495
FZUS63 KMKX 190203
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
903 PM CDT Tue Aug 18 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...

Thundestorms will be possible over Lake Michigan until a cold
front exits from north to south by Wednesday morning. North-
northwesterly winds will weaken and become more variable as high
pressure around 30.0 inches tracks through the western Great Lakes
through Thursday. Southwesterly winds and thunderstorm chances
return later Friday as another system drags another cold front
across the Upper Great Lakes region.

LMZ261-362-364-366-563-565-567-868-190915-
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-
903 PM CDT Tue Aug 18 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

.REST OF TONIGHT...North winds 10 to 15 kt. Chance of showers and
thunderstorms late this evening. Waves 2 to 4 ft subsiding to
1 to 3 ft.
.WEDNESDAY...Northwest winds 5 to 10 kt increasing to 10 to 15 kt
late in the morning, then becoming west early in the afternoon and
becoming southwest 10 to 20 kt late. Waves 1 to 2 ft.
.WEDNESDAY NIGHT...South winds 10 to 15 kt diminishing to 5 to
10 kt. Waves 1 to 2 ft.
.THURSDAY...Southwest winds 10 to 15 kt increasing to 10 to
20 kt. Waves 1 ft or less building to 1 to 3 ft.
.THURSDAY NIGHT...South winds 10 to 20 kt increasing to 15 to
25 kt. Showers likely overnight. Waves 1 to 3 ft.
.FRIDAY...Southwest winds to 30 kt. Chance of showers in the
morning, then chance of showers and thunderstorms in the
afternoon. Waves 2 to 4 ft building to 3 to 5 ft.
.FRIDAY NIGHT...Southwest winds 15 to 25 kt veering to northwest
10 to 20 kt. Chance of showers. Waves 3 to 5 ft subsiding to 2 to
4 ft.
.SATURDAY...Northwest winds 15 to 25 kt becoming north to 30 kt.
Waves 2 to 4 ft.
.SUNDAY...North winds to 30 kt. Waves 4 to 6 ft occasionally to
8 ft.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-190915-
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-
903 PM CDT Tue Aug 18 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.REST OF TONIGHT...West winds 10 to 20 kt veering to northwest
10 to 15 kt. Chance of showers and thunderstorms late this
evening, then slight chance of showers and thunderstorms
overnight. Waves 2 to 4 ft.
.WEDNESDAY...North winds 10 to 15 kt. Waves 1 to 3 ft.
.WEDNESDAY NIGHT...Northeast winds 10 to 15 kt becoming southeast
5 to 10 kt. Waves 1 to 2 ft.
.THURSDAY...Southeast winds 5 to 10 kt becoming south 10 to 20 kt
in the afternoon. Waves 1 ft or less building to 1 to 3 ft.
.THURSDAY NIGHT...South winds 10 to 20 kt becoming southwest.
Waves 1 to 3 ft.
.FRIDAY...Southwest winds 10 to 20 kt increasing to 30 kt in the
afternoon. Chance of showers. Waves 2 to 4 ft building to 3 to
5 ft.
.FRIDAY NIGHT...Southwest winds 15 to 25 kt becoming west 10 to
20 kt. Chance of showers. Waves 3 to 5 ft.
.SATURDAY...Northwest winds 15 to 25 kt becoming north to 30 kt.
Waves 3 to 5 ft.
.SUNDAY...North winds to 30 kt. Waves 4 to 7 ft occasionally to
9 ft.

$$

LMZ761-190915-
MAFOR 1904/
MICHIGAN NORTH 12810 12700 11710 11610 11510 11400. Waves 1 to 3
feet overnight. Waves 2 feet or less Wednesday and Wednesday
evening.

MICHIGAN SOUTH 11610 11710 11810 12800 11810 11110 11200. A
chance of showers and thunderstorms late this evening. Waves 1 to
3 feet overnight and Wednesday. Waves 2 feet or less Wednesday
evening.

$$


Cronce

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

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