119
FXUS66 KSEW 222244
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
244 PM PST MON DEC 22 2025
SYNOPSIS
A FRONTAL SYSTEM WILL CONTINUE TO CROSS THE REGION TODAY,
BRINGING AN ADDITIONAL ROUND OF BREEZY WINDS, LOWLAND RAIN, AND
MOUNTAIN SNOW TO WESTERN WASHINGTON. A LOW PRESSURE SYSTEM WILL
TRACK NORTHWARD ALONG THE COAST ON WEDNESDAY, BRINGING IN
ANOTHER ROUND OF PRECIPITATION AND POTENTIALLY STRONG WINDS.
UNSETTLED CONDITIONS WILL CONTINUE INTO THURSDAY AND BEYOND AS
TROUGHING PERSISTS OVER THE WESTERN US.
SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/
A FRONTAL SYSTEM WILL CONTINUE TO SHIFT INLAND ACROSS WESTERN
WASHINGTON THIS AFTERNOON AND EVENING, BRINGING ANOTHER ROUND OF
LOWLAND RAIN, MOUNTAIN SNOW, AND BREEZY WINDS. WIND GUSTS HAVE
PEAKED FOR THE DAY ALONG THE PACIFIC COAST, AND SNOW IS
BEGINNING TO WIND DOWN OVER THE OLYMPICS. AS THE FRONTAL SYSTEM
CONTINUES EASTWARD, SOUTHERLY WINDS WILL CONTINUE TO INCREASE
ACROSS THE INTERIOR, REACHING 35 TO 45 MPH WITH ISOLATED HIGHER
GUSTS ALONG THE NORTHERN OLYMPIC PENINSULA COASTLINE THROUGH
WHIDBEY ISLAND NORTHWARD. PRECIPITATION WILL ALSO CONTINUE TO
SPREAD EASTWARD ALONG THE FRONT THROUGH THE EVENING WITH SNOW
LEVELS NEAR 2000-2500 FEET. SNOWFALL RATES WILL TOP OUT OVER THE
CASCADE PASSES LATER THIS AFTERNOON AND EVENING, WITH AN
ADDITIONAL 3 TO 6 INCHES OF SNOW ACCUMULATION EXPECTED FOR
SNOQUALMIE AND STEVENS PASSES. POST-FRONTAL SHOWERS WILL
CONTINUE INTO TUESDAY MORNING, ESPECIALLY OVER THE OLYMPICS AND
CASCADES, WITH SOME DRYING AND BRIEF SUN BREAKS FOR THE
LOWLANDS BY TUESDAY AFTERNOON.
THE NEXT INCOMING WEATHER SYSTEM WILL INTENSITY OFF THE COAST OF
CALIFORNIA LATE TUESDAY AND SHIFT NORTHWARD ACROSS WESTERN
WASHINGTON ON WEDNESDAY. WHILE FORECAST MODELS CONTINUE TO
STRUGGLE WITH THE EXACT TRACK OF THIS SURFACE LOW FEATURE, IT
POSES A RISK OF A LOW PROBABILITY, HIGH IMPACT WIND EVENT
ALONGSIDE ADDITIONAL PRECIPITATION. EAST TO SOUTHEAST WINDS ARE
LIKELY TO PICK UP DURING THE MORNING WEDNESDAY ALONG THE WESTERN
SLOPES OF THE OLYMPICS AND CASCADES, FOLLOWED BY A SURGE OF
STRONGER SOUTHERLY WINDS DURING THE DAY WEDNESDAY. WHILE
ENSEMBLE MEAN WIND GUSTS CONTINUE TO RANGE GENERALLY BETWEEN 30
TO 40 MPH ACROSS MUCH OF WESTERN WASHINGTON, A HIGH END SCENARIO
COULD BRING SUDDEN WINDS REACHING 60 MPH OR MORE IF THE LOW
PRESSURE SYSTEM TRACKS IN THE VICINITY OF WESTERN WASHINGTON.
CONFIDENCE WILL INCREASE AS MORE HIGH RESOLUTION FORECAST DATA
BECOMES AVAILABLE AS THE EVENT DRAWS CLOSER. IT WILL REMAIN
EXTREMELY IMPORTANT TO CONTINUE TO MONITOR THE EVOLVING FORECAST
OVER THE NEXT FEW DAYS, ESPECIALLY GIVEN THE ANTECEDENT SOIL
MOISTURE WHICH MAY ALLOW FOR HEIGHTENED IMPACTS AT SLIGHTLY
LOWER WIND SPEEDS. IN ADDITION TO THE POTENTIAL GUSTY WINDS ON
WEDNESDAY, THE LOWLANDS WILL SEE UP TO A QUARTER INCH OF RAIN
WHILE ELEVATIONS ABOVE 2500 FEET WILL SEE A FEW MORE INCHES OF
SNOW ACCUMULATION.
