413
FXUS66 KSEW 031656
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
956 AM PDT SUN MAY 3 2026
UPDATE
CURRENT TEMPERATURES ARE ANYWHERE BETWEEN 5 TO 15 DEGREES
WARMER COMPARED TO THIS TIME YESTERDAY. AN UNSEASONABLY WARM DAY
IS UNDERWAY HERE ACROSS W WA AS DAILY RECORD HIGHS WILL LIKELY
FALL. THE PREVIOUS DISCUSSION REMAINS BELOW ALONG WITH AN
UPDATED MARINE/AVIATION SECTION.
SYNOPSIS
UPPER LEVEL RIDGE OFFSHORE EXTENDING INTO THE BRITISH COLUMBIA
COASTLINE TODAY WILL SAG SOUTH OVER WESTERN WASHINGTON MONDAY
AND TUESDAY. THE RIDGE WILL REMAIN OVER THE AREA THROUGH
THURSDAY THEN SHIFT EAST FRIDAY. A DISSIPATING FRONT WILL ARRIVE
FRIDAY NIGHT AND SATURDAY. IN THE LOWER LEVELS OFFSHORE FLOW
TODAY WILL WEAKEN TONIGHT AND BECOME ONSHORE MONDAY. VARYING
DEGREES OF ONSHORE FLOW FOR THE REMAINDER OF THE WEEK.
SHORT TERM /TODAY THROUGH TUESDAY/
SATELLITE IMAGERY SHOWS CLEAR SKIES OVER WESTERN WASHINGTON
EARLY THIS MORNING. TEMPERATURES AT 3 AM/10Z RANGE FROM THE MID
40S TO THE MID 50S EXCEPT IN AREAS WITH EXPOSURE TO THE EAST
WINDS. THESE LOCATIONS ARE STILL IN THE LOWER 60S. THERE IS A
CHANCE SOME RECORD HIGH MINIMUM TEMPERATURES COULD BE SET TODAY.
LOW LEVEL OFFSHORE FLOW KICKING IT IN GEAR THIS MORNING. WINDS
AT SNOQUALMIE PASS TURNED EASTERLY LATE LAST NIGHT. WINDS AT
OBSERVATION SITES IN THE OLYMPICS, WHICH TURNED EASTERLY
YESTERDAY, ARE INCREASING WITH MULTIPLE SITES REPORTING PEAK
WINDS NEAR 15 MPH. SEATTLE-TACOMA AIRPORT AND PAINE FIELD IN
EVERETT STILL 60 DEGREES. THESE EASTERLY WINDS WILL MIX DOWN TO
THE SURFACE THIS MORNING AND CONTINUE THROUGH THE AFTERNOON
HOURS. RECORD BREAKING HIGHS TODAY IN THE MID 70S TO MID 80S.
CURRENT RECORDS, SEATTLE 77 DEGREES (1992) FORECAST HIGH 83,
OLYMPIA 80 DEGREES (1992) FORECAST HIGH 86, QUILLAYUTE 83 (1992)
FORECAST HIGH 84. OLYMPIA TO BELLINGHAM GRADIENT DOWN TO AROUND
-2 MB IN THE AFTERNOON. LOCATIONS NEAR THE SOUND WILL GET A
COOLING AFTERNOON SEABREEZE KEEPING HIGHS IN THE MID 70S.
LOW LEVEL FLOW GOING FLAT OVERNIGHT INTO MONDAY MORNING. MILD
LOW TEMPERATURES MONDAY MORNING, IN THE UPPER 40S TO MID 50S.
MONDAY A TRANSITION DAY WITH THE LOW LEVEL FLOW GOING ONSHORE.
TEMPERATURES COOLING WAY DOWN ALONG THE COAST WITH HIGHS IN THE
MID 60S. HIGH TEMPERATURES FOR THE INTERIOR A LITTLE TRICKIER.
BY 00Z TUESDAY KOTH-KSEA GRADIENT AROUND PLUS 5 MB, KUIL-KBLI
AROUND PLUS 3 MB AND KHQM-KSEA AROUND PLUS 3 MB. THE KOLM-KBLI
GRADIENT IS FLAT. THE AIR MASS OVER THE INTERIOR WILL STILL BE
WARM MAKING IT HARD FOR THE MARINE LAYER TO MAKE MUCH OF A DENT
IN THE AFTERNOON. TEMPERATURES ALOFT DO COOL SLIGHTLY, 850 MB
TEMPERATURES GOING FROM PLUS 16C TO AROUND PLUS 14C. FOR NOW
WILL GO WITH SOME SLIGHT COOLING, UP TO 5 DEGREES, FOR THE
INTERIOR PUTTING HIGHS IN THE 70S TO LOWER 80S.
