Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 260400
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
900 PM PDT FRI JUL 25 2014

.SYNOPSIS...AN UPPER LEVEL RIDGE WILL CONTINUE TO BUILD INLAND OVER
THE PACIFIC NORTHWEST...ESPECIALLY OVER THE WEEKEND...AND REMAIN NEAR
THE FORECAST AREA THROUGH MUCH OF NEXT WEEK. THIS WILL BRING WARM AND
DRY WEATHER...EXCEPT FOR A SLIGHT CHANCE FOR THUNDERSTORMS IN THE
CASCADES NEAR THE CREST BEGINNING SUNDAY AFTERNOON AND EVENING AS A
FEW WEAK DISTURBANCES LIFT NORTHEAST THROUGH THE REGION. THE MARINE
LAYER WILL BECOME MORE CONFINED TO THE COAST.
&&

.SHORT TERM...CLOUDS CONTINUED TO CLEAR LATE THIS AFTERNOON AND EARLY
EVENING AS AN UPPER RIDGE BUILDS OVER THE AREA. AS OF 8 PM VISIBLE
IMAGERY SHOWS CLEAR SKIES ACROSS THE PORTLAND FORECAST AREA. THERE IS
NOT MUCH SIGNS OF MARINE STRATUS OVER THE WATERS ALTHOUGH NW WINDS
WILL LIKELY PUSH THE STRATO-CUMULUS THAT IS BEYOND 60 NM OFFSHORE
TOWARDS THE COAST LATE TONIGHT. HAVE REDUCED CLOUDS FOR THIS EVENING
ALONG THE COAST...BUT THINK THAT SOME RADIATION FOG OR LOW CLOUDS
COULD STILL DEVELOP ALONG THE COAST AND THE LOWER COLUMBIA RIVER
VALLEY. THINK SOME LOW CLOUDS MAY FORM OVER THE NORTHERN OREGON
CASCADE FOOTHILLS AS WELL...AND POSSIBLY INTO PARTS OF THE NORTHERN
WILLAMETTE VALLEY EARLY SATURDAY MORNING.

AN UPPER RIDGE ANCHORED INLAND OVER THE WESTERN U.S. WILL BUILD MORE
INTO THE PACIFIC NORTHWEST SATURDAY...WITH LIGHT SOUTHWEST FLOW
ALOFT. THIS WILL BRING MORE WARMING TO THE AREA...WITH 850 MB TEMPS
SUPPORTING HIGHS INLAND IN THE LOWER TO MID 80S SATURDAY AFTERNOON.
THE MAIN AREA OF MORNING LOW CLOUDS WILL BE ALONG THE NORTH COAST
WITH A FINGER EXTENDING INLAND ALONG THE COLUMBIA RIVER TO NEAR
PORTLAND. OTHERWISE EXPECT PLENTY OF SUNSHINE SATURDAY.

THE PATTERN SATURDAY WILL CONTINUE SUNDAY. 850 MB TEMPS SUPPORT HIGHS
INLAND IN THE UPPER 80S TO NEAR 90. AGAIN...THE MAIN CHANCE FOR ANY
LOW CLOUDS SUNDAY MORNING WILL BE ALONG THE FAR NORTH COAST...AND
LOCALLY INLAND ALONG THE COLUMBIA RIVER. THERE IS A WEAK DISTURBANCE
MOVING NORTH SUNDAY INTO CENTRAL OREGON FROM OFF THE CALIFORNIA COAST
THAT MAY GIVE A SLIGHT CHANCE OF DRY TYPE THUNDERSTORMS NEAR THE
CASCADE CREST IN OREGON.

