125
FXUS66 KSEW 120335
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
835 PM PDT TUE MAR 11 2025
SYNOPSIS
LIGHT RAIN AND MOUNTAIN SNOW WILL SLOWLY SPREAD
INLAND TONIGHT, CONTINUING INTO WEDNESDAY. WIDESPREAD SHOWERS
WILL LINGER THURSDAY WITH LOWER SNOW LEVELS AND A CHANCE FOR
THUNDERSTORMS IN THE AFTERNOON. ACTIVE WEATHER WILL CONTINUE
FRIDAY NIGHT, AND THROUGH THE WEEKEND.
SHORT TERM /TONIGHT THROUGH FRIDAY/
LIGHT RAIN CONTINUES TO
SPREAD INLAND TONIGHT DUE TO A WEAK WARM FRONT BRUSHING THE REGION
AND WILL CONTINUE INTO WEDNESDAY MORNING AS A COLD FRONT MOVES
ACROSS THE AREA. THE MOUNTAINS WILL SEE A FEW INCHES OF SNOW WITH
AN INCH OR TWO EXPECTED AT THE PASSES. OVERALL, THE FORECAST
REMAINS LARGELY ON TRACK TONIGHT. THE REMAINDER OF THE PREVIOUS
DISCUSSION FOLLOWS BELOW, WITH UPDATES MADE TO THE AVIATION AND
MARINE SECTIONS. 14
A DEEP, COLD, TROUGH SETS UP OVER THE REGION ON THURSDAY WITH
ADDITIONAL SHOWERS EXPECTED. SNOW LEVELS WILL BE LOW, AROUND
1500-2000 FT, WITH A FEW MORE INCHES OF SNOW IN THE MOUNTAINS AND
PASSES. IT'LL BE CHILLY IN THE LOWLANDS WITH MORNING TEMPS IN THE
30S AND HIGHS IN THE 40S. THE AIR MASS WILL BE SLIGHTLY UNSTABLE
WITH A CHANCE OF THUNDERSTORMS TOO (MAINLY IN SW WASHINGTON).
THE NEXT SYSTEM CLIPS THROUGH ON FRIDAY, ALTHOUGH MOST OF THE
ENERGY AND MOISTURE WILL REMAIN TO OUR SOUTH. TEMPERATURES WILL
REMAIN ON THE COOL-SIDE WITH LOWS IN THE LOWER TO MID 30S AND
HIGHS IN THE 40S.
LONG TERM /SATURDAY THROUGH TUESDAY/
A STRONGER AND WETTER
PACIFIC FRONTAL SYSTEM WILL IMPACT THE REGION THIS WEEKEND,
BRINGING MORE LOWLAND RAIN, GUSTY WINDS AND HEAVY MOUNTAIN SNOW.
WE'RE LOOKING AT 0.75-2" OF RAINFALL THROUGH THE WEEKEND WITH
HIGHEST AMOUNTS AT THE COAST. GUSTIEST WINDS WILL BE AT THE COAST
AND NORTH PART WITH S WINDS TO 30-40 MPH BOTH DAYS. UP IN THE
MOUNTAINS, HEAVY SNOW EXPECTED WITH A 1-2 FEET THROUGH THE PERIOD.
SNOW MAY IMPACT ALL CASCADE PASSES.
A TROUGH MOVES INLAND ON MONDAY, CUTTING OFF THE PRECIP TAP, WITH
HEAVY RAIN/SNOW ENDING (ALTHOUGH WE'LL STILL SEE LINGERING
MOISTURE AND SHOWERS). ENSEMBLE MEMBERS SHOW A DRIER PERIOD MOVING
TOWARD MIDWEEK AS A RIDGE MOVES IN. 33
AVIATION
MAJORITY VFR CEILINGS ACROSS WESTERN WASHINGTON.
SHOWERS CONTINUE TO MOVE PRIMARILY ACROSS THE COAST AND NORTHERN
INTERIOR. RAIN IS EXPECTED TO BECOME MORE WIDESPREAD THIS EVENING,
WHICH WILL BE ACCOMPANIED BY THE LOWERING OF CEILINGS INTO MVFR,
WITH LOCALIZED IFR POSSIBLE IN THE HEAVIER BANDS OF PRECIPITATION.
