Small Craft Advisory 664, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST THU MAR 10 2011

.SYNOPSIS...A LOW PRES TROUGH WILL MOVE EAST OF THE CASCADES BY
MIDNIGHT ALLOWING WINDS TO SLOWLY SUBSIDE ACROSS WESTERN WASHINGTON.
A BRIEF BREAK IN THE ACTION ON FRIDAY AS THE NEXT SYSTEM TO MOVE
INTO THE AREA STALLS OFFSHORE. THE PARADE OF STORMS MOVING INTO
WESTERN WASHINGTON WILL CONTINUE FRIDAY NIGHT INTO SATURDAY WITH THE
NEXT SYSTEM ARRIVING AT THAT TIME. MORE FRONTS WILL MOVE THROUGH THE
AREA APPROXIMATELY 24 HOURS APART THROUGH THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM...THE TROUGH AND BENT BACK OCCLUSION SWEPT INTO WRN WA
THIS AFTERNOON USHERING IN SOME VERY WINDY CONDITIONS ACROSS MOST
THE AREA WITH STRONG PRES RISES INTO THE EARLY EVENING HOURS. THE
LATEST PRES TENDENCIES INDICATE GRADIENTS ARE COMING DOWN AFTER
PEAKING AT OVER +7MB KOLM-KBLI AND OVER +12MB KBLI-KPDX A COUPLE
HOURS AGO. AS GRADIENTS COME DOWN SLOWLY SO WILL THE WINDS WITH THIS
TREND BECOMING MORE EVIDENT OVER THE PAST COUPLE HOURS. MOST SITES
ARE BLOWING WITHIN ADVISORY LEVEL 20-35 MPH...WHICH WILL CONTINUE TO
EASE OVER THE NEXT FEW HOURS. DECIDED TO END THE HIGH WIND WARNING
AND CONTINUE AN ADVISORY FOR THE INTERIOR LOWLANDS THROUGH MIDNIGHT
AS WINDS GRADUALLY EASE.

SNOW CONTINUES TO FALL IN THE MOUNTAIN AREAS...WITH SNOW LEVELS DOWN
AS LOW AS 2000 FEET BEHIND THE FRONT THIS EVENING. SNOW HAS BEEN
PILING UP BUT AMOUNTS SO FAR VARY QUITE A BIT. A CONVERGENCE ZONE
HAS FORMED UP ACROSS SRN SNOHOMISH COUNTY...WITH 2 INCH AN HOUR
SNOWFALL RATES IN STEVENS PASS THE PAST 2-3 HOURS. WILL NEED TO
WATCH THIS CLOSELY BUT IN GENERAL...MODELS SHOW PRECIP AMOUNTS OVER
THE MOUNTAINS COMING WAY DOWN AFTER MIDNIGHT TONIGHT. SOME SPOTS
COULD PUSH WARNING CRITERIA BUT THE HEAVIEST SNOW HAS ALREADY FALLEN
AND SHOULD LIGHTEN UP OVERNIGHT. WILL LEAVE THE ADVISORY IN PLACE.

A WEAK WARM FRONT WILL LIFT ACROSS THE AREA ON FRIDAY AHEAD OF THE
NEXT TROUGH DEVELOPING WELL OFFSHORE. MODELS ONLY GENERATE SPOTTY
LIGHT QPF SO THE CHANCE CATEGORY MAY BE APPROPRIATE. HOWEVER...THE
GFS/NAM BOTH INDICATE CLOUDY SKIES FRIDAY SO THE PARTLY SUNNY SKIES
WORDING MAY BE OPTIMISTIC. THE ASSOCIATED COLD FRONT SWEEPS INTO WRN
WA FRIDAY NIGHT AND SATURDAY WITH ANOTHER ROUND OF WIDESPREAD RAIN
FOR THE AREA. THIS SYSTEM LOOKS WET AND WINDY WITH A RENEWED FLOOD
THREAT POSSIBLE ON SOME RIVERS...AND ESPECIALLY WINDY ALONG THE
COAST AND N INTERIOR. AN EVEN STRONGER SYSTEM IS ON TAP TO AFFECT
THE AREA SUNDAY.  MERCER

