867
FXUS66 KSEW 081603
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
903 AM PDT SUN JUN 8 2025
UPDATE
CLEAR SKIES THIS MORNING WITH TEMPERATURES STILL ON
TRACK FOR A HOT DAY ACROSS WESTERN WASHINGTON TODAY. NO
SIGNIFICANT UPDATES THIS MORNING TO THE PUBLIC FORECAST. REFER TO
AN UPDATED AVIATION, MARINE, AND FIRE WEATHER SECTION BELOW.
SYNOPSIS
UPPER LEVEL RIDGE OVER WESTERN WASHINGTON TODAY WILL
WEAKEN SLIGHTLY MONDAY BEFORE MOVING OFF TO THE EAST TUESDAY.
POSSIBLE RECORD HIGHS IN A FEW LOCATIONS TODAY. WEAK UPPER LEVEL
TROUGH PASSING THROUGH WEDNESDAY. STRONGER UPPER LEVEL TROUGH
ARRIVING THURSDAY WITH ANOTHER UPPER LEVEL TROUGH REMAINING OVER
THE COASTAL WATERS FRIDAY AND SATURDAY.
SHORT TERM /TODAY THROUGH TUESDAY/
UPPER LEVEL RIDGE OVER
WESTERN WASHINGTON TODAY WITH LIGHT SURFACE GRADIENTS. CROSS
CASCADE GRADIENT STILL POSITIVE THIS MORNING AND NEVER TURNS
NEGATIVE TODAY. WINDS IN THE LOWER LEVELS AT 925 MB AND 850 MB
LIGHT EASTERLY THIS MORNING BUT MODELS HAVE THESE WINDS SWITCHING
TO LIGHT NORTHWESTERLY THIS AFTERNOON. 850 MB TEMPERATURES WARMING
TO PLUS 18-20C BY 00Z MONDAY ( IN THIS TYPE OF SITUATION FOR A
QUICK FIRST ATTEMPT AT THE SEATTLE HIGH JUST TAKE THE 850 MB
TEMPERATURES, IN THIS CASE PLUS 19-20C OR 66-68F, AND ADD 20
DEGREES F. IF WE HAD SOME OFFSHORE FLOW ADD 25 DEGREES F ) WHICH
PUTS HIGHS IN THE 80S AND LOWER 90S FOR THE INTERIOR. WITH THE LOW
LEVEL FLOW NOT GOING OFFSHORE, AFTERNOON SEABREEZES WILL KEEP
HIGHS IN THE 70S NEAR THE STRAIT AND ALONG THE OCEAN. RECORDS ARE
POSSIBLE BOTH IN SEATTLE, CURRENT RECORD 87 IN 2015, AND HOQUIAM,
CURRENT RECORD 75 IN 1972. OTHER LOCATIONS CLOSE TO RECORDS
BELLINGHAM, FORECAST HIGH 80 RECORD 82 IN 1955 AND OLYMPIA
FORECAST HIGH 91 RECORD 94 IN 1948.
UPPER LEVEL RIDGE REMAINING OVER THE AREA TONIGHT WITH LIGHT FLOW
IN THE LOWER LEVELS. THE LACK OF OFFSHORE FLOW WILL ALLOW LOWS TO
DROP INTO THE 50S AND LOWER 60S.
UPPER LEVEL RIDGE WEAKENING SLIGHT MONDAY BUT REMAINING OVER
WESTERN WASHINGTON. SURFACE GRADIENTS TURNING ONSHORE IN THE LATE
MORNING AND AFTERNOON. TEMPERATURES ALOFT COOLING SLIGHTLY WITH
MODEL 850 MB TEMPERATURES A DEGREE OR TWO COOLER THAN TODAY. ALL
THIS LEADS TO A SLIGHTLY COOLER DAY MONDAY, LESS THAN 5 DEGREES OF
COOLING, FOR THE INTERIOR. HIGHS IN THE MID 70S TO MID 80S.
INCREASING ONSHORE FLOW IN THE AFTERNOON WILL COOL THE COAST DOWN
MORE THAN THE INTERIOR WITH HIGHS IN THE MID TO UPPER 60S.
