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000
FXUS66 KSEW 252215
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
315 PM PDT SAT MAY 25 2013

.SYNOPSIS...LOW PRESSURE ALOFT WILL REMAIN OVER THE REGION THROUGH
THE MIDDLE OF THE UPCOMING WEEK. THIS WILL KEEP THE WEATHER PATTERN
UNSETTLED OVER THE AREA. DAYTIME TEMPERATURES ARE EXPECTED TO RUN
BELOW NORMAL.

&&

.SHORT TERM...
PRECIP AMOUNTS OVER THE WESTERN PART OF THE FORECAST AREA ENDED UP A
LITTLE HIGHER THAN PREDICTED...WITH A FEW GAUGES ON THE OLYMPIC
PENINSULA RECEIVING CLOSE TO A HALF INCH OF RAIN DURING THE 12-HOUR
PERIOD ENDING AT 3 PM PDT. UP TO A QUARTER OF AN INCH IS EXPECTED
OVER THE FAR SOUTHWEST OVERNIGHT.

NO MAJOR CHANGES IN THE OVERALL PATTERN IS ANTICIPATED DURING THIS
PERIOD. THE UPPER LOW PRESENTLY OVER THE REGION WILL WEAKEN WITH
TIME AND WILL EXIT THE AREA BY MEMORIAL DAY. ALAS...ANOTHER LOW
PRESSURE SYSTEM WILL QUICKLY FOLLOW ON ITS HEELS DURING MEMORIAL
DAY. THIS SYSTEM WILL LINGER OVER THE REGION THROUGH TUE. EXPECT
UNSETTLED CONDITIONS TO PERSIST AND DAYTIME TEMPS WILL CONTINUE TO
RUN BELOW NORMAL. THE MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL
BE THE TIMING AND LOCATION OF THE MAIN PRECIP BANDS.

.LONG TERM...
THIS PERIOD WILL START OFF UNSETTLED DUE TO AN UPPER TROF REMAINING
OVER THE PACIFIC NORTHWEST. HOWEVER...BY THE END OF THE PERIOD...THE
MEDIUM RANGE MODELS WERE GENERALLY IN AGREEMENT THAT HEIGHTS AND
THICKNESSES WILL RISE DURING THE LATTER PART OF THE PERIOD.
THEREFORE HAVE SHOWN A TEND TOWARD WARMER AND DRIER WEATHER. SOME
MOISTURE AND INSTABILITY FROM AN UPPER LOW OFF TO OUR EAST MAY WRAP
INTO THE CASCADES ON SATURDAY FOR A SLIGHT RISK OF AFTERNOON SHOWERS
OR TSTMS.

&&

.AVIATION...WEAK UPPER LEVEL TROUGH WILL REMAIN OVER WESTERN WA
TODAY WITH LIGHT SOUTHWESTERLY FLOW ALOFT AND LIGHT LOW LEVEL FLOW
AS WELL. AIR MASS MOIST AND SLIGHTLY UNSTABLE.

CIGS EXPECTED TO BE MAINLY WITHIN VFR...RANGING FROM 4K FT TO 6K FT.
THE EXCEPTION BEING NEAR SHOWERS...WHERE CIGS WILL LOWER TO MVFR/IFR
RANGE...OR AROUND 1000 FT. THERE WILL BE OCCASIONAL BREAKS IN THE
CLOUDS...MAINLY EAST OF PUGET SOUND...BUT THESE BREAKS WILL BE SHORT
LIVED.

KSEA...S WIND 4 TO 8 KNOTS TODAY...BECOMING LIGHT AND NORTHERLY
DURING THE OVERNIGHT. VFR CIGS EXPECTED. SHOWERS MAY WORK THEIR WAY
INTO THE VICINITY...WHICH MAY DROP CIGS INTO MVFR CONDITIONS
MOMENTARILY. SMR

&&

.MARINE...LIGHT GRADIENTS TODAY AND TONIGHT AS A WEAK SURFACE LOW
OVER THE OFFSHORE WATERS SLOWLY MOVES SOUTHEAST AND DISSIPATES.
LIGHT ONSHORE FLOW DEVELOPING ON SUNDAY. THE NEXT ORGANIZED FRONT
REACHES THE WATERS ON MONDAY WITH SMALL CRAFT WINDS POSSIBLE OVER
THE COASTAL WATERS. ONSHORE FLOW PATTERN WILL RESUME FOR TUESDAY AND
WEDNESDAY. FELTON/SMR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

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