Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 161007
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
305 AM PDT THU OCT 16 2014

.SYNOPSIS...MOIST SOUTHWEST FLOW WILL GIVE CLOUDS AND A CHANCE OF
SHOWERS THIS MORNING. CONDITIONS WILL DRY THIS AFTERNOON AS A RIDGE
OF HIGH PRES BUILDS OVER THE AREA. RAIN WILL SPREAD INLAND TONIGHT
THROUGH FRIDAY AS A SLOW MOVING FRONTAL SYSTEM APPROACHES THE AREA.
THE FRONT WILL MOVE INLAND FRIDAY NIGHT GIVING RAIN AND LOCALLY
WINDY CONDITIONS. A FEW SHOWERS WILL PERSIST ON SATURDAY AS THE
FRONT MOVES EAST OF THE AREA AND DISSIPATES. ANOTHER RIDGE WILL MOVE
OVER THE AREA LATE SATURDAY INTO SUNDAY GIVING WARMER AND DRIER
WEATHER.

&&

.SHORT TERM...SATELLITE IMAGERY SHOWS DEVELOPING LOW PRESSURE
CENTERED NEAR 40N 142W. AS THIS LOW DEVELOPS AND STARTS TO CURL NNE
TOWARD HAIDA GWAII...A STRONG RIDGE OF HIGH PRES AT THE SURFACE AND
ALOFT WILL DEVELOP DOWNSTREAM OF THIS OFFSHORE DEVELOPMENT...AND
MODELS SHOW LONG WAVE RIDGING DOMINATING THE INLAND NORTHWEST FOR
THE NEXT SEVERAL DAYS.

SHORT TERM MODELS ARE SHOWING GOOD CONSISTENCY AND CONTINUITY THIS
MORNING. THE RIDGING TO OUR EAST AND THE LOW PRES DEVELOPMENT
OFFSHORE WILL INDUCE OFFSHORE FLOW OVER WESTERN WASHINGTON THIS
AFTERNOON AND EVENING FOR DRYING AND DECREASING CLOUDS. BUT BEFORE
THE DRYING...A WEAK SHORT WAVE TROUGH CENTERED OVER THE COASTAL
WATERS WILL SPREAD CLOUDS AND SOME SHOWERS NE ACROSS THE
AREA...MAINLY ALONG THE COAST...THIS MORNING.

THE RIDGE OVER THE ROCKIES AND INTERMOUNTAIN WEST WILL CONTINUE TO
BUILD ON FRIDAY. AS A RESULT...THE FRONTAL SYSTEM OFFSHORE THAT IS
ASSOCIATED WITH THE LOW THAT IS MOVING NNE INTO HAIDA GWAII WILL
BECOME INCREASINGLY N-S ORIENTED. RAINFALL THAT DEVELOPS ON THE
COAST LATER TONIGHT WILL BE SLOW TO MOVE INLAND ON FRIDAY. THE
FRONT WILL FINALLY MOVE INLAND FRI NIGHT AS IT STRETCHES AND SPLITS.
WITH ELY PRES GRADIENTS AHEAD OF A STRETCHING N-S ORIENTED
FRONT...WINDY CONDITIONS SHOULD BE MAINLY CONFINED TO THE IMMEDIATE
PACIFIC BEACHES. LOCALLY HEAVY RAINFALL...ONE TO TWO INCHES...CAN BE
EXPECTED ON THE COAST AND ON THE SW SLOPES OF THE OLYMPIC MOUNTAINS
AHEAD OF AND WITH THE FRONTAL PASSAGE.

THE DISSIPATING FRONT WILL SLOWLY MOVE INLAND FRI NIGHT WITH RAIN
TURNING TO SHOWERS. SHOWERS WILL GRADUALLY DIMINISH ON SAT AS THE
FRONT MOVES INTO THE WEST COAST RIDGE AND DISSIPATES OVER THE
CASCADES.

