169
FXUS66 KSEW 131000
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PDT FRI JUN 13 2025
SYNOPSIS
UPPER LEVEL TROUGH REMAINING OFFSHORE THROUGH THE
PERIOD. A WEAK SYSTEM WILL SPIN OUT OF THE TROUGH INTO WESTERN
WASHINGTON LATER TUESDAY OR WEDNESDAY. VARYING DEGREES OF LOW
LEVEL ONSHORE FLOW THROUGH THE MIDDLE OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
SATELLITE IMAGERY SHOWS
STRATUS HAS FILLED IN OVER MOST OF THE AREA EARLY THIS MORNING.
THE NORTHWEST INTERIOR AND THE SAN JUAN ISLANDS ARE THE MOST
NOTABLE AREAS WITH SOME CLEAR SKIES. IT'S A LITTLE COOL OUT THERE
AT 2 AM/09Z WITH TEMPERATURES IN THE MID 40S TO LOWER 50S.
STRATUS WILL CONTINUE TO FILL IN THROUGH A COUPLE OF HOURS AFTER
SUNRISE MAKING FOR A CLOUDY MORNING. WEAK CONVERGENCE OVER
SNOHOMISH COUNTY COULD PRODUCE A LITTLE DRIZZLE OR A LIGHT
SHOWER. COULD ALSO SEE A LIGHT SHOWER IN THE NORTH AND CENTRAL
CASCADES. ONSHORE FLOW WEAKENING THIS AFTERNOON. THIS COMBINED
WITH THE STRONG MID JUNE SUN WILL DISSIPATE THE STRATUS BY MID
AFTERNOON LEAVING MOSTLY SUNNY SKIES. CLOUD COVER MOST OF THE DAY
AND A SLIGHTLY COOLER THAN NORMAL AIR MASS OVER THE AREA WILL KEEP
HIGHS IN THE 60S.
NOT MUCH GOING ON TONIGHT INTO SATURDAY. UPPER LEVEL TROUGH
REMAINING OFFSHORE WITH SOUTHWESTERLY FLOW ALOFT. NOTHING EMBEDDED
IN THE FLOW ALOFT. LOW LEVEL FLOW ONSHORE FLOW INCREASING
OVERNIGHT WITH STRATUS FILLING BACK IN OVER MOST OF THE AREA BY
SUNRISE. LOW LEVEL ONSHORE FLOW WEAKENING LATER IN THE DAY WITH
THE STRATUS DISSIPATING IN THE AFTERNOON FOR ANOTHER ROUND OF LATE
DAY SUNSHINE. LOWS TONIGHT IN THE 40S AND LOWER 50S. HIGHS
SATURDAY IN THE 60S AND LOWER 70S.
SLIGHT CHANGE IN THE PATTERN SATURDAY NIGHT AND SUNDAY WITH THE
UPPER LEVEL TROUGH OFFSHORE DIGGING SOUTH. 500 MB HEIGHTS
INCREASING SLIGHTLY OVER THE AREA. SURFACE GRADIENTS GOING FLAT
RESULTING IN LESS MORNING CLOUD COVER THAN TODAY AND SATURDAY.
MORE SUNSHINE AND SLIGHTLY WARMER TEMPERATURES ALOFT COMBINING TO
WARM HIGHS INTO THE MID 60S TO MID 70S. WITH LESS CLOUD COVER
OVERNIGHT LOWS SUNDAY MORNING IN THE 40S. SOME OF THE COOLER
LOCATIONS COULD DROP INTO THE UPPER 30S.
LONG TERM /MONDAY THROUGH THURSDAY/
CONFIDENCE NOT REAL HIGH IN
THE EXTENDED FORECAST. MODELS HAVE BEEN HAVING TROUBLE COMING UP
WITH A CONSISTENT SOLUTION FOR THE FIRST HALF OF NEXT WEEK. THERE
IS GENERAL AGREEMENT THAT A LARGE UPPER TROUGH OVER THE EASTERN
PACIFIC WILL REMAIN IN PLACE THROUGH THE PERIOD. MODEL
INCONSISTENCY COMING IN TO PLAY WITH THE FINER DETAILS OF WHEN
WEAK SHORTWAVES SPINNING OUT OF THE TROUGH WILL MOVE THROUGH
WESTERN WASHINGTON. 00Z OPERATIONAL RUNS AND THE ENSEMBLES GOING
FOR THE BEST CHANCES FOR SHOWERS IN THE TUESDAY NIGHT AND
WEDNESDAY TIME FRAME. A FEW RUNS AGO THE STRONGEST SHORTWAVE WAS
FORECAST TO MOVE THROUGH MONDAY. WILL NOT BE SURPRISED IF THE
BEST CHANCE FOR SHOWERS GETS PUSHED LATER IN THE WEEK WITH FUTURE
RUNS.
SOUTHWESTERLY FLOW ALOFT CONTINUING MONDAY ALONG WITH WEAKER
ONSHORE FLOW FOR HIGHS IN THE MID 60S TO MID 70S. UPPER LEVEL FLOW
WEAKENING AND COOLING A LITTLE FOR THE REMAINDER OF THE PERIOD.
