FXUS66 KPQR 072249
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
249 PM PST MON DEC  7 2009

.SYNOPSIS...A COLD UPPER TROUGH WILL SLOWLY DROP SOUTH OF THE REGION
TODAY. A MODIFIED ARCTIC AIR MASS WILL CONTINUE THROUGH TUESDAY WHILE
GUSTY NORTHEAST WINDS SLOWLY TAPER OFF. COLD DRY WEATHER WILL PERSIST
THROUGH MUCH OF THE WEEK WITH PRECIPITATION CHANCES INCREASING AGAIN
THIS WEEKEND WITH THE POSSIBILITY OF PRECIPITATION BEGINNING AS SNOW
OR A WINTERY MIX.

&&

.SHORT TERM...GUSTY NORTH TO NORTHEAST WINDS CONTINUE THIS AFTERNOON
AS MUCH OF THE AREA AS AN UPPER TROUGH SLIDES TO THE SOUTH OF THE
AREA. WINDS WILL DECREASE A LOT OVERNIGHT AS ANOTHER SHORTWAVE TROUGH
ARRIVES FROM THE NORTH. BY TOMORROW AFTERNOON THIS SHORTWAVE TURNS
THE 850 MB FLOW ONSHORE...WHILE THE LOW LEVELS REMAIN OFFSHORE.
MODELS ARE INDICATING IT WILL BE TOO DRY FOR ANY PRECIPITATION. IT
BEARS WATCHING AS SOME LIGHT SNOW MAY OCCUR OVER THE SOUTH COAST AND
COAST RANGE TUE AFTERNOON AND EVENING.	ANOTHER SHORTWAVE DROPS IN
WED...BUT THIS IS AN INSIDE SLIDER AND WILL NOT AFFECT THE AREA. 

WINDS WILL EVENTUALLY BE CONFINED TO THE WESTERN GORGE OVERNIGHT
WHERE THE COLD LOW LEVEL AIR MASS STACKED UP OVER THE COLUMBIA BASIN
AND E SLOPES WILL MAINTAIN A MODERATE GRADIENT THROUGH THE GORGE
THROUGH TUE MORNING.

CALMER AND MORE STABLE CONDITIONS IN MUCH OF THE COAST AND INLAND
VALLEYS TONIGHT AND TUE MORNING WILL LIKELY BRING THE COLDEST SURFACE
TEMPERATURES TO THE LOW LYING INVERSION PRONE AREAS. GUIDANCE SHOWS
THE OFFSHORE FLOW WEAKENING TUE AFTERNOON AND TUE NIGHT...THEN
BECOMING NEUTRAL BY WED AFTERNOON. WITH THE WEAKER OFFSHORE FLOW
SHOULD ALLOW FOR SLIGHTLY WARMER DAYTIME TEMPERATURES. 

.LONG TERM...DRY CONDITIONS PREVAIL THROUGH MID NEXT WEEK AS NW FLOW 
ALOFT CONTINUES OVER THE REGION. MODELS AGREE THAT THE NEXT SYSTEM 
SHOULD ARRIVE AROUND LATE FRI/EARLY SAT. PRECIP CHANCES WILL 
INCREASE BY LATE FRI...WITH THE BIGGEST THREAT OF FREEZING RAIN OR 
MIXED PRECIP FOR THE EASTERN PORTION OF THE CWA BEGINNING AROUND FRI 
NIGHT. HAVE EXTENDED THE POSSIBILITY OF FREEZING RAIN INTO THE 
FOOTHILLS AND VALLEY MAINLY FRI NIGHT...BECOMING LIKELY INTO SAT 
MORNING. EXPECT WET BUT WARMER CONDITIONS TO PERSIST INTO THE 
FOLLOWING WEEK. LRAMIREZ

&&

.AVIATION...DRY OFFSHORE FLOW IS EXPECTED THROUGH THE NEXT 24 HOURS 
WITH VFR CONDITIONS. GUSTY EAST WINDS EXPECTED THROUGH GAPS IN 
TERRAIN.

KPDX AND APPROACHES...VFR CONDITIONS ARE EXPECTED THROUGH THE NEXT 
24 HOURS. BRISK EASTERLY WINDS WILL CONTINUE THROUGH TUE MORNING.
WOLFE

&&

.MARINE...STRONG OFFSHORE FLOW CONTINUES TO GENERATE EASTERLY WIND 
WAVES OVER THE WATERS. SEAS AROUND 9 FT IN THE OUTER MARINE
ZONES. WEST SWELL AROUND 3 FT AND EASTERLY WIND WAVES WILL RESULT
IN CHOPPY SEAS THROUGH EARLY THIS WEEK. LARGER SWELL TRAIN WILL
MOVE INTO WATERS MIDWEEK PUSHING SEAS TO NEAR 12 FT. NO ORGANIZED
SYSTEMS EXPECTED UNTIL THE WEEKEND. WOLFE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.

&&

$$

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.