FZUS63 KMKX 222007 GLFLM OPEN LAKE FORECAST for Lake Michigan National Weather Service Milwaukee/Sullivan WI 307 PM CDT Sat Aug 22 2026 FOR WATERS BEYOND FIVE NAUTICAL MILES OF SHORE ON Lake Michigan. Waves are provided as a range of significant wave heights, which is the average of the highest 1/3 of the wave, along with the average height of the highest 10% of the waves which will occasionally be encountered. .SYNOPSIS... 29.8 inch low pressure is centered over the southern Hudson Bay this afternoon, resulting in generally northwest winds across the open waters of Lake Michigan. These winds will continue into this evening as a weak cold front moves across the lake and 30.2 inch high pressure builds into the northern Great Plains. Isolated showers and thunderstorms are possible along the passing front this afternoon & evening. Severe weather potential is low in this activity, though an isolated stronger storm with gusty winds or a waterspout can't be entirely ruled out. Will be watching radar trends for any potential marine weather statements or special marine warnings through this evening. Northwest winds will continue through the day Sunday, ultimately weakening by Sunday night as the aforementioned area of high pressure approaches Lake Michigan. Light and variable winds will continue Monday with high pressure lingering in the vicinity. The high will shift east into Ontario by Tuesday, resulting in a south-southwest wind shift across the waters. 29.7 inch low pressure will approach from the northern Great Plains Tuesday night into Wednesday, reinforcing the south- southwesterly wind pattern. The low will cross Lake Michigan during the second half of the day Wednesday, bringing a northwest wind shift. Gales are not expected as this occurs. Showers and thunderstorms will accompany the approaching/passing surface low Tuesday night into Wednesday afternoon. It remains too early to tell if any of these storms could be severe, with trends being monitored into the beginning of next week. LMZ261-362-364-366-563-565-567-868-230315- Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM offshore to Mid Lake- Lake Michigan South of a line from Seul Choix Point to the Mackinac Bridge and north of a line from Charlevoix MI to South Fox Island 5 NM offshore- Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to Mid Lake- Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to Mid Lake- Lake Michigan from Rock Island Passage to Sturgeon Bay WI- Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to Mid Lake- Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to Mid Lake- Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid Lake- 307 PM CDT Sat Aug 22 2026 SHEBOYGAN WI TO PENTWATER MI NORTH... .TONIGHT...North winds to 30 kt becoming northwest 15 to 25 kt. Slight chance of showers this evening. Slight chance of waterspouts. Waves 4 to 6 ft occasionally to 8 ft. .SUNDAY...Northwest winds 15 to 25 kt becoming north to 30 kt. Waves 4 to 6 ft occasionally to 8 ft. .SUNDAY NIGHT...North winds to 30 kt becoming northwest 15 to 25 kt. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft. .MONDAY...Northwest winds 15 to 25 kt becoming north. Waves 2 to 4 ft. .MONDAY NIGHT...North winds 10 to 20 kt backing to west 5 to 10 kt overnight. Waves 1 to 3 ft subsiding to 1 to 2 ft. .TUESDAY...Southwest winds 10 to 15 kt increasing to 15 to 25 kt in the afternoon. Waves 1 ft or less building to 1 to 3 ft. .TUESDAY NIGHT...South winds 15 to 25 kt diminishing to 10 to 20 kt. Chance of showers. Waves 2 to 4 ft. .WEDNESDAY...Southwest winds 15 to 25 kt becoming south to 30 kt. Chance of showers. Waves 4 to 6 ft occasionally to 8 ft. .THURSDAY...Northwest winds 10 to 20 kt becoming north 15to 25 kt. Waves 1 to 3 ft. $$ LMZ080-669-671-673-675-777-779-870-872-874-876-878-230315- Lake Michigan from Michigan City IN to St. Joseph MI 5 NM offshore to Mid Lake- Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore to Mid Lake- Lake Michigan from Port Washington to North Point Light WI 5 NM offshore to Mid Lake- Lake Michigan from North Point Light to Wind Point WI 5 NM offshore to Mid Lake- Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM offshore to Mid Lake- Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM offshore to Mid Lake- Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM offshore to Mid Lake- Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid Lake- Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to Mid Lake- Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid Lake- Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid Lake- Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to Mid Lake- 307 PM CDT Sat Aug 22 2026 SHEBOYGAN WI TO PENTWATER MI SOUTH... .TONIGHT...North winds 15 to 25 kt becoming northwest 10 to 20 kt. Slight chance of waterspouts. Slight chance of showers and thunderstorms this evening, then slight chance of showers overnight. Waves 3 to 5 ft. .SUNDAY...Northwest winds 15 to 25 kt becoming north to 30 kt. Slight chance of waterspouts in the morning. Waves 4 to 7 ft occasionally to 9 ft. .SUNDAY NIGHT...North winds 10 to 20 kt diminishing to 10 to 15 kt. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft. .MONDAY...Northwest winds 10 to 20 kt becoming north. Waves 2 to 4 ft. .MONDAY NIGHT...Northeast winds 10 to 15 kt veering to south. Waves 1 to 3 ft. .TUESDAY...South winds 10 to 15 kt increasing to 15 to 25 kt in the afternoon. Waves 1 to 2 ft building to 1 to 3 ft. .TUESDAY NIGHT...South winds 15 to 25 kt becoming southwest 10 to 20 kt. Waves 2 to 4 ft. .WEDNESDAY...Southwest winds 15 to 25 kt increasing to 30 kt. Chance of showers. Waves 4 to 6 ft occasionally to 8 ft. .THURSDAY...Northwest winds 10 to 20 kt becoming north. Waves 2 to 4 ft. $$ LMZ761-230315- MAFOR 2222/ MICHIGAN NORTH 12840 11830 13730 12840. A chance of showers and thunderstorms early this evening. Waves 2 to 4 feet building to 3 to 5 feet tonight. Waves 3 to 6 feet Sunday. MICHIGAN SOUTH 11830 13820 13730 11830. A chance of showers and thunderstorms early this evening. Waves 2 to 4 feet subsiding to 1 to 3 feet, then building to 3 to 5 feet tonight. Waves 3 to 6 feet Sunday. $$ Sheppard Experimental modernized open lake forecast is available online at weather.gov/mkx/glftable Graphical marine forecasts are available online at: weather.gov/greatlakes