Great Lakes Forecast
Issued by NWS
Issued by NWS
259 FZUS63 KMQT 182006 GLFLS Open Lake Forecast for Lake Superior National Weather Service Marquette MI 406 PM EDT Wed Sep 18 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 30.1 inch high pressure ridge extending from the Saint Lawrence Valley back into the Great Lakes region tonight reorients from Quebec into the Great Lakes region Thursday. Meanwhile, a 29.3 inch low pressure over the east half of Montana tonight spins into southern Manitoba Thursday with its associated 29.6 inch trough sweeping east into western Minnesota. As the low continues to track northeast to Hudson Bay Friday, the associated trough will fill to 29.8 inches as it approaches western Lake Superior. This trough will then dissipate, allowing weak 29.9 inch ridging to anchor over the Upper Great Lakes Saturday morning. A new low pressure of 29.7 inches over southern Manitoba Saturday morning will then track into far northern Ontario Saturday night with its associated 29.9 inch trough sweeping across Lake Superior. In its wake, 30.2 inch high pressure build into Ontario Sunday. A 29.7 in low moves into the Upper Great Lakes on Sunday afternoon deepening to 29.6 inches over Lake Superior on early Monday morning. High pressure at 30.0 inches over the northern Plains clips western Lake Superior by Monday afternoon. LSZ162-190415- Lake Superior west of a line from Saxon Harbor WI to Grand Portage MN beyond 5NM- 406 PM EDT Wed Sep 18 2024 /306 PM CDT Wed Sep 18 2024/ .LATE THIS AFTERNOON...East winds 10 to 20 knots. Waves calm to 2 feet. .TONIGHT...Southeast winds 10 to 20 knots becoming south 5 to 15 knots after midnight, then becoming southeast 10 to 20 knots late. A slight chance of showers and thunderstorms after midnight. Waves calm to 2 feet. .THURSDAY...East winds 10 to 20 knots veering southeast in the afternoon, then backing east late. A chance of showers and thunderstorms. Waves calm to 2 feet. .THURSDAY NIGHT...South winds 10 to 20 knots veering southwest late. A chance of showers and thunderstorms. Waves building to 1 to 3 feet. .FRIDAY...Southwest winds 10 to 20 knots. Waves subsiding to calm to 2 feet. .FRIDAY NIGHT...West winds 5 to 15 knots. Waves calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots becoming south 10 to 20 knots by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...North winds 10 to 20 knots. A chance of showers. Waves calm to 2 feet. .SUNDAY...Northwest winds 10 to 20 knots veering north. A chance of showers. Waves calm to 2 feet. .MONDAY...Northeast winds 10 to 20 knots veering east. A chance of showers. Waves building to 2 to 4 feet, then subsiding to 1 to 3 feet. $$ LSZ263-190415- Lake Superior from Saxon Harbor WI to Upper Entrance to Portage Canal MI 5NM off shore to the US/Canadian border including Isle Royale National Park- 406 PM EDT Wed Sep 18 2024 .LATE THIS AFTERNOON...Southeast winds 5 to 15 knots. Waves calm to 2 feet. .TONIGHT...Southeast winds 5 to 15 knots veering south after midnight. Waves calm to 2 feet. .THURSDAY...South winds 10 to 20 knots backing southeast in the afternoon. A slight chance of showers. A slight chance of thunderstorms by mid afternoon. Waves building to 1 to 3 feet. .THURSDAY NIGHT...South winds 10 to 20 knots. A chance of showers and thunderstorms. Waves building to 2 to 4 feet, then subsiding to 1 to 3 feet. .FRIDAY...Southwest winds 10 to 20 knots. A slight chance of showers and thunderstorms through early afternoon. Waves subsiding to calm to 2 feet. .FRIDAY NIGHT...Southwest winds 5 to 15 knots becoming west less than 10 knots after midnight. Waves calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots backing south by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...South winds 5 to 15 knots backing north after midnight. A chance of showers. Waves calm to 2 feet. .SUNDAY...Northwest winds 10 to 20 knots veering north. A chance of showers. Waves calm to 2 feet. .MONDAY...Northeast winds 10 to 20 knots veering east. A chance of showers. Waves building to 1 to 3 feet. $$ LSZ264-190415- Lake Superior from Upper Entrance to Portage Canal to Manitou Island MI 5NM off shore to the US/Canadian Border- 406 PM EDT Wed Sep 18 2024 .LATE THIS AFTERNOON...Southeast winds 5 to 15 knots. Waves 1 to 3 feet. .TONIGHT...Southeast winds 10 to 20 knots veering south after midnight, then diminishing to 5 to 15 knots late. Waves 1 to 3 feet. .THURSDAY...South winds 10 to 20 knots backing southeast in the afternoon. A slight chance of showers and thunderstorms by mid afternoon. Waves building to 3 to 5 feet occasionally to 7 feet. .THURSDAY NIGHT...Southeast winds 15 to 25 knots veering south after midnight, then diminishing to 10 to 20 knots late. A chance of showers through midnight. A chance of thunderstorms. Showers likely after midnight. Waves building to 3 to 6 feet occasionally to 8 feet, then subsiding to 2 to 4 feet. .FRIDAY...South winds 5 to 15 knots. A chance of showers and a slight chance of