739
FZUS63 KMKX 202059
GLFLM
OPEN LAKE FORECAST FOR LAKE MICHIGAN
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
359 PM 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
HIGH PRESSURE AROUND 30.0 INCHES CONTINUES TO TRACK THROUGH THE
WESTERN GREAT LAKES REGION THIS AFTERNOON. 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.
LMZ261-362-364-366-563-565-567-868-210315-
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-
359 PM CDT THU AUG 20 2026
SHEBOYGAN WI TO PENTWATER MI NORTH...
TONIGHT
SOUTH WINDS 10 TO 20 KT. WAVES 1 TO 3 FT.
FRIDAY
SOUTH WINDS 10 TO 20 KT INCREASING TO 30 KT. CHANCE OF
SHOWERS IN THE MORNING, THEN CHANCE OF SHOWERS AND SLIGHT CHANCE
OF THUNDERSTORMS IN THE AFTERNOON. WAVES 3 TO 5 FT BUILDING TO
4 TO 6 FT OCCASIONALLY TO 8 FT.
FRIDAY NIGHT
SOUTH WINDS 10 TO 20 KT VEERING TO NORTHWEST.
CHANCE OF SHOWERS. WAVES 4 TO 6 FT OCCASIONALLY TO 8 FT SUBSIDING
TO 2 TO 4 FT.
SATURDAY
NORTHWEST WINDS 15 TO 25 KT INCREASING TO 30 KT.
CHANCE OF SHOWERS IN THE AFTERNOON. WAVES 2 TO 4 FT.
SATURDAY NIGHT
NORTH WINDS TO 30 KT DIMINISHING TO 15 TO
25 KT. WAVES 4 TO 6 FT OCCASIONALLY TO 8 FT.
SUNDAY
NORTH WINDS TO 30 KT. WAVES 4 TO 6 FT OCCASIONALLY TO
8 FT.
SUNDAY NIGHT
NORTH GALES TO 35 KT DIMINISHING TO 10 TO 20 KT.
WAVES 3 TO 5 FT SUBSIDING TO 2 TO 4 FT.
MONDAY
NORTHWEST WINDS 10 TO 20 KT INCREASING TO 15 TO 25 KT.
WAVES 1 TO 3 FT.
TUESDAY
SOUTHWEST WINDS 10 TO 20 KT BECOMING SOUTH TO 30 KT.
WAVES 1 TO 3 FT BUILDING TO 3 TO 5 FT.
LMZ080-669-671-673-675-777-779-870-872-874-876-878-210315-
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-
359 PM CDT THU AUG 20 2026
SHEBOYGAN WI TO PENTWATER MI SOUTH...
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 INCREASING TO 15 TO 25 KT.
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
WAVES 3 TO 5 FT.
FRIDAY NIGHT
SOUTH WINDS 10 TO 20 KT VEERING TO WEST. CHANCE
OF SHOWERS IN THE EVENING, THEN CHANCE OF SHOWERS AND
THUNDERSTORMS OVERNIGHT. WAVES 3 TO 5 FT SUBSIDING TO 1 TO 3 FT.
SATURDAY
NORTHWEST WINDS 15 TO 25 KT BECOMING NORTH. WAVES
4 TO 6 FT OCCASIONALLY TO 8 FT.
SATURDAY NIGHT
NORTH WINDS 15 TO 25 KT. WAVES 4 TO 6 FT
OCCASIONALLY TO 8 FT BUILDING TO 4 TO 7 FT OCCASIONALLY TO 9 FT.
SUNDAY
NORTH WINDS TO 30 KT. WAVES 5 TO 8 FT OCCASIONALLY TO
10 FT.
SUNDAY NIGHT
NORTH WINDS 15 TO 25 KT DIMINISHING TO 10 TO
15 KT. WAVES 4 TO 6 FT OCCASIONALLY TO 8 FT SUBSIDING TO 2 TO
4 FT.
MONDAY
NORTHWEST WINDS 10 TO 20 KT BECOMING NORTH. WAVES 1 TO
3 FT.
TUESDAY
SOUTH WINDS 10 TO 20 KT INCREASING TO 15 TO 25 KT.
WAVES 1 TO 3 FT BUILDING TO 3 TO 5 FT.
LMZ761-210315-
MAFOR 2022/
MICHIGAN NORTH 12410 14420 12430. A CHANCE OF SHOWERS FRIDAY.
WAVES 2 FEET OR LESS TONIGHT. WAVES 1 TO 3 FEET BUILDING TO 3 TO
5 FEET FRIDAY.
MICHIGAN SOUTH 11810 11110 11310 11410 11420 11520 12430. WAVES 2
FEET OR LESS TONIGHT. WAVES 1 TO 3 FEET BUILDING TO 3 TO 5 FEET
FRIDAY.
CMILLER
EXPERIMENTAL MODERNIZED OPEN LAKE FORECAST IS AVAILABLE ONLINE AT
WEATHER.GOV/MKX/GLFTABLE
GRAPHICAL MARINE FORECASTS ARE AVAILABLE ONLINE AT:
WEATHER.GOV/GREATLAKES
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