737
FXUS66 KSEW 091640
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
940 AM PDT WED JUL 9 2025
SYNOPSIS
A WEAK FRONT WILL SLIDE ACROSS WESTERN WASHINGTON
TODAY, BRINGING IN LIGHT RAIN ALONGSIDE COOLER TEMPERATURES AND
LOCALLY BREEZY WINDS. HIGH PRESSURE WILL REBOUND BY FRIDAY,
WITH A WARMING AND DRYING TREND THROUGH THE WEEKEND AND INTO
EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH FRIDAY/
SATELLITE IMAGERY SHOWS
CLOUDY SKIES OVER MOST OF THE AREA THIS MORNING. DOPPLER RADAR HAS
SOME LIGHT RAIN ALONG THE COAST AND OVER THE NORTHWEST INTERIOR.
NOT MUCH SPREAD IN THE TEMPERATURES AT 9 AM WITH READING IN THE
LOWER TO MID 60S.
COLD FRONT JUST REACHED THE NORTH COAST AT 16Z/9AM THIS MORNING.
LIGHT RAIN SHOWERS AND VIRGA WILL CONTINUE TO SHIFT SOUTHWARD
THROUGHOUT THE MORNING AND INTO THE EARLY AFTERNOON. LOCALLY
BREEZY WINDS AS WELL UP TO 25-30 MPH. THE BULK OF THE MOISTURE
WITH THIS SYSTEM WILL BE FOCUSED OVER THE NORTH CASCADES, WHERE
GENERALLY UP TO A HALF INCH OF RAIN IS FORECAST. ELSEWHERE, AREAS
ALONG THE COAST AND LOWLANDS NORTH OF EVERETT WILL SEE UP TO A
QUARTER OF AN INCH OF RAIN THROUGHOUT THE DAY. RAIN SHADOWING
WILL CAUSE AREAS AROUND THE PUGET SOUND TO SEE LITTLE TO NO RAIN
ACCUMULATION. A CONVERGENCE ZONE WILL DEVELOP LATER THIS AFTERNOON
BETWEEN SEATTLE AND EVERETT, WITH ADDITIONAL RAINFALL
ACCUMULATIONS OF A TENTH OF AN INCH OVER THE CENTRAL CASCADES AND
FOOTHILLS. THE INCOMING MOIST MARINE AIR WILL COOL TEMPERATURES
CONSIDERABLY, WITH HIGHS TODAY PEAKING IN THE MID TO UPPER 60S TO
LOW 70S FOR MOST LOWLAND AREAS.
ONSHORE FLOW WILL PERSIST INTO THURSDAY MORNING, AND AN ADDITIONAL
ROUND OF INCOMING MOISTURE MAY BRING A DRIZZLE TO SOME AREAS
EARLY THURSDAY MORNING WHILE MUCH OF THE REGION WILL SEE LITTLE
MORE THAN CLOUDY SKIES LINGERING INTO THE MORNING HOURS. SKIES
WILL CLEAR BY THURSDAY AFTERNOON, WITH TEMPERATURES RETURNING TO
NEAR NORMAL IN THE LOW TO MID 70S ACROSS THE LOWLANDS.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO WESTERN WASHINGTON ON
FRIDAY, ALLOWING FOR A WARMING AND DRYING TREND. TEMPERATURES WILL
REBOUND BACK INTO THE 80S FOR MUCH OF THE INTERIOR AND INTO THE
70S ALONG THE COAST. THIS WILL RESULT IN WIDESPREAD MINOR (YELLOW)
HEATRISK, WITH POCKETS OF MODERATE (ORANGE) HEATRISK THROUGH THE
OLYMPIA AND TACOMA METRO AREAS SOUTH OF THE PUGET SOUND.
