896
FXUS66 KSEW 081646
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
946 AM PDT MON JUN 8 2026
SYNOPSIS
COOL AND UNSETTLED CONDITIONS WILL CONTINUE ACROSS
WESTERN WASHINGTON FOR THE FIRST HALF OF THE WEEK AS A PAIR OF
SYSTEMS MOVE THROUGH THE REGION. A PATTERN SHIFT TOWARD DRY AND
CONSIDERABLY WARMER CONDITIONS IS EXPECTED LATE IN WEEK AS
STRONG HIGH PRESSURE ALOFT BUILDS INTO THE REGION.
SHORT TERM /TODAY THROUGH WEDNESDAY/
LATEST IR SATELLITE
IMAGERY SHOWS LEADING EDGE OF THE NEXT INCOMING SYSTEM STILL OUT
OVER THE COASTAL WATERS WITH JUST THE SLIGHTEST HINTS AT
ASSOCIATED PRECIP SHOWING UP ON CURRENT RADAR. THIS REFLECTS THE
CONSISTENT MODEL DATA SUGGESTING A VERY SLOW APPROACH, MAKING
IT TO THE COASTLINE BY LATE THIS MORNING AND BEGINNING ITS
INLAND INTRUSION THIS AFTERNOON. WIDESPREAD RAINFALL STILL ON
TAP BY THIS EVENING AND INTO THE OVERNIGHT HOURS WITH QPF VALUES
SUGGESTING PERIODS OF MODERATE RAINFALL RATES OVER THE SOUTHERN
HALF OF THE CWA, STRETCHING AS FAR NORTH AS EVERETT.
THE PARENT UPPER LOW WILL BE THE MAIN HEADLINE FOR TUESDAY AS RAINS
OVER W WA PERSIST. THE PLACEMENT AND TRACK OF THE MAIN LOW REMAINS A
POINT OF CONTENTION AMONGST MODEL DATA AND WHILE THIS WILL NOT
SPECIFICALLY IMPACT THE AMOUNT OF CHANCES OF PRECIP, IT DOES PLAY A
ROLE IN ANY POTENTIAL THUNDERSTORM DEVELOPMENT. LEVELS OF CAPE
AVAILABLE HAS SEEN SOME VARIATION, BUT LIS REMAIN ON THE POSITIVE
SIDE OF THINGS WHICH WOULD NOT BE HELPFUL TO ANY DEVELOPMENT.
PERSISTENT CLOUDY CONDITIONS AND COOLER DAYTIME TEMPS WILL CERTAINLY
BE ANOTHER FACTOR TO OVERCOME CONVECTION-WISE. THIS LEAVES A LOT OF
THE WORK TO BE DONE BY THE UPPER LOW AND THE UNCERTAINTY REGARDING
ITS PATH DOES NOT FOSTER CONFIDENCE IN POTENTIAL THUNDERSTORM
DEVELOPMENT. NBM REMAINS CONSISTENT IN ITS ADVERTISING AND GIVEN
ASSOCIATED MESSAGING, FELT PRUDENT TO LEAVE THE PROSPECT IN THE
FORECAST AT THIS TIME...ALTHOUGH GIVEN THE FACTORS LISTED ABOVE, AN
EMPHASIS ON ISOLATED DEVELOPMENT IS CERTAINLY WARRANTED.
WEDNESDAY WILL SEE THE UPPER LEVEL TROUGH PULL AWAY FROM W WA AND
THUS WILL SEE PRECIP CHANCES WHITTLE AWAY THROUGH THE DAY. LATEST
DATA SUGGESTS THIS TO BE A BIT FASTER THAN PREVIOUSLY ADVERTISED,
WITH THE MAJORITY OF THE CWA DRY BY AFTERNOON /WITH ONLY SOME LOW
END POPS TO CONTEND WITH/.
