932
FXUS66 KSEW 081746
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
1046 AM PDT TUE JUL 8 2025
SYNOPSIS
WARM AND DRY CONDITIONS WILL PERSIST TODAY UNDER HIGH
PRESSURE. A WEAK SYSTEM WILL CROSS THE REGION ON WEDNESDAY,
BRINGING LIGHT RAIN AND COOLER TEMPERATURES. HIGH PRESSURE WILL
REBOUND TOWARDS THE END OF THE WEEK, BRINGING A RETURN OF WARMER
AND DRY CONDITIONS BY FRIDAY AND INTO EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH THURSDAY/
FORECAST ON TRACK THIS
MORNING. SATELLITE IMAGERY SHOWS NEXT FRONTAL SYSTEM NOW
APPROACHING THE NORTHERN TIP OF VANCOUVER ISLAND. HIGH CLOUDS OUT
AHEAD OF THE SYSTEM WILL BEGIN MOVING OVER THE NORTHWEST PORTION
OF THE STATE THIS AFTERNOON. OUTSIDE OF A PATCH OF STRATUS ALONG
THE COAST SUNNY SKIES FOR THE REMAINDER OF THE AREA. HIGHS
SIMILAR TO MONDAY WITH A COUPLE OF DEGREES OF COOLING POSSIBLE
AS THE SURFACE WINDS REMAINING SOUTHWESTERLY. HIGHS FOR THE
INTERIOR IN THE MID 70S TO MID 80S. HIGHS ALONG THE COAST IN THE
60S. IT IS ANOTHER DAY OF MODERATE (ORANGE) HEATRISK TO MOST METRO
AREAS SURROUNDING THE PUGET SOUND, WITH MINOR (YELLOW) HEATRISK
ELSEWHERE.
PREVIOUS DISCUSSION FOLLOWS...CLOUDY SKIES WILL FILL IN THIS
EVENING AS THE NEXT SYSTEM APPROACHES.
THE APPROACHING DISTURBANCE WILL BRING A SIGNIFICANT COOL DOWN ON
WEDNESDAY AS A STRONG PUSH OF MARINE AIR MOVES INTO THE REGION.
LIGHT RAIN WILL SPREAD INLAND THROUGHOUT THE DAY WEDNESDAY, WITH
THE BULK OF THE MOISTURE FOCUSED OVER THE CASCADES, WHERE
GENERALLY UP TO HALF AN INCH OF RAIN IS POSSIBLE THROUGH THURSDAY
MORNING. AREAS IN THE NORTH CASCADES MAY SEE LOCALLY HIGHER
RAINFALL AMOUNTS CLOSER TO AN INCH. ELSEWHERE, LOWER ELEVATIONS
WILL SEE LIGHT ACCUMULATIONS, GENERALLY RANGING FROM A FEW
HUNDREDTHS TO A QUARTER OF AN INCH. THE MOIST MARINE AIR WILL COOL
TEMPERATURES CONSIDERABLY, WITH HIGHS WEDNESDAY PEAKING IN THE
MID TO UPPER 60S FOR MOST LOWLAND AREAS.
CONDITIONS WILL DRY OUT BY THE LATE MORNING THURSDAY AS HIGH
PRESSURE STARTS TO BUILD INLAND, WITH CLOUDY SKIES IN THE MORNING
CLEARING BY THE AFTERNOON. TEMPERATURES WILL REBOUND SEVERAL
DEGREES AND RETURN TO NEAR NORMAL, WITH MOST OF THE INTERIOR
SEEING HIGHS IN THE LOW TO MID 70S.
LONG TERM /FRIDAY THROUGH MONDAY/
ENSEMBLES REMAIN IN GOOD
AGREEMENT OVER HIGH PRESSURE BUILDING INTO THE REGION OVER THE
WEEKEND AND INTO EARLY NEXT WEEK. FRIDAY WILL BRING A RETURN OF
WARM AND DRY CONDITIONS ACROSS WESTERN WASHINGTON, WITH WIDESPREAD
AREAS OF MINOR (YELLOW) HEATRISK ACROSS THE LOWLANDS AND HIGHS
RETURNING INTO THE 80S EAST AND SOUTH OF THE PUGET SOUND.
TEMPERATURES WILL CONTINUE TO WARM UP THROUGH THE WEEKEND AS A
RIDGE OFFSHORE AMPLIFIES. THIS WILL GIVE ANOTHER POTENTIAL
PERIOD OF INCREASED HEATRISK AS WELL AS AN INCREASE IN FIRE
WEATHER CONCERNS OVER THE WEEKEND AND INTO THE START OF NEXT
WEEK.
15/FELTON
AVIATION.
WIDESPREAD VFR CONDITIONS ACROSS THE INTERIOR
TERMINALS THIS MORNING. THE MARINE STRATUS IS EXPECTED TO REMAIN
CONFINED TO THE PACIFIC COAST THIS MORNING, WITH CEILINGS DROPPING
TO IFR/LIFR AND POTENTIAL FOR VISIBILITIES TO ALSO DROP IN THESE
CATEGORIES, WITH IMPROVEMENT NOT EXPECTED TODAY.