LONG TERM /SATURDAY THROUGH TUESDAY/
ENSEMBLES CONTINUE TO SHOW
GOOD AGREEMENT OVER HIGH PRESSURE BUILDING OFFSHORE THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK, ALLOWING FOR WARMER AND DRY
CONDITIONS ACROSS WESTERN WASHINGTON. THIS WILL GIVE ANOTHER
POTENTIAL PERIOD OF INCREASED HEATRISK AS WELL AS AN INCREASE IN
FIRE WEATHER CONCERNS OVER THE WEEKEND AND INTO EARLY NEXT WEEK.
HOWEVER, ONSHORE FLOW WILL KEEP TEMPERATURES SLIGHTLY MODERATED
THROUGH THE WEEKEND WHILE PROVIDING DECENT OVERNIGHT HUMIDITY
RECOVERIES. FORECAST MODELS AMPLIFY THE HIGH PRESSURE OFFSHORE ON
TUESDAY, ALLOWING TEMPERATURES TO CLIMB WELL ABOVE NORMAL WITH
HIGHS PEAKING IN THE UPPER 80S ACROSS THE LOWLANDS. THIS MAY
BRING WIDESPREAD MODERATE (ORANGE) HEATRISK TO THE REGION,
ESPECIALLY IF WINDS SHIFT EASTWARD AS OFFSHORE FLOW DEVELOPS.
15/FELTON
AVIATION
A WEAK SYSTEM CONTINUES TO MOVE ACROSS WESTERN
WASHINGTON THIS MORNING, BRINGING SHOWERS AND BREEZY CONDITIONS TO
THE TERMINALS. LOWERED CEILINGS THIS MORNING RANGING FROM MVFR TO
LIFR. LATEST SATELLITE IMAGERY SHOWS SHOWERS MAKING THEIR WAY
INLAND, WITH THE LATEST GUIDANCE HAVING THE MAJORITY OF SHOWERS
ALONG THE COAST AND NORTHERN INTERIOR THIS MORNING AND AFTERNOON.
EXPECT REDUCED VISIBILITY WITH THESE SHOWERS. SHOWER ACTIVITY WILL
GRADUALLY TAPER OFF THIS EVENING, HOWEVER GUIDANCE DOES HINT AT A
CONVERGENCE ZONE DEVELOPING ALONG SNOHOMISH/KING COUNTIES TONIGHT
INTO THURSDAY MORNING. CEILINGS WILL GRADUALLY LIFT TONIGHT, WITH
THE POTENTIAL TO SEE LOW-END VFR ACROSS A FEW OF THE TERMINALS.
BREEZY CONDITIONS EXPECTED THIS MORNING AND AFTERNOON, WITH SPEEDS
OF 8-13 KT, AND GUSTS UP TO 20 KT. NORTHERLY WINDS ASSOCIATED WITH A
CONVERGENCE ZONE THIS AFTERNOON (AFTER 22Z-23Z) ARE EXPECTED TO BE
CONFINED TO KPAE, BUT MAY MAKE IT SOUTH TO KBFI.
KSEA...LOWERED CEILINGS CONTINUE THIS MORNING AND WILL LIKELY
PERSIST THROUGH THE REMAINDER OF TODAY AND THURSDAY MORNING. THERE
IS THE POTENTIAL TO SEE SOME IMPROVEMENT THIS TONIGHT/OVERNIGHT INTO
LOW-END VFR. HOWEVER CONFIDENCE IS LOW AT THIS TIME, AS MODELS ARE
STRUGGLING TO ARRIVE TO A CONSENSUS. A CONVERGENCE ZONE WILL FORM TO
THE NORTH OF THE TERMINAL AFTER 22Z-23Z AROUND KPAE. AT THIS TIME,
THE NORTHERLY WINDS ARE NOT EXPECTED TO MAKE IT TO THE TERMINAL.
BREEZY CONDITIONS THIS MORNING AND AFTERNOON, WITH SUSTAINED SPEEDS
OF 10-13 KT, AND GUSTS UP TO 20 KT.
