Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 260400
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT FRI JUL 25 2014

.SYNOPSIS...HIGH PRESSURE ALOFT AND WEAK LOW LEVEL ONSHORE FLOW WILL
PREVAIL FOR THE NEXT WEEK. THIS WILL GIVE A STRETCH OF SUNNY AND
WARM WEATHER TO WESTERN WASHINGTON.

&&

.SHORT TERM...UPPER HEIGHTS WILL GRADUALLY RISE ACROSS THE PACIFIC
NORTHWEST THROUGH MONDAY. AT THE SAME TIME...LOW LEVEL NORTHERLY
FLOW WILL PREVAIL WHICH SHOULD LIMIT NIGHT AND MORNING CLOUDS. THE
LOW LEVEL AIR MASS WILL WARM AT LEAST A FEW DEGREES EACH DAY WHICH
SHOULD TRANSLATE INTO A WARMING TREND ACROSS THE AREA. BY
MONDAY...MOST INLAND AREAS WILL BE IN THE LOWER TO MID 80S EXCEPT
FOR 70S IN THE USUAL COOLER SPOTS NEAR THE WATER. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...AN UPPER RIDGE WILL DOMINATE THE
WEATHER PATTERN OVER THE REGION DURING THIS PERIOD. THE RIDGE AXIS
WILL REMAIN TO OUR EAST...THUS EXPECT LOW LEVEL ONSHORE FLOW TO
PERSIST. THE ONSHORE PRESSURE GRADIENT MAY STRENGTHEN LATE IN THE
PERIOD...LEADING TO MORE CLOUDS BUT THIS WAS TOO FAR IN THE FUTURE
TO BANK ON. ALSO...THERE IS A CHANCE THAT THERE COULD BE SOME TSTMS
OVER THE CASCADES ON DAY 7...DEPENDING ON WHICH MODEL ONE PREFERS.
CHOSE TO BROAD-BRUSH THE FORECAST BY INDICATING ABOVE NORMAL TEMPS
AND CONFINING LOW CLOUDS TO MAINLY THE COAST.

&&

.AVIATION...WEAK UPPER LEVEL RIDGING AND LOW LEVEL ONSHORE FLOW WILL
PERSIST THROUGH THE WEEKEND. MODERATE WESTERLY FLOW ALOFT WILL
BECOME SOUTHWESTERLY SATURDAY AFTERNOON AS THE UPPER LEVEL RIDGE
AXIS SHIFTS EAST AND OVER THE GREAT DIVIDE AND AMPLIFIES.

THE AIR MASS OVER WESTERN WASHINGTON WILL REMAIN GENERALLY DRY AND
STABLE THROUGH TONIGHT. AREAS OF LINGERING LOW CLOUDS HAVE CLEARED
THIS AFTERNOON TO CLEAR SKIES. THE FORECAST CHALLENGE OVERNIGHT WILL
BE THE EXTENT TO WHICH LOW CLOUDS AND STRATUS REFORM...ESPECIALLY
OVER THE INTERIOR. GIVEN THE DRYING TREND OVER THE LAST 24 HOURS
OVER THE INTERIOR...EXPECT LOWER CLOUDS TO REFORM ALONG THE
COAST...CHEHALIS GAP...AND STRAIT...WHILE THE REMAINDER OF THE
INTERIOR WILL REMAIN RELATIVELY CLEAR AND VFR THROUGH THE MORNING.

KSEA...EXPECT VFR CONDITIONS OVERNIGHT WITH FEW-SCT025-040 POSSIBLE
EARLY SATURDAY MORNING. NORTHERLY WINDS 6 TO 8 KTS WILL BECOME
NORTHEASTERLY 2 TO 4 KTS AROUND 06Z AND PERSIST THROUGH SATURDAY
MORNING.

&&

.MARINE...A PERSISTENT PATTERN OF HIGH PRESSURE OVER THE COASTAL
WATERS AND LOWER PRESSURE INLAND WILL SUPPORT ONSHORE FLOW THROUGH
EARLY NEXT WEEK. AS IS TYPICAL WITH THIS SORT OF PATTERN...EXPECT
STRONGEST WESTERLIES THROUGH THE STRAIT...WITH SMALL CRAFT ADVISORY
LEVEL WINDS POSSIBLE AT TIMES ESPECIALLY DURING THE LATE AFTERNOON
AND EVENING HOURS. HAVE UPDATED TO THE FORECAST TO REFLECT SOMEWHAT
STRONGER WESTERLIES THIS EVENING...REACHING SMALL CRAFT ADVISORY
LEVELS THROUGH 09Z. WINDS WILL WEAKEN SATURDAY MORNING BEFORE
STRENGTHENING AGAIN FOR SAT AFTERNOON AND EVENING...AND AGAIN ON
SUNDAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





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