LOW LEVEL ONSHORE FLOW PEAKING MONDAY NIGHT WITH THE MARINE
LAYER GETTING INTO THE INTERIOR BY TUESDAY MORNING. LOWS IN THE
MID 40S TO MID 50S.
UPPER LEVEL RIDGE, CURRENTLY ALONG THE BRITISH COLUMBIA
COASTLINE, WILL BE OVER THE TOP OF WESTERN WASHINGTON TUESDAY.
STRATUS GETTING EAST OF PUGET SOUND IN THE MORNING BUT WITH THE
LOW LEVEL ONSHORE FLOW GOING FLAT IN THE AFTERNOON DO NOT
EXPECT THE STRATUS TO BE AROUND EXCEPT ALONG THE COASTLINE IN
THE AFTERNOON. A LITTLE MORE COOLING FOR THE INTERIOR WITH HIGHS
IN THE UPPER 60S TO MID 70S. HIGHS ALONG THE COAST IN THE LOWER
60S.
IN SEATTLE THE NORMAL NUMBER OF DAYS WITH HIGHS 80 PLUS IN MAY
IS 2. THE RECORD FOR THE MONTH IS 7 IN 1958. IN 81 YEARS OF
RECORDS AT SEATTLE-TACOMA AIRPORT THERE HAVE BEEN 21 YEARS ( 26%
OF THE TIME ) WITHOUT AN 80 DEGREE PLUS DAY IN MAY. THE LAST
YEAR WITHOUT AN 80 DEGREE PLUS DAY IN MAY IN SEATTLE WAS 2022.
OUT OF THE 145 DAYS IN MAY WITH A HIGH 80 DEGREES PLUS ONLY 13
OF THEM ( 9% ) HAVE OCCURRED IN THE FIRST WEEK. THE LAST TIME
THERE WAS AN 80 DEGREE PLUS DAY IN THE FIRST WEEK OF MAY, MAY 7,
2016 ( 82 DEGREES ). FELTON
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
EXTENDED MODELS SHOWING GOOD CONSISTENCY THIS MORNING. UPPER
LEVEL RIDGE WILL VARY IN STRENGTH OVER WESTERN WASHINGTON INTO
THURSDAY WITH VARYING DEGREES OF LOW LEVEL ONSHORE FLOW AS WELL.
THE RIDGE SHIFTS EAST FRIDAY. DISSIPATING FRONT ARRIVING FRIDAY
NIGHT OR SATURDAY BRINGING SLIGHT CHANCE POPS TO THE AREA.
HIGHS REMAINING ABOVE NORMAL FOR THE INTERIOR THROUGH THURSDAY,
IN THE MID 60S TO LOWER 70S. HIGHS LOWERING BACK INTO THE 60S
FRIDAY AND SATURDAY. ONSHORE FLOW WILL KEEP HIGHS IN THE LOWER
60S ALONG THE COAST.
AVIATION
NORTH TO NORTHEAST FLOW ALOFT CONTINUES WITH AN UPPER
RIDGE LOCATED OFFSHORE. VFR CONDITIONS THROUGH THIS EVENING WITH FEW
HIGH CLOUDS AT TIMES. A SHALLOW LIFR/IFR MARINE LAYER IS EXPECTED TO
REACH HQM BY MONDAY MORNING, BUT VFR CONTINUING MONDAY FOR INTERIOR
LOCATIONS. INCREASING NORTH WINDS THIS AFTERNOON, BECOMING LIGHT
TONIGHT.
KSEA...VFR CONDITIONS THROUGH THE TAF PERIOD. SURFACE WINDS N/NW
THROUGH THIS EVENING RANGING 7 TO 12 KTS. NE WINDS TONIGHT AT 4 TO 7
KTS. JD
MARINE
THERMALLY INDUCED LOW PRESSURE WILL LEAD TO WEAK NORTHERLY OR
OFFSHORE FLOW TODAY. THE THERMAL TROUGH WILL SHIFT INLAND ON MONDAY
FOR A RETURN TO ONSHORE FLOW THAT WILL PERSIST INTO THE WEEK AHEAD
AS A SURFACE RIDGE REMAINS ANCHORED OFFSHORE.
27
HYDROLOGY
NO RIVER FLOODING IN THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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