998
FXUS66 KSEW 302316
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
316 PM PST SUN NOV 30 2025
SYNOPSIS
THE OVERALL PATTERN FOR THE WEEK LOOKS TO REMAIN ON THE COOL
WITH A FEW PERIODS OF PRECIPITATION. SHOWERY PRECIPITATION WILL
BRUSH THE AREA MONDAY INTO TUESDAY AND NOT AGAIN UNTIL MORE
WIDESPREAD PRECIPITATION THREATENS THE REGION THURSDAY INTO
FRIDAY. TEMPERATURES LATE IN THE WEEK SHOULD ALSO TREND A BIT
WARMER.
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/
COOL, BUT SUNNY AND DRY CONDITIONS WILL CLOSE THE WEEKEND OUT
THIS AFTERNOON. ALREADY SEEING SOME HIGH LEVEL CLOUDS STREAM
INTO WESTERN WASHINGTON FROM THE NORTHWEST, THIS WILL CONTINUE
OVERNIGHT AS AN UPPER LEVEL SYSTEM RIDES OVER THE RIDGE INTO
BRITISH COLUMBIA. ANOTHER CHILLY AND FOGGY START LOOKS TO BE ON
TAP FOR PARTS OF WESTERN WASHINGTON LATE TONIGHT INTO MONDAY
MORNING, ESPECIALLY ACROSS THE SOUTHERN SOUND AND CHEHALIS
VALLEY. ONE WILDCARD HERE MAY BE THE HIGH CLOUDS OVERNIGHT -
ESPECIALLY TO OVER THE NORTHERN HALF OF THE AREA - WHICH MAY
HELP LIMIT SOME OF THE RADIATIONAL COOLING. HREF AND REFS
CONTINUE TO SHOW A SERIES OF WEAK UPPER LEVEL DISTURBANCES
WAVES RIDING OVER THE UPSREAM RIDGE MONDAY INTO TUESDAY. SOME
MEMBERS SHOW THE FIRST OF THESE WAVES EARLIER MONDAY MORNING,
WITH POTENTIALLY A SECOND SOMETIME MONDAY NIGHT INTO EARLY
TUESDAY. THIS WILL BRING PERIODS OF SHOWERS MONDAY INTO TUESDAY
MORNING. FOR THE MOST PART THIS WILL BE LIGHT RAIN TO THE
LOWLANDS - HOWEVER OVERNIGHT LOWS ESPECIALLY IN THE OUTLYING
AREAS AWAY FROM THE WATER WILL DIP TO NEAR FREEZING, SO THAT ANY
EARLY MORNING SHOWERS THAT DO PAN OUT ESPECIALLY MONDAY MORNING,
COULD CONTAIN A RAIN/SNOW MIX. FOR THE MOUNTAINS LIGHT SNOW
WITH ACCUMULATIONS LESS THAN 2 INCHES IS EXPECTED - MOSTLY
STEVENS PASS NORTHWARD. TEMPERATURES MONDAY AND TUESDAY WILL
TREND A LITTLE COOLER THAN NORMAL - ESPECIALLY THE OVERNIGHT
LOWS.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
THE UPPER LEVEL RIDGE WILL CONTINUE TO DRIVE THE DOWNSTREAM
WEATHER THROUGH WEDNESDAY NIGHT. ENSEMBLES ARE CONSISTENTLY
MAINTAINING THE EASTERN PACIFIC RIDGE WELL INTO THURSDAY, WITH
SOME VARIABILITY SHOWING UP IN THE FORM OF A SYSTEM RIDING OVER
THE RIDGE INTO BRITTISH COLUMBIA THURSDAY. LREF ENSEMBLES DO
HINT AT A SCENARIO BEHIND THIS WITH A SECOND, MORE ORGANIZED
PACIFIC SYSTEM MOVING INTO THE GULF OF ALASKA FRIDAY. THIS WOULD
RESULT IN A REGIONALLY WETTER PATTERN FOR MUCH OF BRITISH
COLUMBIA, WASHINTON AND OREGON. 35% OF THE LREF MEMBERS ARE
SHOWING A STRONGER VARIATION OF THIS PATTERN, WHICH WOULD FOCUS
MOST OF THE HEAVIER PRECIPITATION ON THE NORTHERN BRITISH
COLUMBIA COAST AND LESSER AMOUNTS THROUGH MUCH OF WESTERN
WASHINGTON THROUGH FRIDAY INTO AT LEAST THE START OF THE
WEEKEND. THIS PATTERN WILL LIKELY RESULT IN WARMER CONDITIONS
GOING INTO FRIDAY WITH BOTH LOW AND HIGH TEMPERATURES TRENDING
ABOVE NORMAL FRIDAY INTO THE WEEKEND.
