Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 050443
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
843 PM PST THU FEB 4 2016

.SYNOPSIS...A WARM FRONT WILL LIFT NORTHEAST ACROSS WESTERN
WASHINGTON TONIGHT FOR AREAS OF LIGHT RAIN. A STRONGER FRONTAL
SYSTEM WILL MOVE THROUGH FRIDAY AND FRIDAY NIGHT FOR RAINY AND
WINDY WEATHER. SHOWERS WILL LINGER SATURDAY...AND A STRONG UPPER
RIDGE SHOULD BRING DRY MILD WEATHER SUNDAY THROUGH WEDNESDAY. THE
NEXT FRONT WILL PROBABLY MOVE INTO THE REGION ON THURSDAY.

&&

.SHORT TERM...A WARM FRONT WILL LIFT THROUGH THE AREA TONIGHT.
NOT MUCH IS CURRENTLY SHOWING UP ON RADAR BUT THERE COULD BE SOME
SPOTTY LIGHT RAIN THIS EVENING. DRY WEATHER IS EXPECTED AFTER
MIDNIGHT AS THE WARM FRONT MOVES NORTH OF THE AREA.

A VIGOROUS COLD FRONT WILL BRING RAIN AND WIND FRIDAY. RAIN SHOULD
REACH THE COAST IN THE MORNING AND THE INTERIOR BY LATE AFTERNOON.
THE COAST AND NORTH INTERIOR WILL HAVE THE STRONGEST WINDS AHEAD
OF THE FRONT FRIDAY. ADVISORIES AND WARNINGS ARE ALREADY UP. SNOW
LEVELS WILL RISE TO 4500 TO 5500 FEET FRIDAY WHICH SHOULD LIMIT
ACCUMULATIONS OVER THE MOUNTAINS.

THERE ARE SOME FLOODING CONCERNS WITH THE FRIDAY FRONT...MAINLY
THE SKOKOMISH RIVER IN MASON COUNTY. A FLOOD WATCH IS IN EFFECT.
MODELS SEEM TO BE TRENDING A BIT DRIER FOR WHAT IT IS WORTH. THERE
IS ALSO AN ELEVATED THREAT OF LANDSLIDES WITH THE RECENT WET
WEATHER. SEE THE HYDROLOGY SECTION BELOW FOR MORE DETAILS.

RAIN WILL CHANGE TO SHOWERS PRETTY QUICKLY FRIDAY NIGHT AS THE
FRONT MOVES INLAND. THERE WILL BE A BURST OF BREEZY TO WINDY
CONDITIONS ALL AREAS IN STRONG ONSHORE FLOW IMMEDIATELY BEHIND THE
FRONT FRIDAY EVENING...WITH WINDS EASING AFTER MIDNIGHT.

SHOWERS WILL TAPER SATURDAY AND BE MAINLY CONFINED TO THE
MOUNTAINS BY AFTERNOON AS AN UPPER RIDGE BEGINS TO BUILD OVER THE
REGION. THE UPPER RIDGE WILL BE OVER THE AREA ON SUNDAY. A WARM
FRONT CLIPPING THE AREA COULD BRING A LITTLE RAIN COAST AND NORTH.
OTHERWISE IT LOOKS DRY. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...THE UPPER RIDGE WILL
STRENGTHEN OVER THE AREA SUNDAY NIGHT AND MONDAY...THEN GRADUALLY
WEAKEN AND SHIFT SLOWLY EAST TUESDAY AND WEDNESDAY. THIS SHOULD BE
A DRY PERIOD WITH MOSTLY SUNNY DAYS AND HIGHS MAINLY IN THE MID
50S TO LOWER 60S. THE NEXT FRONTAL SYSTEM WILL PROBABLY ARRIVE
AROUND THURSDAY. MCDONNAL

&&

.AVIATION...UPPER LEVEL RIDGE OVER WESTERN WA WILL CONTINUE
EASTWARD...WITH THE RIDGE AXIS MOVING EAST OF THE CASCADES BY EARLY
MORNING TOMORROW. UPPER LEVEL FLOW WESTERLY TONIGHT AND INTO FRIDAY
MORNING...TURNING SOUTHWESTERLY BY FRIDAY AFTERNOON.

