048
FXUS66 KSEW 170942
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
242 AM PDT SUN MAY 17 2026
SYNOPSIS
UPPER LEVEL RIDGE CENTERED OFFSHORE BUILDING TODAY AND TONIGHT.
THE RIDGE WILL REMAIN IN PLACE THROUGH MOST OF THE WEEK. WEAK
SYSTEMS MOVING OVER THE TOP OF THE RIDGE AT TIMES. RIDGE WEAKENS
SATURDAY WITH AN UPPER LEVEL TROUGH APPROACHING THE COAST.
SHORT TERM /TODAY THROUGH TUESDAY/
SATELLITE IMAGERY SHOWS SKIES HAVE CLEARED ALONG THE COAST AND
OVER PORTIONS OF THE INTERIOR. CLOUDS HANGING TOUGH OVER THE
INTERIOR FROM ABOUT SEATTLE NORTHWARD. PATCHY FOG REDUCING THE
VISIBILITY TO LESS THAN A MILE AROUND TACOMA. TEMPERATURES AT 2
AM/09Z RANGING FROM THE MID 30S IN THE SOUTHWEST INTERIOR TO
THE UPPER 40S IN MANY LOCATIONS.
WESTERN WASHINGTON GETTING OFF THE WEATHER ROLLER COASTER THIS
WEEK. UPPER LEVEL RIDGE BUILDING OFFSHORE TODAY WITH THE RIDGE
REMAINING IN PLACE THROUGH TUESDAY. FOR TODAY AND MONDAY WEAK
ONSHORE FLOW WITH AREAS OF MORNING CLOUDS AND SUNNY AFTERNOONS.
PATCHY FOG THIS MORNING SOUTH SOUND. WEAK SYSTEM RIDING BY TO
THE NORTH TUESDAY WILL INCREASE THE LOW LEVEL ONSHORE FLOW FOR
MORE CLOUD COVER. HIGHS WARMING INTO THE LOWER TO MID 60S TODAY
AND 60S ALL AREAS MONDAY. A LITTLE COOLER WITH MORE CLOUD COVER
TUESDAY, UPPER 50S TO MID 60S. THE SYSTEM ON TUESDAY COULD
PRODUCE A SHOWER IN THE NORTH CASCADES IN THE AFTERNOON. FELTON
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
LITTLE CHANGE IN THE PATTERN WITH FLAT UPPER LEVEL RIDGE
CENTERED OFFSHORE AND WEAK SYSTEMS MOVING BY TO THE NORTH AT
TIMES THROUGH FRIDAY. WEAK UPPER LEVEL TROUGH APPROACHING THE
COAST SATURDAY WILL STILL BE FAR ENOUGH OFFSHORE TO HAVE A DRY
FORECAST. HIGHS IN THE 60S AND LOWER 70S WEDNESDAY AND THURSDAY,
MID 60S TO MID 70S FRIDAY AND SATURDAY. LOWS MOSTLY IN THE 40S.
AVIATION
NORTHERLY FLOW ALOFT WILL PERSIST TODAY AS AN UPPER LEVEL
TROUGH EXITS THE REGION TO THE SOUTHEAST AND AN UPPER LEVEL
RIDGE STARTS TO BUILD BACK INTO THE AREA FROM THE NE PACIFIC.
RADAR SHOWS A FEW LIGHT SHOWERS LINGERING ACROSS THE INTERIOR
THIS MORNING, BUT MOST OF THE ACTIVITY HAS TAPERED AS A RESULT.
CONDITIONS AT THE AREA TERMINALS LARGELY REMAIN VFR EARLY THIS
MORNING, BUT DO EXPECT TO SEE SOME MVFR CIGS DEVELOP BY THE
EARLY MORNING HOURS. SCATTERING OF CIGS IS EXPECTED BY THE
AFTERNOON AND WILL CONTINUE INTO THE EVENING. WINDS FOR THE
INTERIOR TERMINALS HAVE PRIMARILY SWITCHED BACK TO THE SOUTH AND
HAVE BECOME LIGHT, WHILE WINDS ALONG THE COAST REMAIN OUT OF
THE NORTHWEST. KCLM REMAINS A BIT ELEVATED, WITH WESTERLY WINDS
PERSISTING AT 10-15 KT, THOUGH EXPECT WINDS TO EASE THROUGH THE
MORNING HOURS. WINDS ACROSS THE INTERIOR TERMINALS WILL SWITCH
TO THE NORTH BETWEEN 17-19Z AND PERSIST AT 5-10 KT INTO THE
EVENING HOURS BEFORE EASING TONIGHT.
KSEA...VFR CONDITIONS EARLY THIS MORNING WITH WINDS OUT OF THE
SOUTHEAST AT 4-8 KT. EXPECT ANY LOWER CIGS TO LARGELY REMAIN
BETWEEN 3000-4000 FT THIS MORNING, THOUGH THERE REMAINS A 20
PERCENT CHANCE OF CIGS DIPPING DOWN TO MVFR BETWEEN 12-15Z.
WINDS WILL SWITCH TO THE NORTH AROUND 18Z AND PERSIST AT 5-8 KT
THIS AFTERNOON AND EVENING BEFORE EASING OVERNIGHT.
14
MARINE
HIGH PRESSURE WILL BUILD BACK OVER THE WATERS TODAY. ONSHORE
FLOW ALONG THE STRAIT OF JUAN DE FUCA WILL EASE THROUGH THE
EARLY MORNING HOURS, SO WILL ALLOW FOR THE SMALL CRAFT ADVISORY
TO EXPIRE EARLY THIS MORNING. THIS WILL BE SHORT-LIVED, HOWEVER,
AS ANOTHER PUSH OF SMALL-CRAFT WESTERLY WINDS IS EXPECTED ALONG
THE CENTRAL AND EASTERN STRAIT THIS AFTERNOON AND EVENING. SEAS
ACROSS THE COASTAL WATERS HAVE ALSO STARTED TO SUBSIDE AND WILL
PRIMARILY RANGE BETWEEN 6-8 FT THROUGHOUT THE DAY.
A WEAK, DISSIPATING FRONTAL SYSTEM WILL MOVE ACROSS THE AREA
WATERS MONDAY INTO TUESDAY, BEFORE HIGH PRESSURE BUILDS BACK IN
ITS WAKE ON WEDNESDAY. ONSHORE FLOW WILL PERSIST THROUGH THE
FIRST HALF OF THE WEEK AND WILL RESULT IN DAILY PUSHES OF WESTERLY
WINDS THROUGH THE STRAIT OF JUAN DE FUCA. ANOTHER WEAK FRONTAL
SYSTEM LOOKS TO MOVE INTO THE AREA WATERS ON THURSDAY. SEAS
WILL GENERALLY HOVER BETWEEN 6-8 FT THROUGH THE FIRST HALF OF
THE WEEK, BEFORE SLIGHTLY INCREASING TOWARDS 8-10 FT BY LATE WEEK.
14
HYDROLOGY
THE DAILY HYDROLOGY DISCUSSION HAS ENDED UNTIL THE
START OF THE NEXT RAINY SEASON; IT WILL ONLY BE UPDATED DURING
THIS TIME AS NEEDED.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT EARLY THIS MORNING FOR
ADMIRALTY INLET-CENTRAL U.S. WATERS STRAIT OF JUAN DE
FUCA-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM PDT
MONDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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