537
FXUS66 KSEW 292200
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT SUN JUN 29 2025
SYNOPSIS
RIDGING OVER THE WESTERN US WILL KEEP THE START OF
THE WEEK WARM AND DRY. TEMPERATURES WILL TREND COOLER MIDWEEK
INTO THE HOLIDAY WEEKEND, NEAR OR A BIT WARMER THAN NORMAL.
CONDITIONS ALSO LOOK TO REMAIN GENERALLY DRY FOR MOST AREAS
OTHER THAN THE PERIODS OF LIGHT RAIN ALONG THE NORTH COAST
SATURDAY AND NORTH CASCADES SUNDAY.
SHORT TERM /TODAY THROUGH TUESDAY NIGHT/
HIGH TEMPERATURES
WARMING WELL INTO THE UPPER 70S AND LOW 80S AS THE UPPER LEVEL
RIDGE MOVES ONSHORE THIS AFTERNOON. WITH THE RIDGE AXIS
OVERHEAD AND LIGHT LOW LEVEL OFFSHORE FLOW MONDAY CONTINUES TO
LOOK TO BE THE WARMEST DAY OF THE STRETCH FOR MANY AREAS. THIS WILL
BRING TEMPERATURES INTO THE MID TO UPPER 80S WITH A FEW SPOTS
EXPECTED TO REACH THE 90 DEGREE MARK. THIS WILL RESULT IN A
CORRIDOR OF MODERATE (ORANGE) HEATRISK FOR THE INTERIOR FROM
THE CENTRAL PUGET SOUND SOUTHWARD AND AND SOME OF THE FOOTHILLS
AND CASCADE VALLEYS.
DEVELOPING ONSHORE FLOW TUESDAY WILL RESULT IN A COOLDOWN FOR
AREAS WEST OF PUGET SOUND, LEAVING ANOTHER WARM DAY FOR THE
URBAN CORRIDOR FROM SEATTLE TO TACOMA AS WELL AS IN THE CASCADES
FOOTHILLS AND VALLEYS. THIS WILL YIELD A SECOND MODERATE
HEATRISK DAY FOR THESE AREAS ON TUESDAY.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
A MORE FULLY DEVELOPED
ONSHORE PUSH WILL RETURN WEDNESDAY BRINGING A RETURN OR MORNING
CLOUDS AND TEMPERATURES CLOSER TO SEASONAL NORMALS WEDNESDAY
AND THURSDAY. THE MOST LIKELY FORECAST REMAINS GENERALLY DRY
THROUGH THE PERIOD FOR MOST AREAS. THE ZONAL PATTERN DOES LEAVE
THE DOOR OPEN FOR THE POTENTIAL FOR THE ODD WEAK SHORTWAVE
TROUGH TO BRUSH THE REGION. THE NBM HAS BACKED OF THE POTENTIAL
FOR SHOWERS INTO SATURDAY AND SUNDAY - MOSTLY ALONG THE NORTH
COAST AND NORTH CASCADES, WITH MOST LOCATIONS REMAINING
OTHERWISE DRY.
AVIATION
HIGH PRESSURE OVER THE REGION FOR DRY AND STABLE
CONDITIONS. LOW LEVEL STRATUS CLOUDS WILL IMPACT THE COAST TONIGHT
AND MONDAY MORNING WITH VFR CONDITIONS ELSEWHERE. N WINDS IN THE
INTERIOR, GUSTING TO 20 KT THIS EVENING.
KSEA...VFR WITH N WINDS GUSTING TO 20 KT THIS EVENING. 33
MARINE
A THERMAL TROUGH ALONG THE COAST WILL LEAD TO STRONG NW
WINDS OVER THE COASTAL WATERS - A SMALL CRAFT ADVISORY REMAINS IN
EFFECT. ONSHORE FLOW WILL INCREASE MONDAY AND TUESDAY AS THE
THERMAL TROUGH MOVES INLAND. GALES ARE LIKELY THROUGH THE STRAIT
OF JUAN DE FUCA TUESDAY NIGHT. A WEAK FRONT WILL CROSS THE WATERS
ON WEDNESDAY. 33
FIRE WEATHER
WARM AND DRY CONDITIONS ARE EXPECTED TO PERSIST
TODAY THROUGH TUESDAY AS HIGH PRESSURE REMAINS OVERHEAD. WITH
THESE TEMPERATURES, RELATIVE HUMIDITY VALUES DURING THE DAY
MONDAY WILL BE AS LOW AS 25% IN SOME OF THE SOUTHERN CASCADE
VALLEYS (PORTIONS OF ZONES 658 AND 659), WITH REMAINING CASCADE
AND PUGET SOUND/SOUTH INTERIOR AREAS SEEING RH'S AS LOW AS
30-40%. THIS WILL ELEVATE FIRE WEATHER CONCERNS DUE TO THE DRY
CONDITIONS THROUGH TUESDAY, AS RH'S IN SOME OF THESE AREAS MAY
NOT FULLY RECOVER. THE PATTERN TRENDS COOLER BY WEDNESDAY, WHICH
WILL IMPROVE RH'S ACROSS WESTERN WA AND WILL LESSEN FIRE
CONCERNS. WINDS ARE EXPECTED TO REMAIN LIGHT THROUGH THE WEEK,
WITH LIGHT NORTH TO NORTHEAST AND VARIABLE WINDS.
HPR
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT MONDAY 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 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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