WHILE SOME CLOUDS CONTINUE TO LINGER...CLEAR SPOTS ARE PRESENT AS
WELL. CIGS ARE GENERALLY VFR TO MVFR...ALTHOUGH ISOLATED SPOTS ARE
REPORTING IFR. EXPECT CONDITIONS TO CONTINUE TO IMPROVE OVERNIGHT
BEFORE CIGS START TO FALL LATE TOMORROW MORNING IN ADVANCE OF
UPCOMING FRONT FOR FRI AFTERNOON. ALONG WITH FALLING CIGS...RAIN AND
REDUCED VISIBILITIES ARE EXPECTED. WINDS WILL ALSO INCREASE AS FRONT
APPROACHES FRIDAY AFTERNOON AND CONTINUING INTO THE OVERNIGHT
PERIOD. LOW LEVEL WIND SHEAR MAY BE AN ISSUE IN SOME
LOCATIONS...MOST NOTABLY NEAR TAF SITES KHQM AND KBLI. SMR

KSEA...CIGS CONTINUING TO IMPROVE THIS EVENING AND
TONIGHT...GENERALLY REMAINING VFR WITH WINDS SE AT AROUND 5 KTS.
STRONG COLD FRONT APPROACHING FRIDAY DROPPING CIGS DOWN TO MVFR
RANGE BY AFTERNOON. RAIN EXPECTED TO START APPROX 17Z AND CONTINUE
FOR REMAINDER OF TAF FORECAST PERIOD. FRONTAL PASSAGE AT APPROX 00Z
WILL BRING WIND SHIFT FROM SE TO S-SW...WITH WINDS REMAINING GUSTY
AFTER FROPA. SMR

&&

.MARINE...SE WINDS WILL CONTINUE TO INCREASE OVER THE COASTAL WATERS
THIS EVNG IN ADVANCE OF A STRONG COLD FRONT THAT WILL CROSS THE
WATERS LATE FRI AFTN. SMALL CRAFT ADVISORY WINDS STARTING TO POP UP
NOW ON COASTAL WATERS...SPREADING EASTWARD AS TIME PROGRESSES...THUS
SMALL CRAFT ADVISORIES WILL GRADUALLY TAKE EFFECT ACCORDINGLY. GALES
WILL START TO EMERGE STARTING LATE TONIGHT AND FRI MORNING FOR THE
COAST...NORTHERN INLAND WATERS...AND BOTH ENTRANCES TO THE STRAIT.
FOLLOWING THE FRONT ON FRI NIGHT...LOOKING FOR WEAKER SW
GRADIENTS...BUT IT WILL STILL BE ENOUGH FOR A BRIEF WESTERLY GALE
THROUGH THE STRAIT...AND SMALL CRAFT WINDS AROUND THE SOUTH END OF
THE OLYMPIC MTNS INTO PUGET SOUND. HIGH PRES WILL CROSS THE WATERS
ON SAT...WITH MUCH LIGHTER WINDS. AN OFFSHORE FLOW PATTERN WILL
DEVELOP FOR SUNDAY THROUGH TUE.

ANOTHER ROUND OF SWELL IS EXPECTED ON FRI...BUT THE HIGHEST WAVES
COINCIDE WITH LOW TIDE ON FRI AFTN...SO AM NOT ISSUING HIGHLIGHTS
FOR THE BEACH EROSION ISSUES AT OCEAN SHORES AND WESTPORT AT THIS
TIME. BEYOND TOMORROW...LOOKS LIKE A TAMER WEEKEND AND EARLY WEEK
AHEAD IN TERMS OF OCEAN SWELL. HANER/SMR

&&

.HYDROLOGY...PREVIOUS DISCUSSION...FLOODING IS POSSIBLE ON THE
EXCEPTIONALLY FLOOD-PRONE SKOKOMISH RIVER BY LATE FRIDAY OR
FRIDAY NIGHT. OTHERWISE RIVER FLOODING IS NOT EXPECTED THE NEXT 7
DAYS.

