247  
FZUS63 KDTX 211315  
GLFSC  
 
LAKE ST CLAIR FORECAST  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
915 AM EDT TUE OCT 21 2025  
 
WAVES ARE THE SIGNIFICANT WAVE HEIGHT - THE AVERAGE OF THE HIGHEST  
1/3 OF THE WAVE SPECTRUM. OCCASIONAL WAVE HEIGHT IS THE AVERAGE OF  
THE HIGHEST 1/10 OF THE WAVE SPECTRUM.  
   
SYNOPSIS  
LOW PRESSURE OF 29.40 INCHES TRACKS OVER LAKE SUPERIOR  
TODAY, AND THROUGH NORTHERN LAKE HURON ON WEDNESDAY. MUCH COLDER  
AIR WILL FILTER INTO THE GREAT LAKES REGION LEADING TO UNSETTLED  
WEATHER AND HAZARDOUS CONDITIONS FOR SMALL BOATS.  
 
LCZ460-212200-  
LAKE ST CLAIR-  
915 AM EDT TUE OCT 21 2025  
   
..SMALL CRAFT ADVISORY IN EFFECT THROUGH LATE WEDNESDAY NIGHT  
 
   
REST OF TODAY  
SOUTHWEST WINDS 15 TO 20 KNOTS. GUSTS 25 KNOTS.  
PARTLY SUNNY. LIGHT SHOWERS LIKELY LATE IN THE AFTERNOON. WAVES 1  
TO 3 FEET.   
TONIGHT  
SOUTHWEST WINDS 20 TO 25 KNOTS INCREASING TO 30 KNOTS  
EARLY IN THE MORNING. PARTLY CLOUDY UNTIL EARLY MORNING BECOMING  
MOSTLY CLOUDY. LIGHT SHOWERS LIKELY UNTIL EARLY MORNING...THEN A  
CHANCE OF LIGHT SHOWERS EARLY IN THE MORNING. WAVES 1 TO 3 FEET  
BUILDING TO 2 TO 4 FEET IN THE LATE EVENING AND OVERNIGHT.   
WEDNESDAY  
SOUTHWEST WINDS TO 30 KNOTS DIMINISHING TO 20 TO 25  
KNOTS WITH GUSTS TO 30 KNOTS IN THE LATE MORNING AND AFTERNOON.  
LIGHT SHOWERS. WAVES 2 TO 4 FEET.   
WEDNESDAY NIGHT  
WEST WINDS 20 TO 25 KNOTS. GUSTS TO 30 KNOTS  
EARLY IN THE EVENING. LIGHT SHOWERS EARLY IN THE EVENING...THEN  
LIGHT SHOWERS LIKELY IN THE LATE EVENING AND EARLY MORNING. A CHANCE  
OF LIGHT SHOWERS AFTER MIDNIGHT. WAVES 2 TO 4 FEET.   
THURSDAY  
WEST WINDS 15 TO 20 KNOTS. MOSTLY CLOUDY WITH A CHANCE  
OF LIGHT SHOWERS IN THE MORNING...THEN PARTLY CLOUDY WITH LIGHT  
SHOWERS LIKELY IN THE AFTERNOON AND EVENING. WAVES 1 TO 3 FEET.   
FRIDAY  
NORTHWEST WINDS 15 TO 20 KNOTS. MOSTLY CLEAR. WAVES 2 FEET  
OR LESS.   
SATURDAY  
LIGHT AND VARIABLE WINDS. MOSTLY CLEAR. WAVES 2 FEET OR  
LESS.  
 
 
 
TF  
 
EXPERIMENTAL MODERNIZED OPEN LAKE FORECAST IS AVAILABLE ONLINE AT  
WEATHER.GOV/DTX/GLFTABLESC  
 
GRAPHICAL MARINE FORECASTS ARE AVAILABLE AT WEATHER.GOV/GREATLAKES  
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