317
FZUS63 KMKX 201351
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
851 AM CDT Thu Aug 20 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...

Light to modest winds are expected today, as high pressure around
30.0 inches tracks through the western Great Lakes region. As the
high pressure exits to the southeast later tonight, south to
southwest winds will develop. Theses winds will increase for
Friday, along with shower and thunderstorm chances, as low
pressure around 29.8 inches moves across the region and drags a
cold front through Lake Michigan. Gusty winds will then shift to
the northwest later Friday night into Saturday after the front
exits. Another high pressure system around 30.2 inches is expected
to build into the region later this weekend, which may maintain
gusty northerly winds as it moves in.

LMZ261-362-364-366-563-565-567-868-202115-
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-
851 AM CDT Thu Aug 20 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

.REST OF TODAY...South winds 5 to 10 kt becoming southwest. Waves
1 to 2 ft.
.TONIGHT...South winds 10 to 15 kt increasing to 10 to 20 kt.
Slight chance of showers overnight. Waves 1 to 3 ft.
.FRIDAY...South winds 10 to 20 kt increasing to 15 to 25 kt.
Chance of showers. Waves 3 to 5 ft.
.FRIDAY NIGHT...Southwest winds 10 to 20 kt veering to northwest.
Chance of showers. Waves 3 to 5 ft subsiding to 2 to 4 ft.
.SATURDAY...Northwest winds 10 to 20 kt increasing to 30 kt in
the afternoon. Waves 2 to 4 ft.
.SATURDAY NIGHT...North winds to 30 kt diminishing to 15 to
25 kt. Waves 3 to 5 ft.
.SUNDAY...Northwest winds to 30 kt becoming north gales to 35 kt.
Waves 4 to 6 ft occasionally to 8 ft.
.MONDAY...Northwest winds 10 to 20 kt backing to southwest. Waves
1 to 2 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-202115-
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-
851 AM CDT Thu Aug 20 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.REST OF TODAY...Northeast winds 10 to 15 kt becoming north.
Waves 1 to 2 ft.
.TONIGHT...North winds 10 to 15 kt backing to south 10 to 20 kt.
Waves 1 to 2 ft.
.FRIDAY...South winds 10 to 20 kt. Waves 3 to 5 ft.
.FRIDAY NIGHT...Southwest winds 10 to 20 kt becoming west. Chance
of showers. Waves 3 to 5 ft subsiding to 1 to 3 ft.
.SATURDAY...Northwest winds 10 to 20 kt increasing to 15 to
25 kt. Waves 4 to 6 ft occasionally to 8 ft.
.SATURDAY NIGHT...North winds 10 to 20 kt. Waves 3 to 5 ft.
.SUNDAY...North winds 15 to 25 kt increasing to 30 kt. Waves 4 to
7 ft occasionally to 9 ft.
.MONDAY...North winds 10 to 15 kt becoming northeast 10 to 20 kt.
Waves 1 to 2 ft.

$$

LMZ761-202115-
MAFOR 2016/
MICHIGAN NORTH 12510 12410 14420. A chance of showers Friday
morning. Waves 2 feet or less this afternoon. Waves 1 to 3 feet
tonight. Waves 1 to 3 feet building to 2 to 4 feet Friday
morning.

MICHIGAN SOUTH 11110 12810 11110 11310 11410 11420 11520. Waves 2
feet or less this afternoon and tonight. Waves 1 to 3 feet Friday
morning.

$$
Wood

Experimental modernized open lake forecast is available online at
weather.gov/mkx/glftable

Graphical marine forecasts are available online at:
weather.gov/greatlakes