968
FXUS66 KSEW 150918
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
218 AM PDT THU OCT 15 2026
SYNOPSIS
A RIDGE WILL BRING DRY AND WARM CONDITIONS THROUGH
FRIDAY. WETTER AND COOLER WEATHER ARRIVES ON SATURDAY. SUNDAY
REMAINS COOL WITH MORE WET WEATHER HEADED OUR WAY ON MONDAY.
ANOTHER FRONT MAY REACH US MIDWEEK.
SHORT TERM /TODAY THROUGH SATURDAY/
HIGH PRESSURE AND
OFFSHORE FLOW WILL LEAD TO DRY AND STABLE CONDITIONS ACROSS
WESTERN WA TODAY AND FRIDAY. FOG IS FORMING ACROSS THE LOWLANDS
THIS MORNING, ESPECIALLY IN AREAS WITH CALM WINDS, WITH POCKETS
OF DENSE FOG EXPECTED. THE FOG WILL BE SHALLOW AND BURN OFF
LATE THIS MORNING. FORECAST HIGHS WILL TRACK WARMER THAN NORMAL
WITH LOWER 70S EXPECTED. AREAS NEAR THE WATER WILL BE IN THE
60S. OFFSHORE FLOW WILL PEAK OVERNIGHT WITH GUSTY EAST WINDS
ALONG THE CASCADE CREST AND IN THE GAPS (GUSTS TO 20-30 MPH).
FRIDAY WILL BE SLIGHTLY WARMER WITH INTERIOR TEMPERATURES
REACHING THE MID 70S.
SATURDAY'S WEATHER WILL BE COOLER AND WETTER AS THE RIDGE SHIFTS
EAST AND A FRONT/TROUGH MOVE IN FROM THE WEST. RAIN WILL MOSTLY
FALL DURING THE MORNING HOURS WITH HIGHEST CHANCES OF SEEING
WETTING RAINS ALONG THE COAST AND NORTH PART. THE SEATTLE AREA
ON SOUTH MAY ONLY SEE A TRACE TO A FEW HUNDREDTHS. ONSHORE FLOW
WILL INCREASE SATURDAY AFTERNOON WITH SHOWERS AND A CONVERGENCE
ZONE OVER SNOHOMISH COUNTY. 33
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
WE'RE IN BETWEEN
WEATHER SYSTEMS ON SUNDAY BUT THE AIR MASS WILL REMAIN COOL.
SUNDAY'S MORNING LOWS WILL BE IN THE 30S TO MID 40S WITH
TEMPERATURES NEAR FREEZING ACROSS THE SOUTH SOUND. HIGHS WILL BE
AROUND 60 DEGREES. AN UPPER LOW WILL SPIN OFFSHORE EARLY NEXT
WEEK KEEPING THE WEATHER COOL AND UNSETTLED THROUGH MONDAY. THE
UPPER LOW WILL SHIFT FARTHER SOUTH ON TUESDAY FOR GENERALLY DRY
WEATHER ACROSS WESTERN WA. RAIN CHANCES INCREASE AGAIN ON
WEDNESDAY AS A WEAK FRONT TRACKS DOWN FROM B.C. 33
AVIATION
AREAS OF FOG AND LOW STRATUS BRINGING IFR TO LIFR
CONDITIONS ARE BEGINNING TO DEVELOP ACROSS PORTIONS OF WESTERN
WASHINGTON, MOST PROLIFICALLY ALONG AND NORTH OF THE METRO AREA.
STRATUS AND FOG SHOULD CONTINUE TO SLOWLY FILL IN THIS MORNING.
THE BIGGEST UNCERTAINTY IS REGARDING THE VISIBILITY--LIGHT
NORTH/NORTHEASTERLY WINDS FOR SOME LOCATIONS MAY ALLOW FOR
CEILINGS TO REMAIN A FEW HUNDRED FEET ABOVE THE GROUND.
CONDITIONS SHOULD IMPROVE AFTER 17-19Z THIS MORNING FOR MOSTLY
CLEAR SKIES WITH HIGH CLOUDS THROUGH THE REMAINDER OF THE DAY.
HIGH CLOUD COVER WILL PERSIST TONIGHT. HIGH-RES GUIDANCE IS
SHOWING LITTLE TO NO DEVELOPMENT FRIDAY MORNING, BUT NBM LAMP
GUIDANCE IS MUCH MORE EXCITED ABOUT DEVELOPMENT. GIVEN THE
CURRENT DISCREPANCY, WILL ONLY INTRODUCE FOG IN THE MORE PRONE
LOCATIONS FOR FRIDAY MORNING AT THIS TIME.
WINDS REMAIN NORTH/NORTHEASTERLY 5 TO 10 KT THROUGH THE PERIOD.