.LONG TERM...MORE OF THE SAME IN STORE FOR WESTERN WASHINGTON NEXT
WEEK AS THE FASHIONABLY LATE LA NINA WEATHER CONTINUES. UNTIL MID
WEEK. THE MODELS ARE STARTING TO SHOW THE PATTERN FINALLY BREAKING
DOWN NEXT FRIDAY. UNTIL THEN A SERIES OF FRONTS WILL MOVE THROUGH
WESTERN WASHINGTON ABOUT 24 HOURS OR SO APART. THE MODELS HAVE SOME
DIFFERENCES ON THE TIMING AND INTENSITY OF THE FRONTS SO THE BROAD
BRUSH RAIN LIKELY IN THE EXTENDED WILL CONTINUE. FELTON

&&

.HYDROLOGY...RECENT HEAVY RAIN WILL CAUSE SOME RIVERS IN THE
CHEHALIS BASIN TO REACH FLOOD STAGE OR NEAR FLOOD STAGE AND A WATCH
REMAINS IN EFFECT FOR GRAYS HARBOR...LEWIS...AND THURSTON COUNTIES.
FLOOD WARNINGS ARE CURRENTLY IN PLACE FOR SEVERAL RIVERS...SEE THE
LATEST FLOOD STATEMENTS FOR DETAILS ON INDIVIDUAL RIVERS. NO
FLOODING ON THE GREEN RIVER IS EXPECTED. DTM

STORMS WILL CONTINUE MOVING INTO WESTERN WASHINGTON THROUGH THE
MIDDLE OF NEXT WEEK BUT WITH THE PROGRESSIVE NATURE OF THE FRONTS
AND THE 24 HOURS OR SO BREAKS BETWEEN SYSTEMS ADDITIONAL FLOODING IS
NOT LIKELY ON MOST WESTERN WASHINGTON RIVERS IN THE NEXT TEN DAYS
INCLUDING THE GREEN RIVER. THE SKOKOMISH RIVER COULD FLOOD AGAIN
DURING THIS TIME FRAME AS THE PRECIPITATION ADDS UP OVER THE SOUTH
SLOPES OF THE OLYMPICS. FELTON

&&

.AVIATION...THE DEEP LOW BRINGING STRONG WINDS TO THE AREA THIS
EVENING IS OVER CENTRAL BRITISH COLUMBIA AND IS MOVING AWAY AND
WEAKENING. EXPECT WINDS TO DIMINISH RAPIDLY FROM SOUTH TO NORTH
AFTER ABOUT 06Z. FROM LATER TONIGHT THROUGH FRIDAY AFTERNOON EXPECT
VFR CONDITIONS TO PREVAIL WITH SCATTERED SHOWERS CONFINED TO THE
TERRAIN AND A PUGET SOUND CONVERGENCE ZONE THAT WILL DRIFT NORTH OF
EVERETT. THE CONVERGENCE ZONE WILL DIE OUT DURING THE EARLY MORNING
HOURS AS A BRIEF AND WEAK RIDGE OF HIGH PRES MOVES ACROSS THE AREA.

THE NEXT FRONTAL SYSTEM WILL APPROACH THE AREA FROM THE WEST LATER
FRI AFTERNOON AND FRI NIGHT. EXPECT MID TO HIGH CLOUDS THROUGH FRI
AFTERNOON WITH THE RAIN SHIELD ASSOCIATED WITH THE FRONT MOVING ONTO
THE COAST ABOUT 00Z AND INTO THE INTERIOR VALLEYS AROUND 06Z.