DAYTIME HIGHS FOR THE NEAR TERM DO NOT SEE MUCH IN THE WAY OF
VARIATION WITH UPPER 50S TO LOWER 60S EXPECTED TODAY AND TUESDAY. AS
THE SYSTEM EXITS THE AREA WEDNESDAY, THAT SHOULD ALLOW SOME BREAKS
IN THE CLOUDS, LETTING PEEKS OF SUNSHINE TO NUDGE TEMPS UPWARD, BUT
NOT BY TOO MUCH...RANGING IN THE LOWER TO MID 60S.
18
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
DRY CONDITIONS
AREAWIDE BY WEDNESDAY NIGHT AS THE INFLUENCE FROM AN UPPER LEVEL
RIDGE BUILDING OVER THE EASTERN PACIFIC BEGINS TO NUDGE ITS WAY
INTO W WA. WITH THIS FEATURE BEING VERY SLOW TO MOVE EASTWARD
THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD, THE SONG WILL
REMAIN THE SAME FOR THE LATTER HALF OF THE WEEK AS CONDITIONS
WILL REMAIN DRY AND TEMPERATURES BEGIN A STEEP WARMING TREND.
DAYTIME HIGHS THURSDAY JUMP UP INTO THE UPPER 60S TO LOWER 70S.
FRIDAY SEES FURTHER UPWARD MOTION INTO THE MID TO UPPER 70S.
SATURDAY GETS MANY INTERIOR LOCATIONS INTO THE UPPER 70S TO MID
80S. SUNDAY FINALLY SEES SOME LOCATIONS BREAK 90 AS TEMPS RANGE
FROM THE MID 80S TO LOWER 90S.
TEMPS OF THIS CALIBER WILL INDUCE THERMAL TROUGHING OVER THE AREA,
ALLOWING FOR OFFSHORE FLOW TO DEVELOP SATURDAY NIGHT INTO SUNDAY.
THIS EASTERLY FLOW IMPORTING MORE HOT AND DRY AIR INTO THE AREA. AS
THIS HEAT PERSISTS, HEATRISK BECOMES AN INCREASING CONCERN. THE
START OF THIS WARMING TREND, THURSDAY AND FRIDAY, CONTINUE TO LOOK
TO BE MINOR IN THESE TERMS. MODERATE HEATRISK AREAS BEGIN TO POP UP,
MAINLY IN THE SW INTERIOR, SATURDAY WHILE WIDESPREAD MODERATE
CONDITIONS EXPECTED FOR SUNDAY. WHILE HAVING ANY MAJOR HEATRISK
EMERGING BEYOND THE FORECAST PERIOD SEEMS TO HAVE LOWER
PROBABILITIES AT THIS TIME, PERSISTING MODERATE CONDITIONS APPEAR
TO BE MORE FAVORABLE.
18
AVIATION
SOUTH TO SOUTHWESTERLY FLOW ALOFT WILL BECOME
WESTERLY TONIGHT AS A SURFACE LOW MOVES INTO THE AREA AND
WEAKENS. STRATIFORM RAIN ALONG THE OLYMPIC PENINSULA SPREADS
INLAND LATER TODAY. MVFR CIGS DEVELOPING ALONG THE COAST THIS
AFTERNOON, WITH MVFR CIGS BY THIS EVENING INTO EARLY TONIGHT FOR
THE INTERIOR. PERIODS OF IFR ARE ALSO LIKELY TONIGHT,
PARTICULARLY ALONG THE OLYMPIC PENINSULA. SHOWERS LINGERING ON
TUESDAY, WITH A CONVERGENCE ZONE DEVELOPING AROUND SNOHOMISH
COUNTY IN THE AFTERNOON. LIGHT, VARIABLE WINDS MAINLY UNDER 7
KTS FOR THE INTERIOR INTO THIS AFTERNOON. SOUTH-SOUTHWEST WINDS
INCREASE TONIGHT INTO TUESDAY.
KSEA...VFR CIGS INTO THIS AFTERNOON. CIGS GRADUALLY LOWERING
INTO THIS EVENING WITH MVFR CIGS DEVELOPING BETWEEN 02-04Z.