29
MARINE
A WEAK COLD FRONT AND ASSOCIATED TROUGH WILL PUSH THROUGH
THE WATERS TODAY. SATELLITE HAS SHOWN SOME PATCHY FOG OVER THE
COASTAL WATERS LATE LAST NIGHT INTO THE MORNING. GIVEN THE PATCHY
NATURE OF THE FOG (BASED ON SATELLITE AND OBSERVATIONS), OPTED TO
ISSUE A MARINE WEATHER STATEMENT FOR THE COASTAL WATERS/GRAYS HARBOR
AREAS THROUGH 18Z. SHOWERS WILL PICK UP LATE THIS MORNING INTO THE
AFTERNOON ACROSS THE COASTAL WATERS (SPREADING INLAND ACROSS
INTERIOR WATERS NOT COVERED FROM THIS MORNING'S SHOWERS IN THE FAR
NORTHERN INLAND WATERS). WINDS WILL PICK UP OUT OF THE SOUTHWEST
TODAY AHEAD OF THE FRONT, BUT THE ONLY AREAS EXPECTED TO SEE WINDS
HAZARDOUS FOR SMALL CRAFT ARE THE CENTRAL/EAST SECTIONS OF THE
STRAIT OF JUAN DE FUCA (ISSUED A NEW SCA FROM THIS AFTERNOON THROUGH
THURSDAY MORNING). A COUPLE SPOTS IN PUGET SOUND MAY ALSO SEE A
COUPLE GUSTS TO 20 KT.
POST FRONT, HEIGHTS WILL BUILD OFFSHORE WITH HIGH PRESSURE REMAINING
DOMINANT THROUGH THE WEEKEND INTO NEXT WEEK. THE FLOW OVER THE
COASTAL WATERS WILL TURN NORTHERLY AS A RESULT. SOME FOG/LOW STRATUS
WILL BE POSSIBLE AGAIN THURSDAY MORNING.
SEAS WILL INCREASE FROM 2 TO 4 TO 6 TO 8 FEET THIS WEEKEND, WITH THE
SEAS THIS WEEKEND POTENTIALLY BECOMING STEEP (WITH SHORTER PERIODS).
HPR
FIRE WEATHER
A WEAK FRONTAL SYSTEM WILL MOVE THROUGH THE REGION
TODAY, WITH ELEVATED ONSHORE FLOW BRINGING IN COOLER AND MORE
MOIST CONDITIONS WITH SOME LIGHT PRECIPITATION. WETTING RAINS ARE
POSSIBLE ACROSS PORTIONS OF THE NORTHERN CASCADES AND PACIFIC
COAST.
UPPER RIDGING WILL THEN BUILD BACK INTO WESTERN WASHINGTON LATE
THURSDAY, RESULTING IN THE RETURN OF WARM, DRY WEATHER AND ELEVATED
FIRE WEATHER CONDITIONS ON FRIDAY. THIS WILL BE THE DRIEST DAY OF
THE PERIOD, WITH RH VALUES DROPPING BACK INTO THE 25% TO 35% RANGE
OVER THE MOUNTAINS AND ACROSS THE LOWLANDS SOUTH OF THE PUGET SOUND.
WARM AND DRY CONDITIONS LOOK TO PERSIST INTO NEXT WEEK BUT THE
DETAILS REMAIN UNCERTAIN AT THIS POINT TO THE DEGREE OF ONSHORE FLOW
GOING INTO NEXT WEEK.
CONDITIONS WILL WARM UP SIGNIFICANTLY BY THE MIDDLE OF NEXT WEEK,
WITH FORECAST MODELS HINTING AT A SHIFT TO OFFSHORE FLOW AND EAST
WINDS THROUGH THE CASCADE GAPS. THESE CONDITIONS WILL CONTINUE TO
BE CLOSELY MONITORED.
15
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 AM PDT
THURSDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-
EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
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