FXUS66 KPQR 021654
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
853 AM PST WED DEC  2 2009

.SYNOPSIS...A STRONG/SHARP UPPER RIDGE WAS ALONG THE WEST COAST THIS
MORNING AND WILL CONTINUE OVER THE PACIFIC NORTHWEST WITH DRY WEATHER
AND OFFSHORE FLOW. A WEATHER SYSTEM SYSTEM IN THE NORTHEAST PACIFIC
AND EASTERN GULF OF ALASKA WILL DROP IN FROM THE NORTHWEST ON
FRIDAY...THEN DEVELOP INTO A CLOSED LOW OVER THE INTERIOR OF THE
PACIFIC NORTHWEST FRIDAY NIGHT AND SATURDAY. THIS MAY BRING SOME
PRECIPITATION TO THE AREA...WITH LOW SNOW LEVELS. DRY AIR FROM THE
CURRENT OFFSHORE FLOW COULD LEAD TO A FEW FLURRIES CLOSE TO SEA LEVEL
INITIALLY BEFORE THE LOW LEVEL FLOW TURNS ONSHORE. THE FLOW TURNS
OFFSHORE AGAIN FRIDAY NIGHT AND OVER THE WEEKEND FOR ANOTHER CHANCE
OF FLURRIES NEAR SEA LEVEL. ENERGY CONTINUES TO DUMBBELL AROUND THE
LOW THIS WEEKEND AND INTO EARLY NEXT WEEK BUT MOISTURE IS A BIT
SPARSE. THE MODELS SUGGEST MORE SUBSTANTIAL MOISTURE IS POSSIBLE FROM
THE WEST AROUND THE MIDDLE OF NEXT WEEK.
&&

.SHORT TERM...A SHARP UPPER RIDGE WAS CLOSE TO THE PACIFIC NORTHWEST
COAST THIS MORNING...WITH DRY NORTHERLY FLOW DIVING DOWN THROUGH
CENTRAL AND EASTERN WASHINGTON AND OREGON. A COLD HIGH SETTLED IN
EAST OF THE CASCADES INCREASING OFFSHORE FLOW OVERNIGHT. GRADIENTS
THROUGH THE GORGE ARE AROUND 7 MB THIS MORNING WITH GUSTS
IN THE GORGE PUSHING 40 MPH. THE DRYING OFFSHORE FLOW HAS PUSHED
SOUTH DOWN THROUGH THE CENTRAL WILLAMETTE VALLEY AND THE WESTERN PART
OF THE SOUTH VALLEY...BUT A FINGER OF FOG AND STRATUS REMAINS ALONG
THE FAR SOUTH CASCADE FOOTHILLS. THIS SHOULD ALL CLEAR OUT
TODAY...WITH JUST PATCHY FOG DOWN SOUTH FOR THE NEXT DAY OR TWO. THE
OFFSHORE FLOW SHOULD NOT CHANGE MUCH THROUGH AT LEAST THURSDAY.

THEN THE MODELS SHOW A SYSTEM THAT IS CURRENTLY BETWEEN 130W AND 140W
WILL CRASH THROUGH THE RIDGE AND INTO THE PACIFIC NORTHWEST LATE
THURSDAY NIGHT AND FRIDAY. THE OFFSHORE FLOW SHOULD WEAKEN THURSDAY
NIGHT...THEN TURN ONSHORE DURING THE DAY ON FRIDAY AS THE SYSTEM
MOVES THROUGH. THE GFS MODEL STILL IS FARTHER NORTH WITH THE TRACK OF
THE SYSTEM AND HENCE WEAKER...AND THE ECMWF AND CANADIAN CLOSER TO
OUR AREA AND MORE CONSISTENT. THE 00Z ECMWF SHIFTED THIS SYSTEM
FURTHER TO THE EAST AND LOOKS DRIER. WILL CONTINUE WITH THE CURRENT
POPS AND WAIT FOR THE 12Z ECMWF BEFORE DECIDING ON CHANGES.
WITH THE DRY AIR IN PLACE AND THIS SYSTEM COMING IN FROM THE
NORTH...IF PRECIPITATION OCCURS IS COULD BE AS FLURRIES CLOSE TO SEA
LEVEL BEFORE THE LOW LEVEL FLOW TURNS ONSHORE AND MOISTENS AND
MODERATES. QPF EVEN ON THE STRONGER ECMWF IS LIGHT SO DO NOT EXPECT
MUCH OF AN IMPACT AT THIS POINT. STILL IT COULD BE THE FIRST BRUSH
WITH WINTER. TOLLESON/HIGA

.LONG TERM...THE LOW LEVEL FLOW TURNS OFFSHORE AGAIN FRIDAY NIGHT AND
SATURDAY AS THE SYSTEM FROM FRIDAY DEVELOPS INTO A CLOSED OVER OVER
THE INTERIOR OF THE PACIFIC NORTHWEST. THE GFS REDEVELOPS OFFSHORE
FLOW DURING THIS PERIOD OVER OUR AREA THE FASTEST AND MOST
STRONGLY...WITH THE ECMWF DELAYING IT MORE UNTIL SATURDAY. STILL...
THIS COULD BRING FLURRIES BACK DOWN TO NEAR SEA LEVEL AGAIN... THOUGH
THE MODELS REMAIN A BIT MEAGER ON ANY MOISTURE IN OUR AREA. DETAILS
EARLY NEXT WEEK NOT CERTAIN THOUGH THE MODELS INDICATE SOME ENERGY
DUMBBELLS AROUND BACK OFF THE COAST THEN SWINGS INLAND MONDAY INTO
TUESDAY. STILL...THE MAIN MOISTURE SKIRTS OUR AREA A BIT... THOUGH IT
REMAINS RATHER COLD. THE MODELS INDICATE THE WESTERLIES MAY BREAKS
THROUGH WITH SOME MORE SIGNIFICANT MOISTURE IN THE MIDDLE OF NEXT
WEEK...BUT A LOT CAN HAPPEN BETWEEN NOW AND THEN THOUGH IT BEARS
WATCHING. TOLLESON
&&

.AVIATION...PATCHY IFR FOG IN THE SOUTH VALLEY WILL MIX OUT THIS 
MORNING. ELSEWHERE VFR CONDITIONS WILL PERSIST AS DRY OFFSHORE FLOW 
CONTINUES THE NEXT 24 HOURS.

KPDX AND APPROACHES...VFR CONDITIONS THROUGH THU. EAST WINDS OUT OF 
THE COLUMBIA RIVER GORGE WILL STRENGTHEN TO THE EAST OF THE KPDX 
TERMINAL AND MAY IMPACT THE RUNWAYS AT TIMES. LRAMIREZ/RUTHFORD

&&

.MARINE...OFFSHORE FLOW COULD RESULT IN SOME GUSTS TO 20 TO 25 KT 
NEAR COASTAL GAPS THIS AFTERNOON. OTHERWISE...RELATIVELY BENIGN 
CONDITIONS EXPECTED OVER THE COASTAL WATERS THE NEXT COUPLE OF DAYS. 
WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT LEVELS THROUGH AT LEAST 
THURSDAY. MODELS DELAYED THE ARRIVAL OF THE NEXT WEAK FRONT. 
PREVIOUSLY THOUGHT TO ARRIVE THU....RATHER IT WILL ENTER THE WATERS 
ON FRI FOR SEAS NEAR 10 FT...FOLLOWED BY NEAR SMALL CRAFT 
NORTHERLIES AFTER FRONTAL PASSAGE FOR THE REMAINDER OF THE WEEKEND. 
LRAMIREZ

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THIS
AFTERNOON.

&&

$$

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.