132
FXUS66 KSEW 162204
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
304 PM PDT TUE JUN 16 2026
SYNOPSIS
AN UPPER LEVEL RIDGE CENTERED WELL OFFSHORE WITH NORTHWESTERLY
FLOW ALOFT AND LIGHT LOW LEVEL ONSHORE FLOW WILL MAINTAIN DRY
CONDITIONS THROUGH THE WEEKEND WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES, WARMEST ON FRIDAY. DRY WEATHER THEN CONTINUES INTO
EARLY NEXT WEEK, WITH TEMPERATURES BECOMING WARMER AS AN UPPER
LEVEL RIDGE BUILDS OVER THE REGION.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
MINIMAL CHANGE IS EXPECTED WITH THE WEATHER PATTERN TONIGHT
THROUGH WEDNESDAY NIGHT. THE SHORT TERM FORECAST REMAINS
HIGHLIGHTED BY DRY CONDITIONS WITH SEASONABLE TEMPERATURES. AN
UPPER LEVEL RIDGE CENTERED WELL OFFSHORE IS EXPECTED TO REMAIN
IN PLACE, WITH NORTHWESTERLY FLOW ALOFT OVER WESTERN WASHINGTON.
WHILE LOW-LEVEL ONSHORE FLOW IS ALSO EXPECTED TO REMAIN IN
PLACE, THE STRENGTH OF THE ONSHORE FLOW WILL BEGIN TO WEAKEN
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. AS SUCH, SOME LOCATIONS
MAY END UP A DEGREE OR TWO WARMER ON WEDNESDAY, ESPECIALLY IN
AREAS AWAY FROM THE PUGET SOUND WITH MINIMAL MORNING CLOUD
COVER.
MODELS AND THEIR ENSEMBLES SUGGEST NORTHWEST FLOW ALOFT WILL
CONTINUE THURSDAY THROUGH THURSDAY NIGHT, WITH THE LOW LEVEL
FLOW GOING LIGHT. THIS WILL RESULT IN MOSTLY CLEAR SKIES ON
THURSDAY WITH SLIGHTLY ABOVE AVERAGE TEMPERATURES. THE
DETERMINISTIC NBM SUGGESTS HIGHS WILL REACH INTO THE MID 70S TO
LOWER 80S OVER THE INTERIOR LOWLANDS ON THURSDAY, EXCEPT 60S
ALONG THE COAST AND MID 80S OVER THE LOWLANDS OF LEWIS AND
SOUTHERN THURSTON COUNTIES AND THE MIDDLE CHEHALIS RIVER VALLEY.
-23
LONG TERM /FRIDAY THROUGH TUESDAY/
THE LONG TERM FORECAST IS
HIGHLIGHTED BY CONTINUED DRY WEATHER AND A WARMING TREND, ASIDE
FROM A BRIEF COOLDOWN OVER THE WEEKEND. THE LATEST SUITE OF
MODEL GUIDANCE SUGGESTS AN UPPER LEVEL RIDGE WILL AMPLIFY OVER
THE GULF OF ALASKA ON FRIDAY BEFORE GRADUALLY MOVING EASTWARD
OVER THE WEEKEND. IT APPEARS THE RIDGE AXIS WILL REACH THE B.C.
COAST LATE SUNDAY, AND THEN MOVE INTO WESTERN WA EARLY NEXT WEEK
WHILE DEAMPLIFYING. NOTE A COMPACT UPPER LEVEL LOW ON THE
EASTERN PERIPHERY OF THIS RIDGE IS SET TO MOVE THROUGH SOUTHERN
B.C. ON SUNDAY, WHICH WILL BRING A 10% CHANCE OF LIGHT SHOWERS
TO THE NORTH CASCADES.
THE TIMING OF THE AFOREMENTIONED RIDGE AND UPPER LOW WILL BRING
WARMER TEMPERATURES ON FRIDAY FOLLOWED BY RELATIVELY COOLER
TEMPERATURES OVER THE WEEKEND AND THEN WARMER TEMPERATURES AGAIN
EARLY NEXT WEEK. OVERALL MODEL SPREAD FOR TEMPERATURES IS FAIRLY
LOW EACH DAY, SUGGESTING CONFIDENCE IN THE TEMPERATURE FORECAST
IS HIGH. FORECAST HIGHS ON FRIDAY ARE GENERALLY IN THE 80S
ACROSS THE LOWLANDS, EXCEPT 60S AT THE COAST. HIGHS COOL INTO
THE 70S FOR INLAND VALLEYS OVER THE WEEKEND. TEMPERATURES THEN
WARM AGAIN MONDAY INTO TUESDAY AS THE RIDGE AXIS MOVES OVER
WESTERN WA. THE NBM 25TH-75TH PERCENTILE SUGGESTS HIGHS WILL
LIKELY PEAK ON TUESDAY, RANGING ANYWHERE FROM THE MID TO UPPER
80S. IN FACT, HIGHS OF 90 DEGREES OR WARMER CANNOT BE RULED OUT
ON TUESDAY FOR INLAND VALLEYS; THERE IS CURRENTLY A 50-70%
CHANCE AREAS TO THE SOUTH AND SOUTHWEST OF THE PUGET SOUND WILL
REACH 90 DEGREES OR WARMER, A 30-50% CHANCE FROM KENT TO RENTON
TO BELLEVUE, AND A 5% CHANCE IN SEATTLE. AS SUCH, A MODERATE
HEATRISK RETURNS TO THE GREATER SEATTLE METRO AREA ON TUESDAY.
