Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 270416
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 PM PDT SUN OCT 26 2014

.SYNOPSIS...HIGH PRESSURE WILL GIVE RELATIVELY DRY WEATHER THROUGH
MONDAY MORNING. A WET WEATHER SYSTEM WILL REACH THE COAST MONDAY
AFTERNOON AND MOVE INLAND MONDAY NIGHT AND TUESDAY. THIS SYSTEM
COULD BRING SIGNIFICANT RAIN TO THE AREA WITH THE REMAINS OF
HURRICANE ANA EMBEDDED IN THE SYSTEM. ANOTHER WEATHER SYSTEM WILL
ARRIVE AROUND THURSDAY.

&&

.SHORT TERM...SHOWERS ARE WINDING DOWN OVER THE AREA THIS EVENING...
AND ARE MOSTLY CONFINED TO THE CASCADES AT THIS POINT. WEAK HIGH
PRESSURE ALOFT WILL BUILD OVER THE AREA TONIGHT FOR A DRY PERIOD
INTO MONDAY MORNING. A PACIFIC FRONTAL SYSTEM WILL BRING RAIN TO THE
COAST IN THE AFTERNOON AND TO THE INTERIOR MONDAY EVENING. RAIN WILL
CHANGE TO SHOWERS TUESDAY MORNING AS THE FRONT MOVES EAST OF THE THE
CASCADES. AN UPPER RIDGE WILL MOVE OVER THE AREA ON WEDNESDAY FOR A
GENERALLY DRY DAY.

THE MONDAY NIGHT/TUESDAY MORNING WEATHER SYSTEM WILL BE ACCOMPANIED
BY A DEEP SURFACE LOW MOVING INTO BRITISH COLUMBIA NORTH OF
VANCOUVER ISLAND TUESDAY MORNING. BREEZY TO WINDY CONDITIONS ARE
EXPECTED AT THE COAST AND NORTHWEST INTERIOR...WITH WIND ADVISORY
TYPE WINDS LIKELY FOR THESE AREAS. THE OLYMPICS WILL ALSO GET
ANOTHER 2-3 INCHES OF RAIN WHICH COULD DRIVE THE SKOKOMISH RIVER TO
FLOOD STAGE TUESDAY OR TUESDAY NIGHT. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...MODELS HAVE BEEN SHOWING THE
FRONT FROM MONDAY NIGHT MOVING SOUTHEAST AND OUT OF THE AREA FOR A
FEW DAYS...BUT THEN GETTING REENERGIZED AND MOVING BACK NORTH. IT
ARRIVES THURSDAY AND SO RAIN IS BACK IN THE FORECAST FOR PERIODS
AROUND THURSDAY. BOTH THE GFS AND EURO SHOW AN UPPER TROUGH MOVING
THROUGH THE REGION ON SATURDAY. SHOWERS WITH VARIOUS POPS ARE IN THE
FORECAST FRIDAY NIGHT THROUGH SUNDAY. BURKE

&&

.HYDROLOGY...THERE WILL BE A BREAK IN THE RAIN THROUGH MIDDAY MONDAY
WILL ALLOW THE SKOKOMISH RIVER TO RECEDE. THE SYSTEM ARRIVING MONDAY
NIGHT COULD HAVE ENOUGH RAIN TO DRIVE THE SKOKOMISH BACK TO FLOOD
STAGE. A FLOOD WATCH IS IN EFFECT FOR FOR MASON COUNTY TUESDAY AND
TUESDAY NIGHT.

ON ALL OTHER RIVERS FLOODING IS UNLIKELY OVER THE NEXT 7 DAYS.

&&

.AVIATION...A WEAK UPPER LEVEL RIDGE WILL MOVE BRIEFLY OVER W WA
TONIGHT ALLOWING ISOLATED SHOWERS TO END. THE LOWER AIR MASS IS
SOMEWHAT MOIST...SO WHILE VFR CONDITIONS WILL PREDOMINATE OVERNIGHT
AND MONDAY MORNING...AREAS OF MVFR CIGS WILL FORM. A STRONG FRONTAL
SYSTEM WILL APPROACH THE REGION MONDAY WITH OVC080-100 LAYERS
REACHING THE AREA AFTER 18Z MONDAY. RAIN WILL SPREAD INLAND 19Z-00Z
WITH CIGS OVER THE INTERIOR LOWERING TO OVC030-050 AROUND 00Z.
STRONG SURFACE PRESSURE GRADIENTS WILL PRODUCE WINDY CONDITIONS
ALONG THE COAST AND OVER PARTS OF THE N INTERIOR.

KSEA...VFR LAYERS SCT-BKN040-060 EXPECTED TONIGHT. MVFR CIGS AROUND
BKN020 ARE POSSIBLE 11Z-17Z BUT CONFIDENCE IS NOT HIGH. SURFACE
WINDS WILL REMAIN SE 4-7 KT. KAM

&&

.MARINE...A WEAK SURFACE RIDGE WILL REMAIN OVER W WA TONIGHT THEN
SHIFT EAST EARLY MONDAY MORNING. THE STRONG FRONTAL SYSTEM OFFSHORE
IS STEADILY APPROACHING THE REGION...AND MODELS HAVE BEEN CONSISTENT
IN THEIR DEPICTION. THIS SYSTEM WILL BE ALMOST ALL STRONG WARM FRONT
WITH JUST A VERY WEAK TRAILING COLD FRONT. SOUTHERLY GALES WILL
DEVELOP OVER THE COASTAL WATERS MONDAY AFTERNOON...SPREADING TO THE
NORTHERN INTERIOR WATERS MONDAY EVENING. THE WARM FRONT WILL CROSS
THE COAST AROUND MIDNIGHT FOLLOWED BY THE WEAK COLD FRONT BEFORE
SUNRISE. GALE WATCHES ARE UP FOR THE ABOVE MENTIONED AREAS AND WILL
BE UPGRADED TO GALES AT 3 AM. A TROUGH WILL BE OVER THE AREA
TUESDAY...GIVING WAY TO WEAK SURFACE RIDGE ON WEDNESDAY. ANOTHER
FRONT WILL REACH THE AREA THURSDAY. KAM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL STRAIT OF JUAN DE FUCA...EAST
      ENTRANCE STRAIT EARLY THIS EVENING.
     SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR THIS
      EVENING.
     GALE WATCH COASTAL WATERS...ENTRANCES TO THE STRAIT...NORTHERN
      INLAND WATERS LATE MONDAY AND MONDAY NIGHT.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML








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