Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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010
FXUS66 KSEW 060427
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
827 PM PST FRI FEB 5 2016

.SYNOPSIS...A COLD FRONT WILL PUSH INLAND TONIGHT WITH DECREASING
SHOWERS. A FEW SHOWERS WILL LINGER IN THE CASCADES EARLY SATURDAY.
A WEAK WARM FRONT WILL CLIP THE COAST AND NORTH CASCADES ON
SUNDAY. EXPECT DRY AND MILD WEATHER EARLY NEXT WEEK AS A STRONG
RIDGE BUILDS OVER THE PACIFIC NORTHWEST.

&&

.SHORT TERM...A COLD FRONT MOVED THROUGH THE AREA EARLIER THIS
EVENING. SHOWERS AND BLUSTERY CONDITIONS BEHIND THE FRONT WILL
GRADUALLY SUBSIDE TONIGHT. ON SATURDAY...SHOWERS WILL BECOME MOSTLY
CONFINED TO THE CASCADES IN THE MORNING AS AN UPPER RIDGE BEGINS
TO BUILD OVER THE AREA. THE UPPER RIDGE WILL BE OVER WESTERN
WASHINGTON ON SUNDAY FOR A MAINLY DRY DAY. A WARM FRONT CLIPPING
THE NORTHWEST PART OF THE AREA WILL BRING A LITTLE RAIN TO THE
COAST AND FAR NORTH. THE RIDGE WILL STRENGTHEN OVER THE AREA ON
MONDAY FOR A DRY DAY. HIGHS WILL WARM INTO THE MID TO UPPER 50S
BY MONDAY AND SUNSHINE SHOULD BECOME ABUNDANT. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...AN UPPER LEVEL RIDGE AND
OFFSHORE FLOW WILL KEEP WESTERN WA DRY AND MILD THROUGH EARLY NEXT
WEEK. THE RIDGE WILL SHIFT FARTHER INLAND WEDNESDAY NIGHT OR
THURSDAY AS A TROUGH FORMS OVER THE NE PAC. THIS TROUGH WILL BRING
A FRONT INTO WESTERN WA FOR A CHANCE OF RAIN ON THURSDAY. A LONG
WAVE TROUGH WILL REMAIN OVER THE PAC NW THROUGH THE END OF THE
WEEK FOR COOLER WEATHER AND A CHANCE OF RAIN THROUGH THE PERIOD.
33

&&

.AVIATION...UPPER LEVEL FLOW WILL CONTINUE TO SHIFT FROM CURRENT
SOUTHWESTERLY FLOW TO MORE WESTERLY BY VERY LATE TONIGHT...FINALLY
BECOMING NORTHWESTERLY BY EARLY SATURDAY MORNING AS FRONTAL SYSTEM
WITH ASSOCIATED UPPER LEVEL TROF MOVE QUICKLY THROUGH WESTERN
WASHINGTON OVER THE NEXT 6 TO 8 HOURS. WITH THE MAIN FRONT ALREADY
THROUGH MUCH OF THE AREA...PRECIP WILL COME MAINLY IN THE FORM OF
SHOWERS...MOST OF WHICH ARE CURRENTLY FOCUSED ON THE OLYMPIC
PENINSULA AT THE TIME OF THIS WRITING...BUT ARE EXPECTED TO SPREAD
EASTWARD AS THE NIGHT PROGRESSES.

CIGS OVER THE AREA ARE SURPRISINGLY VFR TO MVFR...ALTHOUGH AS
SHOWERS SPREAD EASTWARD...MAY SEE CIGS DIP INTO MVFR TO IFR RANGE.
ONCE TROF PASSES...NORTHWESTERLY FLOW AND UPPER LEVEL RIDGING WILL
START TO DRY THINGS OUT...ALLOWING FOR CIGS TO START LIFTING TO
WIDESPREAD VFR AROUND MID TO LATE AFTERNOON SATURDAY. SMR

KSEA...BRIEF PERIOD OF REST AS FRONTAL PRECIP IS EAST OF TERMINAL
WHILE SHOWERS STILL OFF A BIT TO THE WEST. MAY START TO SEE SHOWERS
MAKE THEIR WAY INTO KSEA AREA BETWEEN 05-07Z...MORE LIKELY TOWARD
THE END OF THAT WINDOW IF CURRENT RADAR TIMING HOLDS. MAY SEE SOME
SLIGHT CIG IMPROVEMENT NOW THAT FRONT HAS PASSED THOUGH...ALTHOUGH
WILL BE TEMPORARY AS EXPECTING CIGS TO DROP AGAIN WITH ANY INCOMING
SHOWERS...ULTIMATELY YIELDING A NET CHANGE OF ZERO. WINDS REMAINING
SOUTH TO SOUTHWEST AND GUSTY...ALTHOUGH SLOWLY TAPERING OFF
OVERNIGHT.  SMR