-23
AVIATION
AS THE UPPER LEVEL RIDGE CONTINUES TO FLATTEN, PREVAILING
WEST/NORTHWEST WINDS PERSIST. GUSTY WESTERLY WINDS WILL CONTINUE
THROUGH THIS EVENING NEAR THE COAST AS WELL AS IN AND ADJACENT
TO THE STRAIT OF JUAN DE FUCA. WINDS BEGIN TO EASE TONIGHT. AS
OF 22Z TUESDAY, VFR CONDITIONS WERE BEING OBSERVED AT ALL TAF
SITES WITH SKIES VARYING FROM MOSTLY CLEAR TO PARTLY CLOUDY.
THAT SAID, LOW MARINE STRATUS IS EXPECTED TO FILL BACK IN AT
THE COAST BY 03-06Z WEDNESDAY (60-75% CHANCE FOR CEILINGS BELOW
3000 FT). MOST INLAND AREAS SHOULD GENERALLY REMAIN VFR TONIGHT
INTO TOMORROW MORNING, HOWEVER THERE IS A 20-30% CHANCE FOR
BROKEN MVFR CEILINGS BELOW 3000 FT AT ALL INLAND TAF SITES
BETWEEN 07-17Z WEDNESDAY, EXCEPT A 5-10% CHANCE AT KCLM.
KSEA...VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. THAT
BEING SAID, THERE IS A 20-30% CHANCE FOR BROKEN MVFR CEILINGS
BELOW 3000 FT BETWEEN 07-17Z WEDNESDAY. ALTHOUGH WINDS HAVE
REMAINED VARIABLE AROUND 5 KT FOR MOST OF THE DAY THUS FAR,
NORTHERLY WINDS ARE EXPECTED TO DEVELOP AROUND 23Z TUESDAY AT
AROUND 10 KT. WINDS SHOULD EVENTUALLY BECOME LIGHT AND VARIABLE
AFTER 08Z WEDNESDAY, BEFORE BECOMING NORTHWESTERLY NEAR 7-9 KT
BY 21-22Z WEDNESDAY. -23
MARINE
ONSHORE FLOW CONTINUES TODAY INTO TONIGHT. NORTHWESTERLY WINDS
WILL GUST TO 25 KTS OVER THE COASTAL WATERS, WITH A SMALL CRAFT
ADVISORY IN EFFECT NOW THROUGH EARLY THURSDAY MORNING. SEAS
WILL BECOME LOCALLY-WIND DRIVEN AND BECOME VERY STEEP. WAVE
HEIGHTS WILL INCREASE THROUGH TONIGHT, REACHING UP TO 10 TO 13
FT WITH A DOMINANT PERIOD OF AROUND 10 SECONDS LATE TUESDAY
EVENING INTO TUESDAY NIGHT. WAVES IN THE OUTERMOST WATERS MAY
REACH UP TO 15 FT ON WEDNESDAY AND FRIDAY.
A GALE WARNING REMAINS IN EFFECT FOR THE CENTRAL AND EASTERN
WATERS OF THE STRAIT OF JUAN DE FUCA, WITH GUSTS UP TO 40-45 KTS
EXPECTED TODAY ASSOCIATED WITH A STRONG MARINE PUSH. SMALL
CRAFT ADVISORY WINDS WILL ALSO FUNNEL DOWN INTO ADMIRALTY INLET
BY THIS AFTERNOON. MARGINAL SMALL CRAFT ADVISORY WIND GUSTS UP
TO 25 KT ARE ALSO EXPECTED OVER THE WEST ENTRANCE OF THE STRAIT
OF JUAN DE FUCA WINDS THIS AFTERNOON AND EVENING, MAINLY TO THE
EAST OF NEAH BAY. WINDS WILL EASE BY LATE TONIGHT. -23
FIRE WEATHER
THE RETURN OF LOW LEVEL ONSHORE FLOW TODAY HAS EASED FIRE
WEATHER CONCERNS WEST OF THE CASCADES. ELEVATED FIRE WEATHER
CONCERNS RETURN ON FRIDAY AND MONDAY AS A WARMER AND DRIER
AIRMASS WILL BE IN PLACE AT THAT TIME. MINIMUM RELATIVE HUMIDITY
VALUES ARE FORECAST TO DROP TO AROUND 30 PERCENT BOTH DAYS
ALONG WITH SOME BREEZY CONDITIONS IN THE AFTERNOON AND EVENING
HOURS. -FELTON/23
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR WEST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING UNTIL 11 PM PDT THIS EVENING FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
ADMIRALTY INLET.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY FOR COASTAL
WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10
NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10
TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT
GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE
TO CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT
GRENVILLE TO CAPE SHOALWATER OUT 10 NM.
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