400
FXUS66 KSEW 190303
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
803 PM PDT SAT OCT 18 2025
SYNOPSIS
A STRONGER, WETTER SYSTEM WILL PASS OVER THE AREA THIS
AFTERNOON THROUGH SUNDAY BRINGING BREEZY WINDS, LOWLAND RAIN, AND
MOUNTAIN SNOW. SHOWERS WILL CONTINUE THROUGH SUNDAY WITH A
CHANCE OF THUNDERSTORMS. A BRIEF LULL IN THE ACTION MONDAY BEFORE
MORE WEATHER SYSTEMS TAKE AIM AT WESTERN WASHINGTON WEDNESDAY
THROUGH THE END OF NEXT WEEK, KEEPING THE CONDITIONS WET AND
UNSETTLED.
SHORT TERM /TONIGHT THROUGH TUESDAY/
WET AND WINDY TONIGHT AS A
STRONGER PACIFIC FRONTAL SYSTEM MOVES IN. WINDS ARE HIGHEST OVER
THE NORTH INTERIOR WITH S/SE GUSTS TO 30-40 MPH. WINDS WILL EASE
BY 10PM-MIDNIGHT BUT WILL STILL SEE RANGES OF 20-30 MPH OVERNIGHT.
33
PREVIOUS DISCUSSION...INCREASING CLOUDS AS RAIN SHOWERS MOVE
ONSHORE THIS AFTERNOON WITH THE FRONTAL SYSTEM RAPIDLY APPROACHING
WESTERN WASHINGTON. RAIN WILL BECOME MORE WIDESPREAD AND FILL IN
LATER THIS EVENING INTO THE OVERNIGHT HOURS, WITH HIGH
TEMPERATURES IN THE MID TO UPPER 50S. WINDS WILL START TO BECOME
BREEZY LATER THIS EVENING AS WELL, WITH SOUTHERLY WINDS GUSTING
FROM 20 TO 30 MPH AT TIMES ACROSS THE INTERIOR, WITH THE MORE
NOTICEABLY BREEZIER WINDS IN THE SOUTHWEST INTERIOR AND THE
NORTHWEST INTERIOR. SNOW LEVELS WILL BE AROUND 8000 TO 1000 FEET
THIS EVENING DROPPING TO 4500 TO 5000 FEET BY SUNDAY MORNING IN
THE WAKE OF THE FRONT. THIS WILL BRING SOME SNOW TO THE HIGHER
ELEVATIONS OF THE MOUNTAINS, ESPECIALLY THE NORTH CASCADES, WHERE
A WINTER WEATHER ADVISORY WILL BE IN EFFECT. MOST OF THE
ACCUMULATIONS WILL BE ABOVE 4500 FEET, EFFECTING RAINY PASS. TOTAL
QPF AMOUNTS WILL GENERALLY BE 1-2 INCHES ACROSS THE MOUNTAINS
WITH LOCALLY HIGHER AMOUNTS, ESPECIALLY WITH THE CHANGING SNOW
LEVELS. AREAS ACROSS THE INTERIOR WILL SEE TOTALS AROUND A HALF AN
INCH TO AN INCH OF RAIN. THOUGH THIS EVENT WILL BE A GOOD PRIMER
FOR AREA RIVERS, THE ANTECEDENT DRY CONDITIONS LEND LITTLE CONCERN
FOR ANY RIVER FLOODING AT THIS TIME.
THE AIR MASS WILL DESTABILIZE ON SUNDAY WHICH COULD BRING THE
POSSIBILITY FOR AN ISOLATED THUNDERSTORM OR TWO ACROSS THE AREA
SUNDAY EVENING, BUT CHANCES REMAIN LOW (20-25%) OF THIS OCCURING.
