Great Lakes Forecast
Issued by NWS
Issued by NWS
017 FZUS63 KMQT 210147 GLFLS Open Lake Forecast for Lake Superior National Weather Service Marquette MI 947 PM EDT Fri Sep 20 2024 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...A 29.7 inch trough is moving across Lake Superior tonight as a deeper parent low heads towards Hudson Bay. This trough will dissipate early Saturday, allowing weak 29.9 inch ridging to anchor over the Upper Great Lakes on Saturday morning. A new low pressure of 29.6 inches over southern Manitoba Saturday morning will then track across far northern Ontario Saturday afternoon and night. Its associated 29.9 inch trough will sweep across Lake Superior during Saturday night and Sunday morning. In its wake, 30.1 inch high pressure will build from the Northern Plains into northern Ontario during Sunday and Monday. Also on Monday, a 29.7 inch low pressure will track northeast to southern Wisconsin. 30.0 inch high pressure builds over the Lower MS Valley Tuesday, building to 30.1 inches Wednesday. LSZ162-211000- Lake Superior west of a line from Saxon Harbor WI to Grand Portage MN beyond 5NM- 947 PM EDT Fri Sep 20 2024 /847 PM CDT Fri Sep 20 2024/ .REST OF TONIGHT...Southwest winds 5 to 15 knots. Waves calm to 2 feet. .SATURDAY...South winds 5 to 15 knots backing southeast in the afternoon, then veering west late. A chance of showers. A slight chance of thunderstorms by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...Northwest winds 10 to 20 knots increasing to 15 to 25 knots after midnight. A slight chance of showers and thunderstorms through midnight. Waves building to 3 to 5 feet occasionally to 7 feet, then subsiding to 2 to 4 feet. .SUNDAY...Northwest winds 15 to 25 knots diminishing to 10 to 20 knots by mid afternoon. Waves subsiding to calm to 2 feet. .SUNDAY NIGHT...Northwest winds 10 to 20 knots veering north after midnight. Waves calm to 2 feet. .MONDAY...North winds 10 to 20 knots veering south by mid afternoon. Waves calm to 2 feet. .MONDAY NIGHT...East winds 5 to 15 knots veering south after midnight. Waves calm to 2 feet. .TUESDAY...Southwest winds 5 to 15 knots veering west. Waves calm to 2 feet. .WEDNESDAY...West winds 5 to 15 knots veering northwest. Waves calm to 2 feet. $$ LSZ263-211000- Lake Superior from Saxon Harbor WI to Upper Entrance to Portage Canal MI 5NM off shore to the US/Canadian border including Isle Royale National Park- 947 PM EDT Fri Sep 20 2024 .REST OF TONIGHT...Southwest winds 5 to 15 knots. Waves 2 to 4 feet subsiding to calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots backing southeast in the afternoon. A chance of showers. A slight chance of thunderstorms by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...West winds 10 to 20 knots veering northwest after midnight, then increasing to 15 to 25 knots late. A chance of showers and a slight chance of thunderstorms. Waves building to 3 to 5 feet occasionally to 7 feet. .SUNDAY...Northwest winds 10 to 20 knots. Waves subsiding to calm to 2 feet. .SUNDAY NIGHT...Northwest winds 5 to 15 knots veering north after midnight. Waves calm to 2 feet. .MONDAY...North winds 5 to 15 knots veering northeast by mid afternoon. Waves calm to 2 feet. .MONDAY NIGHT...Southeast winds 5 to 15 knots. Waves calm to 2 feet. .TUESDAY...Southwest winds 5 to 15 knots veering west. Waves calm to 2 feet. .WEDNESDAY...West winds 5 to 15 knots. Waves calm to 2 feet. $$ LSZ264-211000- Lake Superior from Upper Entrance to Portage Canal to Manitou Island MI 5NM off shore to the US/Canadian Border- 947 PM EDT Fri Sep 20 2024 .REST OF TONIGHT...Southwest winds 5 to 15 knots veering west after midnight, then backing southwest late. Waves 2 to 4 feet subsiding to calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots backing southeast in the afternoon. A chance of showers by mid afternoon. Waves building to 1 to 3 feet. .SATURDAY NIGHT...South winds 10 to 20 knots becoming northwest 15 to 25 knots after midnight. A chance of showers and a slight chance of thunderstorms. Waves building to 3 to 6 feet occasionally to 8 feet. .SUNDAY...Northwest winds 15 to 25 knots diminishing to 10 to 20 knots by mid afternoon. Waves subsiding to 1 to 3 feet. .SUNDAY NIGHT...North winds 5 to 15 knots. Waves subsiding to calm to 2 feet. .MONDAY...North winds 5 to 15 knots. Waves calm to 2 feet. .MONDAY NIGHT...East winds 5 to 15 knots veering southeast after midnight. Waves calm to 2 feet. .TUESDAY...East winds 5 to 15 knots veering west. Waves calm to 2 feet. .WEDNESDAY...Northwest winds 5 to 15 knots backing west. Waves calm to 2 feet. $$ LSZ265-211000- Lake Superior West of Line from Manitou Island to Marquette MI Beyond 5NM from shore- 