022
FXUS66 KSEW 101546
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
846 AM PDT MON MAR 10 2025
UPDATE
NO CHANGES TO THE OVERALL FORECAST. PLEASE SEE THE
AVIATION AND MARINE SECTIONS BELOW FOR UPDATES TO THOSE FORECASTS.
PREV DISCUSSION
/ISSUED 331 AM PDT MON MAR 10 2025/
SYNOPSIS
ZONAL FLOW ALOFT WITH WEAK LOW LEVEL ONSHORE FLOW
TODAY. NEXT FRONT APPROACHING THE NORTH COAST TONIGHT WILL STALL
AS A DEEP UPPER LEVEL TROUGH DIGS SOUTH OUT OF THE GULF OF ALASKA.
THE FRONT WILL REMAIN STALLED OFF THE COAST TUESDAY THEN MOVE
INLAND TUESDAY NIGHT INTO WEDNESDAY MORNING. COOL UPPER LEVEL
TROUGH BEHIND THE FRONT MOVING OVER THE AREA THURSDAY. NEXT FRONT
SPLITTING BEFORE IT MOVES INLAND FRIDAY NIGHT. ANOTHER SYSTEM IS
POSSIBLE LATER IN THE WEEKEND.
SHORT TERM /TODAY THROUGH WEDNESDAY/
SATELLITE IMAGERY SHOWS
FRONTAL SYSTEM OFF TO THE SOUTHEAST WITH MOSTLY CLOUDY SKIES OVER
WESTERN WASHINGTON. DOPPLER RADAR ONLY PICKING UP A FEW SHOWERS
AT 3 AM/10Z AND MOST OF THOSE ARE IN THE DYING CONVERGENCE ZONE
OVER SNOHOMISH COUNTY. TEMPERATURES WERE IN THE MID 30S TO LOWER
40S.
NOT MUCH GOING ON TODAY. ZONAL FLOW ALOFT OVER THE AREA WITH WEAK
ONSHORE FLOW IN THE LOWER LEVELS. THIS WILL KEEP SKIES MOSTLY
CLOUDY. SATELLITE IMAGERY HAS NO COLD TOP CUMULUS OFFSHORE. A GOOD
INDICATION THAT SHOWER ACTIVITY WILL BE MINIMAL. CLOUD COVER WILL
PREVENT MUCH WARMING TODAY KEEPING HIGHS IN THE MID 40S TO LOWER
50S.
NEXT FRONTAL SYSTEM MOVING INTO THE BRITISH COLUMBIA COASTLINE
OVERNIGHT WITH THE FRONT EXTENDING BACK TO THE SOUTHWEST OVER THE
COASTAL WATERS. LARGE COLD UPPER LEVEL TROUGH DROPPING DOWN OUT OF
THE GULF OF ALASKA WITH THE TROUGH AXIS NEAR 140W. THE DIGGING
TROUGH WILL STOP THE EASTWARD PROGRESSION OF THE FRONT LEAVING IT
OFFSHORE INTO TUESDAY MORNING. RAIN AHEAD OF THE SYSTEM FROM
ABOUT HOQUIAM TO BELLINGHAM BEGINNING OVERNIGHT. RAINFALL AMOUNTS
WILL BE LIGHT. FOR THE REMAINDER OF THE AREA INCREASING CLOUDS.
LOWS IN THE MID 30S TO LOWER 40S.
UPPER LEVEL TROUGH CONTINUING TO DIG SOUTH TUESDAY KEEPING THE
FRONT STALLED OFFSHORE. BEST CHANCES FOR RAIN WILL CONTINUE TO BE
ALONG THE COAST AND OVER THE NORTHWEST INTERIOR. SLIGHT CHANCE OR
CHANCE OF RAIN ELSEWHERE. HIGHS IN THE MID 40S TO LOWER 50S.
