337
FXUS66 KSEW 150243
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
743 PM PDT WED OCT 14 2026
SYNOPSIS
HIGH PRESSURE WILL BUILD INTO THE NORTHWEST THROUGH THE REST OF
THE WEEK, BEFORE BECOMING UNSETTLED AGAIN AS A SERIES OF WEAK
SYSTEMS TRAVERSE THE AREA OVER THE WEEKEND. THE PATTERN LOOKS TO
REMAIN UNSETTLED INTO THE FIRST HALF OF NEXT WEEK WITH COOLER
TEMPERATURES IN THE FORECAST.
SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/
SKIES HAVE BEGUN TO CLEAR EARLY THIS AFTERNOON WITH RESIDUAL
CLOUD COVER LINGERING ALONG THE COAST AND SOUTHWEST INTERIOR.
HIGH PRESSURE IS BUILDING IN EARNEST TODAY THROUGH THE END OF
THE WEEK, WITH HIGHS CLIMBING INTO THE UPPER 60S AND LOW 70S
TOMORROW, AND AGAIN ONCE MORE INTO THE MID 70S BY FRIDAY. THIS
WILL CORRESPOND TO SOME MINOR HEATRISK OVER THESE TWO DAYS.
GIVEN A MOIST ATMOSPHERE IN THE LOW LEVELS AND A LIGHT WIND
GRADIENT, THERE IS POTENTIAL FOR SOME STRATUS AND POSSIBLY FOG
ON THURSDAY MORNING. OFFSHORE FLOW WILL GET A LITTLE BREEZY,
PARTICULARLY IN THE CASCADES AND FOOTHILLS THURSDAY NIGHT. GUSTS
WILL BE BETWEEN 25-30 MPH. RH VALUES IN THE CASCADES AND
SOUTHERN OLYMPICS COULD SEE MINIMUMS AROUND 35-40%, WITH A MORE
WIDESPREAD REDUCTION ON FRIDAY AS THE TEMPERATURES CLIMB.
MINIMUMS ON FRIDAY WILL RANGE FROM 35-45%.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
HIGH PRESSURE DAMPENS OVER THE WEEKEND, WITH MORE SOUTHWESTERLY
FLOW ALOFT. THE NEXT SYSTEM ARRIVES ON SATURDAY, LIKELY BRINGING
RAIN TO WESTERN WASHINGTON THROUGHOUT THE DAY. MORE OF THIS RAIN
IS FORECAST TO FALL IN THE NORTH CASCADES WITH ONLY A FEW
HUNDREDTHS OF AN INCH EXPECTED IN LOWLAND LOCATIONS. AREAS OF
THE SEATTLE METRO MAY BE SHADOWED ENTIRELY. MORE NOTABLY,
TEMPERATURES DROP BACK INTO THE LOW 60S WHICH WILL BE A SHARP
DROP OUT OF FRIDAY'S HIGHS IN THE MID 70S.
ZONAL FLOW WITH BROAD TROUGHING IN THE NE PACIFIC KEEPS
CONDITIONS COOLER AND DRIER ON SUNDAY. MORNING LOWS WILL DROP
INTO THE LOW 40S FOR THE PUGET SOUND REGION, AND MID 30S IN THE
CASCADE FOOTHILLS. MODEL GUIDANCE IS STILL KEEPING THAT TROUGH
OFFSHORE INTO SUNDAY FOR LESS OF A WIND THREAT IN WESTERN
WASHINGTON, BUT THIS TRACK WILL BE MONITORED FOR CHANGES.
TROUGHING WILL CONTINUE INTO EARLY NEXT WEEK FOR ADDITIONAL
CHANCES FOR LIGHT RAIN, PARTICULARLY ON TUESDAY. BEYOND THAT,
THERE IS A BIT OF A DISCREPANCY IN WHAT PATTERN IS FAVORED.
21
AVIATION
HIGH PRESSURE BUILDING INTO THE REGION ALOFT WILL ALLOW
FOR NORTHERLY FLOW IN THE MID LEVELS TO BECOME MORE SOUTHERLY BY
THURSDAY MORNING. AT THE SURFACE, MOST TERMINALS WILL EXPERIENCE
SOME FORM OF NORTHERLY WINDS WITH SOME DEVIATIONS TO THE NE OR NW
DEPENDING ON LOCATION/TERRAIN WITH A FAVORING OF NEERLY EMERGING BY
THURSDAY AFTERNOON. SPEEDS THIS EVENING AND OVERNIGHT WILL GENERALLY
BE 5 KTS OR LESS, BEFORE MOSTLY INCREASING TO 5-10 KTS THURSDAY
AFTERNOON.
