FXUS66 KPQR 221636
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
834 AM PST TUE DEC 22 2009

.SYNOPSIS...SHOWERS CONTINUE TO WIND DOWN THIS MORNING AS LOW 
PRESSURE MOVES AWAY TO THE SOUTHEAST. THE FEW REMAINING SHOWERS THIS 
MORNING WILL FALL AS SNOW ABOVE 1000 FEET WITH A MIX OF RAIN AND 
SNOW DOWN TO ABOUT 500 FEET. DRY WEATHER WILL PREVAIL FROM TONIGHT 
THROUGH AT LEAST CHRISTMAS AS A STRONG UPPER LEVEL RIDGE BUILDS 
ALONG THE COAST. BRISK EAST WINDS WILL DEVELOP NEAR THE COLUMBIA 
RIVER GORGE WEDNESDAY NIGHT AND MAY CONTINUE THROUGH THE WEEKEND AS 
THE RIDGE CONTINUES TO HOLD.

&&

.SHORT TERM...DOPPLER RADAR CONTINUES TO SHOW SHOWERS WINDING DOWN
THIS MORNING. NOT MUCH SHOWER ACTIVITY UPSTREAM SO WILL END THE SNOW
ADVISORIES WITH THE MORNING PACKAGE. ANY REMAINING SHOWERS THIS 
MORNING WILL FALL AS SNOW ABOVE 1000 FEET WITH A MIX OF RAIN AND SNOW 
DOWN TO ABOUT 500 FEET.

AN UPPER LEVEL RIDGE WILL BUILD OVERHEAD TONIGHT AND WEDNESDAY. THE 
MODELS ARE NOW IN BETTER AGREEMENT KEEPING US DRY THROUGH THE SHORT 
TERM. THE MAIN FORECAST ISSUES IN THE WEDNESDAY-FRIDAY TIME FRAME 
WILL BE THE DEVELOPMENT OF GUSTY EAST WINDS NEAR THE GORGE AND 
VALLEY FOG AWAY FROM THE GORGE.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...THE UPPER
LEVEL RIDGE TRANSITIONS THROUGH THE FORECAST AREA THROUGH THE END OF
THE WEEK...WITH DRY WEATHER CONTINUING FRIDAY AFTER LATE NIGHT AND
EARLY MORNING VALLEY FOG. MODELS VARY A LOT WITH THE BREAKDOWN OF THE
RIDGE NEXT WEEKEND AND THE ARRIVAL OF ANY SUBSEQUENT SYSTEMS...AS
SHOWN BY INCREASING ENSEMBLE SPREADS. HAVE LOWERED POPS THROUGH THE
EXTENDED TO SLIGHTLY BELOW CLIMATOLOGY GIVEN THE CONTINUED INFLUENCE
OF THE RIDGE. BROWN

&&

.AVIATION...NO MAJOR CHANGES. ONSHORE FLOW CONTINUES...ALONG WITH 
SCATTERED LIGHT SHOWERS. OVERALL...MOSTLY VFR CONDITIONS WITH LOCAL 
MVFR CIGS UNDER THE SHOWERS. WORST CONDITIONS OVER THE CASCADES 
WHERE PASSES AND MTS WILL BE FREQUENTLY OBSCURED TODAY. AS AIR MASS 
STABILIZES THIS AFTERNOON AND TONIGHT...WILL SEE LARGE AREAS OF 
CLEARING. BUT THAT CLEARING WILL INCREASE THE THREAT OF FOG AND LOW 
CLOUDS. AT THIS TIME...WILL SEE AREAS OF FOG FORMING OVER INLAND 
AREAS AFTER 07Z...AND PERSISTING WELL INTO WED AM. 

KPDX AND APPROACHES...VFR...BUT WILL SEE VERY BRIEF OCCASIONAL HIGH 
MVFR CIGS OF 2500 TO 3000 FT THROUGH 19Z. AFTER 19Z...BECOMING 
PARTLY CLOUDY WITH VFR. WILL SEE FOG OR IFR STRATUS FORMING AROUND 
KPDX OPS AREA BETWEEN 08Z AND 10Z TONIGHT. 

&&

.MARINE...NO MAJOR CHANGES. HIGH PRES OFFSHORE WILL KEEP GUSTY NW 
WINDS ON THE COASTAL WATERS...ALTHOUGH WINDS WILL GRADUALLY BE 
EASING TODAY. SEAS REMAIN 13 TO 15 FT...BUT THESE TOO WILL 
SUBSIDE...DROPPING BELOW 10 FT TONIGHT. NO MAJOR WEATHER EXPECTED 
FROM WED THROUGH FRI AS HIGH PRES OVER PAC NW KEEPS COASTAL WATERS 
DRY WITH OFFSHORE WINDS.

&&

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

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON FOR 
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR 
     FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM PST TUESDAY 
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR FROM
     10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 5 PM 
     PST TUESDAY.

&&

$$

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

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.