616 
FXUS66 KMFR 210504
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
900 PM PST FRI NOV 20 2009

.DISCUSSION...TONIGHT THROUGH TOMORROW MORNING...PRECIPITATION AND 
WINDS WILL DIMINISH ACROSS THE REGION AS THE COLD FRONT CONTINUES
EASTWARD. SNOW LEVELS WILL DROP TO AROUND 2500 FEET IN
MANY PLACES ON THE WEST SIDE. MODELS HAVE TRENDED STRONGER
RECENTLY WITH NEXT WEATHER SYSTEM TO AFFECT THE CWA ON SATURDAY
NIGHT INTO SUNDAY MORNING..AS A LOW PRESSURE CENTER OF NEAR 990MB
WILL LIKELY MOVE OVER NORTHERN OREGON OR SOUTHERN WASHINGTON ON
SUNDAY. 60 KNOT SOUTHWEST WINDS AT 925 MB OVER COASTAL WATERS ARE
NOTED ON THE LATEST NAM RUN. THIS COULD BE THE THIRD SYSTEM OF
THIS STRENGTH IN THE PAST WEEK. SNOW LEVELS WILL RANGE FROM 4000
TO 5000 FEET ACROSS THE REGION SUNDAY MORNING WHEN THE BULK OF THE
PRECIPITATION ARRIVES. THIS STORM FOCUSES MORE SNOW OVER THE
CASCADES THAN THE SISKIYOUS...BUT WILL NEED TO FINE TUNE THE
EXPECTED SNOWFALL ACCUMULATIONS WITH THE UPCOMING MODEL RUNS AS
THEY HAVE SOME VARIANCE IN RECENT RUNS. WIND-RELATED HEADLINES
WILL LIKELY BE ISSUED FOR THIS STORM ALONG COASTAL WATERS AND
FAVORED INLAND LOCATIONS. ECMWF...GFS...AND NAM SUGGEST UPPER
RIDGING DEVELOPING OVER OR AND NORTHERN CA MONDAY. KEENE

.LONG TERM...LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT IN 
BUILDING A STRONG RIDGE OVER THE REGION TUESDAY-WEDNESDAY. WE EXPECT 
DURING THIS TIME OVERNIGHT AND MORNING VALLEY FOG TO BE COMMON FOR 
AT LEAST THE WEST SIDE...WITH FREEZING FOG IN SOME AREAS AS VALLEY  
MIN TEMPERATURES DIP WELL INTO THE 30S. THE HIGHER ELEVATIONS 
SHOULD HAVE QUITE NICE WEATHER IN THIS TIME PERIOD WITH PLENTY OF 
SUN AND HIGHS NEAR 50. THURSDAY THROUGH THURSDAY NIGHT ANOTHER COLD 
FRONT IS ADVERTISED AND WE'VE TRENDED RAIN CHANCES WEST TO EAST IN 
THIS PERIOD WITH COOLING TEMPERATURES. STAVISH

AVIATION...FLYING WEATHER TODAY FEATURES MVFR VISIBILITY AND 
CEILINGS OVER THE EAST SIDE WITH VFR CEILINGS OVER THE WEST SIDE.
SNOW WILL REDUCE VISIBILITIES ALONG THE CASCADES...SISKIYOUS...AND
THE EAST SIDE THROUGH SATURDAY MORNING. MOUNTAIN OBSCURATION WILL
BE PREVALENT ACROSS THE REGION THROUGH SATURDAY. MVFR CEILINGS
OVER RBG AND MFR WILL LIKELY FALL TO IFR DURING THE NIGHTTIME
HOURS...AND THESE IFR CONDITIONS SHOULD CONTINUE THROUGH AT LEAST
MIDDAY SATURDAY. KEENE

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 1 AM PST SATURDAY FOR ORZ027-
     ORZ028-ORZ029-ORZ030.
     WINTER WEATHER ADVISORY UNTIL 4 AM PST SATURDAY FOR ORZ025.

CA...WINTER WEATHER ADVISORY UNTIL 1 AM PST SATURDAY FOR CAZ080-
     CAZ081-CAZ084-CAZ085.
     WINTER STORM WARNING UNTIL 1 PM PST THIS EVENING FOR CAZ082-
     CAZ083.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 10 AM 
     TO 1 PM PST SATURDAY FOR PZZ350-PZZ356-PZZ370-PZZ376.
     GALE WARNING FROM 1 PM SATURDAY TO 4 AM PST SUNDAY FOR PZZ350-
     PZZ356.
     HAZARDOUS SEAS WARNING UNTIL 4 PM PST SUNDAY FOR PZZ350-PZZ356-
     PZZ370-PZZ376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THIS EVENING FOR 
     PZZ370.
     GALE WARNING FROM 1 PM SATURDAY TO 1 AM PST SUNDAY FOR PZZ370-
     PZZ376.

$$

NK/SN/MS/11