FXUS66 KPQR 301654
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
853 AM PST MON NOV 30 2009

.SYNOPSIS...AN UPPER LEVEL RIDGE OVER THE AREA THIS MORNING IS
BRINGING VALLEY INVERSIONS AND AREAS OF FOG TO THE FORECAST AREA. A
WEAK WEATHER SYSTEM WILL RIDE OVER THE RIDGE LATER TODAY AND
TONIGHT...BUT AT MOST WILL BRUSH THE FAR NORTH PART OF OUR FORECAST
AREA. OTHERWISE...THE UPPER RIDGE IS EXPECTED TO CONTINUE THROUGH
MOST OF THE WEEK AS PACIFIC SYSTEMS DISSIPATE OFFSHORE. COOLER
OFFSHORE FLOW MAY ARRIVE THIS WEEKEND AS HIGH PRESSURE MOVES EAST OF
THE CASCADES.

&&

.SHORT TERM...FOG AND LOW STRATUS COVERING MOST OF THE AREA THIS
MORNING WITH SOME LIGHT DRIZZLE ON THE NORTH COAST AND TO THE LOWER
COLUMBIA ZONES.  LATER IN THE DAY A WEAK SYSTEM WILL MOVE OVER THE
TOP OF THE RIDGE AND SWEEP ACROSS WA...WITH THE SOUTHERN PART OF THIS
SYSTEM FALLING APART AS IT ENCROACHES ON OUR FORECAST AREA. MAIN
AFFECT WILL BE A SWITCH TO LOW-LEVEL ONSHORE FLOW THIS AFTERNOON.
ADDED SLIGHT CHANCE POPS WITH THIS SYSTEM ALONG OUR NORTHERN BORDER
WHERE NAM AND GFS MODELS HINT AT SOME POPS THIS AFTERNOON AND
TONIGHT. 

THE UPPER RIDGE REBOUNDS TUE AS SURFACE HIGH PRES OVER EASTERN BC
DROPS SE...WHICH WILL TURN THE LOW LEVEL FLOW BACK TO OFFSHORE. THIS
DRY PATTERN CONTINUES TUE NIGHT AND WED. LIKENS/HIGA

.LONG TERM...MODELS MAINTAIN THEIR STRUGGLE FROM THU ONWARD AS THEY
CONTINUE WITH VARIATIONS IN POSSIBLE SOLUTIONS WITH THE UPPER RIDGE
RETROGRADING INTO THE NE PAC. FOR NOW WILL CONTINUE WITH POPS WELL 
BELOW CLIMO UNTIL THERE IS BETTER CONSISTENCY IN MODEL SOLUTIONS.
ECMWF HAS BEEN MORE INCONSISTENT FROM RUN TO RUN THAN THE GFS FRIDAY
ON.

&&

.AVIATION...GENERALLY IFR CONDITIONS OVER MUCH OF THE AREA AND WILL 
LIKELY STAY IFR IN THE S WILLAMETTE VALLEY THROUGH THIS AFTERNOON. 
OTHER AREAS WILL LIKELY RETURN TO VFR OR MVFR CEILINGS BY THE 
AFTERNOON AS A BIT OF ONSHORE FLOW AHEAD OF A WEAK FRONT MIXES THE 
BOUNDARY LAYER UP.

KPDX AND APPROACHES...IFR CIGS SHOULD CONTINUE THROUGH 18Z...THEN 
MVFR CONDITIONS ARE EXPECTED THEREAFTER AS A WEAK FRONT DROPS SE 
THROUGH THE AREA.

.MARINE...WINDS WILL REMAIN BELOW SMALL CRAFT LEVELS FOR THE NEXT 
SEVERAL DAYS. SEAS WILL REMAIN HIGH...GENERALLY BETWEEN 14 AND 17 FT 
THROUGH TODAY. SEAS SHOULD SUBSIDE TONIGHT THEN FALLING BELOW 10 FT 
BY TUE MORNING. 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST TUE
       FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR.
     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM
       PST TUE.

&&

&&

$$

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.