718
FXUS66 KSEW 140935
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
235 AM PDT TUE APR 14 2026
SYNOPSIS
COOL, WET AND WINDY CONDITIONS TUESDAY INTO
WEDNESDAY WITH PERIODS OF HEAVY SNOW IN THE MOUNTAINS. DRIER
WEATHER IS IN STORE THURSDAY AND FRIDAY WITH HIGH PRESSURE.
WETTER WEATHER RETURNS OVER THE WEEKEND.
SHORT TERM /TODAY THROUGH THURSDAY/
WET AND WINDY CONDITIONS
ON TAP TODAY AS A STRONG PACIFIC STORM SYSTEM SWEEPS THROUGH
WESTERN WA. THE MAIN IMPACT WILL BE PERIODS OF HEAVY MOUNTAIN
SNOW, INCLUDING SNOW AT ALL CASCADE PASSES - WINTER STORM
WARNINGS ARE IN EFFECT. SNOW LEVELS WILL HOVER AROUND 3500 FT
TODAY BUT WILL DROP TO 1500-2000 TONIGHT INTO WEDNESDAY. THE
BULK OF THE HEAVY SNOW WILL FALL TONIGHT BUT THERE WILL BE
LINGERING SNOW SHOWERS MOVING THROUGH WEDNESDAY. MEAN 48-HR
STORM TOTAL AMOUNTS RANGE FROM 10 TO 20" WITH HIGHEST AMOUNTS
OVER THE VOLCANOES. HEAVY SNOW IS ALSO POSSIBLE FOR THE OLYMPICS
AND A WINTER WEATHER ADVISORY IS ALSO IN EFFECT (PRIMARILY FOR
TODAY AND TONIGHT). IN ADDITION, IT'LL BE WINDY TODAY WITH GUSTS
TO 20-30 MPH COMMON ACROSS MOST LOWLAND AREAS. WINDS WILL PEAK
THIS EVENING BUT STILL REMAIN IN 15-25 MPH RANGE OVERNIGHT.
A DEEP UPPER LOW WILL BE OVERHEAD ON WEDNESDAY WITH COOL AND
SHOWERY CONDITIONS. AS MENTIONED ABOVE, WE'LL STILL SEE SNOW
SHOWERS IN THE MOUNTAINS ALTHOUGH SNOW RATES WILL EASE. THE AIR
MASS IS SLIGHTLY UNSTABLE WITH A CHANCE OF THUNDERSTORMS TOO,
ESPECIALLY NEAR THE COAST. SHOWERS WILL TAPER OFF WEDNESDAY
NIGHT AS THE LOW OPENS TO A TROUGH AND EXITS EAST. IT'S NOT AS
WINDY BUT WILL BE CHILLY WITH MORNING LOWS IN THE 30S AND HIGHS
IN THE 40S TO AROUND 50.
WE'RE UNDER DRY NORTHERLY FLOW ON THURSDAY AS HIGH PRESSURE
FORMS OFFSHORE. MORNING TEMPERATURES WILL REMAIN COOL AND IN THE
30S WITH FREEZING TEMPS AND FROST POSSIBLE ACROSS THE SOUTH
SOUND. HIGHS WILL BE A LITTLE WARMER AND IN THE 50S WITH
SUNBREAKS. 33
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
HIGH PRESSURE WILL
SHIFT INLAND ON FRIDAY FOR MORE DRY AND STABLE WEATHER. MORNING
LOWS WILL STILL TRACK ON THE COOL-SIDE WITH POSSIBLE FROST
AROUND THE SOUTH SOUND. THE RIDGE DEPARTS ON SATURDAY WITH A
RETURN OF MOIST SW FLOW. SHOWERS ASSOCIATED WITH AN OFFSHORE
LOW MAY CLIP THE COAST DURING THE AFTERNOON AND EVENING.
SHOWERS WILL SPREAD INLAND ON SUNDAY AS THE LOW SHIFTS FARTHER
EAST AND INLAND. BY MONDAY, THIS SYSTEM SHIFTS TO OUR SOUTH, OVER
CA/NV, WITH A BRIEF BREAK IN THE WEATHER OVER WESTERN WA. 33
AVIATION
A SHORTWAVE TROUGH/COLD FRONT WILL SWING THROUGH THE TERMINALS
TODAY. FLOW ALOFT WILL REMAIN WESTERLY WITH A JET CORE MOVING ASHORE
AND SOUTHWARD THROUGH THE DAY. SHOWERS IN THE NORTH INTERIOR/COAST
THIS MORNING WILL BECOME WIDESPREAD AND A STEADY RAIN LATER IN THE
DAY (SNOW IN THE MOUNTAINS ABOVE 3,500 FT). THERE IS A 15-20% CHANCE
OF THUNDER IN THE AFTERNOON/EVENING FOR COASTAL TERMINALS, AND THE
NORTH INTERIOR (ESPECIALLY WITH A POST-FRONT CONVERGENCE ZONE LIKELY
TO PRODUCE LOCALIZED HEAVIER RAIN AROUND/EAST OF KPAE).
