Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 281109
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
309 AM PST SAT FEB 28 2015

.SYNOPSIS...AN UPPER LOW WILL CONTINUE TO MOVE SOUTH OF SOUTHWEST
WASHINGTON AND NORTHWEST OREGON THIS MORNING WITH DRYING AND
CLEARING SKIES SPREADING IN FROM THE NORTH AND SOME LOCALLY BREEZY
NORTHEAST WIND. AN UPPER LEVEL RIDGE WILL THEN BE ANCHORED WITH ITS
AXIS ALONG 140W FOR SEVERAL DAYS...WITH COOL NORTHERLY FLOW ALOFT
ACROSS THE PACIFIC NORTHWEST. A WEATHER SYSTEM WILL MOVE SOUTH ALONG
THE COAST SUNDAY NIGHT INTO MONDAY FOR ANOTHER DECENT CHANCE OF SOME
RAIN WITH SOME LIGHT SNOW IN THE CASCADES. LOOK FOR DRY WEATHER IN
THE WAKE OF THE SUNDAY NIGHT AND MONDAY SYSTEM THAT COULD LAST MUCH
OF THE COMING WEEK.
&&

.SHORT TERM...ECHOES ON NATIONAL WEATHER SERVICE DOPPLER RADAR HAVE
DECREASED DRAMATICALLY EARLY THIS MORNING AS AN UPPER LEVEL LOW THAT
HAD BEEN OVER THE PACIFIC NORTHWEST ON FRIDAY WAS MOVING SOUTH OF THE
AREA. CLOUDS WILL BE DECREASING FROM THE NORTH THIS MORNING. A FEW
LINGERING SHOWERS ARE POSSIBLE THIS MORNING IN THE OREGON CASCADES
BEFORE THE CLOUDS COMPLETELY CLEAR. OTHERWISE LOOK FOR INCREASING
SUNSHINE TODAY WITH BREEZY NORTHEAST WINDS ACROSS THE AREA.

AN UPPER LEVEL RIDGE WILL HAVE ITS AXIS OFFSHORE ALONG 140W THROUGH
AT LEAST THE SHORT TERM PERIOD WITH COOL NORTHERLY FLOW ALOFT ACROSS
THE PACIFIC NORTHWEST IN THE WAKE OF THE DEPARTING LOW. THE OFFSHORE
FLOW WILL DECREASE TONIGHT AND SUNDAY...THEN START TO TURN ONSHORE
LATE SUNDAY AND ESPECIALLY SUNDAY NIGHT AS A SHORT WAVE DROPS SOUTH
ALONG THE COAST SUNDAY NIGHT INTO MONDAY...MOVING SOUTH OF THE AREA
BY LATER MONDAY. THIS SYSTEM APPEARS IT WILL HAVE ENOUGH OVERWATER
TRAJECTORY TO GIVE OUR AREA SOME PRECIPITATION. DUE TO THE PATH OF
THIS SYSTEM...THE MODELS FOCUS THE BEST QPF OVER THE COAST WATERS
AND ALONG THE COAST...WITH SOME PRECIPITATION SPREADING INLAND AS
WELL. THE ECMWF MODEL IS THE MOST BULLISH IN PUSHING PRECIPITATION
INLAND...WHILE THE GFS IS THE LEAST BULLISH. HAVE OPTED FOR A BLEND
RIGHT NOW. SNOW LEVELS WILL BE LOW ENOUGH FOR SOME SNOW IN THE
CASCADES TO NEAR OR A BIT BELOW PASS ELEVATIONS. AMOUNTS WILL BE
QUITE MODEST HOWEVER...MUCH LESS THAN WHAT FELL THURSDAY NIGHT AND
FRIDAY. TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MONDAY NIGHT THROUGH FRIDAY...THE MEAN UPPER RIDGE POSITION RETURNS
TO WHERE IT HAS BEEN MUCH OF THIS WINTER TUE/WED...OVER THE NE
PACIFIC. THEREFORE EXPECT AT LEAST A COUPLE DAYS OF DRY WEATHER
TUE/WED...PROBABLY LONGER. IT APPEARS THE BULK OF THE COLD AIR BEHIND
THE SUN NIGHT/MON SYSTEM WILL STAY EAST OF THE ROCKIES...WITH ONLY A
SMALL PIECE OF IT PUSHING INTO THE MID-COLUMBIA BASIN. THUS EXPECT
NEAR NORMAL TEMPERATURES AND DRY WEATHER THROUGH MIDWEEK... CLEAR AND
CHILLY NIGHTS WITH SUNNY DAYS AND AFTERNOON TEMPS IN THE 50S FOR THE
LOWLANDS. OFFSHORE FLOW SHOULD LIMIT FOG FORMATION. HELD POPS BELOW
CLIMO TOWARD THE END OF THE WEEK AS MODELS CONTINUE TO SHOW THE MEAN
RIDGE POSITION ANCHORED NEAR THE WEST COAST.  WEAGLE
&&

