Gale Watch 29, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 AM PDT SAT JUN 30 2012

.SYNOPSIS...AN UPPER LEVEL TROUGH WILL BRING SHOWERS TO WESTERN
WASHINGTON TODAY. ONSHORE FLOW WILL INCREASE TONIGHT WITH CLOUDY AND
COOLER CONDITIONS FORECAST FOR SUNDAY. ANOTHER UPPER LEVEL TROUGH
WILL BRING A FEW SHOWERS TO THE REGION MONDAY NIGHT AND TUESDAY.
DRIER WEATHER IS FORECAST FROM INDEPENDENCE DAY THROUGH THE END OF
THE WEEK. TEMPERATURES WILL REMAIN CLOSE TO NORMAL.

&&

.SHORT TERM...RADAR SHOWS SCATTERED SHOWERS...MORE NUMEROUS NORTH
PART. NEW NAM HAS A FAIR AMOUNT OF INSTABILITY THIS AFTERNOON OVER
MOST OF WESTERN WASHINGTON...FROM THE OLYMPICS TO THE CASCADES. THE
GFS LIMITS INSTABILITY TO THE CASCADES AND PERHAPS THE SOUTHWEST
INTERIOR. THE CURRENT FORECAST HAS A CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS IN THE CASCADES. WILL MONITOR IN CASE EXPANSION OF
THUNDERSTORM AREA IS WARRANTED. OTHERWISE A PUGET SOUND CONVERGENCE
ZONE IS LIKELY TO FORM OVER THE NORTH KING AND SNOHOMISH COUNTY AREA
AND KEEP SHOWERS MORE ACTIVE THERE. THIS WILL LAST INTO TONIGHT.

CLOUD COVER EXTENDS FAR OFFSHORE AND WITH INCREASING ONSHORE FLOW
TONIGHT AND SUNDAY...THERE MAY NOT BE MUCH CLEARING SUNDAY
AFTERNOON. GUIDANCE IS NOW DELAYING THE CLEARING UNTIL SUNDAY NIGHT.
THE NEXT SYSTEM IS A TAD FASTER ON MONDAY...MEANING THERE WILL
LIKELY BE INCREASING CLOUDS MONDAY AFTERNOON WITH RAIN DEVELOPING ON
THE COAST LATE. ALL IN ALL THE NEXT THREE DAYS WILL BE A CLOUDY
PERIOD WITH HIGHS MAINLY IN THE 60S...SEVERAL DEGREES BELOW
CLIMATOLOGY. BURKE

.LONG TERM...PREVIOUS DISCUSSION...AT THIS POINT THE WEATHER FOR THE
4TH IS LOOKING MAINLY DRY ACROSS WESTERN WA. MODELS DO SHOW
TROUGHING OVER THE PAC NW BUT THE DYNAMICS ARE PRETTY WEAK. WE STILL
HAVE LOW-END POPS /20S/ FOR THE AREA BUT MAY WIPE THESE OUT IF
MODELS HOLD ONTO THIS TREND. HOWEVER THE LOW LEVEL FLOW IS ONSHORE
SO WE WILL SEE SOME CLOUDS...PARTY SUNNY TO MOSTLY CLOUDY
CONDITIONS. FORECAST TEMPS ARE CLOSE TO NORMAL.

OTHERWISE THE REST OF THE FORECAST PERIOD IS RATHER BENIGN - NOTHING
ORGANIZED COMING OUR WAY. DRY WEATHER AND SEASONAL TEMPS THROUGH
NEXT WEEKEND IF THIS PATTERN HOLDS. 33

&&

.AVIATION...UPPER LEVEL TROUGH CURRENTLY OFF THE PAC NW COAST WILL
SLOWLY SHIFT ACROSS THE AREA LATER TODAY AND TONIGHT. LIGHT SW FLOW
ALOFT WITH ABUNDANT MOISTURE AT ALL LEVELS AND SHOWERS THROUGH THE
DAY. MAINLY STABLE THIS MORNING BECOMING WEAKLY UNSTABLE THIS
AFTERNOON. THUNDERSTORMS NOT EXPECTED.

CIGS WILL REMAIN WIDESPREAD MVFR...2-4K FT CIGS WITH VIS 3-5SM
THROUGH 18Z. THERE WILL ALSO BE POCKETS OF IFR CIGS/VIS...ESPECIALLY
ALONG THE COAST...SW INTERIOR...AND NEAR PUGET SOUND. EXPECT
IMPROVEMENT TO VFR CONDITIONS THIS AFTERNOON BEFORE A RETURN TO MVFR
OVERNIGHT.

KSEA...MVFR CIGS 3-4K FT W/ VIS 3-5 SM WILL PREVAIL THROUGH
18Z...BEFORE GRADUAL LIFTING OF BASES AND VFR CIGS 19-20Z. NUMEROUS
SHOWERS THROUGH THE DAY WITH CONDITIONS LOWERING AGAIN TONIGHT TO
MVFR THROUGH MID MORNING SUNDAY.

&&

.MARINE...LIGHT GRADIENTS THIS MORNING WITH WINDS BELOW 15 KT
THROUGH MOST WATERS. EXPECT ONSHORE GRADIENTS TO INCREASE THROUGH
THE STRAIT AS THE FRONTAL SYSTEM WILL MOVE INTO WRN WA EARLY THIS
EVENING. HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE CENTRAL/E STRAIT
LATE THIS AFTERNOON THROUGH TONIGHT. A REPEAT IS LIKELY SUNDAY AS
WELL...WITH SOME POTENTIAL FOR GALE STRENGTH WINDS SAME AREAS. HAVE
ISSUED A GALE WATCH FROM SUNDAY MORNING THROUGH EARLY MONDAY MORNING
FOR THE CENTRAL AND EAST STRAIT. ELSEWHERE...W/NW WINDS OVER THE
COASTAL WATERS/W STRAIT MAY APPROACH 20 KT AT TIMES DURING THE
AFTERNOON HOURS BUT SMALL CRAFT WINDS NOT LIKELY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EAST STRAIT JUAN DE FUCA
    THIS AFTERNOON THROUGH TONIGHT.

    GALE WATCH CENTRAL AND EAST STRAIT JUAN DE FUCA SUNDAY
    MORNING THROUGH EARLY MONDAY MORNING.

&&

YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.

WWW.WEATHER.GOV/SEATTLE