Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 211535
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
830 AM PDT MON JUL 21 2014

.SYNOPSIS...SKIES WILL CLEAR TODAY GIVING MOSTLY SUNNY CONDITIONS.
AN UPPER LEVEL LOW WILL APPROACH TUESDAY AND MOVE THROUGH THE AREA
WEDNESDAY. CLOUDS WILL INCREASE TUESDAY AND SHOWERS ARE LIKELY
WEDNESDAY. HIGH PRESSURE WILL BUILD OVER THE AREA LATE IN THE WEEK
AND INTO THE WEEKEND FOR SUNNIER AND WARMER WEATHER.

&&

.SHORT TERM...SATELLITE IMAGERY SHOWS LARGE CLEAR AREAS AND THE
REMAINING CLOUDY AREAS SHOULD CLEAR RAPIDLY. KATX RADAR IS STILL
DOWN BUT A FEW RAIN GAUGES AROUND HOOD CANAL AND THE EASTERN
OLYMPICS HAVE SHOWN A FEW HUNDREDTHS OF RAIN IN THE PAST SEVERAL
HOURS. HAVE CUT BACK THE SHOWER CHANCE THIS MORNING TO JUST THAT
SMALL AREA AND DRIED AND CLEARED OTHER REGIONS. ZONES AND GRIDS ARE
ALREADY UPDATED. TODAY WILL BE MOSTLY SUNNY WITH HIGHS IN THE 70S.

SOUTHERLY FLOW ALOFT WILL INCREASE TUESDAY AS AN UPPER LEVEL LOW
OFFSHORE APPROACHES THE COAST. CLOUDS WILL INCREASE TUESDAY AND
THERE IS A CHANCE OF SHOWERS IN THE AFTERNOON. THIS CHANCE CONTINUES
TUESDAY NIGHT AND BY WEDNESDAY...AS THE UPPER LEVEL LOW MOVES ONTO
THE COAST AND THEN INLAND...SHOWERS ARE LIKELY. CURRENT FORECAST OF
A SLIGHT CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS WEDNESDAY
AFTERNOON AND EVENING SEEMS A BIT UNDERDONE. LIFTED INDICES ARE
NEGATIVE OVER ALL OF WESTERN WASHINGTON DURING THIS PERIOD. MAY MAKE
SOME CHANGES IN THE AFTERNOON PACKAGE.

ON THURSDAY RESIDUAL SHOWERS WILL TAPER AS THE UPPER LEVEL LOW MOVES
OFF TO THE EAST. SHOULD BE SOME WARMING AND CLEARING. BURKE

.LONG TERM...PREVIOUS DISCUSSION...THE UPPER LOW WILL MOVE NORTHEAST
INTO ALBERTA ON THURSDAY...AND AN UPPER RIDGE WILL BEGIN TO BUILD
OFFSHORE. LINGERING SHOWERS AND CLOUDY SKIES ON THURSDAY MORNING
WILL GIVE WAY TO A PARTLY TO MOSTLY SUNNY AFTERNOON. THE GFS40 AND
ECMWF HAVE BEEN RATHER CONSISTENT WITH THE UPPER RIDGE BUILDING INTO
THE AREA TOWARDS THE END OF THE WEEK AND INTO THE WEEKEND. SUNNY AND
WARM DAYS TOWARDS THE END OF THE WEEK ARE A GOOD BET. JSMITH

&&

.AVIATION...UPPER LEVEL TROUGH WELL OFFSHORE DIGGING SOUTH TODAY
WITH THE FLOW ALOFT BECOMING SOUTHWESTERLY BY MID AFTERNOON TODAY.
AT THE SURFACE...HIGH PRESSURE WILL BE OFFSHORE WITH LOWER PRESSURE
INLAND. AIR MASS MOIST AND STABLE... WITH DRYING THIS AFTERNOON.

CURRENT SATELLITE IMAGERY COUPLED WITH A LOOK OUT THE WINDOW SHOWS
CLOUDS STARTING TO BREAK UP. LOOKING AT OBSERVATIONS AROUND THE
AREA...CIGS STARTING TO LIFT WITH MUCH OF WESTERN WASHINGTON SEEING
CIGS IN THE VFR RANGE...ALTHOUGH COASTAL LOCATIONS AS WELL AREAS
NEAR THE SOUTHWESTERN PORTION OF PUGET SOUND ARE STILL UNDER MVFR
CIGS. SKIES ARE EXPECTED TO CONTINUE TO IMPROVE...WITH SCT CLOUDS
EXPECTED BY AFTERNOON OVER MOST LOCATIONS. CIGS WILL START TO LOWER
AGAIN DURING THE OVERNIGHT HOURS...BUT STILL EXPECTED TO BE WITHIN
VFR OR HIGH-END MVFR.

KSEA...CIGS AROUND 3000 FEET NOW...EXPECTED TO CONTINUE IMPROVING AS
MORNING MORNING PROGRESSES. CLOUDS STILL EXPECTED TO SCATTER OUT BY
MID AFTERNOON. VARIABLE WINDS LESS THAN 6 KNOTS BECOMING
SOUTHWESTERLY AROUND NOON TODAY...THEN SHIFTING TO THE NORTHWEST
5-10 KNOTS LATE THIS AFTERNOON. FELTON/SMR

&&

.MARINE...HIGH PRESSURE WILL BE OFFSHORE WITH LOWER PRESSURE INLAND
FOR THE NEXT SEVERAL DAYS...RESULTING IN VARYING DEGREES OF ONSHORE
FLOW. THE EXCEPTION TO THIS WILL BE TUESDAY NIGHT WHEN A WEAK
SURFACE LOW MOVES INTO THE COASTAL WATERS WEAKENING THE ONSHORE FLOW
FOR A SHORT TIME. THIS PATTERN WILL GENERALLY PRODUCE SMALL CRAFT
ADVISORY WEST WINDS FOR THE CENTRAL AND EASTERN STRAIT OF JUAN DE
FUCA EACH EVENING INTO THE EARLY MORNING HOURS WITH THE EXCEPTION OF
TUESDAY EVENING AND EARLY WEDNESDAY MORNING. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.

&&

$$

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





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