Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 202229
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 PM PM PDT MON OCT 20 2014

.SYNOPSIS...SHOWERS WILL DECREASE TONIGHT IN THE WAKE OF A FRONT. A
FRONTAL SYSTEM WILL BRING RAIN AND WIND TO THE COAST TUESDAY
AFTERNOON AND INLAND TUESDAY NIGHT. UNSETTLED WEATHER WILL CONTINUE
FOR THE REST OF THE WEEK AS A SERIES OF WEATHER SYSTEMS MOVE ONSHORE.

&&

.SHORT TERM...SHOWERS ARE LIKELY THIS EVENING AS AN UPPER TROUGH
MOVES OVERHEAD IN THE WAKE OF THE FRONT FROM LAST NIGHT. THERE IS
ALSO A SLIGHT RISK OF THUNDER NEAR THE COAST WHERE THE AIR WILL BE
MOST UNSTABLE. SHOWERS SHOULD BECOME FAIRLY ISOLATED LATER TONIGHT
AND TUESDAY MORNING AS THE UPPER TROUGH PUSHES INLAND AND WEAK HIGH
PRESSURE ALOFT BRINGS MORE STABLE AIR.

A VIGOROUS FRONTAL SYSTEM WILL BRING RAIN TO THE COAST TUESDAY
AFTERNOON AND THEN INLAND TUESDAY NIGHT. THIS SYSTEM WILL BRING A
GOOD SHOT OF RAIN...ESPECIALLY TO THE OLYMPICS WHICH COULD PUSH THE
SKOKOMISH TO FLOOD WEDNESDAY. THERE WILL ALSO BE SOME WINDY
CONDITIONS WITH THIS SYSTEM...MOST NOTABLY FOR THE COAST AND NORTH
INTERIOR TUESDAY NIGHT. WIND ADVISORIES MAY EVENTUALLY BE NEEDED FOR
THAT.

IT LOOKS LIKE THERE WILL BE A BIT OF A LULL IN THE RAINS FOR AT
LEAST PART OF WEDNESDAY...THEN ANOTHER FRONTAL WAVE WILL BRING MORE
RAIN LATER WEDNESDAY OR WEDNESDAY NIGHT WITH SHOWERS LINGERING INTO
THURSDAY. SCHNEIDER

.LONG TERM...FRIDAY WILL BE IN BETWEEN WEATHER SYSTEMS WITH JUST A
SMALL CHANCE OF RAIN. THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT
SHOWING ANOTHER SHOT OF RAIN FRIDAY NIGHT AND SATURDAY AS A FRONTAL
SYSTEM MOVES THROUGH. A WEAK UPPER RIDGE WILL MOVE OVER THE AREA
SUNDAY AND MONDAY FOR DRIER AND MORE TRANQUIL WEATHER. SCHNEIDER

&&

.HYDROLOGY...A VIGOROUS FRONTAL SYSTEM IS EXPECTED TO BRING HEAVY
RAINS TO THE AREA TUESDAY NIGHT. THE HIGHEST AMOUNTS ARE FORECAST TO
BE OVER THE OLYMPICS WHERE UP TO 5 INCHES ARE POSSIBLE BY WEDNESDAY
MORNING. THIS WILL LIKELY PUSH THE SKOKOMISH RIVER IN MASON COUNTY
TO FLOOD STAGE ON WEDNESDAY. A HYDROLOGIC OUTLOOK IS CURRENTLY OUT
TO COVER THIS POSSIBILITY. FOR OTHER AREAS RIVERS...FLOODING IS
UNLIKELY OVER THE NEXT 7 DAYS.

&&

.AVIATION...A TROUGH WILL CONTINUE TO SHIFT OVER THE PACIFIC NW THIS
AFTERNOON AND TONIGHT BEFORE PASSING EAST OF THE CASCADES TUESDAY.
SOUTH TO SOUTHWESTERLY FLOW ALOFT WILL TURN MORE SOUTHWESTERLY
TONIGHT. MOIST AND WEAKLY UNSTABLE AIR MASS IN PLACE. SCATTERED
SHOWERS OVER PORTIONS OF WESTERN WASHINGTON NOT AS WIDESPREAD AS
ACTIVITY WAS THIS MORNING. GREATEST CONCENTRATION OF ACTIVITY
CURRENTLY OVER OLYMPIC PENINSULA...ALTHOUGH SOME SHOWERS ARE ALSO
FURTHER INLAND. ANY LIGHTNING STRIKES HAVE BEEN WELL OFFSHORE OR IN
CANADA. GIVEN BREAKS IN CLOUDS THIS AFTERNOON...POTENTIAL FOR AN
ISOLATED THUNDERSTORM ALONG THE COAST STILL PRESENT THIS EVENING. SMR

KSEA...SCT-BKN CLOUDS EXPECTED THIS AFTERNOON AND EVENING BEFORE OVC
CONDITIONS MOVE IN TONIGHT. SHOWERS IN VICINITY THIS AFTERNOON
THROUGH TONIGHT WITH BEST CHANCE FOR RAIN AT SEA-TAC BEFORE 03Z.
WINDS WILL REMAIN SOUTHERLY AT 5-10 KT. SMR

&&

.MARINE...W-SW SWELL OF 10 TO 14 FEET WILL CONTINUE INTO TOMORROW.
HAVE EXTENDED THE SMALL CRAFT FOR HAZARDOUS SEAS FOR THE WEST
ENTRANCE TO THE STRAIT AND INCLUDED THE COASTAL WATERS.

A SURFACE LOW IS EXPECTED TO APPROACH OFFSHORE TUESDAY...AND MOVE NE
INTO VANCOUVER ISLAND TUESDAY NIGHT. THIS SYSTEM WILL LIKELY PRODUCE
GALES OVER THE COASTAL WATERS...WEST ENTRANCE AND INLAND WATERS N OF
ADMIRALTY INLET. A GALE WATCH REMAINS EFFECT FOR LATE TUESDAY AND
TUESDAY NIGHT. MODEL DATA HAS TRENDED DOWNWARD SLIGHTLY AND HAS THE
SYSTEM A TOUCH MORE PROGRESSIVE...SO TIMING OF THIS WATCH MAY NEED
TO BE TINKERED WITH. YET ANOTHER SURFACE LOW WILL TRACK NEAR OR
THROUGH THE WATERS AROUND FRIDAY. THE STRENGTH AND TRACK OF THIS
SYSTEM REMAINS HIGHLY UNCERTAIN. DM/SMR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL WATERS AND WEST
     ENTRANCE STRAIT OF JUAN DE FUCA.
    .SMALL CRAFT ADVISORY GRAYS HARBOR BAR FOR ROUGH BAR.
    .GALE WATCH COASTAL WATERS...ENTRANCES STRAIT OF JUAN DE FUCA...
     AND NORTHERN INLAND WATERS.

&&

$$

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