AVIATION
A WEAK UPPER LEVEL SYSTEM WILL BRUSH THE AREA MONDAY. NORTHERLY
FLOW ALOFT WILL WEAKEN AND BECOME WESTERLY MONDAY. CEILINGS
WILL REMAIN VFR THROUGH THE REMAINDER OF THE DAY. INCREASING MID
AND HIGH LEVEL CLOUDS MONDAY MORNING WILL RESULT IN OVERALL VFR
CEILINGS RANGING BETWEEN 3,500 AND 10,000 FT. THERE REMAINS A
GOOD CHANCE FOR ANOTHER ROUND OF RADIATIONAL FOG OR LOW
CEILINGS, ESPECIALLY IN THE RIVER VALLEYS FROM KING COUNTY
SOUTHWARD - SIMILAR TO SUNDAY MORNING. CALM WINDS OR VERY LIGHT
WINDS 3-6 KT OUT OF THE EAST/NORTHEAST ARE EXPECTED ACROSS MOST
TERMINALS.
KSEA...
VFR CONDITIONS WITH A FEW HIGH CLOUDS THIS AFTERNOON AND
EVENING. SHALLOW FOG IS EXPECTED TO DEVELOP AGAIN OVERNIGHT TO
THE EAST OF THE TERMINAL ALONG THE GREEN RIVER, AND IS NOT
EXPECTED TO AFFECT THE TERMINAL. LOWER CONFIDENCE IN FOG FORMING
MONDAY MORNING WITH MOST GUIDANCE KEEPING THE ODDS BELOW 40%.
WINDS WILL REMAIN LIGHT NORTH/EAST 3-5 KT.
MARINE
HIGH PRESSURE WILL CONTINUE TO BUILD OVER AREA WATERS
THROUGHOUT THE NEXT WEEK, WITH A SERIES OF SYSTEMS CROSSING THE
WATERS. WHILE CONDITIONS REMAIN BENIGN TODAY, A WEAK FRONT WILL PASS
OVER THE PACIFIC NORTHWEST LATER ON MONDAY, BRINGING IN ELEVATED
NORTHWEST WINDS OVER THE OUTER COASTAL WATERS LIKELY REACHING SCA
CRITERIA ALONGSIDE ELEVATED SEAS. CONDITIONS WILL CALM MID-WEEK
BEFORE AN ADDITIONAL WEATHER SYSTEM TOWARDS THE END OF NEXT WEEK
BRINGS IN ELEVATED WESTERLY WINDS WITH POTENTIAL FOR GALE FORCE
WESTERLIES THROUGH THE STRAIT OF JUAN DE FUCA ON FRIDAY AND NEXT
SATURDAY. HOWEVER, FORECAST MODELS CONTINUE TO SHOW SOME UNCERTAINTY
OVER WIND STRENGTH TOWARDS THE END OF NEXT WEEK.
SEAS AROUND 6 TO 8 FEET TODAY WILL BUILD TO 9 TO 12 FEET ON TUESDAY
AFTERNOON, EASING BACK DOWN TO 5 TO 7 FEET BY LATE WEDNESDAY. SEAS
ARE EXPECTED TO BUILD AS HIGH AS 10 TO 15 FEET FEET TOWARDS NEXT
WEEKEND WITH THE NEXT INCOMING SYSTEM.
15
HYDROLOGY
RIVER FLOODING IS NOT EXPECTED OVER THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page