Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 280412
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 PM PDT MON OCT 27 2014

.SYNOPSIS...A FRONTAL SYSTEM WILL BRING RAIN AND WIND TONIGHT AND
TUESDAY. HIGH PRESSURE ALOFT WILL BUILD OVER THE AREA ON WEDNESDAY
FOR A MOSTLY DRY DAY. A SECOND FRONT WILL BRING ANOTHER ROUND OF
RAIN ON THURSDAY. UNSETTLED WEATHER WILL CONTINUE INTO EARLY NEXT
WEEK AS ADDITIONAL WEATHER SYSTEMS MOVE THROUGH.

&&

.SHORT TERM...A FRONTAL SYSTEM WILL BRING RAIN AND LOCALLY WINDY
CONDITIONS TONIGHT...FOLLOWED BY SHOWERS AND BREEZY CONDITIONS ON
TUESDAY BEHIND THE FRONT. SHOWERS WILL DECREASE TUESDAY NIGHT AND
WEDNESDAY WILL BE MAINLY DRY AS HIGH PRESSURE ALOFT BRIEFLY BUILDS
OVERHEAD. A SECOND FRONT WILL BRING ANOTHER ROUND OF RAIN AND BREEZY
CONDITIONS ON THURSDAY.

FOR TONIGHT...SPOTS OF RAIN HAVE REACHED THE AREA BUT THE MAIN RAIN
WITH THE FRONT IS JUST REACHING THE NORTH COAST. STEADIER RAIN
SHOULD GRADUALLY SPREAD INLAND OVER THE NEXT FEW HOURS...REACHING
THE INTERIOR DURING THE EARLY MORNING HOURS. BREEZY TO WINDY
CONDITIONS WILL DEVELOP AT THE COAST AND NORTHWEST INTERIOR AS THE
FRONT MOVES THROUGH TONIGHT. THE STRONGEST WINDS SHOULD BE FROM LATE
THIS EVENING THROUGH THE EARLY MORNING HOURS TUESDAY. SCHNEIDER

.LONG TERM...AN UPPER TROUGH WILL BE OVER THE AREA ON FRIDAY WITH
SHOWERS. A RELATIVELY WET PATTERN WILL CONTINUE INTO EARLY NEXT WEEK
BUT MODELS ARE NOT IN GOOD AGREEMENT WITH THE DETAILS. CONFIDENCE IN
THE FORECAST SPECIFICS SATURDAY THROUGH MONDAY IS LOW FOR NOW.
SCHNEIDER

&&

.HYDROLOGY...A FRONTAL SYSTEM WILL BRING 2-3 INCHES OF RAIN TO THE
OLYMPICS TONIGHT AND TUESDAY MORNING. THIS COULD BE ENOUGH RAIN TO
PUSH THE SKOKOMISH RIVER IN MASON COUNTY BACK TO FLOOD STAGE LATER
TUESDAY. A FLOOD WATCH IS IN EFFECT.

RIVER FLOODING IS NOT EXPECTED ELSEWHERE FOR THE NEXT 7 DAYS.

&&

.AVIATION...A STRONG WARM FRONT WILL SPREAD RAIN ACROSS W WA TONIGHT
WITH STRONG S-SE WINDS DEVELOPING ALONG THE COAST AND OVER THE NORTH
INTERIOR. THE WEAKER TRAILING COLD FRONT WILL CROSS W WA TUESDAY
MORNING. CIGS ALONG THE COAST WILL LOWER TO MVFR AROUND
07Z...BECOMING IFR AROUND 12Z. OVER THE INTERIOR CIGS WILL GRADUALLY
LOWER AS RAIN MOISTENS THE LOWER AIR MASS...REACHING MVFR LEVELS
AROUND 12Z.

FAIRLY MOIST SW FLOW ALOFT WILL CONTINUE ON TUESDAY WHILE THE LARGE
PARENT SURFACE LOW GRADUALLY FILLS NEAR THE CENTRAL B.C. COAST.
MODERATE LOW LEVEL ONSHORE FLOW WILL MAINTAIN AREAS OF MVFR/IFR
THROUGH 18Z WITH A LITTLE LIFTING AFTER 18Z. SCATTERED SHOWERS WILL
BE AROUND ON TUESDAY.

KSEA...VFR CONDITIONS WILL CONTINUE TONIGHT BUT CIGS WILL SLOWLY
LOWER OVERNIGHT AS WARM FRONTAL RAIN SPREADS OVER THE AREA. CIGS
WILL LOWER DOWN TO MVFR LEVELS AROUND 12Z AND CONTINUE BEYOND 18Z.
A WEAK COLD FRONT WILL CROSS THE AREA TUESDAY MORNING. SURFACE WINDS
WILL REMAIN S-SE 7-14 KT. KAM

&&

.MARINE...SOUTH TO SOUTHEAST FLOW WILL INCREASE ACROSS WESTERN WA
TONIGHT AS A STRONG PACIFIC FRONTAL SYSTEM APPROACHES THE REGION. A
STRONG WARM FRONT WILL MOVE ACROSS W WA TONIGHT BRINGING THE WIND TO
THE COAST AND N INTERIOR. GALES ARE UP FOR ALL WATERS EXCEPT FOR A
SCA FOR PUGET SOUND. A WEAKER COLD FRONT WILL CROSS THE AREA TUESDAY
MORNING. MODELS SHOW THE PARENT 985 MB LOW FAR OFFSHORE GRADUALLY
FILLING AS IT TRACKS NE...NEARING THE  CENTRAL B.C. COAST TUESDAY
AFTERNOON.

THE LARGE LOW WILL LOITER AROUND THE CENTRAL B.C. COAST THROUGH
TUESDAY EVENING BEFORE DISSIPATING. THIS WILL MAINTAIN MODERATE S-SW
FLOW OVER W WA WITH MOST AREAS EXPERIENCING SCA WINDS. WINDS WILL
FINALLY EASE WEDNESDAY AS A WEAK SURFACE RIDGE BUILDS BRIEFLY OVER
THE REGION. MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS EVOLUTION
SO CONFIDENCE IS FAIRLY HIGH.

ANOTHER WEAKER FRONTAL SYSTEM WILL AFFECT THE AREA THURSDAY. KAM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WIND ADVISORY COAST 8 PM THIS EVENING TO 5 AM TUESDAY.
    .WIND ADVISORY NORTHWEST INTERIOR 11 PM TONIGHT TO 8 AM TUESDAY.
    .FLOOD WATCH MASON COUNTY FROM LATE TONIGHT THROUGH LATE TUESDAY.
PZ...GALE WARNING COASTAL WATERS...STRAIT OF JUAN DE
     FUCA...ADMIRALTY INLET...NORTHERN INLAND WATERS.
    .SMALL CRAFT ADVISORY PUGET SOUND AND HOOD CANAL.
    .SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

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