LONG TERM /THURSDAY THROUGH SUNDAY/
LIGHTER PRECIPITATION IS ON TRACK TO SPREAD INTO WESTERN
WASHINGTON ON THURSDAY AND FRIDAY AS THE LOW PRESSURE SYSTEM
EXITS TO THE NORTH. HIGH PRESSURE IS THEN FORECAST TO BUILD
OF THE WESTERN US COAST AND BUILD INLAND TOWARDS THE PACIFIC
NORTHWEST, HELPING TO SHIFT THE BULK OF ANY INCOMING
PRECIPITATION NORTHWARD. CONDITIONS MAY DRY OUT ACROSS MUCH OF
THE LOWLANDS BY NEXT WEEKEND, WITH LOWLAND RAIN AND MOUNTAIN
SHOWERS ALONG THE BRITISH COLUMBIA BORDER. WHILE UNSETTLED AND
COOLER CONDITIONS WILL PERSIST, SIGNALS FOR ANOTHER INCOMING
ATMOSPHERIC RIVER SYSTEM TOWARDS THE END OF NEXT WEEK HAVE
DECREASED, WITH MODELS FOCUSING THIS POTENTIAL SYSTEM NORTHWARD
INTO CANADA.
15
AVIATION
SOUTHWEST FLOW ALOFT WILL CONTINUE INTO TUESDAY WITH A FRONTAL
SYSTEM AND ASSOCIATED UPPER TROUGH MOVING ONSHORE LATER THIS
EVENING. CEILINGS WILL LOWER TO MVFR AT TIMES IN RAIN LATE THIS
AFTERNOON INTO THIS EVENING. PRECIPITATION WILL DIMINISH OVERNIGHT
WITH AREAS OF MVFR CONTINUING. A RETURN TO VFR IS EXPECTED ACROSS
MUCH OF WESTERN WASHINGTON ON TUESDAY MORNING. GUSTY SOUTHERLY
SURFACE WINDS WILL ACCOMPANY THE FRONT BEFORE EASING OVERNIGHT.
KSEA...CEILINGS WILL LOWER TO MVFR IN RAIN AT TIMES LATE THIS
AFTERNOON INTO THE EVENING. MVFR CEILINGS WILL REMAIN IN PLACE AT
TIMES OVERNIGHT BEFORE LIFTING BACK TO VFR AGAIN TUESDAY MORNING.
SURFACE WINDS SOUTHERLY 15 TO 25 KNOTS EASING TO 8 TO 12 KNOTS
OVERNIGHT.
27
MARINE
A FRONTAL SYSTEM WILL MOVE ONSHORE LATE THIS EVENING. A WEAK SURFACE
TROUGH WILL REMAIN OVER THE COASTAL WATERS INTO TUESDAY.
CONSIDERABLE UNCERTAINTY REMAINS IN THE FORECAST FOR MIDWEEK WITH
THE PATH AND STRENGTH OF A SECONDARY TROUGH. A BROAD SURFACE TROUGH
WELL TO THE SOUTH OF THE AREA AND HIGH PRESSURE OVER THE INTERIOR OF
BRITISH COLUMBIA WILL LEAD TO A PERIOD OF NORTHERLY FLOW LATE IN THE
WEEK.
SEAS ARE EXPECTED TO BRIEFLY DROP BELOW 10 FEET MIDWEEK BEFORE
BUILDING BACK TO DOUBLE DIGITS AGAIN FRIDAY ONWARD.
27
HYDROLOGY
RIVERS ACROSS WESTERN WASHINGTON CONTINUE TO TREND DOWNWARD AS
PRECIPITATION ACROSS THE REGION LIGHTENS UP. A FRONTAL SYSTEM
WILL BRING IN GENERALLY HALF AN INCH OF RAINFALL OR LESS THROUGH
TUESDAY WITH SNOW LEVELS NEAR 2000-2500 FEET. NO SIGNIFICANT
RISES ARE EXPECTED ON AREA RIVERS, WITH THE SKOKOMISH RIVER
BEING THE ONLY RIVER TO REMAIN IN FLOOD STAGE UNTIL WEDNESDAY.
ADDITIONAL RAINFALL THROUGHOUT THE WEEK IS NOT EXPECTED TO CAUSE
ANY ADDITIONAL RISES TO AREA RIVERS, AND FLOODING OUTSIDE OF THE
SKOKOMISH RIVER IN MASON COUNTY IS NOT EXPECTED OVER THE NEXT 7
DAYS.
ADDITIONALLY, THE THREAT OF LANDSLIDES HAS DECREASED ACROSS
WESTERN WASHINGTON.
15
SEW WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR ISLAND COUNTY-
LOWLANDS OF WESTERN SKAGIT AND NORTHWESTERN SNOHOMISH
COUNTIES-LOWLANDS OF WESTERN WHATCOM COUNTY-PORT TOWNSEND
AREA-SAN JUAN COUNTY.
WINTER STORM WARNING UNTIL 10 PM PST THIS EVENING FOR CASCADES
OF WHATCOM AND SKAGIT COUNTIES.
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR
OLYMPICS.
WIND ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR GRAYS HARBOR
COUNTY COAST-NORTHERN WASHINGTON COAST.
PZ...SMALL CRAFT ADVISORY UNTIL 10 AM PST TUESDAY FOR GRAYS HARBOR
BAR.
SMALL CRAFT ADVISORY UNTIL 4 AM PST TUESDAY FOR ADMIRALTY
INLET-CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-PUGET
SOUND AND HOOD CANAL-WEST ENTRANCE U.S. WATERS STRAIT OF
JUAN DE FUCA.
GALE WARNING UNTIL 10 PM PST THIS EVENING 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-EAST ENTRANCE U.S.
WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS
INCLUDING THE SAN JUAN ISLANDS.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST
TUESDAY 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-
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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