890
FXUS66 KSEW 130327
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
826 PM PDT THU JUN 12 2025
UPDATE
LOW CLOUDS STILL PRESENT OVER THE COAST WITH INTERIOR MID
TO HIGH LEVEL CLOUDS SCATTERING OUT. WHAT FEW ECHOES THERE ARE ON
RADAR, RESULTING IN LIGHT DRIZZLE AT BEST, CONTINUE TO FIZZLE OUT.
COASTAL STRATUS EXPECTED TO PUSH INLAND AGAIN TONIGHT BEFORE
BREAKING UP IN THE LATE MORNING/EARLY AFTERNOON. INHERITED FORECAST
REMAINS ON TRACK WITH THIS, SO NO EVENING UPDATE WILL BE NEEDED.
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 /TONIGHT THROUGH SUNDAY/
A WEAK UPPER TROUGH IS OVER
THE REGION TODAY WITH A FEW SHOWERS ALONG THE COAST AND OVER THE
BORDER IN B.C. ONSHORE FLOW IS KEEPING TEMPERATURES COOLER AND IN
THE 50S AND 60S. LOWS WILL BE COOLER OVERNIGHT AND IN THE 40S.
A DEEP UPPER LOW WILL SPIN OFF SE AK FRIDAY THROUGH THE WEEKEND.
WESTERN WA IS MOSTLY DRY WITH WEAK RIDGING AND JUST ISOLATED
LIGHT SHOWERS IN THE CASCADES. TEMPERATURES ARE CLOSE TO AVERAGE
WITH HIGHS IN THE 60S AND 70S. LOWS WILL BE SLIGHTLY COOLER AND IN
THE 40S. 33
LONG TERM /MONDAY THROUGH THURSDAY/
A DEEP UPPER LEVEL LOW
CONTINUES TO SPIN OFFSHORE ON MONDAY WITH ONGOING ONSHORE FLOW
ACROSS WESTERN WA. THE LOW EVENTUALLY SHIFTS FARTHER SOUTH WHILE
PUSHING A WEAK FRONT INTO THE REGION MONDAY NIGHT OR TUESDAY FOR A
CHANCE OF SHOWERS. THE LOW STALLS OFF SOUTHERN B.C. MIDWEEK THEN
SHIFTS INLAND TOWARD THE END OF THE WEEK, WITH MORE SHOWERS
EXPECTED. TEMPERATURES LOOK TO TRACK CLOSE TO AVERAGE THROUGHOUT.
33
AVIATION
AN UPPER LEVEL TROUGH WILL EXIT THE AREA TONIGHT
ALTHOUGH THE PARENT UPPER LOW REMAINS IN PLACE OVER THE CANADIAN
COAST, ALLOWING FOR WESTERLY TO SOUTHWESTERLY FLOW ALOFT TO PERSIST.
SURFACE WINDS EASING OVERNIGHT BEFORE BECOMING SOUTHERLY AND
SPEEDING UP TO GENERALLY 7-12 KTS BY FRIDAY AFTERNOON.
VFR CONDITIONS IN PLACE FOR MOST TERMINALS WITH EXCEPTION OF THE
COAST, WHERE STRATUS CONTINUE TO KEEP CIGS WITHIN MVFR RANGE.
STRATUS WILL PUSH INLAND AGAIN TONIGHT WITH WIDESPREAD MVFR
CONDITIONS EXPECTED TO BE IN PLACE BY 12Z FRIDAY MORNING. GRADUAL
CLEARING AFTERWARD FOR AT LEAST INTERIOR TERMINALS, WITH WIDESPREAD
VFR CONDITIONS EXPECTED TO RETURN BETWEEN 18-20Z.
KSEA...VFR CONDITIONS WITH SCATTERED MID TO HIGH CLOUDS THIS EVENING
AND EARLY TONIGHT. MVFR CONDITIONS EXPECTED TO DEVELOP BETWEEN 10-12Z
AND REMAIN THAT WAY BEFORE SCATTERING OUT BY 20Z AND RETURNING TO
VFR. LIGHT AND VARIABLE WINDS THIS EVENING BEFORE RETURNING TO
SOUTHERLY WITH SPEEDS 4-8 KTS OVERNIGHT. SOUTHWESTERLY WINDS BY
EARLY AFTERNOON WITH SPEEDS 5-10 KTS.
18
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 COASTAL WATERS MONDAY. THE SMALL
CRAFT ADVISORY FOR THE COASTAL WATERS CONTINUES WITH THE STEEP
CONDITIONS. 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.
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 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 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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