FXUS66 KPQR 080414
AFDPQR

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

.SYNOPSIS...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...WINDS HAVE DECREASED A LOT THIS EVENING OVER THE
FORECAST AREA. HOWEVER THE  EASTERLY WINDS ARE CONTINUING OVER THE
NORTHERN VALLEY...ESPECIALLY IN THE VICINITY OF THE GORGE. ANOTHER
SHORTWAVE TROUGH WILL ARRIVE FROM THE NORTH TONIGHT. 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. LIKENS

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...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. 

&&

.MARINE...BRISK AND GUSTY OFFSHORE FLOW IS BEGINNING TO EASE THIS 
EVENING ACROSS THE COASTAL WATERS. SEAS HAVE RESPONDED AND ARE 
GENERALLY 5 FT OR LESS THIS EVENING...LIGHT SEAS SHOULD CONTINUE 
THROUGH THE NIGHT TONIGHT. BUILDING WEST SWELL FROM AN ALEUTIAN 
STORM SYSTEM SHOULD CAUSE SEAS TO EXCEED 10 FT IN OUR OUTER WATERS 
BY MIDDAY TUE...WITH THE SWELL SPREADING TO THE COASTLINE BY 
EVENING. WEST SWELL 10-12 FT IS THEN EXPECTED TO AFFECT THE COASTAL 
WATERS THROUGH TUE NIGHT BEFORE SUBSIDING. THE SWELL IS FAIRLY LONG 
IN PERIOD...AROUND 20 SECONDS...SO WHEN IT ARRIVES IT SHOULD RESULT 
IN ROUGH BAR CONDITIONS DURING THE EBBS...ESPECIALLY DURING THE 930 
PM EBB TUE NIGHT. HIGH PRESSURE SHOULD KEEP WINDS RELATIVELY LIGHT 
THROUGH THU...THEN THERE IS THE POTENTIAL FOR A STRONGER LOW TO 
AFFECT THE COASTAL WATERS SOMETIME FRI-SAT.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...SCA FOR HAZARDOUS SEAS CAPE SHOALWATER TO FLORENCE OUT
 10-60 NM OFFSHORE MIDDAY TUE THROUGH TUE NIGHT.
SCA FOR HAZARDOUS SEAS CAPE SHOALWATER TO FLORENCE OUT
 10 NM TUE NIGHT.

&&

$$

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.