FXUS66 KPQR 292220
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
219 PM PST SUN NOV 29 2009

.SYNOPSIS...QUIET THROUGH MONDAY AS AN UPPER LEVEL RIDGE STRENGTHENS
OVER THE AREA. THIS WILL RESULT IN VALLEY INVERSIONS WITH AREAS OF
FOG. ANOTHER WEAK SYSTEM WILL RIDE OVER THE RIDGE LATE MONDAY AND
MONDAY NIGHT...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...LOW CLOUDS CONTINUING TO DECREASE ACROSS MOST NORTHERN
AREAS THIS AFTERNOON...ALTHOUGH HANGING TOUGH OVER SW WA IN THE
VICINITY OF THE OLD FRONTAL ZONE. WITH CLEARING AND VERY LIGHT
OFFSHORE FLOW DEVELOPING...WILL SEE COOL MINIMUMS TONIGHT WITH AREAS
OF VALLEY FOG FORMING. THE PERSISTENT FOG/LOW CLOUDS IN THE S VALLEY
SHOULD BRIEFLY BREAK UP THIS EVENING...THEN REFORM OVERNIGHT. 

THE UPPER RIDGE WILL STRENGTHEN TONIGHT...ALLOWING THE VERY LIGHT
OFFSHORE SURFACE GRADIENTS TO SET UP WITH SURFACE HIGH PRES CENTERED
OVER COOLER TERRAIN E OF THE CASCADES. THE OFFSHORE GRADIENTS SHOULD
PEAK NEAR 3-4 MB FROM KDLS-KTTD BY 12Z MON FOR SOME GUSTS UP TO 30
MPH IN THE W GORGE. 

THE NEXT SYSTEM IS LIKELY TO FALL APART AS A PORTION OF IT PUSHES
ACROSS WA MON AFTERNOON. MAIN AFFECT WILL BE A SWITCH TO LOW-LEVEL
ONSHORE FLOW MON AFTERNOON. MINIMAL...IF ANY...POPS WITH THIS
SYSTEM...WITH 18Z NAM AND GFS HINTING AT SOME POPS IN THE S WA
CASCADES MON NIGHT...POSSIBLY DROPPING INTO THE FAR N OREGON
CASCADES. 

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. RW

.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. 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...VFR ACROSS THE REGION...EXCEPT ALONG THE I5 CORRIDOR 
WHERE IFR FOG AND STRATUS PERSIST IN THE CENTRAL AND S WILLAMETTE 
VALLEY. STILL EXPECTING THAT FOG TO LIFT BETWEEN 19Z AND 
21Z...GIVING WAY TO VFR CONDITIONS. IN THE N WILLAMETTE...MOSTLY VFR 
BUT WILL SEE AREAS OF MVFR CIGS THROUGH 19Z. SHOULD SEE REPEAT OF 
CONDITIONS AGAIN TONIGHT...WITH MORE EXTENSIVE FOG LIKELY. 

KPDX AND APPROACHES...WILL CONTINUE TO SEE MIX OF MVFR AND LOW VFR 
THROUGH 19Z...THEN JUST VFR EXPECTED. LIKELY TO SEE FOG AND/OR LOW 
STRATUS FORM AFTER 09Z TONIGHT.     4CSTR...ROCKEY

&&

.MARINE...WINDS REMAIN UNDER 15 KT FOR THE NEXT SEVERAL DAYS.  SEAS 
REMAIN HIGH...GENERALLY REMAINING IN THE 12 TO 15 FT RANGE THRU MON 
NIGHT. APPEARS THAT SWELL WILL SUBSIDE BELOW 10 FT EARLY TUE. 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR COASTAL WATERS   
  FROM CAPE SHOALWATER TO FLORENCE THROUGH MON. 
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR     
  CONDITIONS THROUGH MON. 

&&

$$

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.