THE REMAINDER OF TODAY STAYS DRY WITH HIGH CLOUDS (MARINE STRATUS
WILL LINGER THE LONGEST ALONG THE COAST WITH ONLY A BRIEF BREAK TO
MVFR/VFR EXPECTED THIS AFTERNOON). THE NEXT DISTURBANCE
TONIGHT/WEDNESDAY MORNING WILL BRING SHOWERS ACROSS ALL TERMINALS,
WITH CEILINGS LOWERING TO MVFR AND WIDESPREAD POCKETS OF IFR
WEDNESDAY MORNING. SOUTHWEST SURFACE FLOW WITH WINDS RANGING 8-13 KT
(COUPLE GUSTS TO 20 KT POSSIBLE). ANOTHER PUSH THROUGH THE STRAIT OF
JUAN DE FUCA THIS AFTERNOON MAY CAUSE SOME DIFFLUENCE AND TURN WINDS
NORTHERLY DOWN TO KBFI.
KSEA...VFR CONDITIONS EXPECTED ALL OF TUESDAY, WITH A 70% CHANCE OF
MVFR (20% CHANCE OF IFR) WEDNESDAY MORNING - GENERALLY AFTER 12Z.
CLEAR SKIES TODAY WITH INCREASING CLOUD COVERAGE LATER TODAY WITH
SHOWERS LIKELY AFTER 12Z WEDNESDAY. SOUTHWESTERLY WINDS AT 7-11 KT,
WITH A COUPLE GUSTS TO 18 KT POSSIBLE). THE NORTHWESTERLY WINDS ARE
EXPECTED AT THIS TIME TO HOLD TO THE NORTH OF KSEA (DOWN TO KBFI),
WITH RATHER WINDS BECOMING MORE WESTERLY-SOUTHWESTERLY.
HPR
MARINE
WINDS ALONG THE STRAIT OF JUAN DE FUCA ALONG THE CENTRAL
AND EASTERN PORTIONS CONTINUE TO DECREASE THIS MORNING, AND THE
SMALL CRAFT ADVISORY WILL BE ALLOWED TO EXPIRE AT 9 AM PDT. MUCH OF
COASTAL WATERS AND THE STRAIT OF JUAN DE FUCA HAVE MARINE STRATUS
AND/OR FOG COVERING MUCH OF THESE WATERS, WHICH MAY LIMIT
VISIBILITIES AT TIMES THROUGH THIS MORNING.
A TROUGH OVER THE COASTAL WATERS WILL BRING A WEAK FRONTAL SYSTEM
ACROSS THE COASTAL WATERS TUESDAY NIGHT INTO WEDNESDAY WITH SHOWERS.
THERE IS A SMALL POSSIBILITY THAT SEAS COULD BRIEFLY UPTICK. PUSHES
THROUGH THE STRAIT OF JUAN DE FUCA WILL CONTINUE THROUGH MUCH OF THE
WEEK, WITH ANOTHER STRONG PUSH LIKELY AGAIN TUESDAY
AFTERNOON/EVENING. OPTED TO ISSUE ANOTHER SMALL CRAFT ADVISORY FOR
THE EAST/CENTRAL STRAIT OF JUAN DE FUCA ZONES (ESPECIALLY WITH THE
FRONT MOVING THROUGH AND INCREASING ONSHORE FLOW). ANOTHER WEAK LOW
MAY PASS THE WATERS THURSDAY. HIGH PRESSURE WILL BUILD OFFSHORE
FRIDAY INTO THE WEEKEND.
SEAS ARE EXPECTED TO HOLD BETWEEN 3-6 FT THROUGH MUCH OF THE WEEK
AND COULD BECOME STEEP AT TIMES WITH PERSISTENT NORTHERLY WINDS OVER
THE COASTAL WATERS.
HPR
FIRE WEATHER
DRY, WARM WEATHER WILL LEAD TO ELEVATED FIRE WEATHER
CONDITIONS TODAY WITH HIGH PRESSURE SITUATED ACROSS WESTERN
WASHINGTON. CONDITIONS ARE ON TRACK DRY OUT THIS AFTERNOON WITH
MINIMUM RH VALUES DROPPING TOWARDS 25% TO 35% OVER THE MOUNTAINS AND
THROUGH THE CASCADE FOOTHILLS AND VALLEYS. A FEW WIND GUSTS UP TO
AROUND 20 MPH MAY BE POSSIBLE ACROSS PORTIONS OF THE SOUTHWEST
INTERIOR ALONG THE SOUTHERN SLOPES OF THE OLYMPICS AS WELL AS THROUGH
THE STRAIT OF JUAN DE FUCA.
A WEAK FRONTAL SYSTEM WILL MOVE ACROSS WESTERN WASHINGTON TONIGHT
INTO WEDNESDAY. THIS WILL INCREASE ONSHORE FLOW, WITH MUCH COOLER
TEMPERATURES AND INCOMING PRECIPITATION FOR SOME AREAS TONIGHT
THROUGH WEDNESDAY. THERE REMAINS A MODERATE (50% TO 70%) CHANCE OF
WETTING RAIN FOR THE CASCADES OF SNOHOMISH COUNTY NORTHWARDS, WITH
LIGHTER RAINFALL AMOUNTS ELSEWHERE.
UPPER RIDGING WILL THEN BUILD BACK INTO WESTERN WASHINGTON LATE
THURSDAY AND CONTINUE INTO NEXT WEEKEND, RESULTING IN THE RETURN OF
WARM, DRY WEATHER AND ELEVATED FIRE WEATHER CONDITIONS. FRIDAY WILL
BE THE DRIEST DAY OF THE PERIOD, WITH RH VALUES DROPPING INTO THE
25% TO 35% RANGE OVER THE MOUNTAINS AND ACROSS THE LOWLANDS SOUTH OF
THE PUGET SOUND. DRY CONDITIONS LOOK TO PERSIST INTO NEXT WEEK BUT
THE DETAILS REMAIN UNCERTAIN AT THIS POINT.
15/62
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM PDT THIS
EVENING FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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