WITH SW TO S FLOW ALOFT...TEMPERATURES WILL BE A BIT ABOVE NORMAL
FOR MID OCTOBER THROUGH SATURDAY NIGHT. ALBRECHT

.LONG TERM...ANOTHER DEEP TROUGH WILL DEVELOP ALONG 140W SAT NIGHT
INTO SUN. MEANWHILE...LONG WAVE RIDGING WILL AMPLIFY SOMEWHAT OVER
THE INTERIOR WEST. PRESSURE FALLS OFFSHORE WITH ANOTHER INCREASINGLY
N-S ORIENTED FRONT COMBINED WITH HIGH PRES E OF THE CASCADES WILL
RESULT IN NICE OFFSHORE FLOW ON SUNDAY FOR A DRY DAY AND QUITE MILD
TEMPERATURES. MOST OF THE INTERIOR LOWLANDS SHOULD SEE TEMPERATURES
NEAR 70 SUNDAY AFTERNOON.

THE RAIN THREAT WITH THE NEXT SPLITTING N-S ORIENTED FRONT WILL
INCREASE ON THE COAST LATE SUN AFTERNOON OR EVENING...THEN INLAND
SUN NIGHT INTO MON. WITH RIDGING TO SOME DEGREE CONTINUING TO OUR
EAST...THE NEXT FRONT UPSTREAM WILL LIKELY SLOW ITS FORWARD PROGRESS
AND BECOME MORE N-S ORIENTED TOWARD THE MIDDLE OF NEXT WEEK.

THROUGH THE LONG RANGE PERIOD...FORECAST MODELS ARE IN VERY GOOD
AGREEMENT AND ARE CONSISTENT WITH THEIR PREVIOUS SOLUTIONS. ALBRECHT

&&

.AVIATION...A TROUGH WILL APPROACH THE PAC NW TODAY WITH MODERATE
SLY FLOW DEVELOPING. GENERALLY MOIST THIS MORNING WITH SOME DRYING
IN THE LOWER LEVELS ON THIS AFTERNOON. WEAKLY UNSTABLE ATMOSPHERE
WITH SCATTERED...BUT THUNDERSTORMS ARE UNLIKELY. BECOMING STABLE BY
THIS EVENING. PATCHY MVFR THIS MORNING...ESPECIALLY ASSOCIATED WITH
SHOWERS. OTHERWISE...VFR CONDITIONS.

KSEA...CIGS GENERALLY 3-5K FT...THEN ABOVE 5K FT THIS AFTERNOON.
ISOLATED SHOWERS. S/SE WIND 5-9 KT. DTM

&&

.MARINE...A STRONG PACIFIC FRONTAL SYSTEM WILL AFFECT THE WATERS
THROUGH FRIDAY NIGHT. PRESSURE GRADIENTS WILL CONTINUE TO TIGHTEN
OVER THE THE COASTAL WATERS TODAY WITH SMALL CRAFT WINDS RAMPING UP
TO GALE FORCE WINDS THIS AFTERNOON THROUGH FRIDAY. COMBINED SEAS OF
12 TO 14 FT WILL BUILD TO OVER 15 FT TONIGHT AND FRIDAY. OVER THE
INTERIOR...SMALL CRAFT WINDS WILL PREVAIL FROM ADMIRALTY INLET NWD
THROUGH TONIGHT. A GALE WATCH REMAINS IN EFFECT FOR THE INLAND
WATERS N OF ADMIRALTY INLAND ON FRIDAY. THIS SYSTEM WILL EXIT FRIDAY
NIGHT WITH HIGH PRES MOVING INLAND ON SATURDAY. ANOTHER STRONG FRONT
WILL APPROACH WASHINGTON SUNDAY. DTM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.

PZ...SMALL CRAFT ADVISORY COASTAL WATERS TODAY.
     GALE WARNING COASTAL WATERS LATE TODAY THROUGH FRIDAY AFTERNOON.
     SMALL CRAFT ADVISORY EASTERN STRAIT OF JUAN DE FUCA AND THE
     NORTHERN INLAND WATERS THROUGH TONIGHT.
     GALE WATCH EASTERN STRAIT OF JUAN DE FUCA AND THE NORTHERN
     INLAND WATERS LATE TONIGHT THROUGH FRIDAY EVENING.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

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