UPPER LEVEL TROUGH PUSHING EAST TUESDAY NIGHT WITH THE TROUGH AXIS
NEAR 130W BY 12Z WEDNESDAY. THIS WILL PUSH THE NOW NORTH SOUTH
ORIENTED FRONT ON TO THE COAST EARLY WEDNESDAY MORNING WITH RAIN
SPREADING INLAND TUESDAY NIGHT. WINDS PICKING UP ALONG THE COAST
AND OVER THE NORTHWEST INTERIOR. LOWS NEAR 40.
FRONT MOVING THROUGH EARLY WEDNESDAY MORNING WITH NUMEROUS POST
FRONTAL SHOWERS OVER THE AREA DURING THE DAY. SNOW LEVELS NEAR
3000 FEET AHEAD OF THE FRONT LOWERING TO 2000-2500 FEET BEHIND THE
FRONT GIVING ALL THE PASSES SOME NEW SNOW. HIGHS REMAINING BELOW
NORMAL, NEAR 50.
LONG TERM /THURSDAY THROUGH SUNDAY/
EXTENDED MODELS IN GOOD
AGREEMENT WITH THE UPPER LEVEL TROUGH MOVING INLAND THURSDAY.
TROUGH AXIS RIGHT OVER WESTERN WASHINGTON THURSDAY AFTERNOON COULD
DESTABILIZE THE AIR MASS ENOUGH TO POP A THUNDERSTORM OR TWO.
TROUGH AXIS MOVING EAST OF THE AREA THURSDAY NIGHT.
NEGATIVELY TILTED FRONT ARRIVING LATER FRIDAY MOVING THROUGH
WESTERN WASHINGTON FRIDAY NIGHT. AIR MASS ON THE COOL SIDE BEHIND
THE TROUGH FRIDAY MORNING WITH SNOW LEVELS AROUND OR JUST A LITTLE
BELOW 1000 FEET. THERE IS A CHANCE FOR A LITTLE SNOW IN THE
CASCADE FOOTHILLS BEFORE THE AIR MASS WARMS A TOUCH WITH SNOW
LEVELS AROUND 1500 FEET IN THE AFTERNOON.
ANOTHER COOL UPPER LEVEL TROUGH SATURDAY KEEPING SHOWERS IN THE
FORECAST. MODELS HAVE BEEN SOMEWHAT INCONSISTENT IN THEIR
SOLUTIONS FOR THE SYSTEM SUNDAY. EARLIER MODEL RUNS HAD IT GOING
INLAND SOUTH OF THE AREA. THE OPERATIONAL RUNS ARE STAYING WITH
THIS IDEA BUT THE ENSEMBLES HAVE THE SYSTEM FURTHER NORTH WITH
NUMEROUS WET SOLUTIONS. MODEL BLEND HAS CATEGORICAL POPS AND WILL
GO WITH THIS FOR THE SUNDAY FORECAST. TEMPERATURES REMAINING
BELOW NORMAL THROUGH THE PERIOD WITH SNOW LEVELS IN THE MOUNTAINS
REMAINING BELOW PASS LEVELS. FELTON
AVIATION
WESTERLY FLOW WILL CONTINUE ALOFT TODAY IN THE WAKE OF
A SHORTWAVE IMPULSE THAT MOVED THROUGH THE AREA EARLY THIS MORNING.
CONDITIONS ARE GENERALLY MOIST ACROSS THE AREA THIS MORNING, WITH
THE GREATER SEATTLE AREA TERMINALS REPORTING MOSTLY A MIX OF MVFR
TO LIFR CONDITIONS IN LOW CLOUDS. ELSEWHERE, TERMINALS TO THE
NORTH AND WEST HAVE CONTINUED TO TREND VFR AS HIGH CLOUD COVER
STREAMS IN OVERHEAD. LATEST RADAR SHOWS SOME SHOWERS LINGERING
ALONG THE COAST AND NORTH INTERIOR. CEILINGS ARE EXPECTED TO
GRADUALLY LIFT THROUGHOUT THE MORNING AND AFTERNOON HOURS BACK TO
VFR, THOUGH EXPECT MORE MID TO UPPER LEVEL CLOUDS TO FILL IN
ACROSS THE REGION. A FEW SPOTS OF FOG ARE OUT THERE THIS MORNING,
THOUGH EXPECT A GRADUAL LIFT OF CEILINGS OVER THE NEXT SEVERAL
HOURS.
