FXUS66 KPDT 272151
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
151 PM PST FRI NOV 27 2009

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...SATELLITE IMAGERY SHOWS 
THE SHARP BACKSIDE OF THE COLD FRONT MOVING INTO THE BLUE MOUNTAINS 
CURRENTLY. A WEATHER DISTURBANCE MOVING SOUTHEAST BEHIND THE FRONT 
IS SPREADING ISOLATED TO SCATTERED SHOWERS ACROSS CENTRAL OREGON. 
BOTH OF THESE SYSTEMS ARE EXPECTED TO MOVE OUT OF THE AREA THIS 
EVENING AND OVERNIGHT. SHOWERS WILL BE ON THE DECREASE WITH DRIER 
CONDITIONS EXPECTED BY SATURDAY. SKIES ARE CLEARING RAPIDLY BEHIND 
THE TWO SYSTEMS WHICH WILL LEAD TO COLD OVERNIGHT LOWS. SOME PATCHY 
FOG AND FREEZING FOG IS POSSIBLE LATE TONIGHT AND INTO SATURDAY 
MORNING IN THE LOWER ELEVATIONS OF THE COLUMBIA BASIN...PARTICULARLY 
NEAR THE BIG RIVERS (COLUMBIA...YAKIMA AND WALLA WALLA RIVERS). A 
RIDGE OF HIGH PRESSURE WILL BUILD AND MOVE INLAND THROUGH THE 
WEEKEND...PUSHING WEATHER SYSTEMS TO THE NORTH. A SYSTEM ON SATURDAY 
MAY BRUSH THE CENTRAL WASHINGTON CASCADES WITH A SLIGHT CHANCE OF 
PRECIPITATION MOVING EAST OF THE CREST. ELSEWHERE...INCREASING 
CLOUDS WILL BE THE MAIN AFFECT OF THE PASSING SYSTEMS. MOIST LOWER 
LEVELS WITH LIGHTER WINDS WILL LEAD TO THE SPREAD OF PATCHY FOG AND 
FREEZING FOG OVERNIGHT SUNDAY MORNING AND SUNDAY NIGHT LEADING INTO 
MONDAY MORNING. DMH

.LONG TERM...MONDAY THROUGH FRIDAY. THE EXTENDED MODELS ARE NOT IN 
VERY GOOD AGREEMENT SO LIMITED CHANGES WERE MADE TO THIS FORECAST 
PACKAGE. EURO AND GFS AGREE ON THE UPPER LEVEL RIDGE OVER THE AREA 
MONDAY WITH A WEAK SYSTEM PASSING BY TO THE NORTH MONDAY NIGHT AND 
TUESDAY. AFTER THIS THE MODELS ARE OUT OF SYNC WITH THE POSITIONS OF 
UPPER RIDGES AND UPPER LOWS. FOR NOW WENT WITH THE UPPER RIDGE 
SCENARIO WHICH WAS ADVERTISED BY BOTH MODELS YESTERDAY. THIS KEEPS 
THE FORECAST MAINLY DRY WITH SEASONAL TEMPERATURES AND AREAS OF 
OVERNIGHT FOG IN THE COLUMBIA BASIN AND VALLEYS.  94

&&

.AVIATION...PREVIOUS DISCUSSION. 18Z TAFS. COLD FRONT WILL BE 
EXITING THE REGION TODAY WITH IMPROVING WEATHER. RAIN HAS ENDED AT 
YKM AND PSC WITH VFR CONDITIONS. LIFR CONDITIONS WITH RAIN AND FOG 
WILL CONTINUE AT PDT ALW AND DLS FOR A FEW MORE HOURS THEN IMPROVE 
THIS AFTERNOON. SCATTERED SHOWERS EXPECTED FOR RDM THIS MORNING. 
WEST TO NORTHWEST WINDS WILL INCREASE SOME THIS AFTERNOON BEHIND THE 
FRONT.  94

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  32  44  32  44 /  10   0   0   0 
ALW  33  45  35  45 /  10   0   0   0 
PSC  27  46  30  45 /  10   0   0   0 
YKM  25  45  28  46 /   0   0   0   0 
HRI  28  45  29  45 /  10   0   0   0 
ELN  27  45  30  47 /   0   0  10   0 
RDM  22  44  23  46 /  10   0   0   0 
LGD  28  40  25  44 /  10   0   0   0 
GCD  29  40  29  45 /  10   0   0   0 
DLS  34  48  33  48 /   0   0   0   0 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&

THREAT INDEX
SATURDAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN

GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

$$

84/94/94