380
FXUS66 KSEW 080830
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
130 AM PDT THU OCT 8 2026
SYNOPSIS
HIGH PRESSURE WILL NOSE INTO THE AREA TODAY FOR WARMER AFTERNOON
TEMPERATURES AND SUNNY SKIES. THE NEXT CHANCE FOR RAIN WILL BE
ON FRIDAY AND SATURDAY AS A FRONTAL SYSTEM MOVES THROUGH THE
REGION. COOLER TEMPERATURES WILL LINGER IN THE WAKE OF THIS
SYSTEM INTO EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH SATURDAY/
AREAS OF FOG AND STRATUS ARE PRESENT ON THE SATELLITE IMAGERY
EARLY THIS MORNING FROM KING COUNTY NORTH ALONG THE WATER AND
ALONG THE PACIFIC COAST. THE FOG AND STRATUS SHOULD BE LESS
EXTENSIVE THIS MORNING COMPARED TO THE LAST FEW DAYS. ONCE THIS
DISSIPATES LATER THIS MORNING, AFTERNOON HIGH TEMPERATURES WILL
CLIMB TO THE LOW TO MID 70S.
THE WARM CONDITIONS ARE SHORT LIVED AS A WEAK FRONTAL SYSTEM
WILL BE ARRIVING FRIDAY INTO SATURDAY AND WILL USHER IN A
PATTERN CHANGE. THE FRONT ISN'T EXPECTED TO BE STRONG, BUT WILL
BRING ABOUT A ROUND OF RAIN TO WESTERN WASHINGTON AS WELL AS
BREEZY SOUTHWESTERLY WINDS THROUGHOUT THE PUGET SOUND REGION.
WESTERLY WIND WILL ALSO BE ELEVATED THROUGH THE STRAIT OF JUAN
DE FUCA. THE QPF IS EXPECTED TO BE AROUND A QUARTER TO HALF
INCH IN THE CASCADES, WITH A FEW HUNDREDTHS TO A TENTH
ELSEWHERE. THIS IS GOING TO BE A COOLER SYSTEM, SO THE SNOW
LEVELS WILL FALL TO AROUND 4,500-5,000 FT FRIDAY NIGHT INTO
SATURDAY AND BRING AN INCH OF SNOW OR LESS PRIMARILY TO THE
NORTH CASCADES. SATURDAY MORNING LOWS WILL BE IN THE LOW 40S FOR
MUCH OF THE PUGET SOUND AREA, BUT IN THE CASCADES AND ADJACENT
FOOTHILLS, LOWS IN THE MID TO UPPER 30S ARE EXPECTED.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
DRIER BUT COOLER CONDITIONS ARE EXPECTED SATURDAY NIGHT INTO
SUNDAY. SUNDAY MORNING LOWS WILL BE A BIT COOLER THAN SATURDAY
WITH MUCH OF THE AREA SEEING THE UPPER 30S AND LOW 40S. SINKING
COLD AIR IN THE CASCADE VALLEYS COULD DROP THE LOWS DOWN TO
AROUND FREEZING. THE PROBABILITIES FOR SEEING LOWS 32 DEGREES OR
LESS FOR SUNDAY MORNING ARE ABOUT 30%, MOST NOTABLY IN THE
CASCADE VALLEYS OF SNOHOMISH AND SKAGIT COUNTIES AS WELL AS THE
MOUNT RAINIER AREA. THIS WILL BE OF NOTE FOR FROST AND FREEZE
IMPACTS FOR THE AGRICULTURAL REALM AND FOR THOSE WITH SENSITIVE
VEGETATION. THE LOWS INCREASE INTO MONDAY AND BEYOND, BUT THE
AFTERNOON HIGHS THROUGH THE MIDDLE OF THE WEEK WILL BE IN THE
LOW TO MID 60S.
THE ENSEMBLES GENERALLY FAVOR WEST CONUS TROUGHING THROUGH
WEDNESDAY, WITH ANOTHER CHANCE AT SOME LIGHT RAIN COME TUESDAY.
THINGS START DIVERGING IN THE MODELS A LITTLE BIT AFTER
WEDNESDAY IN A COMPETITION BETWEEN THE TROUGH LINGERING AND HIGH
PRESSURE ATTEMPTING TO RETURN TO THE AREA.
