Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 261607
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
907 AM PDT SUN APR 26 2015

.SYNOPSIS...A WEAK WARM FRONT WILL DISSIPATE AS IT APPROACHES THE
COASTLINE LATE TODAY OR EARLY THIS EVENING FOR A THREAT OF LIGHT
RAIN. HIGH PRESSURE ALOFT WILL BRING WARMER AND DRIER CONDITIONS
TO THE AREA ON MONDAY. A PAIR OF COLD OR OCCLUDED FRONTS WILL MOVE
ACROSS THE REGION ABOUT MIDWEEK FOR COOLER AND UNSETTLED WEATHER.

&&

.SHORT TERM...
MID AND HIGH CLOUDS CONTINUED TO STREAM ACROSS THE CWA IN ADVANCE
OF A WARM FRONT THAT WAS STILL WELL OFFSHORE AT THIS TIME. THIS
FRONT WILL LIKELY DISSIPATE AS IT APPROACHES THE WASHINGTON AND
BRITISH COLUMBIA COASTS LATE TODAY OR EARLY THIS EVENING. THERE
WILL BE ENOUGH ISENTROPIC LIFT FOR A THREAT OF RAIN OVER THE
AREA...ESPECIALLY ON THE COAST...THROUGH TONIGHT.

MONDAY WILL BE WARMER AND DRIER AS AN UPPER LEVEL RIDGE BUILDS
OVER THE REGION. EXPECT MOSTLY SUNNY SKIES WITH HIGHS IN THE 70S
ACROSS THE INTERIOR...WITH 60S ALONG THE COAST. THE RIDGE WILL
EXIT EAST MONDAY NIGHT AS A TROUGH DIGS OFFSHORE.

SHOWERS WILL RETURN ON TUESDAY AS A COLD FRONT MOVES INLAND.
ONSHORE FLOW WILL INCREASE BEHIND THE FRONT TUESDAY AFTERNOON FOR
BREEZY SOUTHERLY WINDS. MODELS SHOWED A PUGET SOUND CONVERGENCE
ZONE /PSCZ/ FORMING OVER THE CENTRAL SOUND...AND SHOWERS FROM THE
PSCZ MAY LINGER THROUGH TUESDAY NIGHT. 33/05

.LONG TERM FROM THE PREV DISCUSSION...
ANOTHER COLD FRONT WILL CROSS THE AREA ON WEDNESDAY FOR ANOTHER
ROUND OF SHOWERS AND BREEZY WEATHER. EXPECT HIGHS IN THE MID 50S
TO LOWER 60S EACH DAY.

OVERALL CONFIDENCE IN THE LONG RANGE FORECAST REMAINS LOW. MODELS
SHOW ZONAL FLOW THURSDAY AND FRIDAY. A TROUGH OVER B.C. MAY CLIP
WESTERN WA FOR A CHANCE OF SHOWERS EACH DAY. AFTER THAT THE MODELS
DISAGREE ON THE PATTERN THROUGH THE WEEKEND. THEREFORE WILL
MAINTAIN A FORECAST CLOSE TO SEASONAL NORMS. 33

&&

.AVIATION...AN UPPER RIDGE WILL MOVE OVER THE AREA TODAY THEN OVER
EASTERN WASHINGTON TONIGHT WITH NORTHWEST FLOW ALOFT BECOMING
SOUTHWEST. A WEAKENING WARM FRONT WILL MOVE THROUGH THE AREA TODAY
AND TONIGHT. AIR MASS STABLE.

HIGH LEVEL MOISTURE INLAND THIS MORNING WITH MID LEVEL CEILINGS AT
THE COAST. LOW AND MID LEVEL MOISTURE WILL GRADUALLY INCREASE FROM
THE WEST TODAY. CEILINGS SHOULD GENERALLY BE 4000-6000 FEET OVER THE
INTERIOR TONIGHT WITH 2000-4000 FOOT CEILINGS TOWARDS THE COAST.

KSEA...HIGH CLOUDS THIS MORNING...MID LEVEL CLOUDS MOVING IN FROM
THE WEST THIS AFTERNOON. CEILINGS OF 4000-6000 FEET ARE EXPECTED
TONIGHT. SOUTHERLY WIND 4-8 KNOTS. SCHNEIDER

&&

.MARINE...A WEAKENING WARM FRONT WILL BRING SMALL CRAFT SOUTHERLY
WINDS TO THE COASTAL WATERS AND WEST ENTRANCE STRAIT OF JUAN DE FUCA
LATER TODAY. WINDS COULD ALSO RISE TO SMALL CRAFT ADVISORY LEVELS
FOR A FEW HOURS OVER SOME OF THE NORTH INTERIOR WATERS BUT THE
FORECAST IS 10-20 KNOTS FOR NOW.

A SECOND FRONTAL SYSTEM WILL BRING ANOTHER ROUND OF SMALL CRAFT
ADVISORY SOUTHERLY WINDS TO MOST WATERS TUESDAY. MODERATE ONSHORE
FLOW BEHIND THE FRONT LATER TUESDAY IS EXPECTED TO BRING SMALL CRAFT
ADVISORY WEST WINDS TO THE STRAIT. A THIRD FRONT COULD REACH THE
AREA WEDNESDAY. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE COASTAL WATERS
     AND WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.

&&

$$

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