801
FXUS66 KSEW 121644
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
944 AM PDT THU JUN 12 2025
SYNOPSIS
A WEAK UPPER TROUGH WILL MOVE INTO WESTERN WASHINGTON
TODAY THEN REMAIN OVER THE AREA ON FRIDAY. THIS WILL LEAD TO
COOLER TEMPERATURES, INCREASED CLOUD COVER, AND OCCASIONAL CHANCES
FOR MOUNTAIN SHOWERS AND COASTAL DRIZZLE. UPPER RIDGING WILL
WEAKLY REBUILD LATE IN THE WEEKEND FOR A MODEST WARMING TREND
BEFORE ANOTHER TROUGH APPROACHES THE AREA EARLY IN THE COMING
WEEK.
SHORT TERM /TODAY THROUGH SATURDAY/
THE CURRENT FORECAST
REMAINS ON TRACK WITH NO PLANNED UPDATES THIS MORNING. 33
PREVIOUS DISCUSSION...A WEAK UPPER TROUGH WILL MOVE INTO WESTERN
WASHINGTON LATE TODAY FOR A MOSTLY CLOUDY DAY AHEAD AND
TEMPERATURES A LITTLE BELOW AVERAGE. THE TROUGH WILL LEAD TO A
CHANCE OF SHOWERS ACROSS THE NORTH CASCADES AND NEAR THE CANADIAN
BORDER TONIGHT AND FRIDAY AS A COUPLE OF WEAK DISTURBANCES PIVOT
ACROSS THE REGION. OTHERWISE, MAINLY DRY CONDITIONS ARE EXPECTED.
AN UPPER LEVEL TROUGH WILL START TO DIG SOUTHWARD OFFSHORE ON
SATURDAY. THIS WILL LEAD TO A SLIGHT RISE IN HEIGHTS OVER WESTERN
WASHINGTON. INTERIOR HIGH TEMPERATURES WILL EDGE CLOSER TO
NORMAL, BUT CONTINUING ONSHORE FLOW WILL ENSURE THAT COASTAL AREAS
WILL REMAIN MOSTLY CLOUDY AND ON THE COOL SIDE.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
THE PATTERN REMAINS RATHER
STATIC HEADING INTO SUNDAY WITH AN UPPER TROUGH OFFSHORE AND WEAK
RIDGING OVER WESTERN WASHINGTON. MODEL AGREEMENT IS STARTING TO
FALL INTO PLACE EARLY NEXT WEEK MORE SO THAN THE PAST FEW NIGHTS.
A WEAK UPPER TROUGH IS SLATED TO MOVE ONSHORE ON MONDAY, BUT WILL
PROBABLY PRODUCE LITTLE MORE THAN A BUMP IN ONSHORE FLOW AND THE
ASSOCIATED SLIGHT COOLING THAT COMES WITH IT. A MAJORITY OF THE
ENSEMBLES FROM BOTH THE GFS AND EURO ARE NOW TARGETING THE
TUESDAY/WEDNESDAY PERIOD FOR A SOMEWHAT MORE SUBSTANTIAL UPPER
TROUGH (BY MID JUNE STANDARDS) TO MOVE INTO THE REGION AND PRODUCE
SOME LIGHT PRECIP. IT'S NOT SHAPING UP TO PRODUCE MUCH IN THE WAY
OF IMPACTS, BUT IT COULD BE THE BEGINNING OF A MORE PROLONGED
PERIOD OF COOLER, MORE UNSETTLED CONDITIONS THAT WILL SHARPLY
CONTRAST HOW THE MONTH BEGAN. 27
AVIATION
AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION
TODAY WITH SOUTHWEST/WEST FLOW ALOFT TODAY AND TONIGHT. MVFR STRATUS
DECK REMAINS IN PLACE ACROSS THE REGION AND WITH IT BEING A DEEPER
LAYER WILL EXPECT IT TO PERSIST THROUGH AROUND 19-20Z THIS MORNING
BEFORE LIFTING IN THE INTERIOR. COASTAL TERMINALS WILL REMAIN IN
THE STRATUS MUCH OF THE DAY. EXPECT ONSHORE FLOW TO BRING ANOTHER
WIDESPREAD STRATUS PUSH OVERNIGHT WITH THE PUGET SOUND TERMINALS
AGAIN LOWERING INTO THE MVFR RANGE TONIGHT 09-12Z.
KSEA...MVFR CEILINGS HANG ON THIS MORNING, BEFORE LIFTING AROUND
20Z. EXPECT MID/HIGH CLOUD DECK TO REMAIN AT LEAST BROKEN THROUGH
THE DAY, BUT SUFFICIENTLY HIGH. SOUTHERLY SURFACE WIND WILL BECOME
MORE WEST THIS AFTERNOON AT AROUND 6-8 KT, BEFORE RETURNING
SOUTHERLY TONIGHT. EXPECT A RETURN OF MVFR STRATUS TONIGHT AFTER
AROUND 10Z.
MARINE
SURFACE HIGH PRESSURE CENTERED OFFSHORE THROUGH THE END
OF THE WEEK WILL MOVE CLOSER TO THE COASTAL WATERS OVER THE WEEKEND.
A WEAKENING FRONT WILL REACH THE WATERS MONDAY NIGHT. THE SMALL
CRAFT ADVISORY FOR THE COASTAL WATERS HAS BEEN EXPANDED TO INCLUDE
THE INNER COASTAL WATERS AS WELL GIVEN THE CONTINUED STEEP SEAS.
EXPECT SEAS TO CONTINUE TO REMAIN AROUND 7 TO 9 FT WITH THE DOMINANT
PERIOD AROUND 7 OR 8 SECONDS INTO FRIDAY DUE TO THE PERSISTENT
NORTHWESTERLY WINDS MAINTAINING THESE STEEP CONDITIONS.
ELSEWHERE, EXPECT DIURNALLY DRIVEN PUSHES OF WEST WINDS THROUGH THE
CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA EACH OF THE NEXT FEW
NIGHTS. WINDS WILL GENERALLY BE RIGHT AROUND 20 KT EACH NIGHT WITH
SOME GUSTS TO 25 KT. WILL MAINTAIN TONIGHT'S ADVISORY FOR NOW AND
EVALUATE TRENDS TO DETERMINE THE NEED FOR ANY ADDITIONAL ADVISORIES
ON SUBSEQUENT EVENINGS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM PDT FRIDAY
FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 6 PM PDT FRIDAY 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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