464
FZUS63 KMKX 181954
GLFLM

OPEN LAKE FORECAST for Lake Michigan
National Weather Service Milwaukee/Sullivan WI
254 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...

Low pressure around 29.6 inches moving east across the Hudson Bay
region today will drag a cold front southward across Lake
Michigan this afternoon and evening. Expect prevailing west to
southwesterly winds ahead of the cold front along with a few
thunderstorms through this evening. Then the cold front will push
down the Lake by Wednesday bringing a north-northwesterly winds
shift. 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 is progged to bring another cold
front across the Upper Great Lakes region.

LMZ261-362-364-366-563-565-567-868-190315-
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-
254 PM CDT Tue Aug 18 2026

SHEBOYGAN WI TO PENTWATER MI NORTH...

.TONIGHT...West winds 10 to 20 kt becoming north 10 to 15 kt.
Chance of showers and thunderstorms this evening. Waves 2 to
4 ft.
.WEDNESDAY...Northwest winds 5 to 10 kt increasing to 10 to 15 kt
late in the morning, then increasing to 10 to 20 kt early in the
afternoon becoming southwest 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 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.
.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.

$$

LMZ080-669-671-673-675-777-779-870-872-874-876-878-190315-
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-
254 PM CDT Tue Aug 18 2026

SHEBOYGAN WI TO PENTWATER MI SOUTH...

.TONIGHT...Southwest winds 10 to 20 kt veering to northwest 10 to
15 kt. Chance of showers and thunderstorms 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.
.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.

$$

LMZ761-190315-
MAFOR 1822/
MICHIGAN NORTH 11520 11710 12810 11700 12710 11610. A chance of
showers and thunderstorms this evening. Waves 1 to 3 feet
tonight. Waves 2 feet or less Wednesday.

MICHIGAN SOUTH 12520 11620 11710 11810 12800 11810. A chance of
showers and thunderstorms this evening. Waves 1 to 3 feet
building to 2 to 4 feet, then subsiding to 1 to 3 feet tonight.
Waves 2 feet or less Wednesday.

$$


Patterson

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

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