727
FXUS66 KSEW 081733
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
1033 AM PDT FRI AUG 8 2025
UPDATE
MOSTLY CLEAR SKIES ACROSS MOST OF WESTERN WASHINGTON
THIS MORNING, WITH A FEW CLOUDS ACROSS THE STRAIT OF JUAN DE FUCA
AND GRAYS HARBOR. OTHERWISE, NO SIGNIFICANT UPDATES TO THE
FORECAST THIS MORNING. PLEASE REFER TO AN UPDATED AVIATION SECTION
BELOW.
SYNOPSIS
RIDGING FROM THE NORTHEASTERN PACIFIC WILL START TO
BUILD INTO THE AREA TODAY AND WILL PROMOTE A WARMING AND DRYING
TREND ACROSS WESTERN WASHINGTON INTO EARLY NEXT WEEK. MODERATE
HEATRISK IS EXPECTED SUNDAY AND MONDAY WITH HIGHS LIKELY TO BE IN
THE 80S TO NEAR 90. TEMPERATURES LOOK TO MODERATE AGAIN NEAR MIDWEEK
AS THE RIDGE FLATTENS AND UPPER LEVEL TROUGHING REDEVELOPS OVER
THE AREA.
SHORT TERM /TODAY THROUGH SUNDAY/
UPPER LEVEL RIDGING OVER THE
NORTHEASTERN PACIFIC WILL START TO BUILD INTO THE REGION TODAY,
PROMOTING A WARMING AND DRYING TREND ACROSS WESTERN WASHINGTON
THROUGH THE WEEKEND. ONSHORE FLOW WILL CONTINUE IN THE LOW
LEVELS, HELPING TO USHER IN MARINE STRATUS ACROSS PORTIONS OF THE
INTERIOR THIS MORNING. CLOUDS WILL SCATTER BY THIS AFTERNOON,
WITH HIGH TEMPERATURES EXPECTED TO BE IN THE 60S ALONG THE COAST
AND IN THE 70S ACROSS THE INTERIOR.
SATURDAY LOOKS SIMILAR TO FRIDAY, WITH AREAS OF MORNING STRATUS
ACROSS THE INTERIOR SCATTERING OUT BY THE AFTERNOON. TEMPERATURES
WILL STEADILY CLIMB, WITH AFTERNOON HIGHS EXPECTED TO BE IN THE
UPPER 60S TO LOW 70S ALONG THE COAST AND IN THE MID 70S TO LOW 80S
ACROSS THE INTERIOR. WITH MORNING LOWS PRIMARILY IN THE LOW TO MID
50S ACROSS THE AREA, HEATRISK WILL LARGELY REMAIN IN THE MINOR
(YELLOW) CATEGORY FOR THE MAJORITY OF THE AREA.
TEMPERATURES WILL CONTINUE TO CLIMB ON SUNDAY, WITH MORNING LOWS
EXPECTED TO BE IN THE MID TO UPPER 50S ACROSS THE AREA. MEANWHILE,
AFTERNOON HIGHS WILL BE IN THE MID TO UPPER 70S ALONG THE COAST
AND IN THE 80S ACROSS THE INTERIOR. SOME SPOTS, LIKE AREAS WITHIN
THE CASCADE VALLEYS, COULD EVEN APPROACH THE LOW 90S. THIS WILL
ALLOW FOR HEATRISK TO INCREASE, WITH MORE OF THE WIDESPREAD
MODERATE (ORANGE) CATEGORY EXPECTED ACROSS MOST OF THE AREA.
LONG TERM /MONDAY THROUGH THURSDAY/
TEMPERATURES LOOK TO REMAIN
WARM INTO MONDAY, WITH MORNING LOWS INCREASING INTO THE UPPER 50S
TO LOW 60S AND WITH HIGHS EXPECTED TO BE IN THE MID 70S ALONG THE
COAST AND THE 80S TO NEAR 90 AGAIN ACROSS THE INTERIOR. THIS LOOKS
TO YIELD ANOTHER DAY OF MORE WIDESPREAD MODERATE HEATRISK FOR MUCH
OF WESTERN WASHINGTON.
WHILE THERE REMAINS A DECENT SPREAD IN TEMPERATURES ON TUESDAY,
ENSEMBLES CONTINUE TO SUGGEST THE RIDGE STARTING TO FLATTEN OVER
THE AREA AS A SYSTEM MOVES INTO BRITISH COLUMBIA. SHOULD THIS COME
TO FRUITION, HIGHS ON TUESDAY WOULD COOL A COUPLE DEGREES, TOPPING
OUT IN THE 60S ALONG THE COAST AND IN THE MID 70S TO LOW 80S
ACROSS THE INTERIOR. THIS WOULD, IN TURN, LOWER THE HEATRISK BACK
TO THE MINOR (YELLOW) CATEGORY FOR THE MAJORITY OF THE AREA.
