050
FXUS66 KSEW 131927
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
1227 PM PDT MON APR 13 2026
SYNOPSIS
SHOWERS WILL CONTINUE THROUGH TONIGHT. THE NEXT WEATHER SYSTEM
WILL MOVE INTO THE AREA ON TUESDAY, BRINGING LOWLAND RAIN,
MOUNTAIN SNOW, AND BREEZY WINDS TO WESTERN WASHINGTON.
PRECIPITATION WILL LINGER INTO WEDNESDAY, WITH DRIER WEATHER
EXPECTED THURSDAY INTO THE WEEKEND. COLD, NEAR-FREEZING MORNING
LOWS ARE EXPECTED FOR PORTIONS OF THE SOUTH SOUND AND CHEHALIS
VALLEY ON THURSDAY. CHANCES OF PRECIPITATION RETURN LATE IN THE
WEEKEND INTO EARLY NEXT WEEK.
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/
SHOWERY AND UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE
REMAINDER OF THE DAY TODAY. CLOUDY CONDITIONS AND AFTERNOON
HIGHS WILL GENERALLY BE IN THE LOW TO MID 50S ACROSS THE AREA.
THE NEXT SYSTEM WILL THEN MOVE INTO THE AREA ON TUESDAY,
BRINGING THE NEXT ROUND OF LOWLAND RAIN, MOUNTAIN SNOW, AND
BREEZY WINDS. MOUNTAIN SNOW WILL CONTINUE INTO WEDNESDAY AND
ISOLATED CHANCES OF THUNDERSTORMS WILL BE POSSIBLE IN THE WAKE
OF THE SYSTEM. ADDITIONAL DETAILS ON THE HAZARDS HAVE BEEN
OUTLINED BELOW:
WINDS: SOUTHERLY WINDS WILL INCREASE ACROSS WESTERN WASHINGTON
THROUGH THE MORNING HOURS ON TUESDAY. WIND GUSTS WILL GENERALLY
BE BETWEEN 25-40 MPH, THOUGH ISOLATED GUSTS TO 45 MPH WILL BE
POSSIBLE AT TIMES. WITH NEW FOLIAGE ON TREES, TREE DAMAGE MAY
BE POSSIBLE WITH ANY GUSTS BETWEEN 35-45 MPH. WINDS WILL GRADUALLY
EASE AREA-WIDE AGAIN LATE TUESDAY NIGHT INTO WEDNESDAY MORNING.
MOUNTAIN SNOW: SNOW LEVELS WILL START OUT BETWEEN 3000-4000 FT
ON TUESDAY, BUT WILL FALL TO 1000-1500 FT BY WEDNESDAY, BRINGING
ACCUMULATING SNOW FOR THE MOUNTAINS- ESPECIALLY FOR THE CASCADE
PASSES. THE HEAVIEST SNOW WILL OCCUR TUESDAY NIGHT INTO WEDNESDAY
MORNING AND WILL BE FOR ELEVATIONS GENERALLY ABOVE 2500 FT. SNOW
WILL LINGER THROUGH THE DAY WEDNESDAY, BEFORE TAPERING LATE
WEDNESDAY NIGHT INTO THURSDAY.
RAIN: THIS SYSTEM WILL BRING THE NEXT ROUND OF LOWLAND RAIN TO
THE REGION. THE MOST LIKELY RAINFALL AMOUNTS FOR THE INTERIOR
LOWLANDS LOOK TO BE BETWEEN 0.50-1 INCH, WITH THE TYPICAL
SHADOWED AREAS GENERALLY EXPECTED TO SEE A LITTLE LESS- BETWEEN
0.25-0.50 INCHES. AREAS ALONG THE COAST WILL SEE THE MOST RAIN,
WITH RAINFALL AMOUNTS GENERALLY EXPECTED TO RANGE BETWEEN 1-1.25
INCHES FROM TUESDAY MORNING THROUGH WEDNESDAY NIGHT.
THUNDERSTORMS: A SLIGHT CHANCE OF THUNDERSTORMS WILL BE POSSIBLE
IN THE COOL POST-FRONTAL AIRMASS ON WEDNESDAY. THE MOST LIKELY
AREAS FOR ANY THUNDERSTORM DEVELOPMENT WILL BE ALONG THE PACIFIC
COAST. ANY ISOLATED THUNDERSTORMS THAT DO DEVELOP MAY PRODUCE
DANGEROUS LIGHTNING, GUSTY WINDS, SMALL HAIL, AND BRIEF HEAVY
DOWNPOURS.
