726
FXUS66 KSEW 301647
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
847 AM PST SUN NOV 30 2025
SYNOPSIS
OVERALL, A COOLER AND DRIER PATTERN IS EXPECTED TO PERSIST
ACROSS WESTERN WASHINGTON THROUGH THE FIRST HALF OF THE WEEK
WITH RIDGING OFFSHORE, THOUGH A WEAK DISTURBANCE MOVING ACROSS
THE REGION MONDAY NIGHT INTO TUESDAY WILL BRING SOME SHOWERS TO
THE AREA. A CHANGE TO A WETTER PATTERN IS LIKELY LATE IN THE
WEEK AS THE RIDGE WEAKENS AND OPENS THE DOOR FOR STRONGER AND
WETTER SYSTEMS TO APPROACH WESTERN WASHINGTON.
SHORT TERM /TODAY THROUGH TUESDAY/
DRY CONDITIONS ARE EXPECTED ACROSS WESTERN WASHINGTON TODAY AS
A RIDGE OF HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA FROM
THE NORTHEASTERN PACIFIC. CLEARING OVERNIGHT HAS ALLOWED FOR
SOME FOG DEVELOPMENT ACROSS PORTIONS OF THE SOUTH SOUND AND EAST
PUGET SOUND LOWLANDS, WHICH HAS BROUGHT SOME VISIBILITIES DOWN
TO 1 MILE OR LESS IN SPOTS. THE AREAS OF FOG REMAIN RATHER
SHALLOW HOWEVER, SO EXPECT FOG TO DISSIPATE BY THE MID TO LATE
MORNING HOURS TODAY TO MAKE WAY FOR SOME SUN. IN ADDITION TO
FOG, IT WILL ALSO BE A CHILLY START TO THE MORNING AS CLEARING
HAS ALLOWED FOR TEMPERATURES TO COOL TO NEAR FREEZING IN SPOTS,
ESPECIALLY ACROSS PORTIONS OF THE SOUTHERN SOUND AWAY FROM THE
WATER AND ALONG THE CHEHALIS VALLEY. AFTERNOON HIGHS TODAY WILL
BE IN THE MID TO UPPER 40S ACROSS THE AREA.
ANOTHER CHILLY AND FOGGY START IS LIKELY FOR PORTIONS OF WESTERN
WASHINGTON ON MONDAY MORNING, ESPECIALLY ACROSS THE SOUTHERN
SOUND AND CHEHALIS VALLEY. A WEAK DISTURBANCE WILL THEN DROP
DOWN INTO THE AREA UNDER THE NORTHWESTERLY FLOW ALOFT MONDAY
NIGHT INTO TUESDAY, BRINGING CHANCES OF LIGHT RAIN TO THE
LOWLANDS AND SNOW TO THE MOUNTAINS. AT THIS TIME, THIS SYSTEM
DOES NOT LOOK TO BE VERY IMPACTFUL TO THE AREA, WITH MOST SPOTS
ACROSS THE LOWLANDS ONLY EXPECTED TO RECEIVE A COUPLE HUNDREDTHS
TO AROUND A TENTH OF AN INCH OF RAIN. LIGHT SNOW ACCUMULATIONS
ARE EXPECTED FOR THE MOUNTAINS, MAINLY BETWEEN 1-3 INCHES, WITH
ONLY SOME LIGHT SNOW (ROUGHLY AROUND AN INCH OR LESS) EXPECTED
AT THE PASSES.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
CONDITIONS WILL DRY OUT AGAIN TUESDAY NIGHT INTO WEDNESDAY AS
THE RIDGE OF HIGH PRESSURE OVER THE NORTHEASTERN PACIFIC BUILDS
BACK INTO THE REGION. THE PATTERN THEN BECOMES A BIT MORE
UNCERTAIN HEADING INTO THE SECOND HALF OF THE WEEK AS ENSEMBLE
CLUSTERS REMAIN SPLIT ON THE DEGREE OF RIDGING OVER THE NORTHEASTERN
PACIFIC. THE MAJORITY OF THE GEFS MEMBERS HINT AT THE RIDGE
WEAKENING, ALLOWING FOR WETTER SYSTEMS TO MOVE INTO WESTERN
WASHINGTON, WHILE THE MAJORITY OF THE ENS MEMBERS SUGGEST
SOMEWHAT DRIER SOLUTIONS WITH MORE OF AN AMPLIFIED RIDGE
PERSISTING OVER THE PACIFIC. WILL NEED TO SEE HOW GUIDANCE
RESOLVES THE SCENARIOS OVER THE COMING DAYS, BUT THE CURRENT
FORECAST FROM THURSDAY ONWARD GENERALLY TRENDS TOWARDS THE
WETTER SOLUTIONS AT THIS TIME.
