Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 182158
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT FRI OCT 17 2014

.SYNOPSIS...AN UPPER RIDGE WILL GIVE DRY AND WARMER WEATHER SUNDAY
OVER THE INTERIOR AHEAD OF THE NEXT SYSTEM. A FRONT WILL BRING RAIN
TO THE COAST LATE SUNDAY...AND TO THE INTERIOR SUNDAY NIGHT AND
MONDAY. A SERIES OF FRONTAL SYSTEMS WILL MAINTAIN A WET PATTERN THE
REST OF NEXT WEEK.

&&

.SHORT TERM...THERE ARE STILL SOME RESIDUAL SHOWERS IN THE CASCADES
THIS AFTERNOON AS WELL AS SOME NEAR THE OLYMPICS. VISIBLE SATELLITE
IMAGERY SHOWS SUN BREAKS. KEPT A SMALL CHANCE OF SHOWERS GOING THIS
EVENING OVER SOME AREAS. WITH THE NEXT SYSTEM REACHING THE NORTH
COAST SUNDAY AFTERNOON...HIGH AND PERHAPS SOME MID CLOUDS WILL BEGIN
TO MOVE INTO THE INTERIOR BEFORE THEN. HAVE CUT BACK THE MOSTLY
SUNNY FORECAST FOR SUNDAY TO PARTLY SUNNY. HIGHS SUNDAY SHOULD BE
65-70 OVER THE INTERIOR BUT LOWER ON THE NORTH COAST.

RAIN IS LIKELY ON THE NORTH COAST SUNDAY AFTERNOON AND WILL SPREAD
INLAND SUNDAY NIGHT AND MONDAY. SHOWERS MONDAY NIGHT. IT DOES APPEAR
EVERYWHERE WILL GET SOME RAIN ON MONDAY AND POPS ARE CATEGORICAL.
THERE WILL BE A BIT OF A LULL ON TUESDAY. HIGHS MONDAY AND TUESDAY
WILL BE IN THE LOW 60S. BURKE

.LONG TERM...MODELS BRING THE NEXT SYSTEM TO THE COAST TUESDAY
AFTERNOON AND INLAND TUESDAY NIGHT. AS BEFORE THE GFS IS MORE
PROGRESSIVE...BRINGING ANOTHER SYSTEM WEDNESDAY AND ANOTHER THURSDAY
WITH...CRUCIALLY...LULLS IN THE RAINFALL BETWEEN SYSTEMS. THE EURO
PATTERN IS MORE OF AN ATMOSPHERIC RIVER TUESDAY NIGHT THROUGH
THURSDAY NIGHT. BOTH MODELS TURN MORE SHOWERY FRIDAY WITH PERHAPS A
DRY SATURDAY. THE CANADIAN MODEL IS SIMILAR TO THE GFS. THE QPF
GRIDS ARE BASICALLY THE WRF-GFS-EXTENDED WHICH HAS SOME LULLS BUT
ALSO HAS A PARTICULARLY WET PERIOD OVER THE OLYMPICS FROM TUESDAY
AFTERNOON THROUGH WEDNESDAY. THERE IS A BROAD AREA OF 4-5 INCHES OF
RAINFALL OVER THE OLYMPICS DURING THIS PERIOD. TEMPERATURES ARE
REMARKABLY STEADY OVER THE NEXT WEEK OR SO WITH HIGHS NEAR 60 AND
LOWS NEAR 50. BURKE

&&

.HYDROLOGY...THE SYSTEM SUNDAY NIGHT AND MONDAY IS WET BUT DOES NOT
HAVE ENOUGH RAIN TO CAUSE FLOODING. THE SYSTEM LAST NIGHT BROUGHT AN
INCH PLUS TO THE OLYMPICS...AND THE NEXT ONE WILL BRING PERHAPS
ANOTHER 2 INCHES. THESE WILL SERVE TO PRIME THE PUMP...SO TO SPEAK.
PREVIOUSLY DRY AREAS WILL BECOME WET AND NEARLY EMPTY RIVERS ON THE
OLYMPIC PENINSULA WILL RISE TO WET SEASON LEVELS.

THE GFS AND WRF VERSION OF THE HEAVY RAIN BEGINNING TUESDAY NIGHT IS
PROBABLY ENOUGH TO BRING THE SKOKOMISH RIVER TO FLOOD STAGE. IF THE
OUTLIER EURO SOLUTION IS CORRECT THEN SOME MORE RIVERS ON THE
OLYMPIC PENINSULA SHOULD RISE SIGNIFICANTLY...PERHAPS TO FLOOD
STAGE. MODELS DO CONFINE FLOOD-PRODUCING RAINFALL TO THE OLYMPIC
PENINSULA. ANY FLOODING ON THE SKOKOMISH RIVER WOULD PROBABLY OCCUR
WEDNESDAY NIGHT OR THURSDAY. BURKE

&&

.AVIATION...SOUTHWEST FLOW ALOFT...BECOMING MORE SOUTHERLY TONIGHT
AND SUNDAY. AT THE SURFACE...HIGH PRESSURE INLAND WITH LOWER
PRESSURE OFFSHORE. A FRONT WILL MOVE INTO THE COASTAL WATERS SUNDAY.
AIR MASS STABLE WITH MOSTLY MID AND HIGH LEVEL CLOUDS TONIGHT AND
SUNDAY.

KSEA...EXPECT MOSTLY MID AND HIGH CLOUDS TONIGHT AND SUNDAY ALTHOUGH
SOME LOW CLOUDS OR FOG COULD FORM LATE TONIGHT FOR A FEW HOURS IF
THERE IS ENOUGH CLEARING. THE THREAT OF THIS DOES NOT SEEM HIGH
ENOUGH TO PUT IN THE TAF FOR NOW. SOUTHERLY WINDS 3 TO 6 KNOTS
BECOMING EASTERLY TONIGHT. SCHNEIDER

&&

.MARINE...A SERIES OF VIGOROUS FRONTS WILL MOVE THROUGH THE WATERS
OVER THE NEXT SEVERAL DAYS. THE FIRST FRONT WILL REACH THE COASTAL
WATERS SUNDAY...THEN WEAKEN A BIT AND MOVE SLOWLY INLAND SUNDAY
NIGHT AND MONDAY. A SECOND VIGOROUS FRONT WILL MOVE THROUGH THE
WATERS LATER TUESDAY FOLLOWED BY A THIRD SYSTEM ON WEDNESDAY.

EACH OF THESE SYSTEMS WILL BRING AT LEAST SMALL CRAFT ADVISORY WINDS
TO MOST OF THE WATERS. GALES ARE LIKELY FOR THE COASTAL WATERS AS
EACH FRONT MOVES THROUGH. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING COASTAL WATERS AND WEST ENTRANCE STRAIT OF
     JUAN DE FUCA.
    .SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT AND NORTHERN
     INLAND WATERS.

&&

$$

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