Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 022331 CCA
AFDSEW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SEATTLE WA
430 PM PDT TUE SEP 2 2014

CORRECTED SYNOPSIS.

.SYNOPSIS...A FRONTAL SYSTEM WILL BRING SHOWERS TO WESTERN
WASHINGTON THIS EVENING. HIGH PRESSURE WILL PRODUCE SUNSHINE AND
WARMER WEATHER FOR THE REMAINDER OF THE WEEK.

&&

.SHORT TERM...AN UPPER SHORT WAVE WILL MOVE ONSHORE THIS EVENING
WITH DECREASING SHOWERS. THE COMBINATION OF FAIRLY STRONG DYNAMICS
RIGHT ALONG THE FRONT AND INSTABILITY WILL MEAN A FEW LIGHTNING
STRIKES ARE POSSIBLE OVER THE NORTH INTERIOR FOR THE NEXT COUPLE OF
HOURS.

SHOWERS WILL BECOME MOSTLY CONFINED TO THE CASCADES AND A PUGET
SOUND CONVERGENCE ZONE BY SUNSET AS THE SYSTEM QUICKLY MOVES INLAND.
A FEW SHOWERS WILL LINGER OVER THE CASCADES INTO WEDNESDAY MORNING.
OTHERWISE...WEDNESDAY WILL BE DRY WITH DECREASING CLOUDS AS DRIER
NORTHERLY FLOW ALOFT DEVELOPS.

HIGH PRESSURE ALOFT WILL BE IN CONTROL THURSDAY AND FRIDAY
WITH LOW LEVEL OFFSHORE FLOW DEVELOPING. THIS WILL GIVE SUNNY
WEATHER WITH HIGHS WARMING 3-5 DEGREES THURSDAY AND AGAIN FRIDAY.
SCHNEIDER

.LONG TERM...SATURDAY LOOKS LIKE THE WARMEST DAY THIS WEEK WITH HIGH
PRESSURE ALOFT AND LOW LEVEL OFFSHORE FLOW...AND PERHAPS THE LAST
REALLY WARM DAY OF THE SUMMER...WITH HIGHS IN THE LOWER TO MID 80S
COMMON.

AN UPPER TROUGH WILL BEGIN TO MOVE OVER THE AREA ON SUNDAY. FOR
NOW...THIS FEATURE LOOKS DRY. THE MAIN IMPACT WILL BE TO INCREASE
THE LOW LEVEL ONSHORE FLOW AND TO START A COOLING TREND. THERE WILL
PROBABLY BE SOME LOW CLOUDS AT THE COAST BUT THE INTERIOR LOOKS LIKE
IT WILL GET ONE MORE MOSTLY SUNNY DAY WITH HIGHS COOLING 5-10
DEGREES.

THE UPPER TROUGH WILL DRAG ACROSS THE AREA SUNDAY NIGHT AND MONDAY.
NO ORGANIZED SYSTEMS ARE EXPECTED BUT A CHANCE OF SHOWERS CANNOT BE
RULED OUT. SLIGHTLY DRIER NORTHWEST FLOW ALOFT WILL PREVAIL TUESDAY
BUT THERE WILL STILL BE A SMALL THREAT OF SHOWERS. TEMPERATURES BOTH
DAYS WILL BE NEAR NORMAL. SCHNEIDER

&&

.AVIATION...FLOW ALOFT WILL REMAIN WESTERLY THIS EVENING AS AN UPPER
LEVEL TROUGH APPROACHES THE AREA FROM THE NORTH...THEN BECOME
NORTHWESTERLY LATE TONIGHT AS THE TROUGH MOVES INTO EASTERN OREGON.
THE ASSOCIATED COLD FRONT IS CURRENTLY MOVING THROUGH THE CENTRAL
STRAIT OF JUAN DE FUCA AS OF 22Z. EXPECT RAIN AND SHOWERS ASSOCIATED
WITH THE FRONT TO CONTINUE TO SPREAD INTO THE INTERIOR THROUGH THE
REMAINDER OF THE AFTERNOON AS THE FRONT WORKS ITS WAY INLAND. THE
ATMOSPHERE IS MOIST AND WILL BECOME UNSTABLE WITH AND BEHIND THE
FRONT. THERE HAVE BEEN A FEW LIGHTNING STRIKES ASSOCIATED WITH THE
FRONT OVER THE CENTRAL STRAIT...WHILE MORE CANNOT BE RULED OUT
ESPECIALLY UP NORTH...DO NOT EXPECT MUCH THREAT OF THUNDERSTORMS
WITH THIS SYSTEM.

CEILINGS OVER THE AREA REMAIN VFR WITH MVFR MAINLY ASSOCIATED WITH
HEAVIER RAIN SHOWERS. EXPECT CONDITIONS TO REMAIN GENERALLY VFR THIS
EVENING...EXCEPT MVFR CONDITIONS WITH SHOWERS. INCREASING SOUTHERLY
WINDS OVER THE INTERIOR THIS AFTERNOON AHEAD OF THE FRONT WILL EASE
THIS EVENING AND BE FOLLOWED BY WESTERLY TO NORTHWESTERLY LOW LEVEL
FLOW OVER THE EAST STRAIT THROUGH THE NORTH PUGET SOUND AREA. EXPECT
THE RESULTING LOW LEVEL CONVERGENCE TO PRODUCE A PSCZ KING
COUNTY...REMAINING NORTH OF KSEA. THE TRAILING UPPER LEVEL TROUGH
WILL KEEP SHOWERS OVER THE INTERIOR AND CASCADES BEHIND THE FRONT
TONIGHT...GENERALLY WINDING DOWN AFTER MIDNIGHT.

KSEA...VFR CONDITIONS WITH SHOWERS IN THE AREA. CEILINGS MAY LOWER
TO MVFR LEVELS WITH THE FRONT...BUT WILL REMAIN VFR THROUGH THE
EVENING. GUSTY SOUTHERLY WINDS 8 TO 10 KT WILL EASE THROUGH THE
EVENING. EXPECT A PSCZ TO FORM AND REMAIN TO THE NORTH OF THE
TERMINAL THIS EVENING.

&&

.MARINE...ONSHORE FLOW WILL INCREASE THIS EVENING. GALE FORCE WINDS
ARE EXPECTED THROUGH THE CENTRAL AND EAST STRAIT OF JUAN DE FUCA
TONIGHT...ONSHORE FLOW WILL EASE SOMEWHAT LATE TONIGHT. SMALL CRAFT
NORTHWESTERLIES WILL PERSIST OVER THE OUTER COASTAL WATERS INTO
WEDNESDAY EVENING. HIGH PRES OVER THE NE PAC WILL MAINTAIN ONSHORE
FLOW THROUGH WEDNESDAY. NORTHERLY FLOW WILL PREVAIL THU AND FRI AS
LOW PRES FORMS ALONG THE COAST.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING CENTRAL AND EAST STRAIT OF JUAN DE FUCA.
    .SMALL CRAFT ADVISORY COASTAL WATERS...WESTERN STRAIT...
     NORTHERN INLAND WATERS...AND ADMIRALTY INLET.

&&

$$

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