Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 051020
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
220 AM PST THU MAR  5 2015

.SYNOPSIS...AN UPPER LEVEL RIDGE OF HIGH PRES WILL REMAIN THROUGH
THE WEEKEND MAINTAINING A DRY AND GENERALLY MILD WEATHER PATTERN.
THE UPPER RIDGE WILL WEAKEN EARLY NEXT WEEK AND A FRONT MAY BRING
RAIN TO THE REGION BY TUESDAY.
&&

.SHORT TERM...HIGH PRESSURE WILL CONTINUE DRY AND MILD WEATHER. SOME
HIGH CLOUDS ARE STREAMING OVER THE AREA AS A FRONTAL SYSTEM
APPROACHES THE NORTHERN WASHINGTON COAST. THESE CLOUDS HAVE REDUCED
RADIATION COOLING OVERNIGHT AND THE TEMPERATURES THIS MORNING ARE NOT
AS COLD AS THEY HAVE BEEN THE PAST COUPLE OF NIGHTS. TEMPERATURES ARE
IN THE 30S IN MOST LOCATIONS BUT THERE ARE ONLY POCKETS OF NEAR
FREEZING TEMPERATURES WITH A COUPLE OF LOCATIONS IN THE SOUTH
WILLAMETTE VALLEY BELOW FREEZING.

TEMPERATURES WILL WARM UP TO THE UPPER 50S TO LOW 60S AGAIN TODAY
WITH PLENTY OF SUNSHINE FILTERING IN THROUGH THE HIGH CLOUDS. LITTLE
CHANGE IN THE WEATHER FOR TONIGHT EXCEPT THE PASSING FRONT TO THE
NORTH MAY INCREASE THE SURFACE LOW LEVEL MOISTURE A TAD AND THERE MAY
BE A A BETTER CHANCE FOR SOME LOCAL FOG LATE TONIGHT.

MODELS STILL SHOW THE WINDS BECOMING SOUTHERLY ALONG THE COAST
FRIDAY. THE CURRENT MODEL RUN FORECASTS LESS MOISTURE WITH THE WIND
REVERSAL THAN THE PREVIOUS RUNS...LESSENING THE CHANCE FOR COASTAL
LOW CLOUDS AND FOG FRIDAY. SATELLITE IMAGERY DOES SHOW AN AREA OF LOW
CLOUDS OFFSHORE OF NORTHERN CALIFORNIA EARLY THIS MORNING...BUT
EASTERLY WINDS SHOULD PREVENT THESE CLOUDS FROM MOVING CLOSER TO THE
COAST TONIGHT. WE SHOULD HAVE A BETTER IDEA OF WHETHER THE SOUTHERLY
WINDS WILL BE ACCOMPANIED BY LOW CLOUDS TONIGHT.

HIGH PRESSURE WILL PERSIST THROUGH THE WEEKEND WITH SUNSHINE AND
WARMING TEMPERATURES. EXPECT WARMING TO THE MID 60S SUNDAY AFTERNOON.
TJ

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...ECMWF AND GEM
MAINTAIN A STRONG UPPER RIDGE THROUGH MON WITH OFFSHORE FLOW. 12Z GFS
BROKE RANKS WITH OTHER MODELS IN DIGGING A TROUGH AND COLD FRONT DOWN
FROM THE NW MON...BUT A LOOK THROUGH THE GFS ENSEMBLE MEMBERS
INDICATED QUITE A BIT OF SPREAD IN THE SOLUTIONS. GIVEN THE BETTER
CONSISTENCY IN ECMWF/GEM SOLUTION PREFER TO CONTINUE CLOSER TO THOSE
MODELS. AFTER DRY AND MILD WEATHER SUN AND MON...A SYSTEM EXPECTED IS
EXPECTED TO EJECT OUT OF THE E PACIFIC TROUGH WEAKENING THE RIDGE AND
BRINGING CHANCES FOR RAIN FOR TUE AND WED.
&&

.AVIATION...VFR THROUGH THURSDAY. THERE MAY BE SOME PATCHY MVFR FOG
TONIGHT AND THURSDAY MORNING...PRIMARILY ALONG THE S WA AND N
OREGON COAST NEAR THE BAYS AS WELL AS NEAR KEUG.

KPDX AND APPROACHES...VFR CONTINUES UNDER DRY STABLE AIR MASS.
BOWEN/MH
&&

.MARINE...RATHER TRANQUIL MARINE CONDITIONS FOR THE NEXT FEW DAYS.
WINDS HAVE EASED OVER THE WATERS AS DIURNAL EFFECTS HAVE
DECREASED. THE THERMALLY INDUCED TROUGH ALONG THE COAST WILL
WEAKEN AND SHIFT INLAND THU. NAM MODEL STILL SUGGESTING A WIND
REVERSAL OVER THE WATERS LATE THU AND THU NIGHT. WEAK SURFACE
GRADIENTS OVER THE WATERS DURING THE WEEKEND AND FIRST PART OF
NEXT WEEK. SIGNIFICANT MODEL DIFFERENCES BEGINNING EARLY NEXT WEEK.
HAVE LEANED TOWARD THE GFS FOR THE END OF THE EXTENDED PERIOD.

SEAS HOLDING IN THE 3 TO 5 FOOT RANGE FOR THROUGH THE WEEKEND.
SPECTRAL ANALYSIS SUGGESTS THERE WILL BE MULTIPLE 2 OR 3 FOOT
COMPONENTS THROUGH AT LEAST FRI...PRIMARILY FROM THE WNW AND SSW.
BOWEN/MH
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&

$$

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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