21
AVIATION
NORTHWESTERLY FLOW ALOFT WILL BECOME MORE WESTERLY BY THIS
EVENING AS AN UPPER RIDGE OVER THE AREA FLATTENS AND AN UPPER
TROUGH DROPS DOWN INTO BRITISH COLUMBIA. ANOTHER ROUND OF FOG/
LOW STRATUS WILL BE THE MAIN CONCERN FOR AREA TERMINALS THIS
MORNING, WITH LATEST SATELLITE IMAGERY ALREADY SHOWING FOG
PRESENT ALONG THE PACIFIC COAST, PORTIONS OF THE CENTRAL SOUND,
AND ACROSS THE NORTH INTERIOR. CONDITIONS ACROSS THE AREA
TERMINALS REMAIN PREDOMINANTLY VFR AS OF 08Z, BUT EXPECT THE
EXTENT OF FOG TO CONTINUE TO EXPAND OVER THE NEXT FEW HOURS.
CONDITIONS WILL LIKELY DETERIORATE TO IFR/LIFR FOR ANY TERMINALS
IN FOG. WITH THE LAYER OF MOISTURE BEING SHALLOWER THAN PREVIOUS
DAYS, EXPECT FOG AND LOW CLOUDS TO SCATTER OUT BY 18Z. VFR
CONDITIONS WILL THEN PREVAIL THIS AFTERNOON AND EVENING, WITH
ONLY HIGH CLOUDS STREAMING IN OVERHEAD AHEAD OF A FRONTAL SYSTEM
ON FRIDAY. LIGHT AND VARIABLE WINDS THIS MORNING WILL PICK UP
FROM THE NORTH AND PERSIST BETWEEN 5-10 KT THIS AFTERNOON AND
EVENING.
KSEA...FOG/LOW STRATUS IS LIKELY TO MOVE INTO THE TERMINAL THIS
MORNING, WITH GUIDANCE HINTING AT A 35-40% CHANCE OF IFR CONDITIONS
DEVELOPING BY 12Z AND A 25-35% CHANCE OF CONDITIONS DROPPING TO LIFR.
CONDITIONS WILL GRADUALLY IMPROVE THROUGH THE MORNING HOURS, WITH
FOG/LOW CLOUDS EXPECTED TO SCATTER BY 18Z FOR A RETURN TO VFR
CONDITIONS. WINDS ARE LIGHT AND VARIABLE THIS MORNING, BUT WILL
PICK UP FROM THE NORTH AT 5-10 KT THIS AFTERNOON AND EVENING.
14
MARINE
HIGH PRESSURE WILL REMAIN SITUATED OVER THE COASTAL WATERS TODAY
WHILE A THERMAL TROUGH PUSHES INLAND. THE RETURN OF ONSHORE FLOW
WILL BRING SMALL CRAFT WESTERLIES TO THE CENTRAL AND EASTERN
STRAIT OF JUAN DE FUCA THIS AFTERNOON AND EVENING. A FRONTAL
SYSTEM WILL THEN MOVE ACROSS THE AREA WATERS ON FRIDAY, BRINGING
GUSTY WINDS AND BUILDING SEAS. THE NORTHERN AND CENTRAL COASTAL
WATERS AND THE STRAIT OF JUAN DE FUCA WILL LIKELY SEE THE STRONGEST
WINDS, WITH LATEST REFS GUIDANCE INDICATING ROUGHLY A 50-75%
CHANCE OF GUSTS EXCEEDING 34 KT ACROSS THE COASTAL WATERS AND A
30-50% CHANCE OF GUSTS EXCEEDING 34 KT ALONG THE CENTRAL AND
EASTERN STRAIT. AS GUIDANCE HAS CONTINUED TO TREND UPWARD, HAVE
GONE AHEAD AND ISSUED GALE WATCHES FOR THESE AREAS. SEAS WILL
BUILD IN THE SYSTEM'S WAKE, WITH LATEST GEFS PROBABILITIES
INDICATING A 60-80% LIKELIHOOD OF SEAS EXCEEDING 12 FT ACROSS
THE COASTAL WATERS BY FRIDAY NIGHT.
WINDS WILL EASE AND SEAS WILL GRADUALLY SUBSIDE THROUGH THE DAY
ON SATURDAY AS THE SYSTEM EXITS THE AREA. HIGH PRESSURE WILL
THEN BUILD BACK INTO THE COASTAL WATERS BY SUNDAY, WHILE A
THERMAL TROUGH EXPANDS NORTHWARD ALONG THE COAST. THIS PATTERN
WILL PERSIST INTO MONDAY, BRINGING PERIODS OF OFFSHORE FLOW BACK
TO THE AREA WATERS. SEAS WILL PERSIST BETWEEN 5-8 FT AND MAY
BECOME STEEP AT TIMES EARLY NEXT WEEK. THE NEXT FRONTAL SYSTEM
THEN LOOKS TO MOVE INTO THE AREA WATERS ON TUESDAY.
14
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 3 AM PDT
FRIDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WATCH FROM LATE TONIGHT THROUGH FRIDAY EVENING FOR
CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-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-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE
FUCA.
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