UPPER LEVEL TROUGHING MAY THEN REDEVELOP OVER THE REGION AROUND
MIDWEEK, BRINGING THE RETURN OF COOLER AND CLOUDIER CONDITIONS
(AND EVEN THE POTENTIAL FOR SOME LIGHT SHOWER CHANCES) WEDNESDAY
INTO THURSDAY.
14
AVIATION
HIGH PRESSURE BUILDING ACROSS THE REGION
TODAY, MAINTAINING PREDOMINANTLY CLEAR SKIES ACROSS WESTERN
WASHINGTON. EXPECT A FEW LINGERING PATCHES OF LOW CLOUDS NEAR THE
COAST AND INTERIOR RIVER VALLEYS, CLEARING BY 19-20Z. OTHERWISE,
BREEZY NORTHWESTERLY WINDS DEVELOPING THIS AFTERNOON ACROSS THE
REGION. MOST AREAS SHOULD REMAIN FREE OF LOW CLOUDS TONIGHT WITH
BUILDING HIGH PRESSURE AND DRYING LOW LEVELS, BUT THE COAST AND
AREAS SUCH AS KPWT AND KOLM MAY AGAIN SEE SOME PATCHY LOW CLOUDS.
OTHERWISE, REPEAT EXPECTED THROUGH THE DAY ON SATURDAY WITH VFR
CONDITIONS PREVAILING.
KSEA...NORTHEAST SURFACE WINDS BECOMING NORTHWEST BY AFTERNOON, WITH
SPEEDS GENERALLY 7-8 KT THROUGH THE AFTERNOON. FEW CLOUDS AROUND BUT
NO CEILING CONCERNS WITH VFR THROUGH THE PERIOD. A FEW PATCHES OF
LOW CLOUDS COULD DEVELOP BEYOND THE TERMINAL AREA LATE TONIGHT/EARLY
SATURDAY, BUT ARE NOT EXPECTED TO DEVELOP AT KSEA. CULLEN
MARINE
A WEAK FRONTAL SYSTEM WELL OFFSHORE WILL DISSIPATE NEAR
THE AREA WATERS ON FRIDAY, THEN, HIGH PRESSURE WILL SLOWLY REBUILD
OVER THE NORTHEAST PACIFIC THIS WEEKEND INTO NEXT WEEK. A DIURNALLY
DRIVEN WESTERLY PUSH DOWN THE STRAIT OF JUAN DE FUCA LOOKS
BORDERLINE SCA AS PER MODEL DATA, BUT GIVEN THE PATTERN, OPTED TO GO
WITH THE HEADLINE. AS HIGH PRESSURE BUILDS OVER THE WATERS, WITH A
WEAK THERMAL TROUGH ALONG THE COASTLINE, NORTHWESTERLY WINDS WILL
BUILD ALONG THE COAST STARTING SUNDAY INTO NEXT WEEK.
SEAS 4 TO 6 FT EASING A BIT BY LATE MORNING TO AROUND 3 OR 4 FT, BUT
WILL RISE TO 6 TO 8 FT BY SUNDAY. DEPENDING ON THE STRENGTH OF THE
NORTHWEST WINDS, WAVES MAY GET UP TO 10-12 FT THROUGH THE OUTER
COASTAL WATERS EARLY NEXT WEEK.
18/62
FIRE WEATHER
INCREASED ONSHORE FLOW AND AREAS OF MORNING
STRATUS WILL YIELD GOOD OVERNIGHT RH RECOVERIES TODAY. THE NEXT
ELEVATED FIRE WEATHER CONCERN IS THE HOT AND DRY PATTERN EXPECTED
LATE THIS WEEKEND INTO EARLY NEXT WEEK AS RIDGING BUILDS IN OVER
THE AREA FROM THE PACIFIC. WARMING TEMPERATURES, WITH HIGHS IN THE
80S TO LOW 90S AND MINIMUM RELATIVE HUMIDITIES DIPPING DOWN INTO
THE 20S AND 30S BY EARLY NEXT WEEK WILL ELEVATE FIRE WEATHER
CONCERNS ACROSS PORTIONS OF THE INTERIOR. ENSEMBLES THEN SUGGEST
TROUGHING REDEVELOPING ACROSS THE REGION AGAIN BY MIDWEEK, WHICH
WOULD HELP MODERATE TEMPERATURES AND INCREASE ONSHORE FLOW.
14
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 2 AM PDT
SATURDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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