508
FXUS66 KSEW 111731
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
1031 AM PDT THU SEP 11 2025
SYNOPSIS
BROAD UPPER LEVEL TROUGHING WILL SLOWLY SLIDE EAST
THURSDAY AND FRIDAY, BRINGING MOSTLY DRY CONDITIONS TO THE
REGION THAT WILL PERSIST INTO SATURDAY. BY SUNDAY, THE NEXT
WEATHER SYSTEM WILL BRING A CHANCE FOR PRECIPITATION BACK TO THE
REGION.
SHORT TERM /TODAY THROUGH SATURDAY/
AN UPPER LEVEL LOW
CONTINUES TO SPIN OVER THE PAC NW TODAY WITH SHOWERS MAINLY TO
OUR EAST (OVER EASTERN WA/OR). LOW CLOUDS WILL COVER MUCH OF THE
LOWLANDS THIS MORNING WITH SUNBREAKS EXPECTED THIS AFTERNOON.
EXPECT HIGH TEMPERATURES IN THE 70S WITH 60S ALONG THE COAST.
THE UPPER LOW WEAKENS AS IT SHIFTS SLIGHTLY EASTWARD ON FRIDAY,
WHILE WEAK HIGH PRESSURE BUILDS OVER WESTERN WA. OVERALL, A DRY
DAY ON TAP BUT ALSO A LITTLE COOLER WITH INCREASING ONSHORE FLOW.
THE NEXT INCOMING PACIFIC FRONTAL SYSTEM WILL STALL OFFSHORE ON
SATURDAY WITH THE RIDGE OVER WA STILL INTACT. THE AIR MASS WILL BE
WARMER WITH INTERIOR TEMPERATURES REACHING THE MID TO UPPER 70S.
HIGHS ALONG THE COAST WILL TRACK IN THE 60S TO LOWER 70S. 33
LONG TERM /SUNDAY THROUGH WEDNESDAY/
RAIN WILL INCREASE ON
SUNDAY AS AN UPPER LEVEL TROUGH SHIFTS INLAND. MOST AREAS WILL SEE
MEASURABLE RAIN WITH WETTING RAINS IN THE MOUNTAINS. THE COOLER
AIR MASS WILL KEEP TEMPERATURES DOWN AND IN THE 60S. SHOWERS WILL
LINGER INTO MONDAY BUT WILL TAPER DOWN AS THIS SYSTEM EXITS EAST.
DRIER WEATHER IS FAVORED MOVING TOWARD MIDWEEK AS HIGH PRESSURE
RETURNS. TEMPERATURE TRENDS LOOK CLOSE TO NORMAL. 33
AVIATION
UPPER LEVEL LOW CENTERED OVER NORTHERN CALIFORNIA WILL
SLOWLY MOVE EAST TODAY AND TONIGHT. TEMPORARY UPPER LEVEL RIDGE
BUILDING INTO WESTERN WASHINGTON LATER TONIGHT INTO FRIDAY.
NORTHEASTERLY FLOW ALOFT BECOMING WESTERLY TONIGHT. LIGHT ONSHORE
FLOW IN THE LOWER LEVELS.
IFR/LIFR STRATUS CONTINUE TO COVER THE LOWLANDS OF W WA SO FAR THIS
MORNING. TERMINALS WILL SEE VISIBILITY LESS THAN A MILE THROUGH 17-
18Z. STRATUS DISSIPATING BACK TO THE COAST 19Z-21Z WITH CLEAR SKIES
OVER THE INTERIOR AFTER 21Z. MVFR CEILINGS REMAINING ALONG THE
COAST. STRATUS MOVING INLAND AGAIN EARLY FRIDAY MORNING.
KSEA...LIFR STRATUS AT THE TERMINAL THIS MORNING WITH VISIBILITIES
LESS THAN A MILE BUT IMPROVING TOWARDS 17-18Z. STRATUS LIFTING TO
IFR AROUND 18Z AND MVFR 19Z BEFORE SCATTERING OUT AROUND 20Z. CLEAR
SKIES INTO TONIGHT WITH IFR STRATUS RETURNING TO THE TERMINAL AROUND
12Z FRIDAY MORNING. SURFACE WINDS BECOMING SOUTHWESTERLY 4 TO 6
KNOTS. WINDS TRYING TO COME AROUND TO NORTHWEST 22Z-02Z BUT LIKELY
ENDING UP IN THE 250-280 DEGREE RANGE BEFORE GOING BACK TO
SOUTHWESTERLY AFTER 06Z.
FELTON/MCMILLIAN
MARINE
A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE INLAND WATER
ZONES OF PUGET SOUND, NORTHERN INLAND, ADMIRALTY INLET AND EAST
STRAIT UNTIL 11 AM THIS MORNING.
WEAK HIGH PRESSURE OVER THE WATERS WITH LOWER PRESSURE
EAST OF THE CASCADES WILL KEEP ONSHORE FLOW PATTERN GOING THROUGH
FRIDAY NIGHT. FRONT MOVING INTO THE COASTAL WATERS SATURDAY AND
INLAND SUNDAY. HIGH PRESSURE REDEVELOPS AGAIN FOR THE FIRST PART
OF NEXT WEEK.
SMALL CRAFT ADVISORY WESTERLY WINDS IN THE CENTRAL AND EASTERN
STRAIT OF JUAN DE FUCA TONIGHT AND AGAIN SUNDAY NIGHT. SMALL CRAFT
ADVISORY WINDS POSSIBLE OVER THE COASTAL WATERS SUNDAY.
SEAS GENERALLY IN THE 4 TO 6 FOOT RANGE WITH SLIGHTLY HIGHER SEAS
POSSIBLE SUNDAY INTO SUNDAY NIGHT. FELTON/MCMILLIAN
SEW WATCHES/WARNINGS/ADVISORIES
WA...DENSE FOG ADVISORY UNTIL 11 AM PDT THIS MORNING FOR CITY OF
SEATTLE-DOWNTOWN EVERETT / MARYSVILLE AREA-EASTERN KITSAP
COUNTY-EASTSIDE-ISLAND COUNTY-LOWLANDS OF PIERCE AND
SOUTHERN KING COUNTIES-LOWLANDS OF WESTERN SKAGIT AND
NORTHWESTERN SNOHOMISH COUNTIES-LOWLANDS OF WESTERN
WHATCOM COUNTY-NORTHERN HOOD CANAL-OLYMPIA AND SOUTHERN
PUGET SOUND-PORT TOWNSEND AREA-SHORELINE / LYNNWOOD /
SOUTH EVERETT AREA-SOUTHERN HOOD CANAL.
PZ...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM PDT FRIDAY
FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
DENSE FOG ADVISORY UNTIL 11 AM PDT THIS MORNING FOR ADMIRALTY
INLET-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-
NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS-
PUGET SOUND AND HOOD CANAL.
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