thunderstorms. Waves subsiding to calm to 2 feet. .FRIDAY NIGHT...South winds 5 to 15 knots becoming west less than 10 knots after midnight. Waves calm to 2 feet. .SATURDAY...West winds 5 to 15 knots backing south by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...South winds 5 to 15 knots backing north after midnight. Waves calm to 2 feet. .SUNDAY...West winds 10 to 20 knots becoming north 5 to 15 knots. A chance of showers. Waves calm to 2 feet. .MONDAY...Northeast winds 10 to 20 knots veering east. A chance of showers. Waves building to 1 to 3 feet. $$ LSZ265-190415- Lake Superior West of Line from Manitou Island to Marquette MI Beyond 5NM from shore- 406 PM EDT Wed Sep 18 2024 .LATE THIS AFTERNOON...Southeast winds 10 to 20 knots. Waves 1 to 3 feet. .TONIGHT...Southeast winds 10 to 20 knots veering south after midnight. Waves subsiding to calm to 2 feet. .THURSDAY...Southeast winds 10 to 20 knots increasing to 15 to 25 knots late. Waves building to 2 to 4 feet. .THURSDAY NIGHT...Southeast winds 15 to 25 knots veering south after midnight, then diminishing to 10 to 20 knots late. A chance of showers through midnight. A chance of thunderstorms. Showers likely after midnight. Waves building to 3 to 5 feet occasionally to 7 feet, then subsiding to 1 to 3 feet. .FRIDAY...South winds 10 to 20 knots backing southeast by mid afternoon. Showers likely through early afternoon. A chance of thunderstorms. A chance of showers by mid afternoon. Waves subsiding to calm to 2 feet. .FRIDAY NIGHT...South winds 5 to 15 knots veering southwest after midnight. Waves calm to 2 feet. .SATURDAY...West winds 5 to 15 knots becoming east 10 to 20 knots by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...Southeast winds 5 to 15 knots becoming west 10 to 20 knots after midnight. Waves calm to 2 feet. .SUNDAY...Northwest winds 10 to 20 knots veering north. A chance of showers. Waves calm to 2 feet. .MONDAY...Northeast winds 10 to 20 knots veering east. A chance of showers. Waves calm to 2 feet. $$ LSZ266-190415- 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- 406 PM EDT Wed Sep 18 2024 .LATE THIS AFTERNOON...Southeast winds 10 to 20 knots. Waves 1 to 3 feet. .TONIGHT...South winds 10 to 20 knots. Waves 1 to 3 feet. .THURSDAY...South winds 10 to 20 knots backing southeast in the afternoon. Waves building to 2 to 4 feet. .THURSDAY NIGHT...South winds 15 to 25 knots. A chance of showers and thunderstorms. Waves building to 3 to 5 feet occasionally to 7 feet, then subsiding to 2 to 4 feet. .FRIDAY...South winds 10 to 20 knots. Showers likely through early afternoon. A chance of thunderstorms. A chance of showers by mid afternoon. Waves subsiding to calm to 2 feet. .FRIDAY NIGHT...South winds 5 to 15 knots. A chance of showers and thunderstorms. Waves calm to 2 feet. .SATURDAY...Southwest winds 5 to 15 knots backing east by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...Southeast winds 5 to 15 knots veering south after midnight. Waves calm to 2 feet. .SUNDAY...Northwest winds 10 to 20 knots veering north. A chance of showers. Waves calm to 2 feet. .MONDAY...Northeast winds 10 to 20 knots veering east. A chance of showers. Waves building to 1 to 3 feet, then subsiding to calm to 2 feet. $$ LSZ267-190415- Lake Superior from Grand Marais MI to Whitefish Point MI 5NM off shore to the US/Canadian border- 406 PM EDT Wed Sep 18 2024 .LATE THIS AFTERNOON...Southeast winds 10 to 20 knots. Waves calm to 2 feet. .TONIGHT...South winds 10 to 20 knots. Waves calm to 2 feet. .THURSDAY...Southeast winds 10 to 20 knots. Waves calm to 2 feet. .THURSDAY NIGHT...South winds 10 to 20 knots backing southeast after midnight. A slight chance of showers and thunderstorms after midnight. Waves building to 1 to 3 feet. .FRIDAY...South winds 10 to 20 knots backing southeast by mid afternoon. Showers likely and a chance of thunderstorms. Waves subsiding to calm to 2 feet. .FRIDAY NIGHT...Southeast winds 10 to 20 knots becoming south 5 to 15 knots after midnight. Showers likely through midnight. A chance of thunderstorms. A chance of showers after midnight. Waves calm to 2 feet. .SATURDAY...South winds 5 to 15 knots backing southeast by mid afternoon. Waves calm to 2 feet. .SATURDAY NIGHT...Southeast winds 5 to 15 knots becoming south 10 to 20 knots after midnight. Waves calm to 2 feet. .SUNDAY...South winds 10 to 20 knots backing northeast. A chance of showers. Waves calm to 2 feet. .MONDAY...Northeast winds 10 to 20 knots veering east. A chance of showers. Waves building to 1 to 3 feet, then subsiding to calm to 2 feet. $$ LSZ261-190415- MAFOR 1821/ Superior West 12310 11410 11420 11310 12320 11310. Waves 1 to 2 feet. Superior North Central 12320 12420 11410 11420 12320. Waves 1 to 4 feet. Superior South Central 12320 14410 12320. Waves 1 to 3 feet. Superior East 12310 13410 11300 12310. Waves 1 to 2 feet. $$ JSS Experimental modernized open lake forecast is available online at weather.gov/mqt/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes