FXUS66 KPQR 301023
AFDPQR

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

.SYNOPSIS...AN UPPER LEVEL RIDGE IS OVER THE AREA THIS MORNING
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. 

&&

.SHORT TERM...SATELLITE FOG PRODUCT AND SURFACE OBSERVATIONS SHOW FOG
AND STRATUS BECOMING WIDESPREAD IN THE INLAND VALLEY LOCATIONS THIS
MORNING. ALONG WITH VALLEY FOG. WILL CONTINUE THE DENSE FOG ADVISORY
FOR THE SOUTH WILLAMETTE VALLEY AND WATCH THE REMAINDER OF THE VALLEY
LOCATIONS FOR POSSIBLE INCLUSION IN THE ADVISORY.

THE UPPER RIDGE WILL REMAIN OVER THE AREA THIS MORNING ALLOWING VERY
LIGHT OFFSHORE SURFACE GRADIENTS TO SET UP WITH SURFACE HIGH PRESSURE
CENTERED OVER THE COOLER TERRAIN EAST OF THE CASCADES. THE OFFSHORE
GRADIENTS SHOULD PEAK NEAR 3-4 MB FROM KDLS-KTTD BY 12Z THIS MORNING
FOR SOME GUSTS UP TO 30 MPH IN THE W GORGE. 

A WEAK SYSTEM WILL MOVE OVER THE TOP OF THE RIDGE AND SWEEP ACROSS WA
THIS AFTERNOON/EVE...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

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...MODELS
MAINTAIN THEIR STRUGGLE FROM THU ONWARD AS THEY CONTINUE WITH
VARIATIONS IN POSSIBLE SOLUTIONS WITH THE UPPER RIDGE RETROGRADING
INTO THE NE PAC. GFS ENSEMBLES NOW HINTING AT HIGHER POPS CENTERED 
AROUND THU NIGHT...AND AGAIN BY SUN. WILL CONTINUE WITH POPS WELL 
BELOW CLIMO UNTIL THERE IS BETTER CONSISTENCY IN MODEL SOLUTIONS. RW

&&

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

KPDX AND APPROACHES...IFR CIGS SHOULD CONTINUE THROUGH 18Z. VFR
CONDITIONS ARE EXPECTED THEREAFTER.

&&

.MARINE...WINDS WILL REMAIN BELOW SMALL CRAFT LEVELS FOR THE NEXT 
SEVERAL DAYS. SEAS WILL REMAIN HIGH...GENERALLY BETWEEN 12 AND 16 FT 
THROUGH TONIGHT. SEAS SHOULD SUBSIDE BELOW 10 FT EARLY TUE. 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR SOUTH 
     WILLAMETTE VALLEY.

WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST TUESDAY 
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR.

     SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 4 AM PST TUESDAY FOR 
     COLUMBIA RIVER BAR.

&&

$$

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.