WIDESPREAD VFR CONDITIONS OVER W WA THIS EVENING, ALTHOUGH AN
ISOLATED POCKET OF LOW CLOUDS AROUND KPLU AND PERSISTENT MARINE
STRATUS OVER PORTIONS OF THE NORTHERN PACIFIC COAST HAVE RESULTING
IN SOME AREAS OF MVFR TO IFR CONDITIONS. THE COMBINATION OF MOSTLY
CLEAR SKIES AND HIGH PRESSURE OVERHEAD WILL ALLOW FOR WIDESPREAD
IFR/LIFR CONDITIONS TO DEVELOP DURING THE OVERNIGHT HOURS AND
THROUGHOUT THURSDAY MORNING BEFORE A SLOW RECOVERY BEGINS IN THE
EARLY AFTERNOON. A RETURN TO WIDESPREAD VFR CONDITIONS IS EXPECTED
BY MID-AFTERNOON.
KSEA...VFR CONDITIONS WILL CONTINUE THIS EVENING INTO EARLY TONIGHT.
FOG EXPECTED TO MOVE INTO THE TERMINAL EARLY THURSDAY MORNING, WITH
PROBABILISTIC GUIDANCE SUGGESTING A 25-35% CHANCE OF CEILINGS AND
VISIBILITIES DROPPING TO LIFR BETWEEN 9-12Z. NORTHERLY WINDS REMAIN
LIGHT AT 6 KT OR LESS BEFORE SHIFTING TO THE NORTHEAST BY THURSDAY
MORNING AND INCREASING TO 4-8 KT BY THE AFTERNOON.
14/18
MARINE
HIGH PRESSURE WILL BUILD BACK INTO THE COASTAL WATERS TONIGHT,
WHILE A THERMAL TROUGH BUILDS NORTHWARD ALONG THE COAST. AREAS
OF FOG WILL LIKELY DEVELOP ACROSS PORTIONS OF THE LOCAL WATERS
OVERNIGHT INTO THURSDAY MORNING AND MAY CAUSE VISIBILITIES TO
DROP DOWN TO 1 NM OR LESS IN SPOTS THROUGH THE EARLY MORNING HOURS.
WINDS WILL TURN OFFSHORE BY TONIGHT AND WILL PERSIST THROUGH
FRIDAY MORNING, BECOMING BREEZY THROUGH THE GAPS IN TERRAIN
THURSDAY AFTERNOON AND EVENING. AT THIS TIME, WINDS ARE STILL
FAVORED TO REMAIN BELOW SMALL CRAFT CRITERIA, WITH PROBABILISTIC
GUIDANCE ONLY HIGHLIGHTING A 30-40% CHANCE OF GUSTS EXCEEDING 21
KT ACROSS THE WEST ENTRANCE OF THE STRAIT OF JUAN DE FUCA AND A
SMALL PORTION OF THE NORTHERN COASTAL WATERS.
THE THERMAL TROUGH WILL PUSH INLAND ON FRIDAY AS A FRONT
APPROACHES THE AREA, BRINGING THE RETURN OF ONSHORE FLOW TO THE
WATERS. ONSHORE FLOW WILL THEN INCREASE FRIDAY NIGHT INTO
SATURDAY AS THE SYSTEM MAKES ITS WAY ACROSS THE AREA. ANOTHER
SYSTEM MAY APPROACH THE AREA WATERS SUNDAY NIGHT INTO MONDAY,
THOUGH THERE REMAIN DISCREPANCIES IN REGARDS TO ITS EXACT TRACK.
SEAS WILL LARGELY PERSIST BETWEEN 4-7 FT THROUGH FRIDAY, BUT
WILL STEADILY BUILD TOWARDS 8-11 FT OVER THE WEEKEND AS SYSTEMS
MOVE THROUGH THE REGION. SEAS COULD EVEN BUILD FURTHER EARLY
NEXT WEEK DEPENDING ON THE TRACK OF THE SYSTEMS, WITH THE GEFS
STILL INDICATING A 40-50% OF SEAS EXCEEDING 12 FT ON MONDAY.
14
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page