Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 230356
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
855 PM PDT FRI AUG 22 2014

.SYNOPSIS...NORTHERLY FLOW ALOFT CONTINUES FOR THE WEEKEND
MAINTAINING ONSHORE LOW-LEVEL FLOW AND SEASONAL TEMPERATURES.
AN UPPER LEVEL TROUGH FROM THE NORTH WILL MOVE SOUTHWARD ACROSS
EASTERN WASHINGTON SUNDAY AND POSSIBLY GENERATE SOME AFTERNOON
SHOWERS TO THE NORTHERN CASCADES. HIGH PRESSURE STRENGTHENS MONDAY
BRINGING A WARM UP FOR THE FIRST HALF OF NEXT WEEK.

&&

.SHORT TERM...THROUGH SUNDAY NIGHT...A FEW THUNDERSTORMS DEVELOPED
OVER THE EASTERN HALF OF SKAMANIA COUNTY THIS AFTERNOON BUT NOW JUST
A FEW DEBRIS CLOUDS LEFT OVER. LOW STRATUS BARELY TOUCHING THE NORTH
COAST AND MAY SEEP UP THE LOWER COLUMBIA RIVER TO NEAR KELSO BY SAT
MORNING.  FURTHER SOUTH ALONG THE COAST THE STRATUS REMAINS OFFSHORE.
THE SURFACE PRES PATTERN SHOULD KEEP CENTRAL COAST CLEAR OF THE
STRATUS BUT WITH THE CLEAR SKIES SOME FOG IS LIKELY.

NORTH TO NORTHWEST WINDS WILL PERSIST SATURDAY AS HIGH PRESSURE
CONTINUES TO BUILD OVER THE AREA...AND AFTERNOON TEMPERATURES WILL BE
NEAR THEIR SEASONAL NORMALS...WITH LOW TO MID 80S FOR THE INTERIOR
VALLEYS...AND MID TO UPPER 60S ALONG THE COAST. ANOTHER DAY OF A
SHALLOW MARINE LAYER SHOULD LIMIT THE INLAND PENETRATION OF STRATUS
EVEN MORE SATURDAY NIGHT...BUT AN APPROACHING TROUGH FROM THE NORTH
MAY INFLUENCE SOME VISIBILITY-REDUCING FOG ALONG THE IMMEDIATE COAST.


A SURFACE LOW EAST OF THE CASCADES WILL STRENGTHEN ONSHORE WINDS
SUNDAY AS THE UPPER TROUGH FROM THE NORTH CONTINUES TO DIG SOUTHWARD.
MODELS ARE SHOWING SOME SHOWERS WITH THIS LOW BRUSHING BY THE SOUTH
WASHINGTON CASCADES SUNDAY AFTERNOON...AND HAVE ADDED POPS TO THE
FORECAST. NORTHWEST FLOW SHOULD KEEP THE THREAT FOR THUNDERSTORMS
EAST OF THE CASCADES THOUGH. EXPECT A DEEPER MARINE PUSH SUNDAY NIGHT
AS ANOTHER UPPER SHORTWAVE MOVES OVER THE PACIFIC NORTHWEST. TJ/26

.LONG TERM...THE UPPER LEVEL RIDGE IS STILL FORECASTED TO MOVE
ONSHORE ON TUESDAY ALLOWING OUR TEMPERATURES TO INCREASE SLIGHTLY
ABOVE SEASONAL NORMS FOR THE BEGINNING PART OF NEXT WEEK. AS THIS
RIDGE PROGRESSES EASTWARD WE WILL LIKELY SEE SOME ZONAL UPPER LEVEL
FLOWS DEVELOP OVER THE FORECAST AREA ALLOWING LOW AND MID LEVEL
MOISTURE TO MOVE IN AND PROVIDE FOR AN INCREASE IN CLOUD COVER OVER
MUCH OF THE CWA ON LATE WEDNESDAY. BEYOND WEDNESDAY...BOTH THE GFS
AND ECMWF ARE HINTING AT A SHORTWAVE MOVING THROUGH OUR REGION AS
THE MEAN LONGWAVE TROUGH MOVES DOWN FROM THE GULF OF ALASKA. THIS
COULD BRING A CHANCE OF RAIN SHOWERS TO THE NORTHERN CASCADES FOR
THE LATTER PART OF NEXT WEEK. THE TIMING AND LOCATION ARE STILL
UNCERTAIN AT THIS POINT AND WILL BE NARROWED DOWN WITH FUTURE
UPDATES. /64
&&

.AVIATION...MARINE STRATUS GRADUALLY PUSHING INTO THE SW WA/NW OR
COAST AND WILL CONTINUE TO PUSH SOUTH INTO KTMK TONIGHT. MVFR/IFR
FOG AT KONP IS POSSIBLE AROUND 06Z SAT...BEFORE LOW LEVEL WINDS
TURN NORTHEASTERLY...WHICH WOULD KEEP FOG/LOW STRATUS JUST
OFFSHORE. VFR CONDITIONS PREVAIL INLAND NEXT 24 HRS UNDER LOW
LEVEL NORTHEAST FLOW. /27

KPDX AND APPROACHES...HIGH PRESSURE AND INCREASING NORTHEASTERLY
FLOW OVERNIGHT SHOULD RESULT IN VFR CONDITIONS THROUGH 00Z
SUNDAY. /NEUMAN

&&

.MARINE...HIGH PRESSURE WILL CONTINUE OVER THE NORTHEAST PACIFIC INTO
THE FORESEEABLE FUTURE. HOWEVER...THERMAL LOW PRESSURE OVER INTERIOR
CALIFORNIA WILL SHIFT MORE SQUARELY OVER THE COAST SATURDAY AND AGAIN
EARLY NEXT WEEK...IN A PATTERN THAT HAS BEEN RELATIVELY RARE THIS
SUMMER. THIS SHOULD PRODUCE WIDESPREAD NORTHERLY WINDS OF 25 TO 30
KT ACROSS THE CENTRAL OREGON WATERS. WITH A WESTERLY SWELL REMAINING
4 FT OR LESS DURING THIS TIME...SEAS MAY ALSO BECOME WIND DOMINATED
AND ESPECIALLY STEEP AND HAZARDOUS. HOWEVER...CONFIDENCE IS NOT
PARTICULARLY HIGH YET SO WILL HOLD OFF ON A SMALL CRAFT ADVISORY
FOR HAZARDOUS SEAS. /NEUMAN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM SATURDAY TO 3 AM PDT
     SUNDAY FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE
     OUT 60 NM.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
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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