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  
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