ONCE CONDITIONS HAVE REBOUNDED TO VFR, EXPECT THESE CONDITIONS
TO PERSIST THROUGH THE REMAINDER OF THE DAY WITH INCREASING MID-
LEVEL CLOUD COVER AHEAD OF THE NEXT FRONTAL SYSTEM. THIS SYSTEM
WILL APPROACH THE COAST AND STALL JUST OFFSHORE LATE TONIGHT INTO
EARLY TUESDAY.
WINDS ARE GENERALLY SOUTHERLY AT 3-7 KT AND ARE EXPECTED TO
PERSIST AT THESE SPEEDS THROUGH MUCH OF THE DAY.
KSEA...CONDITIONS HAVE ALREADY STARTED TO REBOUND TOWARDS MVFR
THIS MORNING AND ARE EXPECTED TO LIFT BACK TOWARDS VFR BY THIS
AFTERNOON. MID-LEVEL AND HIGH LEVEL CLOUDS WILL CONTINUE TO STREAM
IN THROUGH THE TAF PERIOD. WINDS ARE SOUTHEASTERLY THIS MORNING
AND WILL SHIFT TO SOUTH/SOUTHWEST THIS AFTERNOON, GENERALLY
PERSISTING AT 6 KT OR LESS.
62/14
MARINE
BROAD HIGH PRESSURE WILL BRIEFLY BUILD OVER THE COASTAL
WATERS TODAY MAKING FOR RELATIVELY LIGHT WINDS OVER THE COASTAL
WATERS. THE NEXT FRONTAL SYSTEM WILL MOVE IN FROM THE NORTHWEST
TONIGHT INTO EARLY TUESDAY MORNING, WITH A SMALL AREA OF INCREASED
WINDS ALONG THE BOUNDARY. THE STRONGEST WINDS WILL BE FOCUSED ACROSS
THE NORTHERN-MOST AREAS OF THE COASTAL WATERS AS WELL AS THE EAST
STRAIT OF JUAN DE FUCA. THE FRONT WILL STALL ON TUESDAY WITH THE
PARENT LOW PRESSURE ARRIVING TUESDAY NIGHT INTO WEDNESDAY, ALLOWING
WINDS TO INCREASE AS IT MOVES THROUGH THE AREA WITH MORE WIDESPREAD
SMALL CRAFT ADVISORY CONDITIONS ACROSS THE COASTAL WATERS AS WELL AS
ANOTHER THROUGH THE INTERIOR WATERS NORTH OF PUGET SOUND GOING INTO
WEDNESDAY MORNING.
THE PATTERN LOOKS TO CONTINUE TO REMAIN ACTIVE WITH SEVERAL
ADDITIONAL SYSTEMS MOVING THROUGH LATE WEEK INTO THE WEEKEND KEEPING
WINDS AND SEAS ELEVATED.
SEAS 8 TO 10 FT WILL SLOWLY EASE TODAY AND INTO EARLY TUESDAY. THE
NEXT SYSTEM WILL PUSH SEAS BACK TO 10 TO 13 FT TUESDAY NIGHT INTO
WEDNESDAY. SEAS LOOK TO REMAIN AROUND 10 TO 12 FT THROUGH AT LEAST
THE END OF THE WEEK.
62
HYDROLOGY
NO RIVER FLOODING IN THE NEXT 7 DAYS. THE SKOKOMISH
RIVER IS IN THE LOWER END OF ACTIONS STAGE THIS MORNING. THE RIVER
WILL CONTINUE TO BE NEAR ACTION STAGE THROUGH THE WEEK. FELTON
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM PDT TUESDAY FOR ADMIRALTY
INLET-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 PM PDT TUESDAY
FOR COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT
10 NM.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 AM PDT TUESDAY
FOR COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO
60 NM.
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