.AVIATION...LOW PRES OVER THE S OREGON COAST WILL CONTINUE TO PUSH
SOUTHEASTWARD INTO N CALIF TODAY. THIS WILL ALLOW FLOW TO BECOME N TO
NE THIS AM. MID LEVEL CLOUDS WILL THIN AND CLEAR OVER WASHINGTON THIS
AM...WITH CLEARING WORKING ITS WAY SOUTHWARD ACROSS OREGON TODAY.
WITH COOL AND MOIST LOW LEVELS...WILL SEE PATCHY FOG UNTIL
18Z...MAINLY IN S WILLAMETTE VALLEY AND POSSIBLY IN THE COWLITZ
LOWLANDS.

KPDX AND APPROACHES...VFR WITH MID CLOUDS CLEARING BETWEEN 15Z AND
18Z TODAY. WILL SEE EAST WINDS PICK UP A BIT AFTER 18Z...BUT
GENERALLY IN 10 TO 15 KT RANGE. NO CHANGE TONIGHT WITH VFR AND DRY
EAST WINDS.      ROCKEY.
&&

.MARINE...LOW PRES OVER THE S OREGON WATERS WILL PUSH INTO N CALIF
TODAY. GRADIENT TURNING MORE N TO NE ACROSS THE OREGON AND WASHINGTON
COASTAL WATERS. WILL SEE GUSTS 20 TO 25 KT AT TIMES ON THE WATERS
BEYOND 10 MILES. NO CHANGES TO CURRENT SMALL CRAFT ADVISORY FOR SAID
WINDS. MAY HAVE SOME GUSTS IN COASTAL GAPS TODAY... BUT SUSPECT WILL
NOT BE ALL THAT MANY WITH OVERALL WINDS REMAINING 10 TO 20 KT. WILL
LEAVE THE NEAR SHORE WATERS CLEAR OF ANY ADVISORY AT THIS POINT.
WINDS GUSTS WILL EASE BACK TONIGHT AS TIGHTEST GRADIENT SHIFTS
FURTHER TO THE S OF THE AREA.

HIGH PRES WILL BUILD OVER THE NE PAC MON AND TUE. THIS WILL BRING A
MOSTLY N TO NW WINDS TO THE COASTAL WATERS. NOT MUCH CHANGE IN
PATTERN THIS WEEK...WITH BENIGN CONDITIONS CONTINUING. ROCKEY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM TODAY ON OUTER COASTAL
       WATERS FROM 10 TO 60 NM OFFSHORE FROM CAPE SHOALWATER
       TO FLORENCE.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 PM TODAY FOR WATERS
       FROM CAPE SHOALWATER TO CASCADE HEAD FROM 10 TO 60 NM.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 9 PM TODAY FOR WATERS
       FROM CASCADE HEAD TO FLORENCE FROM 10 TO 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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