030
FXUS66 KSEW 181758
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
958 AM PST THU DEC 18 2025
SYNOPSIS
A SERIES OF WEATHER SYSTEMS WILL MOVE ACROSS WESTERN WASHINGTON
OVER THE NEXT WEEK, BRINGING PERIODS OF LOWLAND RAIN, MOUNTAIN
SNOW, AND BREEZY CONDITIONS AT TIMES.
SHORT TERM /TODAY THROUGH SATURDAY/
NO SIGNIFICANT CHANGE MADE TO THE FORECAST THIS MORNING. THE
PREVIOUS DISCUSSION CAN BE FOUND BELOW ALONG WITH UPDATES TO
AVIATION AND MARINE DISCUSSIONS:
THE NEXT SYSTEM MOVING INTO THE REGION TODAY WILL BRING ANOTHER
ROUND OF GUSTY WINDS, LOWLAND RAIN, AND MOUNTAIN SNOW TO
WESTERN WASHINGTON. LATEST RADAR ALREADY SHOWS LIGHT RAIN
MOVING UP INTO THE REGION THIS MORNING. WHILE THE BULK OF THE
PRECIPITATION WITH THIS SYSTEM WILL BE FOCUSED SOUTH OF THE AREA
OVER NORTHWESTERN OREGON, CAN STILL EXPECT AN UNSETTLED AND
BLUSTERY DAY FOR AREAS ACROSS WESTERN WASHINGTON. RAINFALL
TOTALS FOR THE LOWLANDS REMAIN ON TRACK TO BE BETWEEN 0.25-0.75
INCHES, WITH LOCALLY HIGHER AMOUNTS POSSIBLE SOUTH OF THE SOUND
AND ACROSS THE CHEHALIS RIVER VALLEY. SNOW WILL CONTINUE FOR
THE MOUNTAINS THROUGH THE MORNING HOURS, WITH SNOW LEVELS
GENERALLY HOVERING AROUND 3000 FT. SNOW LEVELS WILL RISE AGAIN
THROUGHOUT THE DAY, INCREASING TO 6000-7000 FT BY THIS AFTERNOON.
WITH WARMER AIR MOVING IN ALOFT, COULD EVEN SEE A BRIEF PERIOD
OF FREEZING RAIN AT THE PASSES AS SNOW CHANGES OVER TO RAIN.
UNCERTAINTY DOES LINGER AS TO HOW LONG THE WARM AIR WILL REMAIN
IN PLACE THOUGH, WITH SNOW LEVELS EXPECTED TO PLUMMET TO 1500-2500
FT AGAIN TONIGHT. SOUTHERLY WINDS WILL PICK UP THIS MORNING,
PEAK THIS AFTERNOON, AND EASE THROUGH THE EVENING HOURS. THE
STRONGEST WINDS WILL BE ALONG THE COAST AND FOR AREAS GENERALLY
NORTH OF EVERETT, THOUGH CONDITIONS WILL BE GUSTY AREA-WIDE.
WINDS WILL PERSIST AT 15 TO 25 MPH, WITH GUSTS TO 45 MPH
POSSIBLE AT TIMES. ANOTHER STRONGER SURGE OF WESTERLY WINDS IN
THE WAKE OF THE FRONT WILL LIKELY KEEP CONDITIONS BLUSTERY FOR
AREAS LIKE WHIDBEY ISLAND THROUGH TONIGHT.
IN ADDITION TO THE PRECIPITATION AND WIND HAZARDS, MINOR COASTAL
FLOODING WILL BE POSSIBLE TODAY WITHIN THE HOURS OF HIGH TIDE
FOR AREAS ALONG THE SAN JUAN ISLANDS AND STRAIT OF JUAN DE FUCA
DUE TO HIGHER ASTRONOMICAL TIDES.
THE SYSTEM WILL SHIFT FURTHER SOUTHWARD ON FRIDAY, THOUGH CONDITIONS
ARE EXPECTED TO REMAIN ACTIVE HEADING INTO THE WEEKEND. ADDITIONAL
ROUNDS OF LOWLAND RAIN AND PERIODS OF SUBSTANTIAL MOUNTAIN SNOW
REMAIN LIKELY AGAIN ON FRIDAY AND SATURDAY WITH SNOW LEVELS
GENERALLY HOVERING BETWEEN 1500-2500 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
CONDITIONS GENERALLY LOOK TO REMAIN RATHER ACTIVE THROUGH THE
LONG TERM, WITH ENSEMBLE CLUSTERS IN DECENT AGREEMENT OF AN
UPPER LEVEL TROUGH DIGGING ACROSS THE NORTHEASTERN PACIFIC AND
SWINGING ADDITIONAL DISTURBANCES ACROSS WESTERN WASHINGTON. WITH
SNOW LEVELS EXPECTED TO REMAIN BELOW PASS LEVEL, THIS WILL
BRING ADDITIONAL ROUNDS OF MOUNTAIN SNOW AND LOWLAND RAIN
THROUGH THE FIRST HALF OF NEXT WEEK. WINDS WILL ALSO BE BREEZY
AT TIMES AS THESE SYSTEMS MOVE THROUGH.
