252
FXUS66 KSEW 120928
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
228 AM PDT FRI SEP 12 2025
SYNOPSIS
WEAK HIGH PRESSURE BUILDS OVER THE INTERIOR WITH DRY
CONDITIONS THROUGH EARLY SATURDAY. A COLD FRONT LIKELY MOVES
THROUGH THE REGION LATE SATURDAY THROUGH SUNDAY, WITH WIDESPREAD
RAIN. WARMER AND DRIER CONDITIONS DEVELOP EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
HIGH PRESSURE IS OVER
WESTERN WA TODAY WITH LIGHT WINDS AND WEAK GRADIENTS. THE LOW
LEVEL AIR MASS REMAINS MOIST WITH LOW CLOUDS AND FOG OVER THE
LOWLANDS. EXPECT A SLOW BURNOFF TODAY WITH THE COAST REMAINING
PARTLY TO MOSTLY CLOUDY. EXPECT HIGHS IN THE 60S TO LOWER 70S THIS
AFTERNOON.
HIGH PRESSURE REMAINS OVER THE REGION ON SATURDAY WHILE THE NEXT
INCOMING PACIFIC FRONTAL SYSTEM STALLS OFFSHORE. THE AIR MASS WILL
BE A LITTLE WARMER WITH HIGHS IN THE INTERIOR REACHING THE MID TO
UPPER 70S.
WETTER CONDITIONS ARE IN STORE FOR SUNDAY AS AN UPPER LEVEL TROUGH
MOVES INLAND. TOTAL RAINFALL AMOUNTS RANGE FROM 0.25-0.50" ALONG
THE COAST AND IN THE MOUNTAINS TO AROUND 0.10-0.25" IN THE
INTERIOR. THE AIR MASS WILL BE SLIGHTLY UNSTABLE WITH A CHANCE OF
THUNDERSTORMS TOO. TEMPERATURES WILL TREND COOLER WITH HIGHS IN
THE 60S. 33
LONG TERM /MONDAY THROUGH THURSDAY/
SHOWERS WILL LINGER INTO
MONDAY BUT WILL TAPER DOWN AS THIS SYSTEM EXITS EAST. DRIER
WEATHER IS FAVORED MOVING TOWARD MIDWEEK AS HIGH PRESSURE RETURNS.
HIGHS TUESDAY AND WEDNESDAY WILL REACH THE MID TO UPPER 70S WITH A
FEW LOW 80S POSSIBLE. CRITICAL FIRE WEATHER CONDITIONS REMAIN LOW
WITH HIGHER HUMIDITIES. A TROUGH MAY BRING COOLER AND WETTER
CONDITIONS MOVING TOWARD THE END OF THE WEEK. 33
AVIATION
AN UPPER LEVEL RIDGE WILL BRIEFLY BUILD OVER WESTERN
WASHINGTON THROUGH LATE FRIDAY WITH FLOW ALOFT BECOMING MORE
WESTERLY. STRATUS ACROSS MUCH OF WESTERN WASHINGTON EARLY THIS
MORNING WITH A MIX OF MVFR/IFR TO LIFR CIGS FOR MOST AREAS. CIGS
WILL GENERALLY LOWER TOWARDS LIFR/IFR BY 12Z WITH SLOW IMPROVEMENTS
BEGINNING AROUND 18Z, WITH CIGS IMPROVING INTO VFR LIKELY LATE
AFTERNOON (21 TO 23Z) FOR THE INTERIOR. VSBY REDUCTIONS ALSO
POSSIBLE THIS MORNING WITH LOWER STRATUS. STRATUS EXPECTED TO
CONTINUE THROUGH THE AFTERNOON FOR MOST OF THE COAST. CIGS WILL THEN
LOWER AGAIN FRIDAY NIGHT INTO SATURDAY MORNING. LIGHT W/SW WINDS
THIS MORNING WITH MORE OF A NW COMPONENT THIS AFTERNOON.
KSEA...MVFR CIGS EARLY THIS MORNING. CIGS EXPECTED TO LOWER INTO IFR
AROUND 11-13Z, WITH LIFR CIGS POSSIBLE BETWEEN 13-17Z. SLOW
IMPROVEMENTS THEN EXPECTED LATE MORNING INTO THE AFTERNOON. VFR CIGS
AROUND 21 TO 22Z. LIGHT SW WINDS THIS MORNING WITH MORE OF A NW
COMPONENT LATE AFTERNOON AND EVENING, WITH WINDS GENERALLY UNDER 6
KTS. JD
MARINE
WEAK HIGH PRESSURE OVER THE WATERS WILL RESULT IN A
CONTINUED ONSHORE FLOW PATTERN THROUGH FRIDAY NIGHT. A FRONT WILL
MOVE INTO THE COASTAL WATERS ON SATURDAY AND MOVE INLAND ON SUNDAY.
WEST TO NORTHWEST WINDS WILL INCREASE ON SUNDAY FOR THE COASTAL
WATERS, AND WILL NEED TO MONITOR THE POTENTIAL FOR SCA WIND GUSTS
FOR THE OUTER COASTAL WATERS DURING THIS PERIOD. IN ADDITION,
INCREASING ONSHORE FLOW SUNDAY NIGHT MAY RESULT IN SCA WINDS THROUGH
THE STRAIT OF JUAN DE FUCA. OFFSHORE FLOW IS THEN EXPECTED TO
DEVELOP ON TUESDAY, WITH ANOTHER POTENTIAL WEATHER SYSTEM MIDWEEK.
SEAS WILL RANGE 6 TO 8 FEET THROUGH EARLY NEXT WEEK. SEAS THEN WILL
SUBSIDE BRIEFLY MONDAY TO 3 TO 5 FEET BEFORE BUILDING TO 5 TO 6 FEET
MIDWEEK. JD
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 2 AM PDT EARLY THIS MORNING FOR
CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE
U.S. WATERS STRAIT OF JUAN DE FUCA.
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