549
FXUS66 KSEW 040304
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
804 PM PDT SUN MAY 3 2026
SYNOPSIS
UPPER LEVEL RIDGE BUILDING INTO THE BRITISH COLUMBIA COAST
TODAY WILL PROGRESS OVER WESTERN WASHINGTON BY TUESDAY. RIDGING
WILL VARY IN INTENSITY THROUGH MIDWEEK BEFORE EXITING ON
FRIDAY. TEMPERATURES REMAINING ABOVE AVERAGE THROUGH MUCH OF THE
UPCOMING WEEK. A DISSIPATING FRONT WILL ARRIVE FRIDAY EVENING
INTO SATURDAY.
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/
THE LATEST FORECAST REMAINS ON TRACK THIS EVENING, WITH SEVERAL
DAILY TEMPERATURE RECORDS BROKEN ACROSS THE REGION TODAY.
TONIGHT, DRY CONDITIONS ARE IN THE FORECAST AREA WIDE AS AN
UPPER-RIDGE SHIFTS GENTLY TOWARDS THE REGION. WE'LL COOL OFF
INTO THE LOWER TO MID 50S, OFFERING A BIT OF REPRIEVE FROM THE
HEAT.
THE HEAT WILL REMAIN INTO MONDAY BUT'LL SHOW SIGNS OF RELENTING.
UPPER-RIDGING HOLDING STEADY OVER THE REGION, ALLOWING FOR MORE
LARGE- SCALE SUBSIDENCE ACROSS THE PNW. HOWEVER, A SURFACE
THERMAL TROUGH PREVIOUSLY ALONG THE COAST WILL SHIFT INLAND AND
CROSS THE CASCADES - BRINGING A RETURN OF NATURAL AC IN THE FORM
OF A MARINE PUSH BY THE EVENING. HIGH TEMPERATURES WILL TOP OUT
WELL INTO THE UPPER 70S TO LOWER 80S ACROSS THE INTERIOR BUT
THE COAST AND ADJACENT AREAS WILL COOL-DOWN INTO THE 60S.
HEATRISK FOR THE MOST PART REMAINS IN THE MINOR CATEGORY ON
MONDAY DUE TO THE TEMPERATURES COOLING OFF NICELY IN THE
OVERNIGHT HOURS.
THE AFOREMENTIONED MARINE PUSH WILL BRING STRATUS INTO TUESDAY
AS THE COOL-DOWN ENSUES. CLOUDS WILL GRADUALLY BURN OFF INTO
THE MORNING TO ABUNDANT SUNSHINE FOR THE REMAINDER OF THE DAY
DAYTIME HIGHS ARE EXPECTED TO BE IN THE UPPER 60S TO MID 70S,
COOLER THAN PREVIOUS DAYS BUT STILL ABOVE AVERAGE. THE COAST
WILL REMAIN IN THE MID 60S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
UPPER LEVEL RIDGE OVER THE AREA WEAKENING WEDNESDAY, REBUILDING
THURSDAY THEN STARTS TO MOVE EAST FRIDAY. LOW LEVEL FLOW
REMAINING LIGHT ONSHORE. RELATIVELY WARM AIR ALOFT COMBINED WITH
ONLY A SHALLOW MARINE LAYER OVER THE INTERIOR IN THE LATE NIGHT
AND MORNING HOURS WILL KEEP DAYTIME HIGHS ABOVE NORMAL THROUGH
THE WEEK. A LITTLE COOLING FRIDAY AS THE RIDGE STARTS TO EXIT
THE AREA AND A WEAK FRONT REPLACES IT INTO SATURDAY. HIGHS
WEDNESDAY AND THURSDAY IN THE 60S TO LOWER 70S, BEFORE SETTLING
INTO THE 60S AREA WIDE ON FRIDAY AND SATURDAY BEFORE POTENTIALLY
WARMING AGAIN INTO EARLY NEXT WEEK.
AVIATION
NORTH TO NORTHEAST FLOW ALOFT THROUGH MONDAY WITH AN UPPER
RIDGE LOCATED OFFSHORE. VFR CONDITIONS CONTINUE THROUGH MONDAY
FOR THE INTERIOR LOCATIONS. A SHALLOW LIFR/IFR MARINE LAYER IS
EXPECTED TO BE REACH HQM MONDAY MORNING (BETWEEN 12-15Z).
STRATUS WILL CONTINUE ALONG THE IMMEDIATE COAST INTO MONDAY
AFTERNOON. STRATUS WILL THEN SLOWLY SPREAD INLAND MONDAY NIGHT.
NORTH SURFACE WINDS THIS AFTERNOON WILL BECOME LIGHT TONIGHT AND
TRANSITION MORE SW ON MONDAY.
KSEA...VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD (THREAT OF
MARINE STRATUS REACHING TERMINAL REMAINS NEAR 0 FOR MONDAY MORNING).
NORTH SURFACE WINDS 7 TO 12 KTS THIS AFTERNOON, BECOMING NE 4 TO 7
KTS TONIGHT. WINDS WILL BECOME LIGHT MONDAY MORNING AND TRANSITION
TO SW MID-LATE MORNING.
JD/HPR
MARINE
THERMALLY INDUCED LOW PRESSURE WILL LEAD TO WEAK NORTHERLY TO
OFFSHORE FLOW INTO TONIGHT. THE THERMAL TROUGH WILL SHIFT INLAND
ON MONDAY. ONSHORE FLOW WILL THEN PERSIST THROUGH THE MAJORITY
OF THE WEEK AS A SURFACE RIDGE IS POSITIONED OFFSHORE. WESTERLY
PUSHES THROUGH THE STRAIT ARE EXPECTED DURING MOST EVENING AND
OVERNIGHT PERIODS THIS WEEK. A SMALL CRAFT ADVISORY HAS BEEN
ISSUED FOR THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA FOR
THE INITIAL WESTERLY PUSH MONDAY NIGHT. SEAS WILL RANGE BETWEEN
7 TO 9 FEET ALONG THE COAST INTO MONDAY, WITH BRIEF 10 FOOT SEAS
POSSIBLE FOR THE OUTER COASTAL WATERS TONIGHT. SEAS WILL THEN
SUBSIDE TO 4 TO 6 FEET ON TUESDAY.
JD
HYDROLOGY
NO RIVER FLOODING IN THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 PM MONDAY TO 5 AM PDT TUESDAY FOR
CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE
U.S. WATERS STRAIT OF JUAN DE FUCA.
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