LONG TERM /THURSDAY THROUGH MONDAY/
DRIER CONDITIONS ARE EXPECTED THE SECOND HALF OF THE WEEK WITH
HIGH PRESSURE BUILDING BACK INTO THE REGION. CLEARING SKIES
OVERNIGHT WILL ALLOW FOR TEMPERATURES TO DIP INTO THE LOW TO MID
30S ACROSS MUCH OF THE AREA BY THURSDAY MORNING. MOST LIKELY
SPOTS TO APPROACH FREEZING WILL BE AREAS AROUND THE SOUTH SOUND
AND THE CHEHALIS VALLEY- WHERE FROST WILL ALSO BE POSSIBLE. DRY
CONDITIONS WILL PERSIST THROUGH SATURDAY AS THE RIDGE OF HIGH
PRESSURE MOVES OVERHEAD. AFTERNOON HIGH TEMPERATURES WILL WARM A
FEW DEGREES EACH DAY- TOPPING OUT IN THE UPPER 50S TO LOW 60S
ACROSS THE REGION BY SATURDAY. AN UPPER LEVEL LOW WILL THEN
APPROACH THE REGION ON SUNDAY, BRINGING THE RETURN OF SHOWER
CHANCES TO THE REGION. SHOWERS THEN LOOK TO LINGER INTO EARLY
NEXT WEEK.
14
AVIATION
NORTHWEST FLOW BECOMING WESTERLY TONIGHT INTO TUESDAY AS AN UPPER-
LOW TRACKS ALONG THE BC COAST. MOSTLY VFR SO FAR THIS AFTERNOON BUT,
MVFR TO IFR CIGS REMAIN FOR TERMINALS (KBFI AND KPAE) IMPACTED BY A
PSCZ. GUIDANCE ALSO SUGGESTS MOSTLY VFR THIS EVENING WITH THE
EXCEPTION OF KPAE (IFR/LIFR) WHERE A CONVERGENCE ZONE WILL CONTINUE
TO MEANDER. A STOUT COLD FRONT WILL ARRIVE AT THE COAST AROUND 14-
16Z TUESDAY AND INLAND 16-18Z. HERE MVFR AND IFR CIGS WILL BECOME
MORE WIDESPREAD ALONG WITH GUSTY WINDS. 25 TO 30 KT GUSTS ARE
FORECAST TUESDAY AFTERNOON INTO THE EVENING.
KSEA...LOW-END VFR CIGS THIS AFTERNOON AS A CONVERGENCE ZONE
MEANDERS JUST NORTH OF THE TERMINAL. BREEZY SSW WINDS WILL PRODUCE
GUSTS UP TO 20 KT BEFORE GRADUALLY DECREASING AFTER 00Z. SSW ARE
FORECAST TO INCREASE AGAIN TUESDAY MORNING AS A COLD FRONT ENTERS.
GUSTS UP TO 30 KT ARE LIKELY DURING THE AFTERNOON AND EARLY EVENING.
AS THE FRONT ARRIVES, LOW CEILINGS ARE TO ACCOMPANY IT AS MVFR
CONDITIONS MANIFEST AS WELL.
41
MARINE
SURFACE HIGH PRESSURE RESIDES WELL OFFSHORE IN THE NE PAC. ONSHORE
FLOW CONTINUES OVER THE AREA WATERS AS WELL FOR THE SMALL CRAFT
ADVISORY IN THE STRAIT OF JUAN DE FUCA FOR ENHANCED WESTERLIES. A
STRONGER FRONTAL SYSTEM IS STILL ON TRACK TO ENTER THE AREA LATE
TONIGHT INTO WEDNESDAY MORNING FOR BREEZY CONDITIONS AND ELEVATED
SEAS. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR ALL OF THE
COASTAL WATER ZONES STARTING EARLY TUESDAY AS S/SW WINDS INCREASE
AHEAD OF THE FRONT. NEW SCAS HAVE ALSO BEEN ADDED FOR THE INLAND
WATER ZONES OF PUGET SOUND, ADMIRALTY INLET, AND THE NORTHERN INLAND
WATERS. CAN'T RULE OUT THE BRIEF THE POTENTIAL FOR GALE STRENGTH
GUSTS, PARTICULARLY IN THE STRAIT.
COASTAL SEAS 4 TO 6 FT TONIGHT BEFORE INCREASING UPWARD TO 9 TO 12
FEET ON TUESDAY EVENING. SEAS 8 TO 10 FT THROUGH THURSDAY BEFORE
DECREASING BY FRIDAY TO 3 TO 5 FEET.
41
HYDROLOGY
WITH RAIN MOVING INTO THE AREA TUESDAY INTO WEDNESDAY, SLIGHT
RISES ON AREA RIVERS WILL BE POSSIBLE. THE SKOKOMISH RIVER IS
EXPECTED TO RISE INTO ACTION STAGE WITH THE ADDITIONAL
PRECIPITATION. SNOW LEVELS WILL FALL MID WEEK TO 1000-1500 FT,
BUT NO RIVER FLOODING IS EXPECTED AT THIS TIME.
14
SEW WATCHES/WARNINGS/ADVISORIES
WA...WINTER STORM WARNING FROM 11 AM TUESDAY TO 11 PM PDT WEDNESDAY
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.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT TUESDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 5 AM PDT WEDNESDAY
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.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page