Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 262203
AFDSEW

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

.SYNOPSIS...SUNDAY NIGHT AND MONDAY MORNING WILL BE RELATIVELY DRY.
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 MOVING INTO THE CASCADES AND WILL LIKELY
BE MOSTLY CONFINED TO THERE THIS EVENING. THE SNOW LEVEL APPEARS TO
BE JUST ABOVE THE LEVEL OF STEVENS AND WHITE PASSES...4000 TO 4500
FEET. AT LEAST A FEW MORE INCHES OF SNOW WILL FALL ABOVE THAT LEVEL
SO THE WINTER STORM WARNING FOR THE CASCADES WILL CONTINUE THIS
EVENING. SHOWERS SHOULD TAPER LATE TONIGHT AND CONDITIONS WILL BE
MOSTLY DRY LATE TONIGHT AND MONDAY MORNING.

THE NEXT SYSTEM WILL BRING RAIN TO THE COAST MONDAY AFTERNOON AND
SPREAD RAIN INLAND MONDAY NIGHT. THIS SYSTEM CONTAINS MOISTURE FROM
HURRICANE ANA AND WILL BRING HEAVY RAIN AT TIMES TO THE COAST AND
OLYMPICS. FOR NOW THE QPF GRIDS HAVE A BLEND OF VARIOUS MESOSCALE
MODELS. THIS BLEND GIVES 1-3 INCHES OF RAIN TO THE COAST AND
OLYMPICS WITH AROUND 2 INCHES OVER THE SKOKOMISH BASIN. MODELS
TYPICALLY HAVE TROUBLE WITH SUBTROPICAL MOISTURE SO AMOUNTS COULD
VARY SIGNIFICANTLY OVER THE NEXT SEVERAL RUNS.

ON TUESDAY RAIN WILL CHANGE TO SHOWERS AND SHOWERS WILL TAPER
CONSIDERABLY WEDNESDAY. TEMPERATURES WILL BE NEAR SEASONAL NORMS
WITH HIGHS 55-60 AND LOWS 45-55. BURKE

.LONG TERM...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...A BREAK IN THE RAIN TODAY THROUGH 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. HAVE
ISSUED A FLOOD WATCH FOR MASON COUNTY TUESDAY AND TUESDAY NIGHT.

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

&&

.AVIATION...NORTHWEST FLOW ALOFT WILL CONTINUE OVER WESTERN
WASHINGTON TONIGHT AS A WEAK UPPER LEVEL RIDGE MOVES INLAND FROM THE
OFFSHORE WATERS. THE FLOW WILL BACK TO SOUTHWEST LATE MONDAY AS THE
RIDGE MOVES EAST AND A PACIFIC FRONTAL SYSTEM NEARS THE AREA. THE
MOIST AND WEAKLY UNSTABLE AIR MASS OVER THE AREA WILL STABILIZE AND
DRY SOMEWHAT TONIGHT...BUT LOW LEVEL MOISTURE WILL REMAIN THROUGH
MONDAY MORNING. THE MID AND UPPER LEVELS WILL BECOME MOIST AGAIN
LATE MONDAY.

SCATTERED SHOWERS CONTINUE ACROSS WESTERN WASHINGTON THIS AFTERNOON
WITH LOCALLY MVFR CONDITIONS. THE SHOWERS WILL GENERALLY DECREASE
THIS EVENING AS THE AIR MASS STABILIZES AND DRIES SOMEWHAT. LOW
LEVEL MOISTURE WILL PROBABLY PRODUCE AREAS OF STRATUS LATE TONIGHT
AND MONDAY MORNING...WITH CEILINGS GENERALLY 012-020 AND LOCAL
VISIBILITY 5SM BR ROUGHLY 13Z-18Z. RAIN WILL SPREAD INTO THE
FORECAST AREA FROM THE WEST MONDAY AFTERNOON AND EVENING.

KSEA...SOUTHWEST WIND 8-14 KT FOR THE NEXT FEW HOURS...BUT IT COULD
OCCASIONALLY SWITCH TO NORTHWEST 6-10 KT AT TIMES...THEN SOUTH WIND
5-10 KT OVERNIGHT AND MONDAY. CEILINGS WILL PROBABLY BE AROUND 015
FOR A FEW HOURS MONDAY MORNING.   MCDONNAL

&&

.MARINE...WEAK SURFACE HIGH PRESSURE OVER WESTERN WASHINGTON WILL
MOVE EAST OF THE CASCADES TONIGHT. MARGINAL SMALL CRAFT ADVISORY
WESTERLIES ARE LIKELY IN THE CENTRAL STRAIT OF JUAN DE FUCA AND EAST
ENTRANCE FOR A FEW MORE HOURS.

ANOTHER VIGOROUS FRONTAL SYSTEM WILL AFFECT THE AREA LATE MONDAY
THROUGH TUESDAY. ITS WARM FRONT WILL PRODUCE SOUTHERLY GALES IN THE
COASTAL WATERS PROBABLY BEGINNING MONDAY AFTERNOON...AND AT THE
ENTRANCES TO THE STRAIT AND NORTHERN INLAND WATERS MONDAY EVENING. A
GALE WATCH IS NOW IN EFFECT. THE COLD FRONT WILL MOVE THROUGH THE
FORECAST AREA LATE MONDAY NIGHT AND TUESDAY MORNING.

A TROUGH WILL BE OVER THE AREA LATER TUESDAY...GIVING WAY TO WEAK
HIGH PRESSURE ON WEDNESDAY. ANOTHER FRONT WILL REACH THE AREA
THURSDAY.   MCDONNAL

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...WINTER STORM WARNING CASCADES ABOVE 4000 FEET THIS EVENING.
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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