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  
 
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