788
FXUS66 KSEW 090939
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
239 AM PDT THU APR 9 2026
SYNOPSIS
DRY CONDITIONS WILL CONTINUE ACROSS WESTERN WASHINGTON THROUGH
FRIDAY, WITH A GRADUAL WARM UP IN TEMPERATURES PEAKING ON
FRIDAY. CLEAR SKIES AND COOL OVERNIGHT TEMPERATURES WILL ALLOW
FOR FROST DEVELOPMENT ACROSS PORTIONS OF THE REGION THIS
MORNING. COOLER AND PRECIPITATION CHANCES RETURN THIS WEEKEND.
SLIGHTLY DRIER CONDITIONS EARLY NEXT WEEK BEFORE A STRONGER
SYSTEM ARRIVES ON WEDNESDAY.
SHORT TERM /TODAY THROUGH SATURDAY/
SATELLITE IMAGERY SHOWS CLEAR SKIES EARLY THIS MORNING. CURRENT
TEMPERATURES ARE IN THE UPPER 30S TO LOW 40S ACROSS WESTERN
WASHINGTON. CLEAR SKIES AND LIGHT WINDS WILL PROMOTE EFFECTIVE
RADIATIONAL COOLING, ALLOWING TEMPERATURES TO CONTINUE
DECREASING THIS MORNING. THE COLDEST SPOTS WILL BE LOCATIONS IN THE
SOUTHERN INTERIOR AND CASCADE FOOTHILLS, WHERE TEMPERATURES ARE
EXPECTED TO DECREASE INTO THE MID TO LOW 30S. AS A RESULT,
FROST DEVELOPMENT IS EXPECTED THIS MORNING, WITH A FROST
ADVISORY REMAINING IN EFFECT THROUGH 9 AM.
WEAK UPPER LEVEL RIDGING OVER THE REGION WILL KEEP CONDITIONS
DRY AND WARMER THROUGH FRIDAY. TEMPERATURES WILL REBOUND THIS
AFTERNOON AND GIVE WAY TO A NICE AFTERNOON WITH CLEAR SKIES AND
TEMPERATURES IN THE LOW 60S ALONG THE COAST AND UPPER 60S TO LOW
70S IN THE INTERIOR. TEMPERATURES ON FRIDAY WILL BE SIMILAR TO
THURSDAY, BUT EXPECT CLOUD COVER TO INCREASE THROUGHOUT THE
DAY.
ENSEMBLE GUIDANCE HAS COME TO GOOD AGREEMENT THAT A LOW PRESSURE
SYSTEM DESCENDING FROM THE GULF OF ALASKA WILL MOVE INTO NORTHERN
CALIFORNIA. AS THIS SYSTEM MOVES THROUGH CALIFORNIA, IT WILL
ADVECT MOISTURE INTO WESTERN WASHINGTON AND BRING PRECIPITATION
BACK INTO THE REGION. IN ADDITION, EXPECT COOLER TEMPERATURES
WITH THIS SYSTEM. HIGH TEMPERATURES WILL BE IN THE LOW 50S ALONG
THE COAST AND UPPER 50S TO LOW 60S IN THE INTERIOR.
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LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE WEEKEND AS THE
PREVIOUSLY MENTIONED LOW PRESSURE SYSTEM CONTINUES TO MOVE
THROUGH CALIFORNIA. SNOW LEVELS WITH THIS SYSTEM WILL REMAIN
ABOVE PASS LEVEL. ON SATURDAY SNOW LEVELS START AROUND 6000-6500
FT AND BY SUNDAY WILL DROP DOWN TO 5000-5500 FT. PRECIPITATION
WITH THIS SYSTEM IS EXPECTED TO BE LIGHT.