PRECIPITATION POST-FRONT WRAPS UP AROUND 10Z. WEDNESDAY'S SYSTEM
WILL PRODUCE SCATTERED SHOWERS UNDER AN UNSTABLE AIRMASS/TROUGH
(THUNDER THREAT IS MORE WIDESPREAD ACROSS THE TERMINALS AT 20-25%).
CEILINGS: MVFR CEILINGS INCREASE IN COVERAGE THROUGH THE MORNING,
WITH HIGHER LIKELIHOOD OF IFR CONDITIONS IN MOUNTAIN/COASTAL AREAS
IN THE AFTERNOON/EVENING, AS WELL AS IN HEAVIER RAIN. VISIBILITIES
WILL DECREASE THIS AFTERNOON WITH RAIN DOWN TO 3-5 SM (LESS THAN 3
SM ALONG THE COAST), WITH LOCALIZED DROPS LIKELY IN HEAVIER SHOWERS.
SOUTHWEST WINDS 8-12 KT GUSTING TO 20 KT INCREASE TO 10-20 KT
GUSTING TO 30 KT FROM 15Z TUESDAY - 06Z WEDNESDAY, THEN BECOMING
LIGHT.
KSEA...SHOWERS ARRIVING THIS MORNING, BECOMING A MORE STEADY RAIN
LATER THIS AFTERNOON/EVENING. POSSIBLE CONVERGENCE ZONE TO THE NORTH
OF THE TERMINAL (AROUND KPAE). MVFR CEILINGS THIS MORNING LIKELY TO
CONTINUE THROUGH LATE TONIGHT/WEDNESDAY BEFORE IMPROVING TO VFR.
VISIBILITY DROPS DOWN TO 3-5 SM LIKELY WITH THE STEADIER
PRECIPITATION THIS AFTERNOON/EVENING. SOUTHWEST WINDS 8-12 KT
GUSTING TO 20 KT INCREASES TO 10-20 KT GUSTING TO 30 KT FROM 15-18Z
TUESDAY THROUGH 06Z WEDNESDAY. THUNDER THREAT OVER THE TERMINAL
TODAY IS LESS THAN 10%, BUT INCREASES TO 20-25% WEDNESDAY, WITH THE
COVERAGE BEING MORE SCATTERED.
HPR
MARINE
A TROUGH/COLD FRONT WILL CUT OVER THE WATERS TODAY
WITH WIDESPREAD SHOWERS/STEADY RAIN. THERE IS A 20% CHANCE OF
THUNDER FOR THE INNER COASTAL WATERS, AND THE NORTH INTERIOR
WATERS. WINDS HAVE BEGUN TO PICK UP OUT OF THE SOUTHWEST THIS
MORNING AHEAD OF THE FRONT. THIS WILL PEAK IN THE INTERIOR
WATERS LATE THIS MORNING/TONIGHT WITH WINDS OF 20-30 KT. THE
COASTAL WATERS/STRAIT OF JUAN DE FUCA WILL SEE THE STRONGEST
WINDS AROUND THE SAME TIME FROM THE WEST, AND AT AROUND THE SAME
MAGNITUDE (20-30 KT). SMALL CRAFT ADVISORIES REMAIN IN EFFECT
IN THESE AREAS WITH THE FRONTAL PASSAGE. THE WINDS DECREASE
WEDNESDAY, ALTHOUGH THE PATTERN WILL REMAIN UNSETTLED WITH A
COOL TROUGH PRODUCING SCATTERED SHOWERS AND A 20-25% CHANCE OF
THUNDER ACROSS ALL WATERS. CONDITIONS DRY OUT THURSDAY THROUGH
NEXT WEEKEND, WITH ANOTHER SYSTEM SUNDAY POTENTIALLY PRODUCING
GUSTY WINDS IN THE COASTAL WATERS.
SEAS INCREASE FROM 4-6 FT TO 9-12 FT TUESDAY, LINGERING AT 8-10 FT
THROUGH THURSDAY, THEN DECREASING TO 3-5 FT FRIDAY THROUGH SUNDAY
BEFORE BUILDING BACK TO 8-10 FT.
HPR
HYDROLOGY
NO RIVER FLOODING THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...WINTER STORM WARNING FROM 11 AM THIS MORNING TO 11 PM PDT
WEDNESDAY FOR CASCADES OF PIERCE AND LEWIS COUNTIES-
CASCADES OF SNOHOMISH AND NORTHERN KING COUNTIES-CASCADES
OF SOUTHERN KING COUNTY-CASCADES OF WHATCOM AND SKAGIT
COUNTIES.
WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
OLYMPICS.
PZ...SMALL CRAFT ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR CENTRAL U.S.
WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
STRAIT OF JUAN DE FUCA-WEST ENTRANCE U.S. WATERS STRAIT
OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 2 AM PDT
WEDNESDAY FOR ADMIRALTY INLET-NORTHERN INLAND WATERS
INCLUDING THE SAN JUAN ISLANDS.
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 2 AM PDT
WEDNESDAY FOR PUGET SOUND AND HOOD CANAL.
SMALL CRAFT ADVISORY FROM 5 AM EARLY THIS MORNING TO 5 AM PDT
THURSDAY 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.
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