TEMPERATURES LOOK TO WARM THE SECOND HALF OF THE WEEK, FROM
LOWS IN THE 30S AND HIGHS IN THE 40S ON WEDNESDAY AND THURSDAY
TO LOWS IN THE 40S AND HIGHS IN THE 50S BY FRIDAY AND SATURDAY.
14
AVIATION
AN UPPER LEVEL RIDGE JUST OFFSHORE WILL BEGIN TO MOVE
INLAND TODAY INTO MONDAY. THE NORTHERLY FLOW ALOFT WILL WEAKEN AND
BECOME WESTERLY MONDAY. THE SHALLOW RADIATIONAL FOG HAS FORMED
IN MANY OF THE LOW LYING AREAS THIS MORNING SHOULD LIFT
RELATIVELY QUICKLY THIS MORNING. CEILINGS WILL REMAIN CLEAR
THROUGH THE REMAINDER OF THE DAY, WITH CEILINGS FILLING IN
MONDAY MORNING (MOST WILL SEE VFR DECKS BETWEEN 3,000
- 10,000 FT BUT AGAIN PROBABILITIES REMAIN MEDIUM FOR
ADDITIONAL RADIATIONAL FOG OR LOW CEILINGS IN THE MORNING IN THE
SAME SPOTS AS THIS MORNING AND POTENTIALLY UP THROUGH METRO
SEATTLE). VERY LIGHT 3-6 KT OR CALM WINDS OUT OF THE
EAST/NORTHEAST ARE EXPECTED ACROSS MOST TERMINALS.
KSEA...
SHALLOW FOG TO THE EAST OF THE TERMINAL ALONG THE GREEN RIVER
WILL CLEAR BY LATE MORNING, AND IS NOT EXPECTED TO AFFECT THE
TERMINAL. LOWER CONFIDENCE IN FOG FORMING MONDAY MORNING WITH
MOST GUIDANCE KEEPING THE ODDS BELOW 40%. HIGH CLOUDS ADVECTING
INTO THE AREA MAY HELP HINDER DEVELOPMENT. WINDS WILL REMAIN
LIGHT NORTH/EAST 3-5 KT.
HPR/COOK
MARINE
HIGH PRESSURE WILL MOVE INLAND NEXT FEW DAYS UNDER A RIDGE
COMING ASHORE. CONDITIONS ARE EXPECTED TO REMAIN CALM THROUGH
TUESDAY WITH SEAS AT 4 TO 6 FT AND CALM OR LIGHT OFFSHORE WINDS. A
WEAK FRONT WILL SKIRT THE OUTER COASTAL WATERS TUESDAY AND
WEDNESDAY. AT THIS TIME, THE BEST CHANCE OF WINDS EXCEEDING 20 KT
REMAINS IN THE OUTER COASTAL WATERS TUESDAY. SEAS WILL BUILD BACK UP
TO 9 TO 12 FT TUESDAY THROUGH WEDNESDAY, THEN DECREASE BACK DOWN TO
4 TO 6 FT WITH LIGHT WINDS THURSDAY WITH ANOTHER SYSTEM POTENTIALLY
PASSING THROUGH NEXT WEEKEND. THIS SYSTEM MAY BRING WINDS EXCEEDING
20 KT TO THE STRAIT OF JUAN DE FUCA, AS WELL AS 9-12 FT SEAS GOING
INTO NEXT WEEKEND.
HPR
HYDROLOGY
RIVER FLOODING IS NOT EXPECTED OVER THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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