FXUS66 KPQR 282227
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
226 PM PST SAT NOV 28 2009

.SYNOPSIS...THE TAIL END OF A WARM FRONT WILL DRIFT ACROSS THE
NORTH ZONES TONIGHT...AND THEN LIFT TO THE NORTH ON SUNDAY. AN UPPER
RIDGE WILL STRENGTHEN OVER THE AREA SUNDAY AND SHOULD PERSIST
THROUGH MONDAY...WHICH WILL RESULT IN VALLEY INVERSIONS AND AREAS OF
FOG. ANOTHER SYSTEM WILL RIDE OVER THE RIDGE MONDAY AND MONDAY
NIGHT...BUT AT MOST BRUSH THE FAR NORTH PART OF OUR FORECAST AREA.
OTHERWISE...THE UPPER RIDGE WILL CONTINUE THROUGH MOST OF NEXT WEEK
WITH AN INVERSION AND VALLEY FOG PERSISTING.

&&

.SHORT TERM...MODELS AND IR SATELLITE SHOW A WARM-FRONTAL FEATURE
OVER THE EASTERN PAC AND ONTO THE WA COAST WHICH WILL SAG INTO 
EXTREME NW OREGON TONIGHT. THIS WILL GIVE SOME DRIZZLE AND/OR LIGHT
RAIN TO THE NORTHERN ZONES ESPECIALLY MOUNTAINS.

THE UPPER RIDGE WILL STRENGTHEN SUN WHICH WILL PUSH RESIDUAL WARM
FRONT MOISTURE TO THE N. VERY LIGHT OFFSHORE SURFACE GRADIENTS SET UP
SUN AFTERNOON WITH SURFACE HIGH PRES CENTERED NEAR THE OREGON AND
IDAHO BORDER....WITH OFFSHORE GRADIENTS PICKING UP A BIT SUN NIGHT
INTO MON. THIS FAVORS A VALLEY FOG PATTERN AS AN INVERSION SETS UP
UNDER THE RIDGE...BUT SHOULD SEE A LITTLE E WIND DEVELOP NEAR THE
GORGE. THE TRAILING COLD FRONT CURRENTLY OVER THE NE PAC WILL PUSH
INTO WA LATE MON/MON NIGHT...BUT IT APPEARS THE UPPER RIDGE WILL HOLD
IT N OF THE FORECAST AREA. THE SYSTEM MAY TURN THE LOW LEVEL FLOW
BRIEFLY ONSHORE...BUT WEAK OFFSHORE FLOW SHOULD RESUME TUE AFTERNOON.
RW 

.LONG TERM...THE UPPER RIDGE IS LIKELY TO HOLD THROUGH MIDWEEK...
ALTHOUGH THE ECMWF HAS A WEAK UPPER LOW CUTTING UNDERNEATH THE RIDGE
ON WED. THAT SOLUTION IS NOT SUPPORTED BY GFS ENSEMBLES OR THE
CANADIAN MODEL. BEGINNING ABOUT THU THE VARIOUS MODEL ARE SHOWING
LARGE VARIATIONS IN POSSIBLE SOLUTIONS AS THE UPPER RIDGE POTENTIALLY
RETROGRADES INTO THE PAC. GFS ENSEMBLES HINT AT HIGHER POPS CENTERED
AROUND FRI. WE HAVE ADDED POPS IN THE THU THROUGH SAT PERIOD BUT KEPT
THEM WELL BELOW CLIMO UNTIL THERE IS BETTER CONSISTENCY IN MODEL
SOLUTIONS. RW

&&

.AVIATION...OVERALL CONDITIONS SLOW TO CHANGE. STILL VFR ACROSS THE 
REGION...WITH CIGS AROUND 4K TO 5K FT. CLOUDS BREAK MORE TONIGHT AS 
LIGHT OFFSHORE FLOW DEVELOPS BRINGING POSSIBILITY OF FOG TO INLAND 
SITES AFTER 08Z. HOWEVER...BEST CHANCE OF FOG WILL BE FROM KSLE 
SOUTHWARD. FEEL ONSHORE FLOW ACROSS NW PART OF THE AREA WILL KEEP 
PLENTY OF CLOUDS IN THE KAST TO KPDX AREA. THIS WILL LIMIT FOG TO BE 
VERY PATCHY AT BEST.  

KPDX AND APPROACHES...VFR CLOUDS TO HOLD ACROSS KPDX OPS AREA 
THROUGH THIS EVENING. NO ADVERSE WEATHER IMPACTS EXPECTED THROUGH 
15Z.  ROCKEY.

&&

.MARINE...WINDS REMAIN UNDER 20 KT FOR NEXT SEVERAL DAYS. SWELL 
GENERATED FROM AFAR HAS ARRIVED. THIS SWELL WILL VARY IN HEIGHT FROM 
TIME TO TIME...BUT GENERALLY REMAIN IN THE 12 TO 15 FT RANGE THRU 
TUE. LARGEST WAVES WILL BE OVER NORTH AND OUTER COASTAL WATERS. 

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR COASTAL WATERS   
      FROM CAPE SHOALWATER TO FLORENCE THROUGH SUN.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR CONDITIONS     
      FOR THIS AFTERNOON...AND AGAIN LATE TONIGHT THRU SUN.

&&

$$

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.