UPPER LEVEL RIDGE CONTINUING TO WEAKEN MONDAY NIGHT WITH THE RIDGE
SLIDING OFF TO THE EAST TUESDAY. LOW LEVEL ONSHORE FLOW DOESN'T
REALLY INCREASE MUCH EVEN WITH THE UPPER LEVEL RIDGE AXIS TO THE
EAST. TEMPERATURES ALOFT COOLING AGAIN WITH MODEL 850 MB
TEMPERATURES DOWN TO PLUS 14-16C BY 00Z WEDNESDAY. WEAK MARINE
PUSH MONDAY NIGHT INTO TUESDAY DROPPING TUESDAY HIGH TEMPERATURES
ANOTHER 5 TO 10 DEGREES OVER THE INTERIOR. HIGHS MOSTLY IN THE
70S. HIGHS ON THE COAST IN THE LOWER TO MID 60S. ONSHORE FLOW
MONDAY NIGHT GIVING THE AREA COOLER MORNING LOWS FOR TUESDAY
MORNING, IN THE LOWER TO MID 50S.
THE HEAT ADVISORY WILL GO INTO EFFECT THIS MORNING AT 10 AM AND
REMAIN IN EFFECT UNTIL 10 PM MONDAY FOR PORTIONS OF THE INTERIOR.
IF YOU ARE THINKING THIS IS AN UNUSUAL START TO JUNE YOU WOULD BE
RIGHT. IN 80 YEARS OF RECORDS AT SEATTLE-TACOMA AIRPORT THE FIRST
10 DAYS OF JUNE HAVE BEEN DRY IN ONLY 9 YEARS. THE LAST TIME IN
2014. IT IS EVEN RARER FOR THE FIRST TWO WEEKS OF JUNE TO BE DRY.
THAT HAS ONLY HAPPENED FOUR YEARS ( 2009, 1996, 1982 AND 1969 ).
HIGHS OF 85 DEGREES PLUS ARE A LITTLE UNCOMMON FOR SEATTLE THIS
TIME OF YEAR. IN THE 80 YEARS OF RECORDS IN THE FIRST 10 DAYS OF
JUNE IT HAS HAPPENED 29 TIMES. 90 DEGREE PLUS DAYS HAVE ONLY
OCCURRED 8 TIMES. THE FEDERAL BUILDING IN DOWNTOWN SEATTLE DID HIT
100 DEGREES ON JUNE 9TH 1955. THE HIGH AT THE OFFICIAL SEATTLE
LOCATION, SEATTLE-TACOMA AIRPORT, WAS 96 DEGREES THAT DAY.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
EXTENDED FORECAST MARKS
THE RETURN TO COOLER JUNE WEATHER BUT STILL NOT MUCH IN THE WAY
OF PRECIPITATION. VERY WEAK UPPER LEVEL TROUGH MOVING THROUGH
WEDNESDAY WITH JUST A LITTLE INCREASE IN ONSHORE FLOW CONTINUING
THE COOLING TREND. STRONGER UPPER LEVEL TROUGH MOVING THROUGH
THURSDAY PUSHING HIGH TEMPERATURES BACK TO BELOW NORMAL WITH AN
INCREASE IN CLOUD COVER. ANOTHER UPPER LEVEL TROUGH HANGS OFF THE
COAST FRIDAY AND SATURDAY WITH SOUTHWESTERLY FLOW ALOFT OVER THE
AREA. PLENTY OF CLOUD COVER BUT OTHER THAN A CHANCE OF SHOWERS
OVER THE NORTHERN AND CENTRAL CASCADES AND FOOTHILLS THE FORECAST
REMAINS DRY. HIGHS FOR THE INTERIOR IN THE MID 60S TO MID 70S
WEDNESDAY, IN THE 60S FOR THURSDAY THROUGH SATURDAY. HIGHS ON THE
COAST REMAINING IN THE LOWER 60S. FELTON
AVIATION
NORTHWEST FLOW ALOFT WILL CONTINUE INTO TONIGHT WITH AN
UPPER RIDGE ACROSS THE PACIFIC NORTHWEST. CLEAR SKIES FOR THE
MAJORITY OF WESTERN WASHINGTON DURING THE TAF PERIOD. THERE IS LOW
POTENTIAL FOR LIFR STRATUS ALONG THE IMMEDIATE COAST NEAR HQM MONDAY
MORNING. N/NW SURFACE WINDS WILL INCREASE INTO THE AFTERNOON BEFORE
BECOMING LIGHTER AGAIN TONIGHT.