14
AVIATION
GENERALLY LOW END VFR TO MVFR THIS MORNING IN LOW CEILINGS AND
POCKETS OF PATCHY FOG. WIDESPREAD RAIN WILL CONTINUE, LOWERING
VISIBILITIES AND CEILINGS IN HEAVIER ACTIVITY. AN INCOMING FRONTAL
SYSTEM THIS AFTERNOON WILL BRING GUSTY WINDS TO THE WESTERN
WASHINGTON TERMINALS, WITH SOUTHERLY/SOUTHWESTERLY GUSTS REACHING UP
TO 40 KT GENERALLY BETWEEN 22Z TO 2Z. WINDS WILL GRADUALLY EASE
THROUGHOUT THE TAF PERIOD BUT WILL REMAIN SOMEWHAT GUSTY OVERNIGHT.
CEILINGS MAY BRIEFLY LIFT TO LOW END VFR OVERNIGHT, BUT A MAJORITY
OF TERMINALS ARE EXPECTED TO STAY MVFR WITH CONTINUED SHOWER
ACTIVITY.
KSEA...GENERALLY HIGH END MVFR TO LOW END VFR THIS MORNING WITH RAIN
OVER THE TERMINAL. A FRONTAL SYSTEM WILL BRING GUSTY SOUTHERLY WINDS
TO THE TERMINAL THIS AFTERNOON BETWEEN 22Z AND 2Z, WITH GUSTS PEAKING
BETWEEN 35-40 KT. CEILINGS MAY ALSO LOWER TO IFR AS THE FRONT MOVES
THROUGH IN HEAVIER RAIN SHOWERS. WINDS WILL SLOWLY TAPER THROUGH THE
FORECAST PERIOD, BUT WILL REMAIN GUSTY AROUND 20 KT OVERNIGHT.
CEILINGS WILL REMAIN BETWEEN LOW END VFR AND HIGH END MVFR OVERNIGHT
AS SHOWERS CONTINUE.
MARINE
A FRONTAL SYSTEM WILL MOVE ACROSS THE WATERS TODAY, BRINGING
ELEVATED WINDS AND SEAS TO THE REGION. THE STRONGEST WINDS WILL BE
ALONG THE COASTAL WATERS AND ALONG THE EASTERN STRAIT OF JUAN DE
FUCA, WHERE GALES WITH FREQUENT GUSTS TO 45 KT WILL BE LIKELY. WINDS
ACROSS THE REMAINDER OF THE INTERIOR WATERS WILL BE GUSTY AS WELL.
SMALL CRAFT ADVISORIES FOR THE NORTHERN INTERIOR WATERS AND
ADMIRALTY INLET HAVE BEEN UPGRADED TO A GALE WARNING THIS MORNING
BASED ON RECENT OBSERVATIONS AND INCREASING CONFIDENCE. A STRONG
WESTERLY PUSH IN THE WAKE OF THE SYSTEM WILL BRING ANOTHER ROUND OF
GALES TO THE CENTRAL AND EAST STRAIT THIS AFTERNOON AND EVENING
BEFORE CONDITIONS EASE SOMEWHAT. THE OVERALL PATTERN REMAINS ACTIVE
OVER THE WEEKEND AND INTO EARLY NEXT WEEK AS ADDITIONAL SYSTEMS MOVE
ACROSS THE AREA WATERS.
SEAS WILL BUILD TOWARDS 14-17 FT TODAY AND LOOK TO GRADUALLY SUBSIDE
BACK BELOW 10 FT OVER THE WEEKEND. AN UPTICK IN SEAS IS LIKELY AGAIN
NEXT WEEK AS ADDITIONAL DISTURBANCES MOVE ACROSS THE WATERS. 14/29
HYDROLOGY
THE NEXT WAVE OF PRECIP IS ALREADY MOVING INTO THE WESTERN HALF OF
THE CWA THIS EARLY MORNING BRINGING ANOTHER ROUND OF STEADY RAINFALL
TO THE AREA. SNOW LEVELS WILL REMAIN LOWER THIS MORNING, AROUND 2500
TO 3000 FEET, BUT ARE STILL EXPECTED TO RISE TO 5000 TO 7000 FEET
THIS AFTERNOON. SNOW LEVELS WILL FALL AGAIN TO 1500 FEET FRIDAY. QPF
AMOUNTS THROUGH FRIDAY MORNING WILL RANGE 2 TO 3 INCHES FOR THE
MAJORITY OF THE OLYMPICS AND CASCADES, WITH LOCALIZED HIGHER AMOUNTS
OVER THE CASCADES OF PIERCE AND LEWIS COUNTIES.
ONGOING RIVER FLOODING CONTINUES FOR NUMEROUS RIVERS OFF THE
CASCADES, AS WELL AS THE SKOKOMISH RIVER IN MASON COUNTY. RIVERS
WILL CONTINUE TO REMAIN ELEVATED DUE TO THE CONTINUED PRECIPITATION.
