510
FXUS66 KSEW 180338
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
838 PM PDT SUN MAY 17 2026
SYNOPSIS
HIGH PRESSURE WILL REMAIN SITUATED OFFSHORE THROUGH
MUCH OF NEXT WEEK, MAINTAINING NEAR-NORMAL TEMPERATURES ACROSS
WESTERN WASHINGTON WITH CLOUDY MORNINGS AND SUNSHINE IN THE
AFTERNOONS. A FEW WEAK SYSTEMS WILL MOVE OVER THE TOP OF THE
RIDGE TOWARDS THE MIDDLE OF NEXT WEEK, BRINGING LITTLE MORE THAN
A FEW PERIODS OF SPRINKLES.
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/
HIGH CLOUDS ARE
INCREASING THIS EVENING ACROSS WESTERN WASHINGTON. DRY
CONDITIONS TONIGHT WITH LOWS DIPPING INTO THE 40S. NO MAJOR
FORECAST UPDATES THIS EVENING, PREVIOUS DISCUSSION BELOW.
A HIGH PRESSURE RIDGE WILL CONTINUE TO BUILD OFFSHORE
THROUGHOUT THE SHORT TERM, BRINGING NORTHWEST FLOW ALOFT AND
ONSHORE FLOW AT THE SURFACE TO WESTERN WASHINGTON. THIS WILL
BRING MORE SPRING-LIKE CONDITIONS TO THE REGION, WITH
TEMPERATURES THROUGH TUESDAY PEAKING NEAR NORMAL GENERALLY IN
THE 60S. IN ADDITION, ONSHORE FLOW WILL ALLOW MARINE STRATUS TO
EXPAND INLAND EACH MORNING, BREAKING UP FOR MOST AREAS BY THE
AFTERNOON. A SPLITTING FRONTAL SYSTEM WILL ATTEMPT TO OVERRUN
THE RIDGE ON TUESDAY, BUT WILL LIKELY BRING LITTLE MORE THAN A
FEW SPRINKLES TO THE AREA.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
WEDNESDAY WILL SEE MORE
OF THE SAME, WITH POTENTIAL FOR A CLOUDY MORNING, MOSTLY SUNNY
AFTERNOON, AND MILD TEMPERATURES PEAKING IN THE 60S TO LOWER
70S.
BY THURSDAY, THE UPPER LEVEL RIDGE OFFSHORE WILL BEGIN TO
FLATTEN AS A LOW PRESSURE SYSTEM SLOWLY STRENGTHENS AND LOWERS
FROM THE GULF OF ALASKA. CONDITIONS ARE FAVORED TO REMAIN DRY
INTO THE FIRST HALF OF THE WEEKEND AS ZONAL FLOW SETS UP ALOFT,
WITH CONTINUED MILD TEMPERATURES.
ENSEMBLES ARE HONING IN ON A POTENTIAL PATTERN CHANGE BY THE END
OF NEXT WEEKEND, WITH INCREASING CHANCES FOR ACCUMULATING
RAINFALL OVER THE NORTH CASCADES ON SATURDAY. HOWEVER, THE
DETAILS REMAIN UNCERTAIN AT THIS TIME.
15
AVIATION
A MARINE PUSH OF STRATUS INLAND IS LIKELY IN THE
MORNING WITH THE RESUMPTION OF ONSHORE FLOW. HIGHEST
PROBABILITIES FOR MVFR CEILINGS IS FROM THE KITSAP PENINSULA
WESTWARD, WITH CHANCES DECREASING (BUT REMAINING ELEVATED) FOR
THE PUGET SOUND TERMINALS MONDAY MORNING. ADDITIONALLY, THERE IS
SOME POTENTIAL AGAIN FOR FOG/MIST UNDER THE CLOUDS FOR THE
KITSAP/SOUTH INTERIOR TERMINALS (BUT THIS IS LOWER CONFIDENCE
DUE TO THE CLOUD COVERAGE). CEILINGS MONDAY AFTERNOON WILL
RETREAT TOWARDS THE COAST (BUT LIKELY REMAIN ALONG THE IMMEDIATE
COASTLINE). WINDS OUTSIDE OF THE INTERIOR TERMINALS WILL REMAIN
NORTHWEST 5-10 KT (COUPLE GUSTS TO 20 KT NEAR THE STRAIT OF
JUAN DE FUCA). NORTH INTERIOR/PUGET SOUND WINDS BOTH AFTERNOONS
WILL FAVOR THE NORTHWEST 5-10 KT, WITH WINDS RETURNING TO THE
SOUTH UNDER 5 KT OVERNIGHT.
KSEA...VFR WITH FEW OR SCATTERED CLOUDS THROUGH TONIGHT. STRATUS
LIKELY TO REACH INTERIOR MONDAY MORNING. LOWER-END VFR IS FAVORED,
BUT THERE IS A 40% CHANCE THE CEILINGS MAY GET DOWN INTO MVFR
CRITERIA IN THE MORNING, BEFORE CLEARING EARLY MONDAY AFTERNOON.
WINDS RETURNING TO THE SOUTH UNDER 5 KT OVERNIGHT, BEFORE RETURNING
TO THE NORTH AGAIN EARLY MONDAY AFTERNOON.
HPR/21
MARINE
HIGH PRESSURE WILL CONTINUE TO BUILD OFFSHORE THROUGH
MUCH OF THE NEXT WEEK. THIS WILL GENERATE A SMALL CRAFT
WESTERLY PUSH THROUGH THE CENTRAL AND EASTERN STRAIT OF JUAN DE
FUCA TONIGHT, AS WELL AS DAILY PUSHES OF WESTERLY WINDS THROUGH
THE STRAIT OF JUAN DE FUCA THROUGH MUCH OF THE COMING WEEK. A
SPLITTING FRONTAL SYSTEM WILL MOVE ACROSS THE AREA WATERS MONDAY
INTO TUESDAY, BEFORE HIGH PRESSURE BUILDS BACK IN ITS WAKE ON
WEDNESDAY. ANOTHER WEAK FRONTAL SYSTEM LOOKS TO MOVE INTO THE
AREA WATERS ON THURSDAY.
SEAS AROUND 6 TO 8 FEET TODAY WILL BUILD TO 8 TO 10 FEET ON MONDAY,
REMAINING NEAR 10 FEET THROUGH WEDNESDAY. SEAS WILL BUILD TO 10 TO
13 FEET BY LATE THURSDAY AND HOVER AROUND 10 FEET HEADING INTO NEXT
WEEKEND.
15/21
HYDROLOGY
THE DAILY HYDROLOGY DISCUSSION HAS ENDED UNTIL THE
START OF THE NEXT RAINY SEASON; IT WILL ONLY BE UPDATED DURING
THIS TIME AS NEEDED.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT MONDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA.
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