WAVES ALONG THE COAST WILL ALSO BUILD UPWARDS TO 15 TO 20 FEET
SUNDAY EVENING AND COULD POSE HIGH SURF IMPACTS TO BEACHES AND
SHORELINES. SHOWERS WILL LINGER THROUGHOUT THE EVENING BEFORE
DISSIPATING, AS WEAK UPPER LEVEL RIDGING BEGINS TO NUDGE INTO THE
AREA INTO MONDAY WITH CONDITIONS DRYING OUT. HIGH TEMPERATURES ON
MONDAY WILL GENERALLY BE IN THE UPPER 50S, MAYBE SOME LOCATIONS
REACHING THE LOWER 60S. UPPER LEVEL RIDGING LOOKS TO STAY AROUND
ON TUESDAY WHICH WILL LEAD TO ANOTHER MOSTLY DRY DAY, WITH SOME
CHANCES OF SHOWERS IN THE MOUNTAINS.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
ENSEMBLES HAVE BEEN
BECOMING MORE CONFIDENT ON ANOTHER WET SYSTEM MOVING THROUGH THE
AREA LATE WEDNESDAY NIGHT INTO THURSDAY, WITH SOME CONSISTENCY
ISSUES REGARDING TIMING AND STRENGTH OF SAID SYSTEM. ECMWF AND GFS
ENSEMBLES HAVE BOTH THE FRONT STALLING OVER INTO THE WEEKEND,
WHICH HAS BEEN INCREASINGLY LIKELY TO BE AN ATMOSPHERIC RIVER OVER
THE AREA. THERE IS STILL UNCERTAINTY REGARDING THE TIMING AND
STRENGTHS OF BOTH OF THESE SYSTEMS, BUT IT DOES LOOK LIKE RAIN
WILL BE A CONSTANT HEADING INTO THE WEEKEND.
MAZURKIEWICZ
AVIATION
WESTERLY TO NORTHWESTERLY FLOW ALOFT AS AN UPPER LEVEL
TROUGH APPROACHES WESTERN WASHINGTON. SURFACE WINDS GENERALLY
FAVORING SOUTHEAST, ALTHOUGH OLM AND PWT ARE SOUTHWESTERLY. MAJORITY
OF TERMINALS SEEING SPEEDS 4-8 KTS AS OF 02Z OBS WITH HQM AND PAE
SEEING SPEEDS 8-12 KTS AND BLI REPORTING 12-17 KTS WITH GUSTS UP TO
25 KTS. SPEEDS AT ALL TERMINALS EXPECTED TO INCREASE BY 06Z TO CATCH
UP TO THOSE ALREADY BEING OBSERVED AT BLI. DIRECTION WILL SHIFT TO
MORE SOUTH TO SOUTHWESTERLY AS THESE SPEEDS INCREASE.
VFR CONDITIONS HANGING ON THIS EVENING WITH SOME EXCEPTIONS AS PWT
HAS GONE IFR/LIFR AND CLM BOUNCES BACK AND FORTH FROM SCT006 AND
OVC006...WITH THE NEXT LAYER OF CLOUDS EITHER IN THE VFR OR MVFR
RANGE. WIDESPREAD MVFR TO IFR CONDITIONS EXPECTED TO SET IN
OVERNIGHT ALTHOUGH SOME INSTABILITY IN THE 12-14Z TIME FRAME MAY
ALLOW FOR PERIODS OF LIFTING...RESULTING IN TEMPORARY VFR
CONDITIONS. CONFIDENCE IS NOT QUITE THERE FOR INCLUSION IN TAFS
HOWEVER. PERSISTENT RAINFALL FOR MUCH OF THE DAY SUNDAY MAY ALLOW
FOR SOME IMPROVEMENTS...HOWEVER NO TERMINAL IS EXPECTED TO RECOVER
BEYOND HIGH-END MVFR OR BARE MINIMUM VFR.
KSEA...VFR THIS EVENING WITH CIGS LOWERING OVER TIME, REACHING MVFR
BY 06Z TONIGHT. AS MENTIONED ABOVE, OVERNIGHT INSTABILITY MAY ALLOW
FOR SOME SLIGHT LIFTING...POSSIBLY INTO LOW-END VFR...BUT HIGHER
CONFIDENCE IN CONDITIONS REMAINING MVFR ONCE CIGS DIP BELOW THIS
THRESHOLD FOR THE TAF PERIOD. SE WINDS 5-10 KTS WILL SHIFT SLIGHTLY
SOUTHWESTERLY OVERNIGHT WITH SPEEDS INCREASING 12-17 KTS WITH GUSTS
UP TO 25 KTS AND REMAINING THAT WAY FOR REMAINDER OF TAF. RAINFALL,
ESPECIALLY OVERNIGHT, MAY ALLOW FOR VIS REDUCTIONS AT TIMES TO 5-6SM.
18
MARINE
WINDS AND SEAS CONTINUE TO INCREASE OVER THE COASTAL
WATERS THIS EVENING AHEAD OF THE NEXT APPROACHING FRONTAL SYSTEM.