HOWEVER, AS THIS SYSTEM IS NOT EXPECTED TO HAVE THE SAME INTENSITY
AS THE PREVIOUS AR EVENTS, SOME RIVERS WILL STILL SEE LEVELS SLOWLY
RECEDE EVEN WITH THE INCOMING RAINFALL. ADDITIONALLY, GIVEN THE
GENERAL BREAK IN PRECIP YESTERDAY, THERE WILL BE A LITTLE BIT OF A
LAG IN RIVERS THAT DO REACT TO THIS CURRENT INCOMING SYSTEM. RIVERS
THAT DO SEE LEVELS RISE BECAUSE OF THIS MAY NOT SEE IMPACTS UNTIL
LATE TONIGHT OR FRIDAY. STAY TUNED TO THE LATEST HYDROLOGICAL
FORECASTS FOR ANY RIVERS IN YOUR AREA, AS THE RISK FOR ADDITIONAL
FLOODING IS STILL POSSIBLE.
THAT SAID, A FLOOD WATCH REMAINS IN EFFECT FOR SKAGIT, KING, PIERCE,
THURSTON, AND GRAYS HARBOR COUNTIES THROUGH FRIDAY AFTERNOON DUE TO
THIS ADDITIONAL INCOMING PRECIP AND AREA RIVERS CURRENTLY RUNNING
HIGH.
THE LANDSLIDE THREAT WILL REMAIN HIGH THROUGH AT LEAST FRIDAY.
18
SEW WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY UNTIL 11 PM PST THIS EVENING FOR ISLAND COUNTY-
LOWLANDS OF WESTERN SKAGIT AND NORTHWESTERN SNOHOMISH
COUNTIES-LOWLANDS OF WESTERN WHATCOM COUNTY-SAN JUAN
COUNTY.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR
CASCADES OF PIERCE AND LEWIS COUNTIES-CASCADES OF
SNOHOMISH AND NORTHERN KING COUNTIES-CASCADES OF SOUTHERN
KING COUNTY-CASCADES OF WHATCOM AND SKAGIT COUNTIES.
FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CASCADES OF PIERCE
AND LEWIS COUNTIES-CASCADES OF SNOHOMISH AND NORTHERN
KING COUNTIES-CASCADES OF SOUTHERN KING COUNTY-CITY OF
SEATTLE-EASTSIDE-FOOTHILLS AND VALLEYS OF CENTRAL KING
COUNTY-FOOTHILLS AND VALLEYS OF PIERCE AND SOUTHERN KING
COUNTIES-FOOTHILLS AND VALLEYS OF SNOHOMISH AND NORTHERN
KING COUNTIES-FOOTHILLS AND VALLEYS OF THURSTON AND LEWIS
COUNTIES-FOOTHILLS OF THE WESTERN AND SOUTHERN OLYMPIC
PENINSULA-GRAYS HARBOR COUNTY COAST-LOWER CHEHALIS RIVER
VALLEY-LOWLANDS OF LEWIS AND SOUTHERN THURSTON COUNTIES-
LOWLANDS OF PIERCE AND SOUTHERN KING COUNTIES-MIDDLE
CHEHALIS RIVER VALLEY-OLYMPIA AND SOUTHERN PUGET SOUND-
OLYMPICS-SHORELINE / LYNNWOOD / SOUTH EVERETT AREA-
WILLAPA AND BLACK HILLS.
WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR CITY OF SEATTLE-
DOWNTOWN EVERETT / MARYSVILLE AREA-EASTERN KITSAP COUNTY-
EASTSIDE-FOOTHILLS AND VALLEYS OF CENTRAL KING COUNTY-
SHORELINE / LYNNWOOD / SOUTH EVERETT AREA.
WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR FOOTHILLS AND
VALLEYS OF PIERCE AND SOUTHERN KING COUNTIES-FOOTHILLS
AND VALLEYS OF THURSTON AND LEWIS COUNTIES-GRAYS HARBOR
COUNTY COAST-LOWLANDS OF LEWIS AND SOUTHERN THURSTON
COUNTIES-LOWLANDS OF PIERCE AND SOUTHERN KING COUNTIES-
NORTHERN WASHINGTON COAST-OLYMPIA AND SOUTHERN PUGET
SOUND-WILLAPA AND BLACK HILLS.
COASTAL FLOOD ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
EASTERN STRAIT OF JUAN DE FUCA.
PZ...SMALL CRAFT ADVISORY UNTIL 6 PM PST THIS EVENING FOR GRAYS
HARBOR BAR.
SMALL CRAFT ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR PUGET
SOUND AND HOOD CANAL-WEST ENTRANCE U.S. WATERS STRAIT OF
JUAN DE FUCA.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 4 AM PST FRIDAY FOR
CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING UNTIL 4 AM PST FRIDAY FOR EAST ENTRANCE U.S.
WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING UNTIL 4 PM PST THIS AFTERNOON FOR ADMIRALTY INLET-
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-
NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS.
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