074
FXUS66 KSEW 070331
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
831 PM PDT FRI JUN 6 2025
SYNOPSIS
HIGH PRESSURE WILL REMAINED CENTERED OFFSHORE THROUGH
SATURDAY AS DRY CONDITIONS CONTINUE. BY SUNDAY, THE HIGH AND
RIDGE WILL MOVE INLAND, RESULTING IN WARM TEMPERATURES SUNDAY INTO
MONDAY. HIGHS THESE DAYS WILL REACH THE UPPER 80S TO LOW 90S IN
INTERIOR AND VALLEY AREAS AWAY FROM WATER, WITH LOWS DROPPING INTO
THE UPPER 50S AND 60S. THIS WILL RESULT IN WIDESPREAD MODERATE
HEATRISK SUNDAY AND MONDAY. ONCE THE HIGH MOVES OUT, TEMPERATURES
WILL DROP SIGNIFICANTLY BY WEDNESDAY BACK INTO THE 70S, FURTHER
DROPPING INTO THE 60S BY THURSDAY. A FEW ENSEMBLES HINT AT A FEW
SHOWERS BEING POSSIBLE LATE NEXT WEEK.
SHORT TERM /TONIGHT THROUGH MONDAY/
IT'S SHAPING UP TO BE A
RATHER NICE EVENING ACROSS WESTERN WASHINGTON TONIGHT, WITH
SATELLITE JUST SHOWING SOME CIRRUS STREAMING IN OVERHEAD AND SOME
STRATUS BANKED UP ALONG THE PACIFIC COAST. EXPECT LOWS OVERNIGHT
TO BE IN THE UPPER 40S TO LOW 50S ACROSS THE REGION. THE FORECAST
REMAINS ON TRACK- AND THE PREVIOUS DISCUSSION FOLLOWS BELOW, WITH
MINOR UPDATES MADE TO THE AVIATION SECTION. 14
HIGH PRESSURE REMAINS CENTERED OFFSHORE IN THE PACIFIC.
SYNOPTICALLY A RIDGE IS BEGINNING TO BUILD TO THE NORTH OVER THIS
HIGH ALONG THE COAST OF ALASKA AND B.C. CANADA. FLOW ALOFT REMAINS
NORTHWESTERLY FRIDAY INTO SATURDAY, ALBEIT DECREASING AS THE JET
MOVES EAST OF OUR AREA.
BY SATURDAY, THE HIGH BEGINS TO TRACK INLAND LATER IN THE DAY INTO
SUNDAY. THE RIDGE WILL INCREASE IN AMPLITUDE ALONG THE PACIFIC
COAST UP INTO CANADA AND UP INTO ALASKA. A THERMAL TROUGH WILL
ALSO MOVE ALONG THE COAST TOO CLOSER TO THE SURFACE. THE
COMBINATION OF ALL THESE THINGS WILL LEAD TO AN INCREASE OF
TEMPERATURES GOING THROUGH THE WEEKEND. SATURDAY WILL SEE HIGHS
CLIMB ONLY A FEW MORE DEGREES COMPARED TO FRIDAY (FEW MORE LOW 80S
AND UPPER 70S FOR AREAS AWAY FROM THE COAST AND NOT AT HIGH
ELEVATIONS). THE WINDS DOWN THE CASCADES WILL BECOME LIGHTLY
NORTHEASTERLY TO EASTERLY IN THE EVENING/OVERNIGHT, WITH WINDS
PARALLEL TO THE PACIFIC COAST. THIS WILL SHUT OFF SOME OF THE
ONSHORE FLOW THAT KEEPS THE REGION COOL. LOWS WILL INCREASE
SLIGHTLY SATURDAY NIGHT INTO SUNDAY, RANGING FROM THE MID 50S
ALONG THE COAST, TO THE UPPER 50S ALONG THE I-5 CORRIDOR AND EVEN
60 IN SOME CASCADE VALLEY AREAS. ONLY A COUPLE POCKETS OF THE
SOUTH INTERIOR WILL SEE MODERATE HEAT RISK SATURDAY (EVERYWHERE
ELSE WILL SEE MINOR HEAT RISK).
