Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 162137
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
230 PM PDT THU OCT 16 2014

.SYNOPSIS...A FRONT WILL NEAR THE COAST TONIGHT AND MOVE THROUGH
WESTERN WASHINGTON FRIDAY AND FRIDAY NIGHT. TEMPORARY HIGH PRESSURE
WILL MOVE OVER THE AREA THIS WEEKEND. SEVERAL FRONTS ARE LIKELY TO
AFFECT THE REGION NEXT WEEK.

&&

.SHORT TERM...A FRONT NEAR 130W WILL SPREAD RAIN TO THE COAST AROUND
MIDNIGHT AND INTO THE INTERIOR OF WESTERN WA AROUND DAYBREAK
FRIDAY. A STRONG PREFRONTAL SOUTHEASTERLY PRESSURE GRADIENT WILL
MOVE INTO THE COASTAL WATERS TONIGHT AND IT MAY BECOME QUITE WINDY
ALONG THE COAST BY ABOUT MIDNIGHT TONIGHT. IT SHOULD BE WINDY AROUND
THE SAN JUANS AND OVER PARTS OF THE WESTERN PORTION OF WHATCOM
COUNTY AS WELL ON FRIDAY. WIND ADVISORIES WERE ISSUED IN THOSE
AREAS...THIS SYSTEM IS A CLASSIC SOUTHEAST SUCKER AND THE WINDIEST
PLACES END UP BEING OVER THE MARINE ZONES. THE WINDIEST SPOT IS
TATOOSH ISLAND AT THE WEST ENTRANCE TO THE STRAIT AND THE UIL-BLI
GRADIENT SHOULD GET UP AROUND -4.5MB OVERNIGHT. THE RAIN WILL MOVE
IN OVER ALL OF WESTERN WA FRIDAY...THEN FRONT WEAKEN AND DISSIPATE
FRIDAY NIGHT AS IT CROSSES THE CASCADES. THE SHOWERS WILL END PRETTY
QUICKLY ON SATURDAY AND SATURDAY AFTERNOON LOOKS DRY WITH AT LEAST
PARTLY SUNNY SKIES.

.LONG TERM...SUNDAY IS LIKELY TO BE A DRY DAY IN OFFSHORE
FLOW...ALTHOUGH ANOTHER FRONT WILL BE APPROACHING. THAT FRONT OUGHT
TO MOVE THROUGH WRN WA MONDAY AND SHOULD BE FOLLOWED BY ANOTHER
BREAK IN THE WEATHER WITH WEAK HIGH PRESSURE ON TUESDAY. OFFSHORE
FLOW CONTINUES TO DRY THE AIR TUESDAY NIGHT...BUT THEN ON WEDNESDAY
THE 12Z GFS SHOWED RAIN DEVELOPING ON THE COAST...SPREADING INLAND
BY AFTERNOON. I THINK IT IS LIKELY TO BE RATHER WET WED-FRI OF NEXT
WEEK WITH A FAIRLY IMPRESSIVE UPPER TROUGH DEVELOPING IN THE NE
PACIFIC BY MIDWEEK.

&&

.AVIATION...STRONG SOUTHWEST FLOW ALOFT WILL DEVELOP TONIGHT AS A
WEATHER SYSTEM APPROACHES THE COAST. AT THE SURFACE SOUTHEASTERLY
PRESSURE GRADIENTS WILL INCREASE THE WIND ON THE COAST AND OVER THE
NORTH TONIGHT. WINDS WILL STILL BE STRONG INTO FRIDAY EVENING. AIR
MASS IS STABLE AND DRY WITH VFR CONDITIONS. CLOUDS WILL THICKEN AND
LOWER FRIDAY WITH RAIN DEVELOPING ON THE COAST AND SPREADING INLAND.

KSEA...JUST HIGH CLOUDS UNTIL FRIDAY MORNING WHEN CEILINGS WILL
LOWER TO 5K FT OR SO. FURTHER LOWERING FRIDAY AFTERNOON AS RAIN
DEVELOPS. SOUTHEAST WIND 5-9 KT. CHB

&&

.MARINE...A STRONG PACIFIC FRONTAL SYSTEM WILL AFFECT THE WATERS
THROUGH FRIDAY NIGHT. OFFSHORE BUOYS HAVE ALREADY SHOWN GALE FORCE
SOUTHERLY WINDS FOR SEVERAL HOURS. GALES WILL SPREAD TO THE COAST
TONIGHT AND CONTINUE THROUGH FRIDAY. THE EAST ENTRANCE AND NORTHERN
INLAND WATERS WILL EXPERIENCE GALES FRIDAY AND FRIDAY EVENING AND
GALE WARNINGS ARE NOW UP FOR THOSE PLACES. THE CENTRAL STRAIT AND
ADMIRALTY INLET SHOULD HAVE SOMEWHAT LESS STRONG WINDS SO SMALL
CRAFT ADVISORIES ARE IN EFFECT. PUGET SOUND WILL REMAIN RELATIVELY
CALM UNTIL THE FRONT PASSES FRIDAY EVENING...WHEN SMALL CRAFT
ADVISORY WINDS ARE LIKELY. COMBINED SEAS OF 12 TO 14 FT WILL BUILD
TO OVER 15 FT TONIGHT AND FRIDAY.

THIS SYSTEM WILL EXIT FRIDAY NIGHT WITH HIGH PRES MOVING INLAND ON
SATURDAY. ANOTHER STRONG FRONT WILL APPROACH WASHINGTON SUNDAY. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WIND ADVISORY NORTH AND CENTRAL COAST 11 PM TONIGHT TO 11 PM ON
FRIDAY. WIND ADVISORY WESTERN WHATCOM COUNTY AND THE SAN JUANS FOR
5AM FRI TO 5AM SAT.

PZ...GALE WARNING COAST...ENTRANCES...AND NORTHERN INLAND WATERS.
     SMALL CRAFT ADVISORY CENTRAL STRAIT AND ADMIRALTY INLET.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

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