A LITTLE STRONGER LOW LEVEL ONSHORE FLOW AND MORE CLOUD COVER WILL
DROP HIGHS TO A LITTLE BELOW NORMAL FOR TUESDAY THROUGH THURSDAY,
IN THE 60S AND LOWER 70S.
IT HAS BEEN AN UNUSUALLY DRY START TO JUNE FOR WESTERN WASHINGTON.
SEATTLE HAS NOT GOTTEN ANY MEASURABLE RAIN THE FIRST 12 DAYS OF
THE MONTH. IN 81 YEARS OF RECORDS AT SEATTLE-TACOMA AIRPORT THIS
IS ONLY THE 7TH YEAR THIS HAS HAPPENED. THE LAST TIME WAS IN 2009.
THE FIRST HALF OF JUNE HAS BEEN COMPLETELY DRY IN SEATTLE ONLY 4
TIMES IN THE LAST 80 YEARS ( 2009, 1996, 1982 AND 1969 ). THE
LONGEST DRY STREAK FOR SEATTLE IN THE MONTH OF JUNE IS 25 DAYS,
JUNE 1 TO 25, 1982. IT THEN RAINED 4 OUT OF THE LAST 5 DAYS IN
JUNE 1982. THE DRIEST JUNE ON RECORD IS 0.13 INCHES IN 1951.
FELTON
AVIATION
SOUTHWESTERLY FLOW ALOFT CONTINUES WITH AN UPPER LEVEL
LOW CENTERED OVER SE ALASKA. CLOUDS ARE BEGINNING TO SLOWLY FILL IN
AND LOWER, WITH VFR CIGS BECOMING MVFR IN THAT PROCESS. MVFR
CONDITIONS SHOULD DEVELOP AREA-WIDE BETWEEN 12-14Z THIS MORNING AND
PERSIST THROUGH AROUND 18-20Z, SCATTERING FIRST THROUGH THE INTERIOR
AND LASTLY ALONG THE COAST. A RETURN TO VFR CONDITIONS IS EXPECTED
AREA-WIDE THIS AFTERNOON AND EVENING. STRATUS DOES LOOK TO
POTENTIALLY REDEVELOP AGAIN EARLY SATURDAY MORNING, FIRST ALONG THE
COAST AFTER AROUND 06Z-12Z SAT, THEN THROUGH THE INTERIOR LATER
AFTER THE END OF THE TAF PERIOD. W TO SW WINDS 7-12 KT WILL PERSIST
THROUGH THE TAF PERIOD, WITH THE EXCEPTION OF KPAE WHERE WINDS WILL
SWITCH TO N THIS EVENING FOLLOWING A PUSH DOWN THE STRAIT OF JUAN DE
FUCA.
KSEA...MVFR CONDITIONS UNDER STRATUS EARLY THIS MORNING. MODELS HAVE
CLOUDS SCATTERING RAPIDLY THIS MORNING FOR A BREAKOUT TIME OF AROUND
18-20Z, THOUGH COULD BE A BIT EARLIER. VFR CONDITIONS PERSIST
THROUGH THE REMAINDER OF THE TAF PERIOD. THERE IS A 25-30% CHANCE OF
STRATUS REFORMING AND PRODUCING MVFR CEILINGS AFTER AROUND 12-15Z
SATURDAY. WINDS REMAIN SW 5-12 KT THROUGH THE TAF PERIOD.
62
MARINE
THE OVERALL WEATHER PATTERN WILL REMAIN CONSISTENT FRIDAY
AND INTO THIS WEEKEND--BROAD HIGH PRESSURE WILL SLOWLY DRIFT
SOUTHWARD, MAINTAINING NORTHWESTERLY WINDS ACROSS THE COASTAL WATERS.
BREEZY WINDS WITH GUSTS UP TO 25 KT ARE POSSIBLE AT TIMES TODAY.
THESE WINDS ARE ALSO CREATING STEEP SEAS, WITH SEAS 7 TO 8 FT WITH A
DOMINANT PERIOD OF AROUND 8 SECONDS.
A WEAKENING FRONT WILL MOVE THROUGH THE WATERS ON MONDAY, WITH A
MORE ACTIVE PATTERN EXPECTED NEXT WEEK WITH SEVERAL SYSTEMS
TRAVERSING THE AREA WATERS THROUGH THE MIDDLE OF NEXT WEEK.
ELSEWHERE, EXPECT DIURNALLY DRIVEN PUSHES OF WESTERLY WINDS DOWN
THE STRAIT OF JUAN DE FUCA EACH EVENING. THE PUSH TONIGHT LOOKS TO
REMAIN BELOW 20 KT, THEREFORE HAVE HELD OFF ON ISSUING A SMALL CRAFT
ADVISORY FOR THIS EVENING. THE PUSH SATURDAY EVENING LOOKS STRONGER
AND WILL LIKELY REQUIRE ANOTHER SMALL CRAFT ADVISORY THEN. TRENDS
WILL BE EVALUATED TO DETERMINE THE NEED FOR ANY ADDITIONAL
ADVISORIES ON SUBSEQUENT DAYS.
62
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 6 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.
SMALL CRAFT ADVISORY UNTIL 6 PM PDT THIS EVENING FOR 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-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE
TO CAPE SHOALWATER OUT 10 NM.
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