EASTERLY WINDS WILL PERSIST THROUGH THE CASCADES WITH GUSTS UP TO 20-
25 KT THROUGH THE GAPS THIS AFTERNOON AND INTO THIS EVENING.
KSEA...VFR EARLY THIS MORNING, WITH IFR TO LIFR CIGS DEVELOPING
AFTER AROUND 11-13Z THIS MORNING. THE BIGGEST UNCERTAINTY WILL BE
WITH VISIBILITY AS THE WINDS MAY KEEP THE VIS HIGHER THAN WHAT IS
CURRENTLY FORECAST. STRATUS AND FOG LOOK TO SCATTER AROUND 18-19Z
FOLLOWED BY VFR CONDITIONS WITH HIGH CLOUDS THROUGH THIS EVENING.
FOG/STRATUS DEVELOPMENT POSSIBLE FRIDAY MORNING BUT HIGH CLOUDS
SHOULD KEEP IT LESS WIDESPREAD AND GUIDANCE SHOWS DIVERGENT
SOLUTIONS. WINDS NORTH/NORTHEASTERLY 5-10 KT THROUGH THIS AFTERNOON.
WINDS MAY TURN EAST/SOUTHEASTERLY BRIEFLY AS EARLY AS 20-22Z THIS
AFTERNOON, BUT MORE LIKELY 00Z FRI THROUGH THIS EVENING BEFORE WINDS
BECOME MORE SOUTH/SOUTHWESTERLY FRIDAY MORNING.
62
MARINE
AREAS OF FOG HAVE ARE BEGINNING TO DEVELOP ACROSS THE
RIVER VALLEYS OF WESTERN WASHINGTON AND IS EXPECTED TO EXPAND
ACROSS PORTIONS OF THE INTERIOR WATERS. WILL CONTINUE TO MONITOR
FOR FOG DEVELOPMENT AND THE POTENTIAL FOR ANY DENSE FOG
ADVISORIES. LIGHT WINDS NEAR THE SURFACE MAY BE ABLE TO KEEP
CEILINGS UP JUST ABOVE THE SURFACE AND LIMIT FOG POTENTIAL.
OFFSHORE FLOW WILL INCREASE THIS MORNING AS A THERMAL TROUGH
DEVELOPS ALONG THE COAST. WINDS WILL PEAK THIS MORNING, BUT REMAIN
OFFSHORE THROUGH EARLY FRIDAY AS THE TROUGH GETS PUSHED INLAND BY AN
INCOMING FRONTAL SYSTEM. THIS SYSTEM WILL FORCE WINDS TO SWITCH TO
ONSHORE ON FRIDAY AND INCREASE FRIDAY NIGHT INTO SATURDAY. THE
STRONGEST WINDS WILL BE MOST LIKELY THROUGH THE STRAIT OF JUAN DE
FUCA WHERE THERE IS A 35-45% CHANCE OF SEEING UP TO LOW-END GALE
FORCE GUSTS, BUT OTHER LOCATIONS SUCH AS THE OUTER COASTAL WATERS
AND THROUGH PUGET SOUND AND HOOD CANAL HAVE 40-70% CHANCES OF SEEING
WIND GUSTS OVER 20 KT. WINDS LOOK TO DECREASE AS THE SYSTEM DEPARTS
SATURDAY EVENING. WINDS LOOK TO REMAIN RELATIVELY BENIGN SUNDAY
THROUGH EARLY NEXT WEEK AS SYSTEMS ARE FAVORED TO PASS BY WELL
OFFSHORE.
SEAS REMAIN 4 TO 6 FT THROUGH TONIGHT, INCREASING TO AROUND 8 TO
NEAR 10 FT FRIDAY THROUGH THE WEEKEND. THE FORECAST GETS MORE
UNCERTAIN ON MONDAY AS A LOW PRESSURE SYSTEM MOVES THROUGH WELL
OFFSHORE, BUT COULD GENERATE AND SEND LARGER WAVES TO THE COASTAL
WATERS. THE MOST LIKELY FORECAST REMAINS IN THE 8 TO 10 FT RANGE,
BUT WAVES COULD GET AS LARGE AS 13 TO 16 FT DEPENDING ON THE EXACT
TRACK OF THIS SYSTEM. EPS AND GEFS SHOW A 20-30% CHANCE OF SEAS
EXCEEDING 12 FT MONDAY INTO TUESDAY.
62
SEW WATCHES/WARNINGS/ADVISORIES
WA...DENSE FOG ADVISORY UNTIL 9 AM PDT THIS MORNING FOR CITY OF
SEATTLE-DOWNTOWN EVERETT / MARYSVILLE AREA-EASTERN KITSAP
COUNTY-LOWLANDS OF LEWIS AND SOUTHERN THURSTON COUNTIES-
LOWLANDS OF PIERCE AND SOUTHERN KING COUNTIES-LOWLANDS OF
WESTERN SKAGIT AND NORTHWESTERN SNOHOMISH COUNTIES-
LOWLANDS OF WESTERN WHATCOM COUNTY-OLYMPIA AND SOUTHERN
PUGET SOUND-SHORELINE / LYNNWOOD / SOUTH EVERETT AREA.
PZ...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR NORTHERN
INLAND WATERS INCLUDING THE SAN JUAN ISLANDS-PUGET SOUND
AND HOOD CANAL.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page