&&

.MARINE...A VIGOROUS COLD FRONT PASSING THROUGH THE AREA. GALE
CONDITIONS CONTINUE OVER THE COASTAL WATERS...THUS THE GALE WARNING
THERE HAS BEEN EXTENDED TO 1 AM PST TONIGHT. GALES WILL LIKELY TAPER
OFF PRIOR TO THAT. GALES REMAIN IN PLACE FOR CENTRAL AND EASTERN
STRAIT...WITH EASTERN STRAIT FLIRTING WITH GALE SPEEDS...CENTRAL
DEFINITELY BLOWING. SMALL CRAFT ADVISORY UP FOR REMAINING
WATERS...AND THAT SEEMS MOSTLY OKAY.

AN AREA OF 18-23 FT SWLY SEAS WITH A DOMINANT PERIOD OF 14 SECONDS
IS OCCURRING WITH AND BEHIND THE FRONT OVER THE COASTAL WATERS. THE
HIGH SEAS ARE MAINLY BEING DIRECTED TOWARD VANCOUVER ISLAND AND HAVE
A SHORT PERIOD...AND ARE EXPECTED TO QUICKLY SUBSIDE AFTER 9 PM.
HENCE...SIGNIFICANT BEACH EROSION PROBLEMS ARE NOT EXPECTED ON THE
DAMAGED BEACHES IN OCEAN SHORES AND WESTPORT AND HIGH SURF
ADVISORIES ARE NOT WARRANTED ELSEWHERE.

ONSHORE FLOW WILL DIMINISH LATE TONIGHT INTO SATURDAY AS A RIDGE OF
HIGH PRESSURE BUILDS INTO THE WATERS. THE RIDGE WILL SHIFT EAST OF
THE CASCADES ON SUNDAY RESULTING IN LIGHT TO MODERATE OFFSHORE FLOW
THAT WILL PERSIST INTO THE MIDDLE OF NEXT WEEK. SMALL CRAFT ADVISORY
CONDITIONS ARE POSSIBLE AT TIMES SUNDAY ONWARD NEAR GAPS IN THE
TERRAIN OVER THE COASTAL WATERS AND POSSIBLY IN THE OUTER PORTIONS
OF THE COASTAL WATERS. SMR/ALBRECHT

&&

.HYDROLOGY...FLOODING IS POSSIBLE ON THE EXCEPTIONALLY FLOOD-
PRONE SKOKOMISH RIVER LATER TONIGHT. OTHERWISE RIVER FLOODING IS
NOT EXPECTED THE NEXT 7 DAYS.

ABOUT AN INCH OF RAIN FELL OVER THE SOUTH SLOPES OF THE OLYMPICS
LATE THIS AFTERNOON AND EARLY THIS EVENING. THE HEAVY RAINS HAVE
ENDED AS OF 8 PM. AN INCH OF RAIN WOULD NOT NORMALLY BE ENOUGH TO
CAUSE FLOODING BUT THE SKOKOMISH IS ALREADY RUNNING HIGH AND THE
GROUND IS SATURATED FROM RECENT RAINS. THE RIVER IS CURRENTLY
RISING SHARPLY AND THE FLOOD WATCH WILL REMAIN IN EFFECT.

IN ADDITION...THE USGS LANDSLIDE HAZARDS DATA SUGGEST THAT THE
RAINFALL FROM THE FRONT TODAY COULD BE ENOUGH TO TRIGGER
LANDSLIDES. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO
ADDRESS THIS POSSIBILITY. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY UNTIL 4 AM PST SATURDAY FOR CASCADES OF
     PIERCE AND LEWIS COUNTIES-CASCADES OF SNOHOMISH AND KING
     COUNTIES-CASCADES OF WHATCOM AND SKAGIT COUNTIES.

     FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR MASON COUNTY.

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

     SMALL CRAFT ADVISORY FROM 1 AM TO 6 PM PST SATURDAY 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-WEST ENTRANCE U.S. WATERS
     STRAIT OF JUAN DE FUCA.

     GALE WARNING UNTIL 1 AM PST SATURDAY 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-WEST ENTRANCE U.S. WATERS STRAIT OF
     JUAN DE FUCA.

     GALE WARNING UNTIL 4 AM PST SATURDAY FOR CENTRAL U.S. WATERS
     STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS STRAIT OF
     JUAN DE FUCA.

     SMALL CRAFT ADVISORY UNTIL 4 AM PST SATURDAY FOR ADMIRALTY INLET-
     NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS-PUGET
     SOUND AND HOOD CANAL.

&&

$$

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