KSEA...CLEAR SKIES DURING THE TAF PERIOD. N/NW WINDS WILL INCREASE
TO 7 TO 12 KTS THIS AFTERNOON BEFORE BECOMING MORE NE TONIGHT, WITH
PERIODIC GUSTS OF 15 TO 20 KTS POSSIBLE. JD
MARINE
HIGH PRESSURE WILL REMAIN OVER THE COASTAL WATERS THROUGH
WEDNESDAY. NORTHERLY DIURNAL DRIVEN WINDS EXPECTED FOR THE INTERIOR
WATERS THROUGH TUESDAY. NORTHWEST WINDS WILL ALSO REMAIN ELEVATED
OVER THE COASTAL WATERS THROUGH THIS WEEK. A SMALL CRAFT ADVISORY
HAS BEEN ISSUED FOR THE OUTER COASTAL WATERS BEGINNING SUNDAY
EVENING DUE TO INCREASED NW WINDS AS WELL AS BUILDING SEAS.
ONSHORE FLOW WILL INCREASE TUESDAY INTO WEDNESDAY AND ALSO BRING
POTENTIAL SCA WINDS DURING THE EVENING PERIODS THROUGH THE STRAIT OF
JUAN DE FUCA. IN ADDITION, WILL NEED TO MONITOR THE POTENTIAL FOR
ANY GALES IN THE STRAIT OF JUAN DE FUCA MIDWEEK WITH THE INCREASED
WEST WINDS.
SEAS OF 4 TO 6 FEET THROUGH TODAY WILL BUILD TO 7 TO 12 FEET MONDAY
INTO TUESDAY. IN ADDITION, PERIODS WILL ALSO RANGE 8 TO 12 SECONDS
LATER SUNDAY INTO MONDAY.
JD
FIRE WEATHER
WARM AND DRY CONDITIONS WILL CONTINUE THROUGH MONDAY
AS AN UPPER LEVEL RIDGE MOVES ACROSS WESTERN WASHINGTON. THIS WILL
ELEVATE FIRE WEATHER CONCERNS TODAY AND MONDAY AS MINIMUM RH VALUES
WILL LIKELY REACH AS LOW AS 20-30% OVER THE MOUNTAINS WITH SLIGHTLY
HIGHER VALUES THROUGH THE INTERIOR. WHILE LIVE FUELS ARE STILL WET
ENOUGH TO CURB FIRE SPREAD, DEAD FUELS REMAIN VERY DRY. IN ADDITION,
SNOWPACK IS BELOW NORMAL AND SOME LOCATIONS ARE EXPERIENCING DROUGHT
CONDITIONS. WINDS REMAIN LIGHT ENOUGH INTO MONDAY SUCH THAT CRITICAL
FIRE WEATHER CONDITIONS ARE NOT EXPECTED BUT THE AREA IS DRYING OUT
FAST. MOIST ONSHORE FLOW WILL RETURN MONDAY NIGHT INTO TUESDAY.
SEW WATCHES/WARNINGS/ADVISORIES
WA...HEAT ADVISORY UNTIL 10 PM PDT MONDAY FOR CITY OF SEATTLE-
DOWNTOWN EVERETT / MARYSVILLE AREA-EASTERN KITSAP COUNTY-
EASTSIDE-FOOTHILLS AND VALLEYS OF CENTRAL KING COUNTY-
FOOTHILLS AND VALLEYS OF PIERCE AND SOUTHERN KING COUNTIES-
FOOTHILLS AND VALLEYS OF SNOHOMISH AND NORTHERN KING
COUNTIES-FOOTHILLS AND VALLEYS OF THURSTON AND LEWIS
COUNTIES-FOOTHILLS AND VALLEYS OF THE NORTH CASCADES-
LOWLANDS OF LEWIS AND SOUTHERN THURSTON COUNTIES-LOWLANDS
OF PIERCE AND SOUTHERN KING COUNTIES-NORTHERN HOOD CANAL-
OLYMPIA AND SOUTHERN PUGET SOUND-SHORELINE / LYNNWOOD /
SOUTH EVERETT AREA-SOUTHERN HOOD CANAL.
PZ...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM PDT
TUESDAY 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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