Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 012214
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
213 PM PST SUN MAR  1 2015

.SYNOPSIS...A WEAK COLD FRONT IS PUSHING SOUTHWARD ACROSS BRITISH
COLUMBIA THIS AFTERNOON. THIS FRONT WILL BRING INCREASING CLOUDS AND
A CHANCE FOR RAIN AND MOUNTAIN SNOW TONIGHT AND EARLY MONDAY. WITH
THE BRUNT OF THIS SYSTEM TRACKING OFFSHORE THE BEST CHANCES FOR
PRECIPITATION WILL BE NEAR THE COAST. THIS SYSTEM WILL BE A FAST
MOVER...AND SOME CLEARING IS EXPECTED MONDAY AFTERNOON. THE UPPER
LEVEL RIDGE WHICH HAS BEEN SO DOMINANT THIS WINTER IS THEN EXPECTED
TO RETURN...LIKELY LEADING TO DRY WEATHER FOR THE REST OF THE WEEK.

&&

.SHORT TERM...TONIGHT THROUGH WEDNESDAY...SATELLITE IMAGERY THIS
AFTERNOON SHOWS A COLD FRONT PUSHING SOUTHWARD INTO NRN VANCOUVER
ISLAND...AND MOVING RAPIDLY DOWN THE BRITISH COLUMBIA COAST. SOME
HIGH CLOUDINESS IS ALREADY STARTING TO FILTER THE SUNSHINE IN THE
PORTLAND METRO AREA...THESE CLOUDS WILL THICKEN AND SPREAD SOUTH AS
THE FRONT APPROACHES.

POP/QPF FORECAST IS ACTUALLY A LITTLE CHALLENGING WITH THIS SYSTEM
FOR TONIGHT. MODELS HAD BACKED OFF ON THE POSSIBILITY OF PRECIP
INLAND OVERNIGHT...FAVORING A MORE OFFSHORE TRACK TO THE BEST JET
DYNAMICS. THAT STILL APPEARS TO BE THE CASE...BUT 18Z NAM/GFS AND 15Z
SREF PLUMES INDICATE A DECENT CHANCE FOR AT LEAST A COUPLE HUNDREDTHS
OF AN INCH OF RAIN IN THE WILLAMETTE VALLEY. THEREFORE WE OPTED TO
KEEP AT LEAST A SLIGHT CHANCE OF RAIN THROUGHOUT THE FORECAST AREA
TONIGHT...WITH CHANCES TAPERING OFF FROM THE NORTH MONDAY. THIS
SYSTEM WILL BE A FAST MOVER...SPEEDING ALONG ON A 100KT+ NORTHERLY
JET STREAM.

18Z NAM BUFR SOUNDINGS CONTINUE TO SUGGEST SNOW LEVELS AROUND IN THE
1500-2000 FT RANGE...SO IT WOULD NOT BE SURPRISING IF THE HIGHER
FOOTHILL/COAST RANGE ELEVATIONS GET A QUICK DUSTING OF SNOW TONIGHT
AND/OR MONDAY MORNING.

NORTHERLY FLOW WILL GENERALLY DRY THINGS OUT QUICKLY BEHIND THE FRONT
MONDAY. HOWEVER THE NORTHERLY FLOW WILL NOT BE AS STRONG NOR AS DRY
AS IT WAS SATURDAY...SO CLOUDS MAY BE A LITTLE MORE SLUGGISH TO
CLEAR. ALSO THE FLOW ALOFT TAKES SOME TIME TO TURN ANTICYCLONIC WITH
SOME SREF MEMBERS AND THE 18Z NAM EVEN HINTING AT SOME SNOW SHOWERS
CONTINUING IN THE CASCADES INTO MON NIGHT. WILL HANDLE THIS WITH SOME
SILENT POPS AND A LITTLE BIT OF EXTRA SKY COVER IN THE HIGHER TERRAIN
FOR NOW. MODELS SHOW GOOD CONSENSUS THAT STRONG UPPER RIDGING WILL
REBUILD OVER THE REGION TUE/WED...BRINGING US BACK TO AN UNSEASONABLY
DRY REGIME.  WEAGLE

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...THE MEAN UPPER RIDGE
POSITION LINGERS WHERE IT HAS BEEN MUCH OF THIS WINTER...OVER THE NE
PACIFIC AND ALONG THE WEST COAST. THIS SHOULD KEEP THE PACIFIC JET
STREAM WELL TO OUR NORTH...AS WELL AS ANY CHANCES OF SIGNIFICANT
PRECIPITATION. THEREFORE OUR FORECAST REMAINS DRY THROUGH NEXT
WEEKEND. CONDITIONS MAY BECOME INCREASINGLY FAVORABLE FOR FOG IN THE
VALLEYS...AS MOST GUIDANCE PUSHES THE UPPER RIDGE AXIS ONSHORE LATE
IN THE WEEK. OTHERWISE EXPECT A GRADUAL RETURN TO ABOVE NORMAL
TEMPERATURES WHICH MAY LAST INTO NEXT WEEKEND.WEAGLE

&&

.AVIATION...CONTINUED LIGHT OFFSHORE WIND WITH VFR THIS AFTERNOON.
HIGH CLOUDS ARE STARTING TO MOVE INTO THE AREA. WILL SEE SOME MID
LEVEL CLOUD DEVELOPMENT AROUND 5000 TO 7000 FT THIS AFTERNOON AND
THEN MVFR CIG AND VIS OVERNIGHT WITH SOME -RA OR -DZ...ESPECIALLY
ALONG THE COAST. MODELS ARE BACKING OFF ON MVFR CONDITIONS INLAND
SO EXPECT MOSTLY VFR INLAND WITH SOME PATCHY MVFR WITH ANY -RADZ.
VFR RETURNS EVERYWHERE MONDAY AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS TODAY...WITH INCREASING MID
AND HIGH CLOUDS THIS AFTERNOON. COULD SEE SOME PATCHY MVFR CIG/VIS
OVERNIGHT BUT CONDITIONS RETURN TO VFR BY ABOUT MIDDAY MONDAY.
BOWEN

&&

.MARINE...HIGH PRES OVER THE NE PAC WILL BE THE DOMINANT WEATHER
PLAYER THIS WEEK. HOWEVER...A WEAK FRONT WILL DROP SOUTHWARD
ACROSS REGION TONIGHT INTO MON AM. NOT A LOT OF WIND EXPECTED
WITH FRONT...BUT ENOUGH TO POP 20 TO 25 KT GUSTS OVER THE OUTER
WATERS...MAINLY OFF CENTRAL OREGON COAST. WILL MAINTAIN SMALL
CRAFT ADVISORY FOR THAT AREA AND WATCH WINDS OFFSHORE THE NORTHERN
OREGON COAST FOR ANY SCA NEED THERE. AFTER TOMORROW...WINDS LOOK
LIKE THEY SHOULD REMAIN BELOW 15 KT THROUGH THE REST OF THE
FORECAST PERIOD.

SEAS WILL REMAIN AROUND 4 TO 6 FT THROUGH THE WEEK. WILL SEE A
MIXED SWELL WEDNESDAY AND THURSDAY WITH PERIODS RANGING FROM
AROUND 8 SECONDS TO AS LONG AS 20 SECONDS. HOWEVER MODELS SHOW
EACH SWELL AT ONLY ABOUT 2 FT SO COMBINED SEAS WILL STILL ONLY BE
3 TO 5 FT. BOWEN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM MIDNIGHT TONIGHT TO NOON
     PST MONDAY FOR WATERS FROM CASCADE HEAD TO FLORENCE OR 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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