Gale Warning 70, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 AM PST WED NOV 19 2008

.SYNOPSIS...HIGH PRESSURE ALOFT WILL PREVAIL OVER THE REGION TODAY
FOR DRY WEATHER. LOOK FOR PRECIPITATION TO GRADUALLY OVERSPREAD THE
AREA TONIGHT AHEAD OF A STORM SYSTEM. THIS SYSTEM WILL BRING A ROUND
OF WET WEATHER AND GUSTY WINDS TO THE REGION ON THURSDAY. ALAS...
ANOTHER VIGOROUS PACIFIC STORM WILL BRING MORE PRECIPITATION AND
GUSTY WINDS TO THE AREA ON FRIDAY.

&&

.SHORT TERM...
AN UPPER RIDGE OVER THE REGION TODAY WILL SERVE TO KEEP THE WEATHER
DRY OVER THE CWA. THERE MAY BE A FEW SPRINKLES OVER THE FAR SERN
PORTION OF THE CWA THIS AFTERNOON AS THE REMNANTS OF AN OLD
BAROCLINIC ZONE MOVES NEWD ACROSS THE AREA. OTHERWISE THE MAIN
PRECIP EVENT WILL HOLD OFF UNTIL THU.

THE THU SYSTEM HAS BEEN DELAYED. THE SLOW-DOWN WAS BEING CAUSED BY
WAVES DEVELOPING ALONG THE BAROCLINIC BOUNDARY...WHICH WAS ORIENTED
NEARLY PARALLEL TO THE FLOW. A STRONG JET DIVING DOWN THE BACK SIDE
OF THE UPPER TROF WILL KICK THE SYSTEM ALONG LATER TODAY AND
TONIGHT. THUS EXPECT RAIN TO INCREASE IN EARNEST ON THE COAST LATE
TONIGHT AND THEN OVERSPREAD THE REMAINDER OF THE CWA THU MORNING.

WAS NOT CONFIDENT THAT THE MODELS HAD A VERY GOOD HANDLE ON THIS
SYSTEM AS IT APPEARED...ON SATELLITE...MORE INTENSE THAN WHAT THE
MODELS INDICATED. WOULD NOT RULE OUT ISOLATED TSTMS THU AFTERNOON AS
THE NEGATIVE TILTED UPPER TROF SWINGS ACROSS THE CWA. WINDS MAY ALSO
END UP A LITTLE STRONGER...WITH THE FRONTAL PASSAGE...THAN WHAT THE
MODELS WERE ADVERTISING. IN FACT...MODEL WIND SPEEDS SEEMED TOO LOW
WITH THIS SYSTEM. WILL NEED TO MONITOR QPF AS WELL SINCE SNOWFALL
AMOUNTS WILL LIKELY REACH ADVISORY CRITERIA IN THE N CASCADES...
ESPECIALLY...BY THU EVENING.

SOMEWHAT IMPROVING WEATHER WILL OCCUR THU NIGHT AS A WEAK...SHORT
WAVE RIDGE MOVES OVER THE REGION. HOWEVER RAIN WILL BEGIN INCREASING
ON THE N COAST LATE THU NIGHT AS THE TAIL END OF A WMFNT ASSOCIATED
WITH THE NEXT VIGOROUS PAC STORM APPROACHES THE AREA. IT APPEARED
THAT THERE MAY BE SIGNIFICANT SNOWFALL IN STORE FOR THE MOUNTAINS ON
FRI...THUS HAVE BUMPED UP POPS AND INCREASED QPF. CONFIDENCE IN THE
TRACK OF THE SURFACE LOW WAS NOT OVERLY HIGH HOWEVER. IF IT ENDS UP
TRACKING FARTHER SEWD...IT WOULD END UP BEING A HIGH WIND EVENT FOR
A PORTION OF THE CWA. FOR NOW...GOING ALONG WITH MODEL CONSENSUS.
SO...FOR NOW...SIGNIFICANT SNOWFALL IS POSSIBLE IN THE MOUNTAINS ON
FRI.

.LONG TERM FROM THE PREV DISCUSSION...WITH COLD ADVECTION...SOME
MOISTURE BEHIND THIS SYSTEM...AND A BIT OF DISTRUST IN THE MODELS...
HAVE LEFT A CHANCE OF PRECIPITATION IN THE FORECAST FOR SATURDAY.
TREND IN THE MODELS CONTINUES TO BE A BUILDING UPPER RIDGE OVER THE
WEST. THUS...I AND SURROUNDING NW OFFICES HAVE BIT OFF ON THAT IDEA
AND DRIED OUT SUNDAY AND MONDAY. IF THIS SCENARIO DOES COME
TRUE...WE SHOULD END UP WITH PARTLY CLOUDY SKIES...COOL NIGHTS AND
MILD DAYS WITH SOME FOG HERE AND THERE. IT IS POSSIBLE THAT THIS DRY
TREND WILL CONTINUE FOR ANOTHER DAY OR SO BUT DID NOTT GO WITH THAT
JUST YET.  CERNIGLIA

&&

.AVIATION...UPPER RIDGE OVER PACIFIC NORTHWEST WITH WESTERLY FLOW
ALOFT. OFFSHORE AND NORTHERLY FLOW AT THE SURFACE. LITTLE CHANGE
THROUGH 00Z THURSDAY.

MOSTLY CLEAR EXCEPT FOR THIN CIRRUS. SOME RESIDUAL STRATUS AND LOCAL
FOG ARE POPPING IN AND OUT AT THE TERMINALS. STRATUS AND FOG SHOULD
BE GONE BY 20Z...THEN MID AND HIGH LEVEL CLOUDS WILL INCREASE.

KSEA...FOG UNLIKELY WITH WINDS NE 6-12 KT. APPARENTLY CEILINGS
CANNOT BE RULED OUT AS STRATUS IS IN AND OUT. CHB

&&

.MARINE...NORTHEAST WINDS HAVE PICKED UP AND NOW THERE ARE SMALL
CRAFT ADVISORY WINDS AT THE WEST ENTRANCE...ADMIRALTY INLET...AND
PUGET SOUND. THESE SHOULD LAST INTO THE EARLY AFTERNOON AT MOST
BECAUSE WINDS SHOULD BE TURNING SOUTHERLY AS SYSTEM OFFSHORE SPINS
UP. HAVE ALSO HOISTED SMALL CRAFT ADVISORY ON THE COAST FOR THESE
SOUTHERLIES LATER THIS MORNING. LATER TONIGHT THE SOUTHERLIES ON THE
COAST AND AT THE WEST ENTRANCE COULD BECOME GALES AND HAVE PUT UP A
GALE WATCH.

THIS GALE SHOULD BE OVER THURSDAY AFTERNOON AS WINDS TURN WESTERLY.
HOWEVER ANOTHER STRONG SYSTEM MOVES IN FRIDAY AFTERNOON AND THIS
SHOULD BRING RENEWED GALES. HIGH PRESSURE REBUILDS QUICKLY OVER THE
WEEKEND AND BOTH SUNDAY AND MONDAY HAVE OFFSHORE SURFACE FLOW. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY IN EFFECT FOR THE COASTAL WATERS...THE WEST
     ENTRANCE TO THE STRAIT OF JUAN DE FUCA...ADMIRALTY INLET...AND
     PUGET SOUND/HOOD CANAL.

     GALE WATCH IN EFFECT FOR THIS EVENING THRU THU AFTERNOON FOR
     THE COASTAL WATERS AND WEST ENTRANCE TO THE STRAIT OF JUAN DE
     FUCA.

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