Expires:201305210800;;440100 FZUS63 KDTX 201953 GLFSC LAKE ST CLAIR FORECAST NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 353 PM EDT MON MAY 20 2013 .SYNOPSIS...A LARGE LOW PRESSURE SYSTEM...AVERAGING 29.40 INCHES...WILL STALL OVER THE NORTHERN PLAINS BRINGING SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS THROUGH MIDWEEK. THIS LOW WILL PASS THROUGH THE SOUTHERN GREAT LAKES LATE IN THE WEEK ALLOWING HIGH PRESSURE TO BUILD BACK IN FROM THE NORTH. LCZ460-210800- LAKE ST CLAIR- 353 PM EDT MON MAY 20 2013 ...SEVERE THUNDERSTORM WATCH 189 IN EFFECT UNTIL 8 PM EDT THIS EVENING... .TONIGHT...SOUTHEAST WINDS 5 TO 10 KNOTS THROUGH MIDNIGHT...BECOMING LIGHT AND VARIABLE OVERNIGHT. A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH MIDNIGHT...THEN SHOWERS AND THUNDERSTORMS LIKELY AFTER MIDNIGHT. PARTLY CLOUDY. WAVES 2 FEET OR LESS. .TUESDAY...SOUTH WINDS 5 TO 10 KNOTS...BECOMING SOUTHWEST 10 TO 15 KNOTS LATE. SHOWERS AND THUNDERSTORMS LIKELY THROUGH EARLY AFTERNOON...THEN SHOWERS AND THUNDERSTORMS BY MID AFTERNOON. WAVES 2 FEET OR LESS. .TUESDAY NIGHT...SOUTHWEST WINDS 5 TO 10 KNOTS THROUGH MIDNIGHT... BECOMING LIGHT AND VARIABLE OVERNIGHT. PARTLY CLOUDY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. WAVES 2 FEET OR LESS. .WEDNESDAY...SOUTH WINDS 5 TO 10 KNOTS...INCREASING TO 10 TO 15 KNOTS BY MID AFTERNOON. CLOUDY WITH SHOWERS AND THUNDERSTORMS LIKELY. WAVES 2 FEET OR LESS. .WEDNESDAY NIGHT...WEST WINDS 5 TO 10 KNOTS. LIGHT SHOWERS LIKELY. MOSTLY CLOUDY THROUGH MIDNIGHT...BECOMING PARTLY CLOUDY OVERNIGHT. WAVES 2 FEET OR LESS. .THURSDAY...NORTHWEST WINDS 5 TO 10 KNOTS...BECOMING NORTH 10 TO 15 KNOTS BY MID AFTERNOON. MOSTLY CLOUDY WITH A CHANCE OF LIGHT SHOWERS. WAVES 2 FEET OR LESS. .FRIDAY...NORTHEAST WINDS 5 TO 10 KNOTS. MOSTLY CLEAR. WAVES 2 FEET OR LESS. .SATURDAY...LIGHT AND VARIABLE WINDS. MOSTLY CLEAR. WAVES 2 FEET OR LESS. $$ MR WAVES ARE THE SIGNIFICANT WAVE HEIGHT - THE AVERAGE OF THE HIGHEST 1/3 OF THE WAVE SPECTRUM. MAXIMUM WAVE HEIGHT IS THE HIGHEST 1/20 WAVE HEIGHT. EXPERIMENTAL GRAPHICAL MARINE FORECASTS ARE AVAILABLE ONLINE AT WEATHER.GOV/DETROIT (ALL LOWER CASE)