FXUS66 KPQR 011011
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
211 AM PST TUE DEC  1 2009

.SYNOPSIS...A WEAK FRONTAL BOUNDARY WAS DROPPING SLOWLY SOUTH THROUGH
THROUGH NORTHWEST OREGON EARLY THIS MORNING WITH A LITTLE LIGHT RAIN
AND DRIZZLE. A TRAILING UPPER SHORT WAVE WILL DIVE SOUTHEAST THROUGH
INTO THE ROCKY MOUNTAIN REGION TODAY...ALLOWING AN EASTERN PACIFIC
UPPER RIDGE TO SHARPEN ALONG THE WEST COAST. A SURFACE HIGH WILL DROP
SOUTH INTO THE AREA EAST OF THE CASCADES TODAY AND INTENSIFY
TONIGHT...WITH INCREASING EAST WINDS THROUGH THE COLUMBIA RIVER
GORGE. THE OFFSHORE FLOW WILL THEN CONTINUE THROUGH AT LEAST
THURSDAY. THE MODELS BEGIN DIVERGING SIGNIFICANTLY AFTER THURSDAY AS
A SYSTEM WILL LIKELY BEGIN AFFECTING THE PACIFIC NORTHWEST AROUND
FRIDAY...AND POSSIBLY AGAIN EARLY NEXT WEEK.
&&

.SHORT TERM...A WEAK FRONTAL BOUNDARY HAS BEEN DROPPING THROUGH
SOUTHWEST WASHINGTON AND NORTHWEST OREGON OVERNIGHT WITH A LITTLE
LIGHT RAIN AND DRIZZLE...AND IS NOW IN THE CENTRAL AND SOUTH
WILLAMETTE VALLEY. THERE ARE PLENTY OF CLOUDS IN ITS WAKE...WITH
LOCAL AREAS OF FOG AS WELL. THE RESPONSIBLE UPPER SHORT WAVE IS
DIVING SOUTHEAST INTO THE ROCKY MOUNTAIN REGION...WITH THE UPPER
RIDGE ALONG THE WEST COAST SHARPENING UP BEHIND IT.

THIS WILL BRING A MORE NORTHERLY FLOW ALOFT TO OUR AREA AS TODAY
PROGRESSES...AND DRAG A SURFACE HIGH SOUTHWARD INTO THE REGION EAST
OF THE CASCADES TODAY. THIS SURFACE HIGH INTENSIFIES TONIGHT. WE
SHOULD BEING GETTING SOME EAST WIND THROUGH THE GORGE BY THIS
AFTERNOON WHICH WILL HELP CLEAR OUT THE NORTH VALLEY AREAS AND THE
COAST...BUT THE SOUTH VALLEY AREAS MAY TAKE QUITE A WHILE TO BREAK
OUT TODAY AS THERE IS NOT MUCH NORTHERLY COMPONENT TO THE OFFSHORE
FLOW.

THE OFFSHORE GRADIENT THROUGH THE GORGE INCREASES FROM 4 OR 5 MB LATE
TODAY TO 6 TO 7 MB TONIGHT AND CONTINUES AROUND THAT VALUE THROUGH
ABOUT THURSDAY. THIS SHOULD GIVE GUSTS TO 40 OR 45 MPH AT THE WEST
END OF THE GORGE BEGINNING TONIGHT. THIS SHOULD ALSO DECREASE THE
AMOUNT OF FOG IN THE PORTLAND AREA...BUT THINK SOME MAY STILL FORM
DOWN NEAR EUGENE IN THE LATE NIGHTS AND MORNINGS. THE GRADIENT
REMAINS MOSTLY EASTERLY...SO MIXING OF DRY AIR DOWN THE WILLAMETTE
VALLEY WILL TAKE SOME TIME AND MAY NOT ENTIRELY PREVENT FOG DOWN
SOUTH THROUGH THURSDAY. PLACES THAT CLEAR AND DO NOT REFORM MUCH FOG
BUT ALSO WHERE THE WINDS EASE AT NIGHT MAY SEE SOME TEMPS DOWN BELOW
FREEZING THE NEXT COUPLE OF MORNINGS. THINGS LOOK DRY THROUGH
THURSDAY AFTER A FEW DRIZZLE PATCHES THIS MORNING. TOLLESON

