160
FXUS66 KSEW 030324
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
824 PM PDT WED JUL 2 2025
UPDATE
NO SIGNIFICANT CHANGES TO THE FORECAST THIS EVENING.
PLEASE REFER TO AN UPDATED AVIATION SECTION BELOW.
SYNOPSIS
ONSHORE FLOW WILL MAINTAIN A COOLING TREND FOR
WESTERN WASHINGTON THROUGH THURSDAY, WITH CONTINUED MORNING
STRATUS AND AFTERNOON SUNSHINE. A WEAK TROUGH WILL MOVE INLAND ON
FRIDAY, INCREASING ZONAL FLOW THROUGH THE HOLIDAY WEEKEND WITH
MOSTLY DRY AND MILD CONDITIONS. HIGH PRESSURE WILL BUILD OVER THE
SOUTHWESTERN US BY THE MIDDLE OF NEXT WEEK, PROMOTING WARMER
CONDITIONS ACROSS WESTERN WASHINGTON.
SHORT TERM /TONIGHT THROUGH SATURDAY/
A LONGWAVE TROUGH SLOWLY
PASSING OVER BRITISH COLUMBIA IS GENERATING ONSHORE FLOW ACROSS
WESTERN WASHINGTON, WITH TEMPERATURES COOLING SEVERAL DEGREES FROM
YESTERDAY. HIGHS TODAY PEAKED IN THE MID TO UPPER 70S ACROSS THE
INTERIOR, AND IN THE UPPER 50S TO LOWER 60S ALONG THE COAST.
PARTLY CLOUDY SKIES THIS EVENING WILL FILL IN TONIGHT, WITH
ANOTHER ROUND OF MORNING STRATUS EXPANDING EASTWARD FROM THE
PACIFIC COAST ACROSS THE CHEHALIS BASIN AND OVER THE PUGET SOUND
EARLY THURSDAY MORNING. SOME AREAS MAY SEE A DRIZZLE BELOW THE
STRATUS IN THE MORNING, BUT CONDITIONS WILL CLEAR UP BY THE
AFTERNOON AND GIVE WAY TO ANOTHER PARTLY CLOUDY AFTERNOON WITH
PLENTY OF SUN BREAKS. TEMPERATURES THURSDAY WILL BE A FEW DEGREES
COOLER THAN TODAY, WITH HIGHS IN THE LOW TO MID 70S ACROSS THE
INTERIOR AND CLOSER TO 60 DEGREES FOR AREAS BY THE WATER.
A WEAK TROUGH WILL LIFT ACROSS THE PACIFIC NORTHWEST ON
INDEPENDENCE DAY, RESULTING IN LITTLE MORE THAN PARTLY CLOUDY
SKIES AND NEAR-NORMAL TEMPERATURES ACROSS WESTERN WASHINGTON FOR
THE HOLIDAY. FORECAST MODELS ARE IN GOOD AGREEMENT THAT THE BULK
OF THE MOISTURE ASSOCIATED WITH THIS SYSTEM WILL STAY TO THE EAST
OF THE CASCADE CREST, BUT THERE IS POTENTIAL FOR ISOLATED LIGHT
SHOWER ACTIVITY OVER THE CASCADES FRIDAY EVENING. ZONAL FLOW WILL
DEVELOP ON SATURDAY AS THE TROUGH MOVES INLAND, WITH CONTINUED
MILD CONDITIONS AND MORNING CLOUD COVER. HIGHS FRIDAY AND SATURDAY
WILL STAY FAIRLY STEADY, REACHING THE MID TO UPPER 70S ACROSS THE
INTERIOR AND THE LOW TO MID 60S ALONG THE COAST.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
ZONAL FLOW IS FAVORED TO
CONTINUE INTO EARLY NEXT WEEK, RESULTING IN CONTINUED MILD
CONDITIONS WITH PERIODS OF MORNING CLOUDS AND AFTERNOON SUNSHINE.
A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE SOUTHWESTERN US
TOWARDS THE MIDDLE OF NEXT WEEK, SIGNALING A RETURN OF WARMER
TEMPERATURES ACROSS WESTERN WASHINGTON, BUT THE DEGREE OF WARMING
REMAINS UNCERTAIN AT THIS TIME.
15
AVIATION
SOUTHWESTERLY FLOW ALOFT WITH LOW LEVEL ONSHORE FLOW.
POCKETS OF MVFR STRATUS LINGERING ALONG THE COAST THE COAST THIS
EVENING WILL FILL TONIGHT 03Z-06Z THEN MOVE INLAND OVERNIGHT. HREF
ENSEMBLES SHOWING A 30-40% CHANCE OF MVFR CEILINGS DEVELOPING FROM
KSEA TO KPAE AS EARLY AS 05/06Z AND 60-80% CHANCE BY 12/14Z. EXPECT
MORE WIDESPREAD STRATUS DEVELOPMENT TO LINGER A BIT LONGER INTO
THURSDAY MORNING BEFORE LIFTING AND MIXING OUT 17/18Z.
KSEA...VFR CONDITIONS WITH SOME HIGH CLOUDS WILL LINGER THROUGH THE
EVENING. AS NOTED ABOVE, HIGH-RES ENSEMBLES SHOWING A 30-40% CHANCE
OF CEILINGS BELOW 3KT FT AS EARLY AS 05/06Z AND HIGHER ODDS BY
13/14Z. WINDS ARE BOUNCING BETWEEN SOUTHWEST AND OCCASIONAL
NORTHWESTERLIES BUT ARE SEEMING TO SETTLE INTO A MORE SOUTHWESTERLY
PATTERN. KBFI WAS NW BUT SEEMS TO BE SETTLING INTO SOUTHWESTERLY AS
WELL. HIGH OVC TO BKN LAYERS AT BOTH TERMINALS.
21
MARINE
HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE COASTAL AND
OFFSHORE WATERS THIS WEEK WITH THERMALLY INDUCED LOW PRESSURE EAST
OF THE CASCADES. A WEAK FRONT WILL DISSIPATE OVER THE OFFSHORE
WATERS SATURDAY.
A TYPICAL DIURNAL PATTERN WITH WESTERLY PUSHES THROUGH THE STRAIT OF
JUAN DE FUCA EACH EVENING THROUGH THE WEEKEND. THE SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR TONIGHT FOR THE CENTRAL AND EASTERN
STRAIT WITH GUSTS TO 30 KNOTS POSSIBLE. THURSDAYS PUSH LOOKS TO BE A
BIT WEAKER, WITH THE PUSH FRIDAY LOOKING MORE LIKELY TO RESULT IN
ANOTHER ROUND OF SMALL CRAFT ADVISORY CONDITIONS FOR THE CENTRAL AND
EASTERN STRAIT.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA.
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