EXPECT TO SEE THE SOUTHEASTERLY/SOUTHERLY WINDS INCREASE THIS
EVENING WITH HIGH-END ADVISORY WINDS ACROSS THE COASTAL WATERS AND
THE EASTERN STRAIT OF JUAN DE FUCA/NORTHERN INLAND WATERS THIS
EVENING. CANNOT RULE OUT A FEW BRIEF, LOCAL GALE GUSTS LATE THIS
EVENING IN THESE AREAS WITH AROUND A 35-40% CHANCE. STRONGER
WESTERLY WINDS DEVELOP LATE SUNDAY MORNING THROUGH THE EVENING, WITH
CURRENT ADVISORIES REMAINING UNCHANGED. HOWEVER, THERE IS SOME
INCREASED POTENTIAL IN THE CENTRAL STRAIT FOR GALE GUSTS. WILL HOLD
OFF ON AN UPGRADE FOR NOW, BUT WILL NEED TO CLOSELY MONITOR THIS
TREND.
MEANWHILE, SEAS WILL BUILD SIGNIFICANTLY SUNDAY OVER THE COASTAL
WATERS IN RESPONSE TO THE WINDS AND THE ARRIVING WAVES FROM THE
ASSOCIATED LOW MOVING TOWARD VANCOUVER ISLAND. EXPECT TO SEE SEAS
BUILDING INTO THE 18-20 FT RANGE OVER THE COASTAL WATERS SUNDAY.
CONDITIONS EASE SOMEWHAT WITH HIGH PRESSURE OVER THE WATERS LATE
SUNDAY THROUGH MONDAY, THOUGH SEAS WILL BE A LITTLE SLOW TO DECAY. A
FEW WEAK SYSTEMS WILL BUILD SEAS ABOVE 10 FT AGAIN TOWARD MIDWEEK,
WITH A STRONGER SYSTEM BRINGING ANOTHER ROUND OF POTENTIAL 20 FT
SEAS AND LIKELY (>60% CHANCE) GALES TO THE COASTAL WATERS AROUND
THURSDAY. CULLEN
HYDROLOGY
A FRONTAL SYSTEM WILL BRING WIDESPREAD RAINFALL TO THE
REGION OVER THE WEEKEND, WITH UP TO AN INCH OF RAIN ACROSS THE
LOWLANDS AND 1 TO 3 INCHES OVER THE MOUNTAINS. WHILE THIS INFLUX OF
MOISTURE IS NOT EXPECTED TO CAUSE ANY RIVER FLOODING, IT COULD CAUSE
RAPID RISES ON SENSITIVE STREAMS AND CREEKS, POTENTIAL IMPACTS TO
BURN SCARS, AND LOCALIZED URBAN FLOODING. CONDITIONS WILL DRY OUT ON
MONDAY AND TUESDAY. ANOTHER SYSTEM ARRIVING WEDNESDAY WILL BRING
ANOTHER ROUND OF RAIN TO THE AREA. A WETTER SYSTEM WILL ARRIVE
THURSDAY OR FRIDAY. THIS SYSTEM COULD BE TAPPING INTO SOME SUB
TROPICAL MOISTURE BRINGING UP THE POSSIBILITY OF HYDROLOGICALLY
SIGNIFICANT RAINFALL OVER THE OLYMPICS THURSDAY NIGHT INTO FRIDAY.
THE FIRST SKOKOMISH RIVER FLOOD OF THE SEASON IS NOT OUT OF THE
QUESTION LATE NEXT WEEK. FELTON
SEW WATCHES/WARNINGS/ADVISORIES
WA...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 11 PM PDT
SUNDAY FOR CASCADES OF WHATCOM AND SKAGIT COUNTIES.
PZ...SMALL CRAFT ADVISORY UNTIL 6 AM PDT MONDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA-GRAYS HARBOR BAR-NORTHERN INLAND
WATERS INCLUDING THE SAN JUAN ISLANDS-WEST ENTRANCE U.S.
WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 6 AM PDT SUNDAY FOR ADMIRALTY INLET-
PUGET SOUND AND HOOD CANAL.
SMALL CRAFT ADVISORY UNTIL 6 PM PDT MONDAY FOR COASTAL WATERS
FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL
WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL
WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-
COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10
NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER
10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
SHOALWATER OUT 10 NM.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page