SUNDAY/MONDAY: THIS IS EXPECTED TO BE THE PEAK OF THE WARM
CONDITIONS WITH THIS HIGH PRESSURE MOVING ASHORE (AND ALSO THE
HOTTEST IN TERMS OF THE DAYTIME AND NIGHTTIME TEMPERATURES). THE
BIGGEST CHANGE TO THE FORECAST IS THAT IT APPEARS THE HEAT WILL
NOW LINGER INTO MONDAY. AREAS EXPECTED TO SEE WIDESPREAD MODERATE
HEAT RISK SUNDAY INTO MONDAY WERE PLACED IN A HEAT ADVISORY TO
COVER THE THREAT (THIS IS PRIMARILY ALONG THE I-5 CORRIDOR UP
THROUGH EVERETT AND IN CASCADE VALLEY/HOOD CANAL/KITSAP AREAS.
AREAS OUTSIDE OF THE ADVISORY WILL STILL SEE MINOR HEAT RISK (AND
POCKETS OF MODERATE RISK AWAY FROM THE WATER). SUNDAY WILL BE THE
HOTTEST DAY (WIDESPREAD HIGHS OF 85-90 WITH A FEW VALLEY AREAS UP
TO 95), AND AREAS JUST OFF THE COASTLINE BETWEEN 75-85 DEGREES.
LOWS SUNDAY NIGHT/MONDAY WILL ONLY DROP BETWEEN 55-65 DEGREES
(WARMEST AREAS IN THE VALLEYS AND THE SOUTH SEATTLE METRO). MONDAY
REMAINS SIMILARLY WARM TO SUNDAY (JUST A DEGREE OR TWO COOLER AND
COASTAL AREAS COOLING OFF MORE WITH ONSHORE FLOW BEGINNING TO
RETURN). LOWS WILL DROP DOWN TOO (BETWEEN 50-60).
IF PLANNING TO DO ACTIVITIES OUTDOORS, MAKE SURE TO STAY HYDRATED
AND TAKE BREAKS IN AIR CONDITIONED ROOMS AS MUCH AS POSSIBLE.
CHECK ON PETS AND CHILDREN. ADDITIONALLY, IF PLANNING TO HEAD TO
THE WATER, USE LIFE JACKETS AND DRESS APPROPRIATELY FOR COLD WATER
TEMPERATURES, AND KNOW THE SIGNS OF COLD SHOCK.
LONG TERM /TUESDAY THROUGH FRIDAY/
RELIEF WILL CONTINUE TO COME
IN WITH DECREASING TEMPERATURES THROUGH THE WEEK. TUESDAY WILL
LIKELY REMAIN WARM WITH HIGHS STILL UP IN THE MID 70S TO LOW 80S
IN THE I-5 CORRIDOR. BY WEDNESDAY TEMPERATURES WILL REMAIN BELOW
80 DEGREES ACROSS THE ENTIRE REGION (WARMEST SPOTS WILL ONLY REACH
MID TO UPPER 70S). AFTER WEDNESDAY, IT BECOMES A QUESTION IN THE
ENSEMBLES IF SOME TROUGHING IS ABLE TO TAKE SHAPE TO BRING AT
LEAST A HINT OF MOISTURE INTO THE REGION. POPS COME BACK UP
THURSDAY TO 20-30% IN THE CASCADES, AND REGION-WIDE FRIDAY FOR A
SLIGHT CHANCE OF SHOWERS. IF THE TROUGHING PATTERN DOES TAKE
PLACE, HIGHS WILL STAY BELOW 70 THURSDAY AND FRIDAY (LOTS OF 50S
AND 60S FOR HIGHS WITH LOWS IN THE 40S AND 50S).