.LONG TERM...AFTER FAIRLY GOOD AGREEMENT IN THE SHORT TERM...THE
MEDIUM RANGE MODELS DIVERGE SIGNIFICANTLY EARLY IN THE LONGER TERM
PERIOD...ESPECIALLY THE NCEP GFS MODEL. THE 00Z GFS TAKES A SHORT
WAVE OVER THE WEST COAST RIDGE INLAND WELL TO OUR NORTH ON FRIDAY...
LEAVING US DRY. IT ATTEMPTS TO TURN THE LOW LEVEL FLOW BRIEFLY
ONSHORE BEFORE TURNING IT STRONGLY OFFSHORE AGAIN THIS WEEKEND AND
EARLY NEXT WEEK. THE ECMWF...CANADIAN...AND EVEN THE NAM12 BRING A
SYSTEM DOWN FROM THE NORTHWEST ON FRIDAY WITH SOME COLD VALLEY RAIN
AND MOUNTAIN SNOW. WILL POSSIBLY NEED TO UP POPS FOR FRIDAY IF THESE
TRENDS CONTINUE. THE CANADIAN AND ECMWF BOTH THEN SHOW A CUT BACK
SYSTEM INTERACTING WITH SOME SOUTHERN STREAM ENERGY AND MOISTURE
EARLY NEXT WEEK WITH A LOW SETTING UP OFF THE COAST. THIS COULD BE AN
INTERESTING PATTERN DEVELOPMENT WITH OFFSHORE FLOW THROUGH THE GORGE.
CURRENT FORECASTS TAKE A CONSERVATIVE APPROACH AND WILL CONTINUE THAT
FOR NOW...BUT WILL NEED TO MONITOR HOW THIS DEVELOPS. TOLLESON
&&

.AVIATION...AN INCONGRUENT SMATTERING OF FLIGHT CONDITIONS THIS
MORNING THOUGH MOST IFR IS DUE TO LOW STRATUS. WHEN STRATUS BREAKS
MAY SEE A BRIEF PERIOD OF VFR BEFORE IFR FOG DEVELOPS. EXPECT A
SIMILAR TREND THROUGH MID MORNING BEFORE EAST WIND PICKS UP AND MIXES
IFR CONDITIONS OUT TO VFR. MAY LINGER A LITTLE LONGER IN THE SOUTH. 

KPDX AND APPROACHES...DITTO ON AVIATION DISCUSSION WITH EAST WINDS
EXPECTED TO PICK UP AFTER 18Z FOR GRADUAL IMPROVEMENT TO VFR
CONDITIONS BY 21Z. WOLFE
&&

.MARINE...SEAS AROUND 10 TO 11 FT SO HOISTED SCA FOR HAZARDOUS SEAS
THROUGH THIS MORNING. WINDS GRADUALLY TURN OFFSHORE AND STRENGTHEN
TODAY. WINDS SHOULD STAY BELOW ADVISORY LEVELS BUT WILL SEE GUSTS TO
20 KT AS THE WINDS VEER FROM NORTH TO NORTHEAST TOMORROW
AFTERNOON...ESPECIALLY NEAR COASTAL GAPS. ANOTHER WEAK FRONT WILL
ENTER THE WATERS ON THU FOR SEAS AROUND 10 FT...FOLLOWED BY NEAR
SMALL CRAFT NORTHERLIES AFTER FRONTAL PASSAGE THU EVENING. WOLFE
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM PST THIS 
     MORNING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE  
     OR.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 8 AM
     PST THIS MORNING.

&&

$$

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.