438
FXUS66 KSEW 102145
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
245 PM PDT THU SEP 10 2026
SYNOPSIS
TROUGHING DEVELOPING OVER THE AREA CONTINUING INTO THIS
WEEKEND, BRINGING THE CHANCES OF UNSETTLED CONDITIONS AND
COOLER TEMPERATURES ACROSS THE REGION. RIDGING LOOKS TO REBUILD
THROUGH THE FIRST HALF OF NEXT WEEK FOR A SLOW WARMING TREND.
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/
AN UPPER LEVEL TROUGH WILL DEVELOP OVER WESTERN WASHINGTON
TODAY, BRINGING INCREASING ONSHORE FLOW OVER THE AREA. EXPECT
COOLER TEMPERATURES OVER THE NEXT COUPLE OF DAYS WITH UNSETTLED
WEATHER. HIGH TEMPERATURES WILL REMAIN IN THE UPPER 60S INTO
LOWER 70S THIS AFTERNOON. AREAS ALONG THE COAST WILL SEE
TEMPERATURES IN THE LOW TO MID 60S. WEAK ZONAL FLOW TONIGHT MAY
LEAD TO A BRIEF CONVERGENCE ZONE LATER TONIGHT ACROSS SNOHOMISH
COUNTY, BUT LATEST GUIDANCE SHOWS IT WOULD BE PRETTY WEAK IF IT
DID DEVELOP.
AS TROUGHING DEEPENS INTO FRIDAY, AN UPPER LEVEL LOW WILL
DEVELOP OFFSHORE OF VANCOUVER ISLAND. ANOTHER ROUND OF MORNING
CLOUDS ON FRIDAY WITH A SLIGHT CHANCE OF DRIZZLE IN THE MORNING.
DRY CONDITIONS THROUGH FRIDAY WITH HIGH TEMPERATURES ONCE AGAIN
IN THE UPPER TO LOWER 70S ACROSS THE REGION. THE UPPER LEVEL LOW
WILL MOVE ONSHORE ON SATURDAY, BRINGING WIDESPREAD RAIN SHOWERS
TO TO THE REGION. ADDITIONALLY, THERE IS A 15-25% CHANCE OF
THUNDERSTORMS, PRIMARILY SOUTH OF SNOHOMISH COUNTY AT TIMES
THROUGHOUT THE AFTERNOON. WINDS MAY BE BREEZY AT TIMES IN AND
AROUND SHOWERS. HIGH TEMPERATURES REMAIN IN THE MID TO UPPER
60S, WHILE OVERNIGHT LOWS STAY IN THE MID 50S.
LONG TERM /SUNDAY THROUGH THURSDAY/
CONDITIONS LOOK TO START
DRYING OUT INTO SUNDAY, WITH SOME LINGERING SHOWERS LIKELY IN
THE CASCADES AND THE OLYMPICS. AN UPPER LEVEL RIDGE WILL BEGIN
TO BUILD OFFSHORE ON MONDAY, INTRODUCING A SLOW WARMING TREND
THROUGH MIDWEEK. SOME ENSEMBLES SUGGEST WEAK TROUGHING
TUESDAY/WEDNESDAY THAT COULD BRING SOME POPS TO THE REGION, BUT
FOR NOW, LOOKS LIKE DRY AND WARM CONDITIONS WILL MANIFEST.
MAZURKIEWICZ
AVIATION
A GENERALLY DRY COLD FRONT PUSHED THROUGH TERMINALS EARLIER THIS
MORNING, WITH THE FRONT SPANNING EAST OF THE CASCADES DOWN TO
VANCOUVER WA THIS AFTERNOON. THE FLOW PATTERN ALOFT WILL REMAIN
INFLUENCED BY TROUGHS, KEEPING THE FLOW WEST/NORTHWEST. CLOUD
COVERAGE HAS DECREASED SOME THIS AFTERNOON, BUT REMAINS BROKEN
ACROSS THE INTERIOR AND AROUND NEAH BAY. VFR TO MVFR CONDITIONS WILL
IMPROVE TO VFR FOR ALL EXCEPT THE COAST THIS AFTERNOON. A WEAK
CONVERGENCE ZONE IN PUGET SOUND MAY PRODUCE BRIEF POCKETS OF MVFR,
BUT SHOWERS AND ERRATIC WINDS ARE NOT EXPECTED THROUGH THE EVENING.
WINDS WILL EASE FROM THE NORTH TO THE NORTHWEST 5-10 KT THIS
EVENING, AND TO THE SOUTH/SOUTHWEST FRIDAY MORNING. THERE REMAINS A
40-50% CHANCE OF MVFR CEILINGS FRIDAY MORNING WITH ANOTHER MARINE
PUSH, WITH THE LOWEST CEILINGS FROM 12Z-21Z.
KSEA...VFR WITH CEILINGS SLOWLY LIFTING THROUGH THE
AFTERNOON/EVENING. A 40-50% CHANCE OF MVFR CEILINGS REMAINS ON
FRIDAY FROM 12Z-21Z, IMPROVING TO VFR IN THE AFTERNOON. NORTH TO
NORTHWEST WINDS 5-10 KT WILL SWITCH TO THE SOUTH FRIDAY MORNING.
HPR
MARINE
A COLD FRONT PUSHED THROUGH THE WATERS THIS MORNING, WITH THE
COASTAL WATERS STILL SEEING GUSTY WINDS OVER 20 KT THIS AFTERNOON.
THE INHERITED SMALL CRAFT ADVISORY WILL CONTINUE THROUGH 5 AM FRIDAY
FOR THE NORTH WINDS, AND SEAS OF 8 TO 11 FT. ANOTHER FRONTAL SYSTEM
WILL MOVE ACROSS THE WATERS FRIDAY INTO SATURDAY. WHILE IMPACTFUL
WINDS AND SEAS ARE NOT EXPECTED WITH THIS SYSTEM, PORTIONS OF THE
SOUTHERN INTERIOR AND COASTAL WATERS WILL HAVE A 20% CHANCE OF
THUNDERSTORMS WITH SHOWER ACTIVITY PRODUCED FROM THIS SYSTEM.
CONDITIONS WILL BECOME MORE BENIGN GOING INTO NEXT WEEK AS HIGH
PRESSURE REBUILDS OVER THE COASTAL WATERS. SEAS DECREASE THIS
WEEKEND INTO NEXT WEEK DOWN TO 4-6 FT.
HPR
FIRE WEATHER
A WEAK AND MOSTLY DRY FRONTAL SYSTEM PASSING OVER THE REGION HAS
BROUGHT A RETURN TO ONSHORE FLOW, MAINTAINING COOLER AND MORE MOIST
CONDITIONS THROUGHOUT THE WEEKEND. LIGHT PRECIPITATION IS LIKELY
LATE FRIDAY INTO SATURDAY AS ANOTHER WEAK SYSTEM MOVES OVER THE
REGION. CONDITIONS ARE EXPECTED TO GRADUALLY WARM AND DRY INTO NEXT
WEEK, THOUGH FIRE WEATHER CONCERNS REMAIN LOW AT THIS TIME.
15
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT FRIDAY FOR COASTAL WATERS
FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL
WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-
COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10
TO 60 NM.
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