Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 280411
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
911 PM PDT THU AUG 27 2015

.SYNOPSIS...A FRONT WILL BRING RAIN TO THE COAST OVERNIGHT. FRIDAY
WILL BE A RAINY DAY ACROSS WESTERN WASHINGTON WITH THE FRONT MOVING
SLOWLY ACROSS THE REGION. A STRONGER FRONTAL SYSTEM WILL ARRIVE
SATURDAY WITH RATHER BLUSTERY WEATHER EXPECTED. AN UPPER LEVEL
TROUGH WILL SHIFT OVER THE REGION THROUGH THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM...A PATTERN CHANGE WILL BRING WET WEATHER ACROSS WESTERN
WA AS A PAIR OF FALL-LIKE SYSTEMS ROLL THROUGH THE PAC NW. THE FIRST
FRONT WILL BRUSH THE COASTAL WATERS TONIGHT THEN SLOWLY SHIFT INLAND
THROUGH FRIDAY. PRECIP AMOUNTS ARE A LITTLE LIGHTER IN THE MODELS
COMPARED TO PREVIOUS RUNS BUT WE WILL STILL SEE MEASURABLE AMOUNTS.
THE LATEST GUIDANCE SHOWS UP TO 0.50 INCHES ALONG THE COAST WITH UP
TO 1 INCH IN THE OLYMPICS AND NORTH CASCADES. THE INTERIOR SHOULD
SEE 0.1 TO 0.25 INCHES. RAIN WILL TAPER OFF FRI EVENING AS THE FRONT
MOVES INTO THE CASCADES. WITH THE CLOUDS AND RAIN TEMPS WILL MAINLY
STICK IN THE 60S.

A STRONGER PAC SYSTEM WILL BRING ANOTHER ROUND OF WET WEATHER ALONG
WITH BLUSTERY WINDS ON SATURDAY. THIS SYSTEM WILL BE WETTER WITH
RAIN EXPECTED THROUGHOUT THE ENTIRE PERIOD. MODELS SHOW RAINFALL
TOTALS OF 1-2 INCHES ALONG THE COAST AND 1-3 INCHES IN THE MOUNTAINS
THROUGH SATURDAY NIGHT. THERE ARE LESSER AMOUNTS IN THE INTERIOR BUT
STILL IN THE 0.5-1.00 RANGE. WE WILL ALSO SEE SOME BLUSTERY WINDS AS
A 997 MB LOW PASSES NE INTO VANCOUVER ISLAND. GALES WATCHES ARE IN
EFFECT FOR MOST MARINE ZONES. THE INTERIOR WILL SEE THE STRONGEST
WINDS DURING THE AFTERNOON WITH WIND ADVISORIES POSSIBLE...THIS IS
SUSTAINED WINDS OF 30-39 MPH WITH GUSTS 45-56 MPH. STRONG MOIST
ONSHORE FLOW WILL CONTINUE THROUGH SAT NIGHT AS A COLD FRONT MOVES
INLAND. HEAVY SHOWERS ARE POSSIBLE ALONG THE WEST SLOPES OF THE
CASCADES...THE SNOW LEVEL WILL BE AROUND 7000 FT.

AN UPPER LEVEL TROUGH WILL MAINTAIN COOL AND SHOWERY WEATHER THROUGH
SUNDAY. SHOWERS ARE LIKELY WITH TEMPERATURES BELOW NORMAL...HIGHS
STILL IN THE 60S. 33

.LONG TERM...PREVIOUS DISCUSSION...AN UPPER LEVEL TROUGH WILL SHIFT
THROUGH THE PACIFIC NORTHWEST THROUGH THE FIRST HALF OF THE WEEK.
THE SNOW LEVEL IN THE MOUNTAINS OUGHT TO BOTTOM OUT AROUND 6000 FT
AND LOWLAND TEMPS WILL BE BELOW NORMAL. THERE WILL BE SHOWERS AT
TIMES...BUT ALSO SOME PARTLY SUNNY PERIODS.

&&

.AVIATION...SOUTHWEST FLOW ALOFT THROUGH FRIDAY. AT THE SURFACE...A
RIDGE ALONG THE COAST WILL WEAKEN AND SHIFT SLIGHTLY INLAND AS A
FRONT MOVES THROUGH. AIR MASS STABLE WITH HIGH LEVEL MOISTURE THIS
EVENING. MID CLOUDS DEVELOPING AFTER MIDNIGHT TONIGHT...THEN LOW
LEVELS BECOMING MOIST FRIDAY MORNING WITH RAIN AS THE FRONT REACHES
THE AREA.

KSEA...HIGHS CLOUDS UNTIL EARLY MORNING. LOW AND MID CLOUDS
DEVELOPING FRIDAY MORNING AS A FRONT REACHES THE AREA. SOUTHERLY
WIND 4-8 KNOTS. SCHNEIDER

&&

.MARINE...WEAK HIGH PRESSURE ALONG THE COAST WILL SHIFT INLAND
FRIDAY AS A FRONT REACHES THE AREA. SMALL CRAFT ADVISORY WEST
WINDS IN THE CENTRAL AND EASTERN STRAIT WILL EASE AFTER MIDNIGHT
TONIGHT. SOUTHERLY SMALL CRAFT ADVISORY WINDS ARE LIKELY FOR THE
COASTAL WATERS SATURDAY.

A STRONG FRONT WILL MOVE THROUGH THE WATERS SATURDAY. GALE FORCE
WINDS ARE LIKELY FOR MOST WATERS. A COUPLE OF ADDITIONAL FRONTAL
WAVES WILL MOVE THROUGH THE WATERS SUNDAY AND MONDAY FOR SMALL
CRAFT ADVISORY WINDS AT TIMES. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY AFTERNOON FOR
     CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-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-EAST ENTRANCE U.S. WATERS STRAIT OF
     JUAN DE FUCA-NORTHERN INLAND WATERS INCLUDING THE SAN JUAN
     ISLANDS-PUGET SOUND AND HOOD CANAL.

     SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM PDT 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.

     SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR CENTRAL U.S.
     WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
     STRAIT OF JUAN DE FUCA.

&&

$$

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