068
FXUS66 KSEW 200348
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
848 PM PDT TUE MAY 19 2026
SYNOPSIS
HIGH PRESSURE ALOFT WILL BEGIN TO REBUILD ACROSS WESTERN
WASHINGTON ON WEDNESDAY AND REMAIN IN PLACE INTO FRIDAY FOR A
RETURN TO SOME SUNSHINE AND WARMER TEMPERATURES. THE RIDGE WILL
WEAKEN OVER THE UPCOMING HOLIDAY WEEKEND FOR A COOLING TREND AND
A CHANCE OF RAIN BY MEMORIAL DAY.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
A BUILDING UPPER RIDGE ON WEDNESDAY WILL LEAD TO CLEARING SKIES
AND WARMER TEMPERATURES. THE RIDGE REMAINS FIRMLY IN PLACE
OFFSHORE INTO THURSDAY WITH LOW LEVEL ONSHORE FLOW WEAKENING.
INTERIOR TEMPERATURES WILL WARM A FEW DEGREES, BUT COASTAL AREA
TEMPERATURES WILL LIKELY STAY FAIRLY STATIC WITH NIGHT AND
MORNING CLOUDS HANGING AROUND AND AN AFTERNOON SEA BREEZE.
LONG TERM /FRIDAY THROUGH TUESDAY/
THE UPPER RIDGE AXIS OFFSHORE BEGINS TO WEAKEN ON FRIDAY WITH
LOW LEVEL ONSHORE FLOW PICKING UP A NOTCH LATE IN THE DAY.
INTERIOR TEMPERATURES SHOULD BE SIMILAR TO THOSE OF
THURSDAY...UPPER 60S TO MID 70S...WHILE COASTAL AREAS REMAIN
MOSTLY IN THE LOWER 60S. THE RIDGE IS EXPECTED TO FLATTEN BY
SATURDAY FOR SLIGHTLY COOLER TEMPERATURES TO BEGIN THE WEEKEND.
THE WEEKEND LOOKS LIKE A TALE OF TWO HALVES. ENSEMBLE HEIGHT
ANOMALIES AGREE THAT A DEEPENING UPPER TROUGH OVER THE
NORTHEAST PACIFIC WILL BEGIN A TRANSITION TOWARD COOLER
TEMPERATURES AND POSSIBLE PRECIPITATION, BUT THE SPEED OF
TRANSITION IS UP FOR DEBATE. IN GENERAL, THE EURO AND CANADIAN
SUITE OF SOLUTIONS ARE MORE AGRESSIVE WITH THE TROUGHS ARRIVAL
WHILE THE GFS IS LESS SO. SUNDAY SHOULD FEATURE ADDITIONAL
COOLING AND CLOUD COVER WITH PRECIP CHANCES INCREASING AREAWIDE
SUNDAY NIGHT INTO MEMORIAL DAY.
27
AVIATION
UPPER RIDGING OFFSHORE WILL CONTINUE TO LEAD TO N/NW FLOW ALOFT OVER
WESTERN WASHINGTON FOR THE ENTIRE TAF PERIOD. SOME DIFFERENCES IN
SURFACE FLOW...WHILE THE MAJORITY OF TERMINALS ARE SEEING WESTERLY
TO NORTHWESTERLY WINDS, PWT IS FAVORING AN EASTERLY DIRECTION WHILE
BLI IS MORE SOUTHERLY. SPEEDS RANGING 4-8 KTS ALTHOUGH HQM IS
RUNNING CLOSER TO 8-12 KTS THIS EVENING. A UNIVERSAL TRANSITION TO
NORTH TO NORTHWESTERLY WINDS EXPECTED BY 06Z TONIGHT AND REMAINING
THAT WAY INTO LATE WEDNESDAY MORNING WITH SPEEDS GENERALLY 5 KTS OR
LESS. MOST TERMINALS EXPECTED TO REMAIN NORTHERLY, WITH SOME
VARIATIONS TO THE NE OR NW, BUT WILL SEE SPEEDS INCREASE TO RANGE
MOSTLY 5-10 KTS.
VFR CONDITIONS HOLD COURT OVER THE EASTERN HALF OF THE CWA WHILE
MVFR CIGS IN PLACE FROM CLM AND POINTS WEST. LOW CLOUDS EXPECTED TO
PUSH WESTWARD THROUGH THE NIGHT WITH WIDESPREAD MVFR EXPECTED BY 12Z
WEDNESDAY MORNING /IFR FOR TERMINALS MORE PRONE TO LOWER CIGS/.
LIFTING LOOKS TO KICK IN DURING THE 18-20Z TIME FRAME WITH
WIDESPREAD VFR CONDITIONS RETURNING. THE STRENGTHENING RIDGE WILL
MAKE LIFE DIFFICULT FOR ANY LOW-LEVEL CLOUDS, SCATTERING OUT THE
LOWER ALTITUDES LEAVING ONLY SCT TO BKN HIGH CLOUDS BY WEDNESDAY
EVENING.
KSEA...VFR CONDITIONS THIS EVENING INTO TONIGHT WITH W TO NW WINDS 4
TO 8 KNOTS, BECOMING MORE NORTHERLY AFTER 06Z. MID TO HIGH LEVEL
CLOUDS BEFORE MVFR CONDITIONS RETURN LATE TONIGHT AND LASTING
THROUGHOUT WEDNESDAY MORNING. VFR CONDITIONS RETURNING AROUND 18Z-
20Z.
18/MAZURKIEWICZ
MARINE
SURFACE HIGH PRESSURE OFFSHORE WILL CONTINUE ONSHORE FLOW
THROUGHOUT THE AREA WATERS THROUGH MAJORITY OF THE WEEK. A SMALL
CRAFT ADVISORY REMAINS IN EFFECT FOR ALL OUTER COASTAL WATER
ZONES, MAINLY FOR ELEVATED SEAS. CAN EXPECT ANOTHER WESTERLY
PUSH DOWN THE STRAIT OF JUAN DE FUCA TONIGHT, WHERE A SMALL CRAFT
ADVISORY IS ALSO IN EFFECT. DIURNALLY DRIVEN PUSHES DOWN THE STRAIT
EXPECTED THROUGH THE END OF THE WEEK. A SYSTEM ON FRIDAY AND
SATURDAY COULD BRING A ROUND OF ELEVATED SEAS AND WINDS TO THE
COASTAL WATERS.
COASTAL SEAS 6 TO 8 FEET THIS EVENING WILL INCREASE TO 8 TO 10 FEET
TONIGHT INTO WEDNESDAY. SEAS WILL THEN LEVEL TO 7 TO 9 FEET
THROUGHOUT THURSDAY, BEFORE RISING ABOVE 10 FEET FRIDAY AND INTO THE
WEEKEND.
MAZURKIEWICZ/18
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 5 AM PDT WEDNESDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-COASTAL WATERS FROM CAPE
FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL WATERS FROM
JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-COASTAL
WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10 TO 60
NM-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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