741
FXUS66 KSEW 222223
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
323 PM PDT FRI MAY 22 2026
SYNOPSIS
WEAK HIGH PRESSURE REMAINS IN PLACE TODAY, BUT WILL BECOME MORE
ZONAL INTO THE WEEKEND. ONSHORE FLOW WILL INCREASE OVER THE
NEXT SEVERAL DAYS. A SYSTEM ARRIVING ON MEMORIAL DAY WILL BRING
WIDESPREAD RAIN AND COOLER TEMPERATURES TO THE REGION. THE REST
OF THE FRONT WILL MOVE THROUGH ON TUESDAY, KEEPING SHOWERS IN
THE FORECAST. WEAK RIDGING IS POSSIBLE THROUGH THE SECOND HALF
OF THE WEEK.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/
WEAK HIGH PRESSURE ALOFT WILL TRANSITION TO MORE ZONAL, ONSHORE
FLOW THROUGH THE WEEKEND. THIS WILL ENABLE A DEEPER PUSH OF
MARINE STRATUS INTO THE INTERIOR EACH OF THE NEXT FEW MORNINGS.
WHILE THE ONSHORE PUSH LOOKS A BIT MORE EXTENSIVE AND WILL
LIKELY LINGER A BIT LONGER THROUGH THE MORNING SATURDAY, THERE'S
LIKELY TO BE SOME IMPROVEMENT IN THE AFTERNOON. THIS WILL BRING
SOME SUNSHINE TO THE INTERIOR AND AFTERNOON HIGHS IN THE UPPER
60S TO AROUND 70 EACH DAY. THIS WILL MAINTAIN ONLY MINOR
HEATRISK ACROSS MOST OF THE LOWLANDS. THE ONSHORE FLOW WILL
ALSO STRENGTHEN THE WESTERLY WINDS THROUGH THE STRAIT OF JUAN DE
FUCA OVER THE WEEKEND.
LONG TERM /MONDAY THROUGH FRIDAY/
THE ZONAL FLOW WILL OPEN THE DOOR TO THE NEXT SYSTEM ARRIVING
LATE SUNDAY NIGHT INTO MONDAY. THIS WILL BRING BREEZY, COOL, AND
WET CONDITIONS TO WESTERN WASHINGTON FOR THE MEMORIAL DAY
HOLIDAY. AMOUNTS OF AROUND A HALF INCH OF RAIN IN THE LOWLANDS
AND ONE TO ONE AND A HALF INCHES IN THE MOUNTAINS ARE EXPECTED.
ADDITIONALLY, THOUGH THE INSTABILITY LATE MONDAY AFTERNOON AND
EVENING LOOKS RATHER MODEST, THERE'S STILL AROUND A 10-15%
CHANCE OF A FLASH OF LIGHTNING OR TWO ESPECIALLY NEAR THE COAST
OR FROM PUGET SOUND SOUTHWARD. IN ADDITION TO THE RAIN, WE'LL
SEE RATHER BREEZY WINDS WITH GUSTS UP TO 20-30 MPH ACROSS MUCH
OF THE AREA AS THIS WEATHER SYSTEM MOVES THROUGH. WHILE THESE
SPEEDS ARE NOT GENERALLY STRONG ENOUGH TO CAUSE WIDESPREAD
IMPACTS, UNSECURED TENTS OR OUTDOOR EQUIPMENT COULD BE IMPACTS.
WITH THIS COOLER AIR MASS IN PLACE, TEMPERATURES ARE UNLIKELY
TO CLIMB OUT OF THE 60S. SHOWERS LINGER EARLY TUESDAY AS THE
UPPER TROUGH MOVES PAST THE AREA, WITH A RETURN TO DRY
CONDITIONS LATE TUESDAY THROUGH MIDWEEK AS WEAK HIGH PRESSURE
AGAIN REBUILDS.
AVIATION
AN UPPER LEVEL RIDGE CENTERED OFFSHORE WILL WEAKEN OVERNIGHT INTO
SATURDAY WITH WEST TO NORTHWEST FLOW ALOFT CONTINUING. INCREASING
LOW LEVEL ONSHORE FLOW AHEAD OF A WEAK SYSTEM MOVING INTO BRITISH
COLUMBIA WILL BRING COASTAL STRATUS INTO THE INTERIOR LOWLANDS
OVERNIGHT. WIDESPREAD IFR OR LOW MVFR CEILINGS ARE EXPECTED WEST OF
THE CASCADES ON SATURDAY MORNING. THE STRATUS IS EXPECTED TO
GRADUALLY LIFT AND SCATTER BY 21Z SATURDAY FOR THE INTERIOR AREAS,
BUT WILL LINGER ALONG THE COAST FOR THE ENTIRETY OF SATURDAY.
KSEA...VFR IS EXPECTED THROUGH THIS EVENING. IFR OR LOW MVFR STRATUS
WILL REACH THE TERMINAL BY AROUND 10Z SATURDAY AND PERSIST INTO
MIDDAY SATURDAY BEFORE SCATTERING OUT MID-AFTERNOON. SURFACE WINDS
WEST TO NORTHWEST 7 KNOTS OR LESS WILL BACK TO SOUTHWESTERLY
LATE THIS EVENING AND INCREASE 7 TO 10 KNOTS SATURDAY MORNING.
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MARINE
SURFACE HIGH PRESSURE CENTERED WELL OFFSHORE WILL CONTINUE TO
PRODUCE ONSHORE FLOW INTO THE WEEKEND. A SYSTEM PASSING WELL NORTH
OF THE WATERS WILL INCREASE ONSHORE TONIGHT INTO SATURDAY. THIS WILL
LEAD TO ADVISORY LEVEL WESTERLIES IN THE CENTRAL/EAST STRAIT TONIGHT
AND NEAR GALE WESTERLIES SATURDAY EVENING. THE OFFSHORE RIDGE WILL
WEAKEN AND SHIFT SOUTHWARD ON SUNDAY AS A FRONTAL SYSTEM ASSOCIATED
WITH A VERTICALLY STACKED LOW WEST OF HAIDA GWAII APPROACHES THE
AREA. THIS SYSTEM IS EXPECTED TO PRODUCE ADVISORY LEVEL WINDS ACROSS
MUCH OF THE WATERS MONDAY ALONG WITH SEAS BUILDING TO AT OR ABOVE 10
FEET OVER THE COASTAL WATERS MONDAY INTO TUESDAY. WEAK SURFACE
RIDGING REBUILDS OFFSHORE LATER TUESDAY INTO WEDNESDAY.
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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 FROM 7 PM THIS EVENING TO 3 AM PDT
SATURDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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