345
FZUS63 KMKX 200159
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
859 PM CDT Tue Aug 19 2025

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...

High pressure around 30.1 inches will remain over the Great Lakes
through Friday. A breezy period of northerly winds will persist
through Wednesday as the high moves in behind a retreating low
pressure around 29.8 inches. Light to moderate north winds are
then expected Wednesday night into early Friday, before winds turn
southerly Friday morning head of an approaching cold front.

LMZ261-362-364-366-563-565-567-868-200915-
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-
859 PM CDT Tue Aug 19 2025

SHEBOYGAN WI TO PENTWATER MI NORTH...

.REST OF TONIGHT...Northeast winds 10 to 20 kt diminishing to
10 to 15 kt. Waves 1 to 3 ft.
.WEDNESDAY...Northeast winds 10 to 20 kt becoming north 15 to
25 kt. Waves 1 to 3 ft building to 3 to 5 ft.
.WEDNESDAY NIGHT...North winds 15 to 25 kt becoming northeast
10 to 15 kt. Waves 3 to 5 ft subsiding to 2 to 4 ft.
.THURSDAY...Northeast winds 5 to 10 kt becoming north 10 to 20 kt
in the afternoon. Waves 1 to 2 ft.
.THURSDAY NIGHT...East winds 10 to 15 kt veering to south. Waves
1 to 2 ft.
.FRIDAY...Southwest winds 10 to 20 kt. Waves 1 to 3 ft.
.FRIDAY NIGHT...Southwest winds 10 to 20 kt becoming west. Chance
of showers and thunderstorms. Waves 1 to 3 ft.
.SATURDAY...West winds 10 to 20 kt increasing to 15 to 25 kt.
Waves 1 to 3 ft.
.SUNDAY...Northwest winds 15 to 25 kt. Waves 2 to 4 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-200915-
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-
859 PM CDT Tue Aug 19 2025

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.REST OF TONIGHT...North winds 10 to 20 kt. Slight chance of
sprinkles. Waves 3 to 5 ft.
.WEDNESDAY...Northeast winds 10 to 20 kt becoming north 15 to
25 kt. Waves 3 to 5 ft.
.WEDNESDAY NIGHT...North winds 15 to 25 kt becoming east 10 to
20 kt. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to
5 ft.
.THURSDAY...Northeast winds 10 to 15 kt becoming north 10 to
20 kt. Waves 2 to 4 ft subsiding to 1 to 3 ft.
.THURSDAY NIGHT...North winds 10 to 20 kt becoming east 5 to
10 kt overnight. Waves 1 to 3 ft.
.FRIDAY...South winds 5 to 10 kt becoming southwest. Waves 1 to
2 ft.
.FRIDAY NIGHT...Southwest winds 10 to 15 kt becoming west 10 to
20 kt. Waves 1 to 2 ft building to 1 to 3 ft.
.SATURDAY...Northwest winds 10 to 20 kt becoming west. Waves 2 to
4 ft.
.SUNDAY...Northwest winds 10 to 20 kt increasing to 15 to 25 kt.
Waves 4 to 6 ft occasionally to 8 ft.

$$

LMZ761-200915-
MAFOR 2004/
MICHIGAN NORTH 12110 12120 11820 12830 11120. Waves 2 feet or
less overnight. Waves 1 to 3 feet building to 2 to 4 feet
Wednesday. Waves 2 to 4 feet Wednesday evening.

MICHIGAN SOUTH 12820 13120 12830 11120. Waves 2 to 4 feet
subsiding to 1 to 3 feet overnight. Waves 1 to 3 feet building to
2 to 4 feet Wednesday. Waves 3 to 6 feet Wednesday evening.

$$


Patterson

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

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