947 PM EDT Fri Sep 20 2024 .REST OF TONIGHT...Southwest winds 5 to 15 knots. Waves calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots backing southeast in the afternoon, then increasing to 10 to 20 knots late. A chance of showers by mid afternoon. Waves building to 1 to 3 feet. .SATURDAY NIGHT...South winds 10 to 20 knots veering west after midnight, then becoming northwest 15 to 25 knots late. A chance of showers and a slight chance of thunderstorms. Waves building to 2 to 4 feet, then subsiding to 1 to 3 feet. .SUNDAY...Northwest winds 20 to 30 knots diminishing to 15 to 25 knots by mid afternoon. A slight chance of thunderstorms through early afternoon. A slight chance of showers. Waves building to 3 to 5 feet occasionally to 7 feet, then subsiding to 1 to 3 feet. .SUNDAY NIGHT...Northwest winds 10 to 20 knots veering north after midnight. Waves 1 to 3 feet. .MONDAY...North winds 10 to 20 knots veering northeast by mid afternoon. Waves subsiding to calm to 2 feet. .MONDAY NIGHT...Northeast winds 5 to 15 knots veering east after midnight. Waves calm to 2 feet. .TUESDAY...Northeast winds 5 to 15 knots becoming west 10 to 20 knots. Waves calm to 2 feet. .WEDNESDAY...Northwest winds 10 to 20 knots diminishing to 5 to 15 knots. Waves calm to 2 feet. $$ LSZ266-211000- 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- 947 PM EDT Fri Sep 20 2024 .REST OF TONIGHT...Southwest winds 5 to 15 knots veering west late. Patchy fog after midnight. Waves 1 to 3 feet subsiding to calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots backing southeast late. A slight chance of showers by mid afternoon. Waves building to 1 to 3 feet. .SATURDAY NIGHT...South winds 10 to 20 knots veering southwest after midnight, then becoming northwest 15 to 25 knots late. A chance of showers and thunderstorms. Waves building to 3 to 6 feet occasionally to 8 feet. .SUNDAY...Northwest winds 20 to 30 knots. A chance of showers and a slight chance of thunderstorms. Waves building to 4 to 7 feet occasionally to 9 feet, then subsiding to 3 to 6 feet occasionally to 8 feet. .SUNDAY NIGHT...North winds 15 to 25 knots. Waves subsiding to 2 to 4 feet. .MONDAY...North winds 10 to 20 knots. Waves subsiding to calm to 2 feet. .MONDAY NIGHT...Northeast winds 5 to 15 knots veering east after midnight. Waves calm to 2 feet. .TUESDAY...Northeast winds 5 to 15 knots backing northwest. Waves calm to 2 feet. .WEDNESDAY...Northwest winds 10 to 20 knots becoming north 5 to 15 knots. Waves calm to 2 feet. $$ LSZ267-211000- Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off shore to the US/Canadian border- 947 PM EDT Fri Sep 20 2024 .REST OF TONIGHT...South winds 10 to 20 knots diminishing to 5 to 15 knots after midnight. A slight chance of thunderstorms by late evening. A slight chance of showers. Areas of fog after midnight. Waves calm to 2 feet. .SATURDAY...South winds 5 to 15 knots veering southwest in the afternoon, then backing southeast late. Waves calm to 2 feet. .SATURDAY NIGHT...South winds 10 to 20 knots veering west late. A chance of showers. A slight chance of thunderstorms after midnight. Waves building to 2 to 4 feet. .SUNDAY...Northwest winds 15 to 25 knots increasing to 20 to 30 knots by mid afternoon. Showers likely through early afternoon. A slight chance of thunderstorms. A chance of showers by mid afternoon. Waves building to 4 to 7 feet occasionally to 9 feet, then subsiding to 3 to 6 feet occasionally to 8 feet. .SUNDAY NIGHT...Northwest winds 15 to 25 knots veering north after midnight. A chance of showers. Waves subsiding to 2 to 4 feet. .MONDAY...North winds 10 to 20 knots. Waves subsiding to calm to 2 feet. .MONDAY NIGHT...North winds 10 to 20 knots veering east after midnight. Waves calm to 2 feet. .TUESDAY...Northeast winds 10 to 20 knots backing north. Waves calm to 2 feet. .WEDNESDAY...Northwest winds 10 to 20 knots veering north. Waves calm to 2 feet. $$ LSZ261-211000- MAFOR 2103/ Superior West 11510 13500 11300 11310 11510 11720. A chance of showers and thunderstorms Saturday afternoon and Saturday evening. Waves 2 feet or less. Superior North Central 11510 11600 11500 12400 12310 11420. A chance of showers Saturday evening. Waves 2 to 4 feet overnight. Waves 1 to 3 feet Saturday and Saturday evening. Superior South Central 14500 11400 11310 11320 11420. A chance of showers Saturday evening. Waves 2 feet or less overnight and Saturday. Waves 2 to 3 feet Saturday evening. Superior East 12500 11504 11400 11500 11400 12310. A chance of showers Saturday evening. Waves 2 feet or less. $$ LC Experimental modernized open lake forecast is available online at weather.gov/mqt/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes