876
FXUS66 KSEW 191804
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
1004 AM PST FRI DEC 19 2025
UPDATE
NO CHANGES MADE TO THIS MORNING'S UPDATE. AT THE 700 MB LEVELS,
A SUBTLE SHORTWAVE IS USHERING IN RAIN SHOWERS AND MOUNTAIN SNOW
AS IT TRACKS INTO VANCOUVER ISLAND AND THE NORTH COAST. SHALLOW
CUMULUS IS PREVALENT ON VISIBLE, INDICATIVE OF A CONVECTIVE
ENVIRONMENT. THE SPC HAS OUTLINED W WA UNDER A GENERAL RISK OF
THUNDERSTORMS FOR TODAY BUT WITH LITTLE TO NO THREAT OF SEVERE
WEATHER.
CURRENT TEMPERATURES SIT AROUND THE UPPER 30S TO LOWER 40S. THE
WINTER STORM WARNING REMAINS IN EFFECT FOR THE CASCADE
MOUNTAINS THROUGH SATURDAY AFTERNOON WITH THE OLYMPICS EXPECTED
TO PICK UP HEFTY TOTALS, TOO. THE PREVIOUS DISCUSSION REMAINS
BELOW ALONG WITH AN UPDATED HYDRO SECTION:
SYNOPSIS
A SERIES OF WEATHER SYSTEMS MOVING ACROSS THE REGION WILL BRING
PERIODS OF LOWLAND RAIN, MOUNTAIN SNOW, AND BREEZY CONDITIONS
TO WESTERN WASHINGTON AT TIMES THROUGHOUT THE NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
SHOWERS PERSIST ACROSS THE AREA THIS MORNING IN THE WAKE OF A
SYSTEM THAT MOVED INTO THE REGION ON THURSDAY, WITH LATEST RADAR
INDICATING A CONVERGENCE ZONE DEVELOPING ACROSS KING COUNTY.
LATEST OBSERVATIONS AS OF 2 AM PT HAVE INDICATED THAT IT'S
STILL RAINING AT SNOQUALMIE PASS THIS MORNING, BUT EXPECT RAIN
TO TRANSITION OVER TO SNOW WITHIN THE NEXT COUPLE OF HOURS AS
TEMPERATURES CONTINUE TO DROP AND SNOW LEVELS CONTINUE TO FALL
TO 1500-2000 FT. SHOWER ACTIVITY WILL CONTINUE THROUGH MUCH OF
THE DAY TODAY AND WILL BRING RAINFALL AMOUNTS OF 0.10-0.25
INCHES TO MOST LOWLAND LOCATIONS. PORTIONS OF THE CENTRAL SOUND
LOWLANDS, INCLUDING SEATTLE, LOOK TO REMAIN SHADOWED, AND WILL
LIKELY SEE LOWER RAINFALL AMOUNTS OF A COUPLE HUNDREDTHS OF AN
INCH. SNOW ACCUMULATIONS WILL START TO RAMP UP ACROSS THE
MOUNTAINS THROUGHOUT THE DAY AND WILL CONTINUE HEADING INTO
SATURDAY.
A WINTER STORM WARNING REMAINS IN EFFECT FOR THE CASCADES
THROUGH SATURDAY AFTERNOON FOR SNOW ACCUMULATIONS EXPECTED TO BE
BETWEEN 1-2 FT FOR THE PASSES AND UP TO 2 TO 3 FT FOR LOCATIONS
LIKE PARADISE AND MOUNT BAKER. SHOWER ACTIVITY WILL CONTINUE
THROUGH MUCH OF THE DAY SATURDAY, KEEPING CONDITIONS RATHER
UNSETTLED ACROSS WESTERN WASHINGTON.
A SHORTWAVE WILL THEN MOVE ACROSS THE REGION ON SUNDAY AND WILL
BRING YET ANOTHER ROUND OF BREEZY SOUTHERLY WINDS, LOWLAND
RAIN, AND MOUNTAIN SNOW. THE COOLER WEATHER PATTERN WILL
CONTINUE INTO EARLY NEXT WEEK.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
CONDITIONS LOOK TO REMAIN ACTIVE THROUGH MUCH OF THE NEXT WEEK
AS ENSEMBLES REMAIN IN GOOD AGREEMENT OF AN UPPER LEVEL TROUGH
DIGGING ACROSS THE NORTHEASTERN PACIFIC AND SWINGING ADDITIONAL
DISTURBANCES INTO THE REGION. THIS WOULD CONTINUE TO BRING
PERIODS OF LOWLAND RAIN AND MOUNTAIN SNOW TO WESTERN WASHINGTON
THROUGH MUCH OF THE NEXT WEEK. THE WEATHER PATTERN WILL ALSO
ALLOW FOR A TREND TOWARDS COOLER TEMPERATURES, ESPECIALLY DURING
THE OVERNIGHT PERIOD, WHERE WE MAY START TO SEE MORNING LOWS
APPROACH FREEZING IN SPOTS BY MIDWEEK.
14
AVIATION
MIX OF CEILINGS RANGING FROM VFR TO MVFR THIS MORNING.
FOR TERMINALS STILL AT VFR THIS MORNING, BROKEN MVFR CEILINGS MAY
FILL IN AT TIMES. SOME SLIGHT RECOVERY IN THE LATE AFTERNOON AND
EARLY EVENING IS POSSIBLE TO VFR, BUT BY TONIGHT THERE WILL BE
PLENTY OF LOW-LEVEL MOISTURE TO DECREASE CEILINGS BACK DOWN TO
WIDESPREAD MVFR. SOUTHWESTERLY WINDS OF 8-14 KT TODAY, WITH GUSTS TO
20-25 KT. BREEZY WINDS EXPECTED TO LINGER INTO SATURDAY.
KSEA...MVFR AT THE TERMINAL THIS MORNING. MAY SEE CEILINGS BOUNCING
AROUND TO VFR AT TIMES, BUT HAVE DECIDED TO TREND TOWARDS MVFR THIS
MORNING. CEILINGS MAY IMPROVE TO VFR IN THE EVENING BRIEFLY BUT ARE
EXPECTED TO DECREASE BACK TO MVFR LATE TONIGHT AND CONTINUE INTO
SATURDAY. BREEZY WINDS AT THE TERMINAL EXPECTED TO PERSIST THROUGH
SATURDAY. EXPECTING SUSTAINED SPEEDS OF 10-14 KT TODAY WITH GUSTS TO
20-25 KT.
29/18
MARINE
EXPECT SOUTHERLY WINDS TO REMAIN BREEZY ACROSS PUGET SOUND AND THE
COASTAL WATERS THROUGH THE DAY TODAY, HOWEVER, WHERE SMALL CRAFT
ADVISORIES ARE IN EFFECT. PROBABILITIES FOR WINDS REACHING SMALL
CRAFT THRESHOLDS WERE LESS THAN 50 PERCENT FOR THE INTERIOR WATERS
FROM ADMIRALTY INLET NORTHWARD, SO HAVE LEFT THESE ZONES OUT OF
ADVISORIES FOR NOW. WHILE OCCASIONAL SMALL CRAFT GUSTS WILL BE
POSSIBLE AT TIMES, THE AERIAL EXTENT OF THESE WINDS REMAINS SMALL.
A WEAKENING FRONTAL SYSTEM WILL THEN MOVE INTO THE AREA WATERS ON
SUNDAY, FOLLOWED BY A STRONGER SYSTEM ON MONDAY. CONDITIONS WILL
REMAIN ACTIVE ACROSS THE AREA WATERS THROUGH MUCH OF THE NEXT WEEK,
WITH ADDITIONAL HEADLINES LIKELY.
SEAS BETWEEN 13-15 FT WILL CONTINUE TO GRADUALLY SUBSIDE TOWARDS 8-
10 FT THROUGH THE WEEKEND. SEAS WILL LIKELY INCREASE AGAIN TOWARDS
12-15 FT BY EARLY NEXT WEEK AS ADDITIONAL SYSTEMS MOVE ACROSS THE
REGION.
14
HYDROLOGY
ADDITIONAL PRECIPITATION WILL CONTINUE AT TIMES TODAY INTO SATURDAY,
PARTICULARLY OVER THE CASCADES AS SHOWERS REMAIN IN THE FORECAST.
HOWEVER, SNOW LEVELS WILL FALL TO NEAR 1500 TO 2000 FEET TODAY,
RESULTING IN SNOWFALL FOR THE MOUNTAINS ABOVE THIS LEVEL. RIVERS
THAT SAW RISES YESTERDAY INTO THIS MORNING HAVE GENERALLY CRESTED AT
THIS POINT AND ARE SLOWLY STARTING TO FALL. OUTSIDE OF REGULATED
RIVERS WHERE FLOWS MAY REMAIN ELEVATED OR INCREASE AS RESERVOIRS AND
DAM OPERATORS MANAGE THE WATER LEVELS, AREA RIVERS ARE EXPECTED TO
CREST THIS AFTERNOON AND FALL BELOW FLOOD STAGE BY TONIGHT WITH THE
EXCEPTION OF THE SKOKOMISH RIVER.
FOR RIVERS DOWNSTREAM OF DAMS, DAM OPERATIONS MAY MAINTAIN ELEVATED
FLOWS OR EVEN INCREASE FLOWS TO MAINTAIN A SAFE FLOOD POOL FOR AREA
DAMS. DAM REGULATION CHANGE RAPIDLY.
ADDITIONAL RISES ON RIVERS REMAIN POSSIBLE INTO SATURDAY, ESPECIALLY
FOR RIVERS IN LEWIS COUNTY, DUE TO THE ONGOING PRECIPITATION FROM A
SYSTEM MOVING JUST TO OUR SOUTH. FOR THESE REASONS, THE FLOOD WATCH,
INCLUDING LEWIS COUNTY, WILL REMAIN IN PLACE INTO THE
WEEKEND...WHICH INCLUDES KING, PIERCE, THURSTON, GRAYS HARBOR AND
LEWIS COUNTIES.
THE LANDSLIDE THREAT WILL REMAIN HIGH THROUGH INTO THE WEEKEND.
15
SEW WATCHES/WARNINGS/ADVISORIES
WA...COASTAL FLOOD ADVISORY UNTIL 9 AM PST THIS MORNING FOR SAN
JUAN COUNTY.
WINTER STORM WARNING UNTIL 4 PM PST SATURDAY 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 SATURDAY MORNING 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.
PZ...SMALL CRAFT ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR GRAYS
HARBOR BAR.
SMALL CRAFT ADVISORY UNTIL 4 AM PST SATURDAY 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-PUGET SOUND AND
HOOD CANAL.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page