Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 292248
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
348 PM PDT FRI APR 29 2016

.SYNOPSIS...A STRONG UPPER RIDGE WILL BRING DRY WARMER WEATHER
SATURDAY THROUGH MONDAY. A CHANCE OF SHOWERS WILL RETURN TUESDAY
THROUGH THURSDAY OF NEXT WEEK...WITH MOIST SOUTHERLY FLOW ALOFT
AND LOW LEVEL ONSHORE FLOW.

&&

.SHORT TERM...SHOWERS WILL QUICKLY END THIS EVENING AS A WEATHER
SYSTEM DEPARTS. HIGH PRESSURE ALOFT WILL BUILD OVER THE PACIFIC
NORTHWEST SATURDAY WITH NORTHERLY LOW LEVEL FLOW DEVELOPING. SOME
CLOUDS WILL LIKELY LINGER IN THE MORNING...THEN SKIES SHOULD
BECOME MOSTLY SUNNY. HIGHS WILL WARM INTO THE 60S.

THE UPPER RIDGE WILL STRENGTHEN OVER THE AREA ON SUNDAY WITH
INCREASING LOW LEVEL OFFSHORE FLOW. THIS WILL BRING ANOTHER SUNNY
DAY WITH HIGHS WARMING WELL INTO THE 70S OR EVEN LOWER 80S IN THE
USUAL WARMER SPOTS.

MONDAY WILL BE THE WARMEST DAY OF THE WEEK. THE COAST WILL SEE A
LITTLE COOLING AS OFFSHORE FLOW WEAKENS BUT INLAND SHOULD BE A
COUPLE DEGREES WARMER. THE GFS HAS BEEN HINTING AS POSSIBLE
ISOLATED CONVECTION LATE IN THE DAY AS SOUTHERLY FLOW ALOFT
DEVELOPS BUT THE FORECAST IS DRY FOR NOW WHICH IS MORE IN LINE
WITH THE ECMWF. SCHNEIDER

.LONG TERM...AN UPPER TROUGH WILL APPROACH FROM THE WEST ON
TUESDAY WITH INCREASINGLY MOIST SOUTHERLY FLOW ALOFT FOR A CHANCE
OF SHOWERS. INCREASING LOW LEVEL ONSHORE FLOW WILL COOL HIGHS ON
THE ORDER OF 10 DEGREES FROM MONDAY.

THIS GENERAL PATTERN WILL CONTINUE ON WEDNESDAY...MOIST SOUTHERLY
FLOW ALOFT FOR A CHANCE OF SHOWERS. THE UPPER TROUGH OFFSHORE WILL
TURN INTO A CUTOFF UPPER LOW WELL TO THE SOUTH ON THURSDAY AND
FRIDAY. THIS WILL KEEP MOST OF THE SHOWER THREAT TO THE SOUTH BUT
SOME ACTIVITY COULD CERTAINLY SNEAK UP FROM THE SOUTH OR EAST. THE
BEST CHANCES WILL BE OVER THE CASCADES. SCHNEIDER

&&

.AVIATION...UPPER LEVEL TROUGH OVER EASTERN WASHINGTON SLOWLY
MOVING EAST WITH UPPER LEVEL RIDGE BUILDING OFFSHORE. LIGHT FLOW
ALOFT BECOMING NORTHWESTERLY. LOW LEVEL ONSHORE FLOW CONTINUING
INTO SATURDAY.

SCATTERED TO BROKEN LAYER NEAR 3500 FEET WITH ANOTHER SCATTERED TO
BROKEN LAYER NEAR 6000 FEET. WITH LIGHT ONSHORE FLOW CEILINGS
LOWERING TO NEAR 2000 FEET 10Z-18Z SATURDAY. CLOUDS SCATTERING OUT
MIDDAY SATURDAY.

KSEA...CEILINGS AROUND 3000 FEET LIFTING TO 5000-6000 FEET THIS
EVENING. CEILINGS LOWER BACK DOWN TO NEAR 2000 FEET AROUND 12Z
SATURDAY. LIGHT NORTHERLY WINDS BECOMING VARIABLE AFTER 06Z.
FELTON

&&

.MARINE...LOW LEVEL ONSHORE FLOW PATTERN CONTINUING INTO SATURDAY
WITH SMALL CRAFT ADVISORIES OVER THE COASTAL WATERS AND IN THE
STRAIT OF JUAN DE FUCA. ONSHORE FLOW TURNS NORTHWESTERLY ON
SATURDAY WITH HIGH PRESSURE BUILDING INTO SOUTHERN BRITISH
COLUMBIA. LOW LEVEL FLOW TURNING OFFSHORE ON SUNDAY WITH THERMALLY
INDUCED TROUGH ALONG THE COAST. A RETURN TO LOW LEVEL ONSHORE FLOW
WILL OCCUR LATER MONDAY INTO TUESDAY. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT SATURDAY FOR COASTAL WATERS
     FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL
     WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-
     COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10
     TO 60 NM.

     SMALL CRAFT ADVISORY UNTIL 5 AM PDT SATURDAY FOR CENTRAL U.S.
     WATERS STRAIT OF JUAN DE FUCA-COASTAL WATERS FROM CAPE
     FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL WATERS FROM
     JAMES ISLAND TO POINT GRENVILLE OUT 10 NM-COASTAL WATERS
     FROM POINT GRENVILLE TO CAPE SHOALWATER OUT 10 NM-EAST
     ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-WEST ENTRANCE
     U.S. WATERS STRAIT OF JUAN DE FUCA.

     SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO NOON PDT SATURDAY
     FOR NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS.

&&

$$

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