THE LATEST MODEL RUNS SHOW SLIGHTLY HIGHER PRECIPITATION AMOUNTS
WITH THE FRONTAL SYSTEM THAT MOVES THROUGH THE AREA FRIDAY AND
FRIDAY NIGHT -- IN THE RANGE OF 1 TO 3 INCHES OVER THE OLYMPIC
MOUNTAINS...AND MOST OF THAT WILL FALL IN LESS THAN 12 HOURS WITH
THE SNOW LEVEL AROUND 6000 FT. THIS COULD DRIVE THE SKOKOMISH
RIVER ABOVE FLOOD STAGE...ESPECIALLY CONSIDERING THE SATURATED
GROUND CONDITIONS AND THE FACT THAT THE RIVER HAS BEEN MORE OR
LESS HOLDING STEADY JUST A FOOT BELOW FLOOD STAGE. WE ISSUED A
FLOOD WATCH LATE THIS MORNING.

IN ADDITION...THE USGS LANDSLIDE HAZARDS DATA SUGGEST THAT THE
RAINFALL ON FRIDAY COULD BE ENOUGH TO TRIGGER LANDSLIDES. WE WILL
ISSUE A SPECIAL WEATHER STATEMENT TO ADDRESS THAT THIS AFTERNOON.
MCDONNAL

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WATCH FROM FRIDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR
     HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-OLYMPICS.

     HIGH WIND WARNING FROM 9 AM TO 7 PM PST FRIDAY FOR SAN JUAN
     COUNTY-WESTERN WHATCOM COUNTY.

     WIND ADVISORY FROM 9 AM TO 7 PM PST FRIDAY FOR ADMIRALTY INLET
     AREA-EASTERN STRAIT OF JUAN DE FUCA-WESTERN SKAGIT COUNTY.

     WIND ADVISORY FROM 6 AM TO 4 PM PST FRIDAY FOR CENTRAL COAST-
     NORTH COAST.

PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 4 PM PST FRIDAY FOR
     GRAYS HARBOR BAR.

     SMALL CRAFT ADVISORY UNTIL 11 PM PST THIS EVENING 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.

     GALE WARNING UNTIL 4 PM PST FRIDAY 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.

     SMALL CRAFT ADVISORY UNTIL 4 AM PST FRIDAY FOR EAST ENTRANCE
     U.S. WATERS STRAIT OF JUAN DE FUCA.

     GALE WARNING FROM 4 AM TO 6 PM PST FRIDAY FOR EAST ENTRANCE U.S.
     WATERS STRAIT OF JUAN DE FUCA.

     SMALL CRAFT ADVISORY UNTIL 7 AM PST FRIDAY FOR NORTHERN INLAND
     WATERS INCLUDING THE SAN JUAN ISLANDS.

     GALE WARNING FROM 7 AM TO 6 PM PST FRIDAY FOR NORTHERN INLAND
     WATERS INCLUDING THE SAN JUAN ISLANDS.

     SMALL CRAFT ADVISORY UNTIL 1 AM PST FRIDAY FOR WEST ENTRANCE
     U.S. WATERS STRAIT OF JUAN DE FUCA.

     GALE WARNING FROM 1 AM TO 4 PM PST FRIDAY FOR WEST ENTRANCE U.S.
     WATERS STRAIT OF JUAN DE FUCA.

     SMALL CRAFT ADVISORY FROM 1 AM TO 6 PM PST FRIDAY FOR CENTRAL
     U.S. WATERS STRAIT OF JUAN DE FUCA.

     SMALL CRAFT ADVISORY UNTIL 6 PM PST FRIDAY FOR ADMIRALTY INLET.

&&

$$

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