SLIGHTLY DRIER CONDITIONS ON MONDAY AS WEAK RIDGING BUILDS OVER
WESTERN WASHINGTON. THERE IS SOME UNCERTAINTY ON TUESDAY
REGARDING THE UPPER LEVEL PATTERN. HOWEVER, THE MAJORITY OF
ENSEMBLE MEMBERS FAVOR THE UPPER LEVEL RIDGE TO REMAIN IN PLACE
THROUGH TUESDAY. AS A RESULT, THIS HAS PUSHED THE NEXT SYSTEM
TO ARRIVE ON WEDNESDAY, WITH GUIDANCE BEING IN GOOD AGREEMENT
FOR A TROUGH TO MOVE THROUGH THE REGION. HIGH TEMPERATURES NEXT
WEEK WILL BE IN THE LOW TO MID 50S AND LOW TEMPERATURES WILL BE
IN THE 40S.
29
AVIATION
AN UPPER RIDGE REMAINS OFFSHORE WITH CONTINUED NORTH TO
NORTHWEST FLOW ALOFT TODAY. FLOW WILL TRANSITION MORE SOUTHERLY
TONIGHT INTO FRIDAY AS AN UPPER LOW SLOWLY MOVES TOWARDS THE CA
COAST. VFR CONDITIONS CONTINUE THROUGH THE TAF PERIOD WITH HIGH
CLOUDS AT TIMES. LOCALIZED FOG MAY DEVELOP IN VALLEY AREAS THIS
MORNING, MAINLY IMPACTING PWT, OLM, AND HQM. HOWEVER, LATEST
PROBABILISTIC GUIDANCE KEEPS LIFR CONDITIONS ONLY AROUND 10% FOR
THESE SITES THIS MORNING, PEAKING BETWEEN 12 TO 16Z. LIGHT NORTH
WINDS WILL INCREASE TOWARDS 5 TO 10 KTS BY MIDDAY.
KSEA...VFR CONDITIONS THROUGH THE TAF PERIOD. NORTH WINDS AROUND 5
TO 8 KTS THIS MORNING, INCREASING TO AROUND 10 KTS BY MIDDAY AND
CONTINUING THROUGH THE AFTERNOON. JD
MARINE
NORTH WINDS WILL CONTINUE OVER THE COASTAL WATERS THROUGH FRIDAY
WITH HIGH PRESSURE OVER THE NE PACIFIC. A LOW PRESSURE SYSTEM
WILL DEVELOP OVER OPEN WATERS ON FRIDAY AND MOVE SOUTH INTO
NORTHERN CALIFORNIA. HIGH PRESSURE WILL REBUILD ON MONDAY. A
FRONTAL SYSTEM WILL THEN MOVE THROUGH AREA WATERS TUESDAY INTO
WEDNESDAY. GUIDANCE IS HINTING AT A LOW TO MODERATE CHANCE
(40-60%) FOR SMALL CRAFT WINDS FOR THE COASTAL WATERS, AND WEST
AND CENTRAL STRAIT OF JUAN DE FUCA.
A DIURNAL PUSH OF WESTERLIES THROUGH THE STRAIT OF JUAN DE FUCA
WILL BEGIN TO DEVELOP OVER THE WEEKEND AND INTO EARLY NEXT WEEK.
THERE IS A LOW TO MODERATE CHANCE (35-55%) OF WINDS REACHING
SMALL CRAFT THRESHOLDS ON MONDAY.
SEAS WILL REMAIN BELOW 10 FT INTO EARLY NEXT WEEK BEFORE
APPROACHING 10 FT ON WEDNESDAY.
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HYDROLOGY
NO RIVER FLOODING IS EXPECTED IN THE NEXT SEVEN DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...FROST ADVISORY UNTIL 9 AM PDT THIS MORNING FOR DOWNTOWN
EVERETT / MARYSVILLE AREA-FOOTHILLS AND VALLEYS OF PIERCE
AND SOUTHERN KING COUNTIES-FOOTHILLS AND VALLEYS OF
THURSTON AND LEWIS COUNTIES-LOWLANDS OF LEWIS AND
SOUTHERN THURSTON COUNTIES-MIDDLE CHEHALIS RIVER VALLEY-
OLYMPIA AND SOUTHERN PUGET SOUND.
PZ...NONE.
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