MVFR CIGS CONTINUE THROUGH TUESDAY AM. CIGS MAY FLUCTUATE TO IFR
AT TIMES TONIGHT, PARTICULARLY BETWEEN 07-12Z. WINDS ARE
EXPECTED TO REMAIN MAINLY W/SW INTO THIS AFTERNOON, ALTHOUGH
PERIODS OF VRB ARE LIKELY INTO THIS EVENING. BRIEF N/NW WINDS
MAY OCCUR, MAINLY BETWEEN 23-00Z, BUT CONFIDENCE REMAINS LOW. JD
MARINE
A SURFACE LOW AND ITS ASSOCIATED FRONTAL SYSTEM WILL
MOVE ACROSS THE COASTAL WATERS THIS MORNING, GRADUALLY PUSH
ONSHORE, AND WEAKEN THIS AFTERNOON AND EVENING. THIS SYSTEM WILL
BRING GUSTY SOUTHEASTERLY WINDS TO THE COASTAL WATERS THROUGH
THIS AFTERNOON HOURS TODAY. STRONG ONSHORE FLOW IS LIKELY TO
DEVELOP IN THE WAKE OF THE SYSTEM, WITH THE LATEST HREF
PROBABILITIES INDICATING A 50-70% CHANCE OF GALES DEVELOPING
ALONG THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA ON TUESDAY.
SOUTHERLY WINDS WILL INCREASE AND BECOME BREEZY FOR PORTIONS OF
THE PUGET SOUND WATERS ON TUESDAY MORNING AS WELL, BEFORE
EASING LATER TUESDAY NIGHT.
HIGH PRESSURE WILL REBUILD BACK INTO THE COASTAL WATERS ON WEDNESDAY
AND THURSDAY, WHILE A THERMAL TROUGH GRADUALLY EXPANDS NORTHWARD
ALONG THE OREGON COAST. NORTHWESTERLY WINDS OVER THE OUTER COASTAL
WATERS COULD BECOME BREEZY AT TIMES THE SECOND HALF OF THE WEEK AS A
RESULT. THE THERMAL TROUGH WILL THEN EXPAND NORTHWARD ALONG THE
WASHINGTON COAST BY THE WEEKEND, ALLOWING FOR FLOW TO TURN OFFSHORE.
SEAS WILL GENERALLY HOVER BETWEEN 6-9 FT THROUGH THE FIRST PART OF
THE WEEK, BEFORE SUBSIDING TOWARDS 5-7 FT NEAR MIDWEEK AND REMAINING
AT THIS RANGE HEADING INTO THE WEEKEND.
14
FIRE WEATHER
AS UPPER LEVEL RIDGING BUILDS INTO THE AREA
STARTING THURSDAY, CONDITIONS, INCLUDING FUELS, WILL NEED TO BE
MONITORED AS TEMPERATURES ARE EXPECTED TO CLIMB TO ABOVE NORMAL
VALUES BY THE END OF THE EXTENDED FORECAST PERIOD. GIVEN THE
STEEP CLIMB IN TEMPERATURES, EXTRA CAUTION WOULD BE ADVISED IN
ANY PLANNING DURING THIS TIME. CURRENT NBM MINIMUM RELATIVELY
HUMIDITY VALUES ARE RUNNING IN THE 25-35 PERCENT RANGE BY DAY 7
ACROSS PORTIONS OF THE AREA, BUT LOWER VALUES ARE ENTIRELY WITHIN
THE REALM OF POSSIBILITY. IF THE CROSS CASCADE GRADIENT GOES
NEGATIVE BY SUNDAY AS ADVERTISED IN A NUMBER OF MODELS, HUMIDITY
VALUES DROPPING INTO THE TEENS IN THE CASCADES VALLEYS AND PORTIONS
OF THE SOUTHWEST INTERIOR BECOME A DISTINCT POSSIBILITY.
27/18
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...GALE WATCH FROM TUESDAY MORNING THROUGH TUESDAY 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 5 PM PDT THIS AFTERNOON 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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