SOUTHERLY SURFACE WINDS WILL INCREASE THIS EVENING AND GRADUALLY
SUBSIDE WEDNESDAY MORNING. WIND GUSTS IN EXCESS OF 25 KT ARE
POSSIBLE (50-80% CHANCE), WITH THE HIGHEST CHANCES ALONG THE
NORTHERN INTERIOR AND THE COAST.
KSEA...CURRENTLY VFR WITH HIGH CLOUDS AHEAD OF A FRONTAL SYSTEM.
CEILINGS WILL LOWER THIS AFTERNOON INTO MVFR AS RAIN BECOMES MORE
WIDESPREAD. RAIN IS EXPECTED TO CONTINUE THROUGH WEDNESDAY NIGHT.
SOUTHERLY/SOUTHEASTERLY SURFACE FLOW WILL INCREASE THIS EVENING AND
PERSIST THROUGH WEDNESDAY MORNING, WITH GUSTY GUSTS POSSIBLE. HIGH-
RESOLUTION GUIDANCE HINTS AT AT 60-90% CHANCE OF SEEING GUSTS
GREATER THAN 20 KT, AND A 40-50% CHANCE OF SEEING GUSTS EXCEEDING 25
KT. WINDS EXPECTED TO SUBSIDE LATE WEDNESDAY MORNING. SURFACE WINDS
WILL SHIFT MORE SOUTHWESTERLY WEDNESDAY AFTERNOON AND BE AROUND 5 KT.
29/21
MARINE
A FRONT CONTINUES TO BE STALLED OVER THE COASTAL WATERS
AND WILL EVENTUALLY MOVE START MOVING INLAND LATE TONIGHT INTO
WEDNESDAY. ACCOMPANIED WITH THIS SYSTEM WILL BE INCREASING WINDS,
WITH GUSTS APPROACHING HIGH-END SMALL CRAFT ADVISORY CRITERIA ACROSS
THE COASTAL WATERS AND THE EASTERN STRAIT OF JUAN DE FUCA. BRIEF
BURSTS OF LOW-END GALE GUSTS REMAIN POSSIBLE ALONG THE COASTAL
WATERS LATE TONIGHT INTO EARLY WEDNESDAY MORNING. WINDS WILL SUBSIDE
ALONG THE COASTAL WATERS LATER ON WEDNESDAY MORNING BELOW SMALL
CRAFT CRITERIA, AND WILL LINGER SLIGHTLY LONGER ACROSS THE INTERIOR
WATERS. IN ADDITION TO GUSTY WINDS, THIS SYSTEM WILL BRING ELEVATED
SEAS OF 10-13 FT BY TUESDAY NIGHT. WAVES WILL GRADUALLY SUBSIDE
THROUGHOUT THE DAY ON WEDNESDAY. AFTER THIS SYSTEM, MULTIPLE WEATHER
SYSTEMS ARE EXPECTED TO MOVE ACROSS THE WATERS. GUIDANCE IS HINTING
AT A STRONG SYSTEM IMPACTING THE COASTAL WATERS LATE THIS WEEKEND,
BRINGING THE POTENTIAL FOR GALES AND WAVES ABOVE 15 FT.
29
HYDROLOGY
NO RIVER FLOODING IS EXPECTED OVER THE NEXT 7 DAYS.
THE SKOKOMISH RIVER WILL FLUX IN AND OUT OF ACTION STAGE WITH EACH
PASSING SYSTEM THROUGH THE WEEK BUT IS PRESENTLY NOT FORECAST TO
FLOOD.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 AM PDT WEDNESDAY FOR WEST ENTRANCE
U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 1 PM PDT WEDNESDAY FOR ADMIRALTY
INLET-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 2 PM PDT WEDNESDAY 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-NORTHERN INLAND WATERS INCLUDING THE
SAN JUAN ISLANDS.
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