Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 202236 AAA
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
315 PM PDT FRI MAR 20 2015

ADDED GALE WARNING TO NORTHERN INLAND WATERS.

.SYNOPSIS...A COLD FRONT WILL MOVE INLAND TONIGHT BRINGING RAIN AND
LOCALLY BREEZY WEATHER. AN UPPER LEVEL TROUGH WILL FOLLOW THE FRONT
ON SATURDAY FOR SHOWERS AND A PUGET SOUND CONVERGENCE ZONE. ANOTHER
COLD FRONT WILL SPREAD RAIN INLAND SUNDAY AFTERNOON...FOLLOWED BY
ANOTHER UPPER LEVEL TROUGH AND SHOWERS ON MONDAY. A GENERALLY WET
WEATHER PATTERN WILL CONTINUE OVER THE AREA THROUGH MID NEXT WEEK.

&&

.SHORT TERM...A PACIFIC FRONT HAS MOVED SLOWLY INLAND TODAY WITH
RAIN SPREADING OVER MOST AREAS BY EARLY AFTERNOON. THERE ARE SOME
BREEZY CONDITIONS ASSOCIATED WITH THE FRONT. MODELS HAVE RAIN
TAPERING AFTER 06Z TONIGHT WITH SHOWERS CONTINUING SATURDAY...
ESPECIALLY IN A PUGET SOUND CONVERGENCE ZONE. HIGH TEMPERATURES WILL
BE A FEW DEGREES LOWER ON SATURDAY THAN TODAY. THE SNOW LEVEL IN THE
MOUNTAINS WILL FALL TO AROUND 4500 FEET AFTER THE FRONT PASSES...
WHICH COUNTS AS WINTRY THIS YEAR.

SHOWERS WILL TAPER SATURDAY EVENING AND SUNDAY MORNING LOOKS DRY.
ANOTHER SYSTEM WILL ARRIVE FROM THE SOUTHWEST AND SPREAD RAIN INTO
THE AREA SUNDAY AFTERNOON. ANOTHER IMPULSE ARRIVES MONDAY AFTERNOON
FOR ANOTHER ROUND OF HIGH POPS. HIGHS ON SUNDAY WILL BE 55-60 BUT
THINGS WILL COOL A BIT ON MONDAY AS HEIGHTS FALL. HIGHS MONDAY ARE
FORECAST TO BE AROUND 55 AND THE SNOW LEVEL WILL FALL TO 4000 FEET
OR SO. BURKE

.LONG TERM...SHOWERS ARE LIKELY TUESDAY AS AN UPPER TROUGH PASSES.
THE SNOW LEVEL WILL FALL TO AS LOW AS 3000 FEET ON TUESDAY WHICH
MEANS THERE COULD BE SNOW IN SNOQUALMIE PASS FOR AWHILE. AN UPPER
RIDGE BUILDS OFF THE COAST WEDNESDAY THOUGH THE GFS KEEPS SOME
MYSTERY RAIN GOING...EVEN IN THE RIDGE AXIS. THE EURO IS DRIER AND
THIS SEEMS MORE LIKELY. FOR NOW HAVE KEPT CHANCE POPS FOR WEDNESDAY
WITH LIKELY POPS OVER WESTERN SECTIONS.

ON THURSDAY THE MODELS ARE STILL IN AGREEMENT ABOUT THE RIDGE THOUGH
THEY DIFFER IN THE QPF DETAILS. HAVE CHANCE POPS FOR THURSDAY. NEXT
FRIDAY THE GFS BRINGS A STRONG SYSTEM INLAND WHILE THE EURO DAMPENS
IT CONSIDERABLY. HAVE CHANCE POPS INLAND WITH LIKELY POPS COAST FOR
FRIDAY. BURKE

&&

.HYDROLOGY...FLOODING IS UNLIKELY OVER THE NEXT 7 DAYS. BURKE

&&

.AVIATION...THE AIR MASS IS MOIST AND STABLE WITH SW FLOW ALOFT.
LATE SATURDAY MORNING...THE FLOW ALOFT WILL SWITCH TO WLY AND THE
AIR MASS WILL BECOME MORE UNSTABLE.

A FRONTAL SYSTEM IS SLOWLY MOVING THROUGH WESTERN WASHINGTON AND THE
FRONTAL PASSAGE WILL OCCUR TONIGHT. RAIN IS MOVING INTO THE AREA AND
WILL AFFECT MOST OF THE TERMINALS THIS EVENING BEFORE TAPERING OFF
INTO SHOWERS OVERNIGHT.

KSEA...SURFACE WIND WILL REMAIN LIGHT AND VARIABLE OR SLY THROUGH
THE PERIOD. RAIN WILL CONTINUE TO AFFECT THE TERMINAL THIS EVENING
AND SHOWERS WILL LIKELY AFFECT THE TERMINAL OVERNIGHT. JSMITH

&&

.MARINE...A COLD FRONT OFFSHORE IS MOVING TOWARDS THE WASHINGTON
COAST. IT PASSED BUOY 206 JUST BEFORE 21Z AND WILL LIKELY AFFECT THE
NORTH COAST AROUND 3Z AND THE GRAYS HARBOR AREA AROUND 5Z TONIGHT.
WITH THE PASSAGE OF THE FRONT...THE WIND DIRECTION WILL CHANGE FROM
SLY TO WLY OR NWLY AND WEAKEN. A GALE WARNING HAS BEEN ISSUED FOR
THE COASTAL WATERS AS WELL AS SOME INLAND WATERS WITH LONG SLY
FETCHES.

ANOTHER FRONT WILL REACH THE AREA AROUND SUNDAY NIGHT AND UNSTABLE
AIR BEHIND IT WILL AFFECT THE WATERS ON MONDAY. JSMITH

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING COAST...EAST ENTRANCE...ADMIRALTY INLET...AND
     NORTHERN INLAND WATERS.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.

&&

$$

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