KSEA...STRONG SW WINDS WILL RAPIDLY DIMINISH 06Z-08Z. BY 12Z EXPECT
S WIND 10 KT THAT WILL CONTINUE THROUGH FRI AFTERNOON THEN BACK TO
SELY FRI EVENING. EXPECT VFR CIGS AND VISIBILITIES WITH CEILINGS
AROUND 050. ALBRECHT

&&

.MARINE...THE DEEP LOW BRINGING GALES TO THE AREA THIS EVENING IS
OVER CENTRAL BRITISH COLUMBIA AND IS MOVING AWAY AND WEAKENING.
EXPECT WINDS TO RAPIDLY DIMINISH BY MIDNIGHT TONIGHT.

THE NEXT APPROACHING FRONT WILL MOVE SLOWLY E THROUGH THE WATERS FRI
NIGHT. GALES ASSOCIATED WITH THIS FRONT WILL LIKELY DEVELOP ON THE
COASTAL WATERS DURING THE AFTERNOON HOURS AND SPREAD INTO THE
ENTRANCES TO THE STRAIT AND NORTHERN INLAND WATERS FRI EVENING.

FRIDAY NIGHTS FRONT WILL BE FOLLOWED BY AN EVEN STRONGER ONE LATER
SUNDAY. GALES MAY OCCUR OVER MOST OF THE WATERS WITH THIS FRONT.

ALL THIS WILL BE FOLLOWED BY A SERIES OF RATHER STRONG FRONTS EVERY
24-30 HOURS THROUGH EARLY NEXT WEEK.  EACH OF THE SYSTEMS WILL BRING
THE POTENTIAL FOR GALE FORCE WINDS ESPECIALLY ALONG THE COAST...THE
ENTRANCES TO THE STRAIT...AND THE NORTHERN INLAND WATERS.  ELSEWHERE
SMALL CRAFT ADVISORY CONDITIONS WILL DOMINATE OVER THE NEXT SEVERAL
DAYS.  ALBRECHT

&&

.AVALANCHE...10 TO 20 INCHES OR MORE NEW SNOW AT WARMING
TEMPERATURES AND VERY STRONG WINDS HAVE CAUSED AN INCREASED
AVALANCHE DANGER THURSDAY. AN AVALANCHE WARNING REMAINS IN EFFECT
FOR THE WEST SLOPE CASCADES, OLYMPICS AND MT HOOD TODAY. NUMEROUS
NATURAL AVALANCHES WERE REPORTED TO HAVE RELEASED OVERNIGHT OR EARLY
THIS MORNING. BETTER TO STAY IN WELL TREE COVERED AND LOW ANGLED
TERRAIN TODAY...OR A SKI AREA! SEE HTTP://NWAC.US FOR DETAILS.
KRAMER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WIND ADVISORY IS IN EFFECT FOR THE INTERIOR LOWLANDS OF
     WESTERN WASHINGTON UNTIL MIDNIGHT TONIGHT.
    .WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE OLYMPICS
     AND CASCADES ABOVE 3500 FEET TIL 4 AM FRI.
    .FLOOD WARNINGS/WATCHES ARE IN EFFECT FOR PORTIONS OF WESTERN
     WASHINGTON...SEE THE LATEST FLOOD STATEMENTS FOR DETAILS.

PZ...GALE WARNING ALL WATERS UNTIL MIDNIGHT TONIGHT.
    .SMALL CRAFT ADVISORY GRAYS HARBOR BAR.
    .SMALL CRAFT ADVISORY COAST...STRAIT...NORTHERN INLAND WATERS
     AND ADMIRALTY INLET MIDNIGHT TONIGHT THROUGH FRIDAY AFTERNOON.
    .GALE WATCH COAST...ENTRANCES TO THE STRAIT...NORTHERN INLAND
     WATERS...ADMIRALTY INLET FRIDAY AFTERNOON THROUGH MIDDAY
     SATURDAY.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
312 PM PST THU MAR 10 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0312 PM     NON-TSTM WND GST 1 NNE NORTH BEND        47.51N 121.78W
03/10/2011  M60 MPH          KING               WA   TRAINED SPOTTER

&&

GRUB