501
FXUS66 KSEW 120336
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
836 PM PDT THU SEP 11 2025
SYNOPSIS
THE UPPER TROUGH OVER THE REGION WILL CONTINUE
SLIDING EASTWARD TONIGHT WITH ANOTHER ROUND OF WIDESPREAD CLOUDS
AND AREAS OF FOG DEVELOPING EARLY FRIDAY. 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 /TONIGHT THROUGH SATURDAY NIGHT/
THE LATEST FORECAST
REMAINS ON TRACK WITH NO UPDATES THIS EVENING. THE CLOUDS HAVE
BEEN THE BIG WEATHER STORY ACROSS WESTERN WASHINGTON TODAY WITH
MANY AREAS OF DENSE FOG EARLY THIS MORNING GIVING WAY TO
PERSISTENT LOW STRATUS THIS AFTERNOON. THE STRATUS CONTINUES TO
SCATTER, WITH SOME BREAKS OF SUN, ESPECIALLY ACROSS THE NORTHERN
PORTIONS OF THE AREA. THE UPPER LOW CONTINUES TO SHIFT EASTWARD
INTO FRIDAY, WITH ONSHORE FLOW LIKELY LEADING TO ANOTHER CLOUDY
START WITH POCKETS OF LOCALLY DENSE FOG. TRANSIENT HIGH PRESSURE
ALOFT ON FRIDAY WILL MAINTAIN DRY CONDITIONS ACROSS THE REGION.
THE NEXT FRONTAL SYSTEM THEN APPROACHES DURING THE DAY SATURDAY,
LIKELY PUSHING ONSHORE LATE SATURDAY EVENING.
LONG TERM /SUNDAY THROUGH THURSDAY/
EXPECT INCREASING RAIN
AREA-WIDE BY EARLY SUNDAY, WITH A STRONGER COLD FRONT SWEEPING
ACROSS THE REGION. FAIRLY STRONG AGREEMENT IN THE ENSEMBLE
GUIDANCE FOR THIS FRONTAL PASSAGE, WITH THE MAJORITY OF THE RAIN
FALLING VERY LATE SATURDAY THROUGH EARLY SUNDAY, WITH LINGERING
SHOWERS DURING THE DAY SUNDAY. AN EARLY LOOK AT MOST LIKELY
RAINFALL AMOUNTS WOULD BRING AROUND ONE HALF INCH OF RAIN TO THE
INTERIOR LOWLANDS AND CLOSER TO AN INCH OR MORE TO THE MOUNTAIN
AND COASTLINE, THOUGH THERE IS STILL A DECENT AMOUNT OF SPREAD
WITH RESPECT TO POTENTIAL RAINFALL AMOUNTS. THE CHANCE OF
WETTING RAIN OF 55% OR BETTER IN THE MOUNTAINS SATURDAY NIGHT
INTO SUNDAY, WITH AROUND A 35% CHANCE THROUGH THE LOWLANDS ARE
CONSISTENT WITH THESE MOST LIKELY AMOUNTS. RAIN TAPERS LATER
SUNDAY INTO MONDAY WITH SOME DIFFERENCES IN THE GUIDANCE
BEGINNING TO EMERGE. A DRYING TREND THEN DEVELOPS INTO TUESDAY
WITH A RIDGE OF HIGH PRESSURE BUILDING OVER THE WESTERN U.S.
IT'S WORTH NOTING THAT THOUGH SEEMINGLY BRIEF, THERE IS SOME
POTENTIALLY FOR OFFSHORE FLOW TO DEVELOP OVER PORTIONS OF THE
AREA. WHILE INITIAL INDICATIONS ARE THAT IT'LL BE SHORT DURATION
AND NOT PARTICULARLY STRONG, IT COULD BRING ABOUT ANOTHER BUMP
IN POTENTIAL FIRE WEATHER CONCERNS DESPITE THE WETTER PATTERN
BETWEEN NOW AND THEN.
CULLEN
AVIATION
UPPER LEVEL LOW CENTERED NEAR THE OREGON NEVADA BORDER
WILL MOVE EAST INTO THE ROCKIES BY FRIDAY NIGHT. UPPER LEVEL RIDGE
OVER WESTERN WASHINGTON THROUGH FRIDAY NIGHT. FLOW ALOFT BECOMING
WESTERLY FRIDAY MORNING. IN THE LOWER LEVELS ONSHORE FLOW INTO
FRIDAY NIGHT.
CEILINGS ALL OVER THE PLACE THIS EVENING AS STRATUS SLOSHES AROUND
OVER WESTERN WASHINGTON. CEILINGS WILL BECOME MORE UNIFORM
OVERNIGHT WITH MOSTLY IFR CEILINGS BY 12Z. SLOW IMPROVING TREND
AFTER 17Z WITH VFR CEILINGS FOR THE INTERIOR BY 22Z.
KSEA...CEILINGS BOUNCING BETWEEN 2000 AND 4500 FEET THE NEXT FEW
HOURS. CEILINGS LOWERING TO IFR AROUND 12Z WITH LIFR CEILINGS
POSSIBLE 13Z-17Z. SLOW IMPROVEMENT LATE MORNING INTO THE
AFTERNOON HOURS WITH VFR CONDITIONS AROUND 22Z. SOUTHWEST WIND 4
TO 6 KNOTS.
FELTON
MARINE
WEAK HIGH PRESSURE OVER THE WATERS WILL KEEP ONSHORE FLOW
PATTERN GOING THROUGH FRIDAY NIGHT. FRONT MOVING INTO THE COASTAL
WATERS SATURDAY AND INLAND SUNDAY. HIGH PRESSURE REDEVELOPS AGAIN
FOR THE FIRST PART OF NEXT WEEK. SMALL CRAFT ADVISORY WESTERLY WINDS
IN THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA TONIGHT AND AGAIN
SUNDAY NIGHT. SMALL CRAFT ADVISORY WINDS POSSIBLE OVER THE COASTAL
WATERS SUNDAY. OFFSHORE FLOW IS FAVORED TO REDEVELOP ON TUESDAY.
SEAS GENERALLY IN THE 5 TO 7 FOOT RANGE WITH SLIGHTLY HIGHER SEAS
POSSIBLE SUNDAY INTO SUNDAY NIGHT. SEAS THEN BELOW 5 FT EARLY NEXT
WEEK.
MCMILLIAN
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 2 AM PDT FRIDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA.
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