3 feet. $$ LSZ261-231400- MAFOR 2309/ Superior West 11810 11820 11810 11500 11510 11500 11600 11700. Waves 2 feet or less. Superior North Central 13830 14720 11820. Waves 3 to 5 feet subsiding to 2 to 4 feet today. Waves 2 to 3 feet tonight. Superior South Central 11830 13840 13740 11730. Waves 3 to 6 feet. Superior East 12830 14740 11730 11740. 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  093 FZUS61 KBUF 230802 GLFLO Open Lake Forecast for Lake Ontario National Weather Service Buffalo NY 402 AM 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 29.6 inch low northwest of the Lake this morning will slowly wobble northeastward across southern Quebec through Monday. In response to the low's track a cold front sweeps eastward across the lake through midday today. Behind the cold 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. LOZ062-231500- Lake Ontario open waters from the Niagara River to Hamlin Beach- 402 AM EDT Sun Aug 23 2026 .TODAY...Southwest winds 15 to 25 knots becoming west. A chance of waterspouts. A chance of showers this morning, then showers with a chance of thunderstorms this afternoon. Waves 1 to 3 feet building to 3 to 6 feet. .TONIGHT...West winds 15 to 25 knots. A chance of waterspouts. Showers likely with a chance of thunderstorms early, then a chance of showers. Showers likely late. Waves 4 to 6 feet. .MONDAY...Southwest winds to 30 knots becoming west. A chance of waterspouts. Showers. Waves 4 to 7 feet building to 6 to 9 feet. Waves occasionally around 11 feet. .MONDAY NIGHT...West winds 15 to 25 knots. A chance of waterspouts. Showers likely in the evening, then a chance of showers overnight. Waves 5 to 8 feet subsiding to 3 to 6 feet. Waves occasionally around 10 feet. .TUESDAY...West winds 15 to 20 knots becoming northwest and diminishing to less than 10 knots. A chance of waterspouts during the day. A chance of showers during the day. Waves 3 to 5 feet subsiding to 1 foot or less. .WEDNESDAY...Southwest winds 10 knots or less becoming south. Waves 1 foot or less. .THURSDAY...South winds 5 to 10 knots becoming southwest. A chance of showers and thunderstorms. Waves 2 feet or less. Winds and waves higher in and near thunderstorms. $$ LOZ063>065-231500- Lake Ontario open waters from Hamlin Beach to the Saint Lawrence River- 402 AM EDT Sun Aug 23 2026 .TODAY...South winds 15 to 20 knots becoming west and increasing to 30 knots. A chance of waterspouts. Showers with a chance of thunderstorms this morning, then a chance of showers and thunderstorms early this afternoon. Showers with a chance of thunderstorms late. Waves 2 to 4 feet building to 4 to 7 feet. Waves occasionally around 9 feet. .TONIGHT...West winds 15 to 25 knots becoming southwest. A chance of waterspouts. Showers with a chance of thunderstorms in the evening, then showers after midnight. Waves 4 to 7 feet. Waves occasionally around 9 feet. .MONDAY...Southwest winds 15 to 25 knots increasing to 30 knots. A chance of waterspouts. Showers in the morning, then showers with a chance of thunderstorms in the afternoon. Waves 3 to 6 feet building to 6 to 9 feet. Waves occasionally around 11 feet. .MONDAY NIGHT...Southwest winds 15 to 25 knots becoming west. A chance of waterspouts. Showers with a chance of thunderstorms in the evening, then showers overnight. Waves 5 to 9 feet subsiding to 4 to 7 feet. Waves occasionally around 11 feet. .TUESDAY...West winds 15 to 20 knots becoming northwest 5 to 15 knots. A chance of waterspouts during the day. Showers during the day. Waves 3 to 6 feet subsiding to 1 to 3 feet. .WEDNESDAY...West winds 5 to 15 knots becoming southeast. Waves 2 feet or less. .THURSDAY...South winds 15 to 20 knots becoming southwest 10 to 15 knots. A chance ofshowers and thunderstorms during the day, then showers likely with a chance of thunderstorms Thursday night. Waves 1 to 3 feet. Winds and waves higher in and near thunderstorms. $$ LOZ061-231500- MAFOR 2309/ ONTARIO WEST 1/2 11510 12620 12636 13620. A chance of waterspouts. A chance of thunderstorms this afternoon and evening. Waves 1 to 3 feet building to 4 to 7 feet, and occasionally around 9 feet today. Waves 4 to 7 feet, and occasionally around 9 feet tonight. ONTARIO EAST 1/2 11426 12520 11620 12636 11526 11520. A chance of waterspouts. A chance of thunderstorms today and this evening. Waves 2 to 4 feet building to 4 to 7 feet, and occasionally around 9 feet today. Waves 4 to 7 feet, and occasionally around 9 feet tonight. $$  108 FZUS61 KBUF 230803 GLFSL Forecast for the Saint Lawrence River including the Thousand Islands Region National Weather Service Buffalo NY 402 AM EDT Sun Aug 23 2026 SLZ022-024-231500- Saint Lawrence River from Cape Vincent to Saint Regis 402 AM EDT Sun Aug 23 2026 .TODAY...Southeast winds 10 to 15 knots becoming southwest. Showers with a chance of thunderstorms. .TONIGHT...Southwest winds 5 to 15 knots. A chance of showers and thunderstorms early, then a chance of showers. Showers likely late. .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 15 knots. Showers with a chance of thunderstorms in the evening, then showers overnight. .TUESDAY...West winds 10 knots or less. A chance of showers. .WEDNESDAY...Southwest winds 10 knots or less becoming south. Partly cloudy. .THURSDAY...South winds 5 to 10 knots. A chance of showers and thunderstorms during the day, then showers likely with a chance of thunderstorms Thursday night. Winds and waves higher in and near thunderstorms. $$