MONDAY IS LOOKING MUCH LIKE A REPEAT OF SUNDAY...WITH TEMPS INLAND
VERY SIMILAR...CLOSE TO 90. THERE REMAINS A SLIGHT CHANCE OF
AFTERNOON AND EVENING DRY TYPE THUNDERSTORMS NEAR THE CASCADE CREST
IN OREGON...MAINLY SOUTH OF MOUNT JEFFERSON OR SOUTH OF SANTIAM PASS.
ANY LOW CLOUDS ON MONDAY MAY NOT REACH PORTLAND. TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...MONDAY NIGHT
THROUGH FRIDAY. MODELS REMAIN IN GENERAL AGREEMENT THAT THE REGION
WILL REMAIN BETWEEN AN UPPER LOW IN THE GULF OF ALASKA AND A
DEVELOPING UPPER RIDGE OVER THE WESTERN CONUS THROUGH MUCH OF NEXT
WEEK. THE RIDGE OF HIGH PRES WILL AMPLIFY AND RETROGRADE WITH THE
AXIS ALIGNED NEAR THE ROCKIES OR EASTERN GREAT BASIN BY MID WEEK.
SOME VARIATION REMAINS IN THE POSITION OF THE RIDGE AXIS IN THE FCST
MODELS AND AMONG ENSEMBLE MEMBERS...WHICH WILL IMPACT WHERE THE
THERMAL TROUGH DEVELOPS. SO WHILE SOME OF THE FINER DETAILS WILL BE
WORKED OUT IN TIME...CONFIDENCE IS INCREASINGLY HIGH IN THE GENERAL
PICTURE. NAMELY...TEMPERATURES ABOVE NORMAL THROUGH THE WEEK AND WITH
MOSTLY CLEAR SKIES ACROSS THE INTERIOR EACH DAY...WITH GUSTY WINDS
ALONG THE COAST IN THE AFTERNOON/EVENING HOURS. MODELS CONTINUE TO
INDICATE POTENTIAL FOR THUNDERSTORMS...PRIMARILY ALONG THE CENTRAL
OREGON AND LANE COUNTY CASCADES AND FOOTHILLS. EXPANDED AREAS FOR WED
ONWARD IN THESE LOCATIONS...GENERALLY IN THE AFTERNOON/EVENING HOURS
BUT ALSO WITH A SLIGHT CHANCE FOR SOME LINGERING OVERNIGHT
THUNDERSTORMS. THEREFORE...GENERALIZED THE AREAS AND TIMING OF
POTENTIAL FOR NOW AND WILL FINE TUNE THIS PART OF THE FORECAST AS WE
GET CLOSER TO NEXT WEEK.  CULLEN
&&

.AVIATION...HIGH PRESSURE AND WEAK ONSHORE FLOW WILL RESULT IN
VFR CONDITIONS DOMINATING AT ALL TAF SITES THROUGH 06Z SUNDAY.
LARGER DEWPOINT DEPRESSIONS THIS EVENING SHOULD RESULT IN
SIGNIFICANTLY FEWER PATCHES OF IFR CONDITIONS DEVELOPING LATER
TONIGHT ACROSS THE AREA. NONETHELESS...THERE IS A CHANCE IFR
CONDITIONS WILL DEVELOP ALONG THE LOWER COLUMBIA RIVER THAT COULD
EVENTUALLY IMPACT KAST...KPDX AND KTTD TOWARDS DAYBREAK.
HOWEVER...CONFIDENCE REMAINS LOW...AND ANY RESTRICTIONS WOULD
LIKELY BE SHORT LIVED.

KPDX AND APPROACHES...VFR CONDITIONS SHOULD DOMINATE THROUGH 06Z
SUNDAY AS HIGH PRESSURE AND WEAK ONSHORE FLOW CONTINUE. THERE IS A
30 PERCENT CHANCE IFR CONDITIONS WILL DEVELOP PRIMARILY BETWEEN
13Z AND 16Z SATURDAY. /NEUMAN
&&

.MARINE...HIGH PRESSURE OVER THE NORTHEAST PACIFIC AND THERMAL LOW
PRESSURE OVER NORTHERN CALIFORNIA WILL REMAIN IN PLACE THROUGH AT
LEAST MONDAY. THIS WILL RESULT IN GUSTY NORTH WINDS OF 25 TO 30 KT
ACROSS THE CENTRAL WATERS...THAT MAY PERIODICALLY EXTEND UP IN
THE NORTHERN WATERS LATER IN THE WEEKEND.

SEAS OF 2 TO 4 FT WILL BECOME MORE WIND DOMINATED AND LIKELY PUSH
INTO THE 5 TO 7 FT RANGE...ESPECIALLY FOR THE CENTRAL OREGON
WATERS LATER THIS WEEKEND AS NORTHERLY WINDS STRENGTHEN AND
EXPAND IN AREAL COVERAGE.

STRONG EBB CURRENTS DURING THE EARLY MORNING HOURS WILL ALSO
CREATE CHOPPY CONDITIONS OVER THE COLUMBIA RIVER BAR EACH DAY THIS
WEEKEND. /NEUMAN
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM SATURDAY TO 5 AM PDT
     SUNDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR
    OUT 60 NM.
&&

$$

MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.


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