HPR
AVIATION
NORTHWEST FLOW ALOFT WILL CONTINUE INTO SATURDAY WITH
UPPER RIDGING BUILDING INTO THE PACIFIC NORTHWEST. WIDESPREAD VFR
CONDITIONS OVER MUCH OF W WA, HOWEVER LINGERING STRATUS ALONG THE
COAST RESULTING IN MVFR TO IFR CONDITIONS THERE. THESE STRATUS
EXPECTED TO PUSH EASTWARD OVERNIGHT INTO SATURDAY MORNING, REACHING
AS FAR EAST AS CLM AND PWT, BEFORE LARGELY HALTING THERE. WHILE SOME
LOW CLOUDS COULD REACH REMAINING TERMINALS, THEY WILL REMAIN
CONFINED TO FEW-SCT. MOST LOCATIONS SHOULD SEE A RETURN TO VFR
CONDITIONS BY LATE MORNING, WITH VFR PERSISTING FOR THE REMAINDER OF
THE TAF PERIOD. W/NW SURFACE WINDS GENERALLY 5-10 KTS INTO THIS
EVENING WILL BECOME LIGHTER TONIGHT BEFORE RETURNING TO THOSE
SPEEDS LATE SATURDAY MORNING..
KSEA...VFR CONDITIONS WITH HIGH CLOUDS AT TIMES INTO TONIGHT.
STRATUS IS EXPECTED TO MOVE INTO SOUTHERN PUGET SOUND SATURDAY
MORNING. AT THIS TIME, STRATUS IS EXPECTED TO REMAIN SW OF THE
TERMINAL SATURDAY AM, BUT WILL HAVE TO MONITOR THE PERIOD BETWEEN 13
TO 16Z FOR ANY EASTWARD PROGRESS IN STRATUS TOWARDS SEA. OTHERWISE,
VFR CONDITIONS ON SATURDAY. W/NW WINDS INTO THIS EVENING WILL
TRANSITION MORE N/NE TONIGHT. JD/18
MARINE
SURFACE HIGH PRESSURE WILL CONTINUE TO BE LOCATED OVER THE
COASTAL WATERS INTO TUESDAY. A THERMALLY INDUCED TROUGH WILL DEVELOP
ALONG THE COAST ON SATURDAY NIGHT BEFORE MOVING OVER THE INLAND
WATERS LATER SUNDAY AND SHIFTING EAST ON MONDAY. SMALL CRAFT
WESTERLIES ARE EXPECTED AT TIMES THROUGH THE CENTRAL AND EASTERN
PORTIONS OF THE STRAIT OF JUAN DE FUCA THIS EVENING, PARTICULARLY
SCA WIND GUSTS. ONSHORE FLOW WILL THEN INCREASE THROUGH THE STRAIT
OF JUAN DE FUCA MONDAY NIGHT AND AGAIN TUESDAY NIGHT.
SEAS OF 8 TO 10 FEET ARE EXPECTED FOR THE OUTER COASTAL WATERS INTO
SATURDAY MORNING, WITH CHOPPY SEAS AT TIMES THROUGH SATURDAY
AFTERNOON DUE TO PERIODS OF 8 TO 10 SECONDS. BRIEF SCA WINDS MAY
ALSO OCCUR FOR THE NORTHERN OUTER COASTAL WATERS INTO TONIGHT. SEAS
WILL BRIEFLY SUBSIDE ON SUNDAY, BEFORE BUILDING ON MONDAY TO 9 TO 12
FEET INTO TUESDAY. JD
FIRE WEATHER
CONDITIONS WILL WARM UP AND DRY OUT GOING INTO THIS
WEEKEND AND MONDAY AS AN UPPER LEVEL RIDGE DEVELOPS AND MOVES OVER
WESTERN WASHINGTON. THIS WILL ELEVATE FIRE WEATHER CONCERNS AS
MINIMUM RH VALUES WILL LIKELY REACH AS LOW AS 20-30% OVER THE
CASCADES AND THE INTERIOR DURING THIS PERIOD. WHILE LIVE FUELS
REMAIN WET ENOUGH TO CURB FIRE SPREAD, DEAD FUELS REMAIN VERY DRY
WITH BELOW-NORMAL SNOWPACK AND PERSISTENT DROUGHT CONDITIONS.
HOWEVER, WINDS DO REMAIN LIGHT ENOUGH THROUGH THE WEEKEND SUCH THAT
CRITICAL CONDITIONS ARE NOT EXPECTED. MOIST ONSHORE FLOW WILL RETURN
TUESDAY AND INTO THE MIDDLE OF NEXT WEEK.
SEW WATCHES/WARNINGS/ADVISORIES
WA...HEAT ADVISORY FROM 10 AM SUNDAY TO 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 UNTIL 2 AM PDT SATURDAY 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 SATURDAY 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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