High Wind in Oregon, December 25, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
300 AM PST SAT DEC 25 2004

.SHORT TERM...TODAY THROUGH MONDAY...A TROUGH OF LOW PRESSURE
CONTINUES TO DIVE SOUTHWARD OFF THE COAST...WITH ITS ASSOCIATED COLD
FRONT SLIDING EASTWARD TOWARD THE COAST.  AHEAD OF THE FRONT WEAK
WARM AIR OVERRUNNING IS GENERATING WIDESPREAD CLOUDINESS ACROSS
WASHINGTON AND OREGON.  LOW CLOUDS AND FOG ARE BEING REPORTED ALONG
THE COLUMBIA RIVER FROM THE DALLES TO HERMISTON WITH AREAS OF MIST
FOUND ELSEWHERE ACROSS THE BASIN AND FOOTHILLS.  EXPECT THE LOW
CLOUDS AND FOG TO LINGER THROUGH AT LEAST MID MORNING TODAY...BUT
MID AND HIGH CLOUDS WILL LIMIT AREAL COVERAGE TO THE LOCAL AREAS
CURRENTLY EXPERIENCING THE FOG.  WINDS REMAIN QUITE STRONG ACROSS
THE SOUTHERN END OF THE GRANDE RONDE VALLEY NEAR THE MOUTH OF LADD
AND PYLES CANYONS.  WITH HIGH PRESSURE LOCKED INTO THE BAKER AND
TREASURE VALLEYS TO THE SOUTHEAST...ALONG WITH THE APPROACHING
FRONT...THE WINDS SHOULD CONTINUE TO BLOW AT OR JUST ABOVE WHERE
THEY ARE NOW THROUGH THE AFTERNOON.  A HIGH WIND WARNING IS IN
EFFECT FOR THE GRANDE RONDE VALLEY WITH THE STRONGEST WINDS EXPECTED
NEAR THE MOUTHS OF THE CANYONS.

PRECIPITATION WILL BE LIMITED EAST OF THE CASCADES TODAY AND TONIGHT
AS THE FRONT STALLS ALONG OR JUST TO THE EAST OF THE CASCADES. SNOW
LEVELS WILL REMAIN FAIRLY HIGH EAST OF THE FRONT.  POCKETS OF RAIN
MAY DEVELOP OVER THE CENTRAL COLUMBIA BASIN IN WASHINGTON AS UPSLOPE
FLOW FROM THE SOUTH IMPINGES ON THE HIGHER TERRAIN OF THE NORTHEAST
CORNER OF WASHINGTON.  THIS UPSLOPE FLOW TO THE NORTH WILL HELP THE
AIRMASS OVER THE BASIN TO SATURATE WITH TIME...MAKING FOR A SLIGHT
CHANCE OF RAIN IN THE AFTERNOON.  OVERNIGHT AND INTO SUNDAY AS THE
TROUGH SAGS SOUTHWARD ALONG THE COAST MID AND UPPER-LEVEL FLOW OUT
OF THE SOUTHEAST WILL BEGIN TO DRIVE UPSLOPE CONDITIONS INTO THE
EAST SLOPES OF THE CASCADES...ESPECIALLY IN CENTRAL OREGON.  WITH A
SURFACE LOW TRACKING TO THE SOUTH AND WEST DURING THE SAME TIME
FRAME...LOW LEVEL FLOW WILL MOVE IN OUT OF THE EAST AND NORTHEAST.
THE POSSIBILITY EXISTS FOR AN AREA OF CONVERGENCE TO SET UP OVER THE
UPPER DESCHUTES PLATEAU THAT WILL FOCUS PRECIPITATION IN THE FORM OF
SNOW.  SHORT TERM MODEL DISAGREEMENTS ADD UNCERTAINTY TO THE
SITUATION AS FAR AS AVAILABLE MOISTURE IS CONCERNED.  PER WATER
VAPOR SATELLITE IMAGERY AM LEANING TOWARD THE WETTER SOLUTION.  SNOW
ACCUMULATIONS COULD RANGE FROM 3 TO 6 INCHES IN THE UPPER DESCHUTES
PLATEAU FROM EARLY SUNDAY TO EARLY MONDAY.  WILL HAVE TO MONITOR THE
TRACK OF THE FRONT AND SURFACE LOW CLOSELY AS A SNOW ADVISORY MAY
HAVE TO BE ISSUED LATER TODAY.

MONDAY THE SYSTEM WILL CONTINUE TO TRACK SOUTHWARD INTO CENTRAL
CALIFORNIA WITH DRIER CONDITIONS MOVING INTO MUCH OF THE AREA.  SNOW
LEVELS WILL LOWER THROUGH THE WEEKEND...WITH BASIN LOCATIONS SEEING
MAINLY THE THREAT OF A MIX OF RAIN AND SNOW TONIGHT AND SUNDAY.
PLATEAU AND MOUNTAIN AREAS WILL LIKELY SEE MAINLY FROZEN
PRECIPITATION THROUGH THE PERIOD. CANTIN

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY...WEAK HIGH PRESSURE ALOFT
OVER THE PACIFIC NORTHWEST WILL GIVE THE REGION DRY CONDITIONS
MONDAY NIGHT AND TUESDAY WHILE THE NEXT UPPER LOW PRESSURE SYSTEM
GATHERS STRENGTH IN THE GULF OF ALASKA. THE UPPER LOW WILL MOVE
SOUTHEAST ON WEDNESDAY PUSHING A COLD FRONT TO THE CASCADES WHILE
BACKING FLOW ALOFT TO THE SOUTHWEST OVER THE FORECAST AREA...THUS
ALLOWING MOISTURE TO STREAM EAST OF THE CASCADES FOR A CHANCE OF
SNOW IN THE MOUNTAINS AND A RAIN/SNOW MIX IN THE LOWER COLUMBIA
BASIN AND ADJACENT VALLEYS ON WEDNESDAY. THE FRONT WILL STALL ALONG
THE CASCADES WEDNESDAY NIGHT AND THEN SWING EASTWARD ACROSS THE
FORECAST AREA ON THURSDAY WHILE THE UPPER LOW REMAINS JUST OFF THE
COAST OF THE PACIFIC NORTHWEST. THE UPPER LOW WILL MOVE INLAND INTO
THE FORECAST AREA ON FRIDAY FOR A SLIGHT CHANCE OF A MIX OF RAIN AND
SNOW IN THE LOWER COLUMBIA BASIN AND A CHANCE OF MOUNTAIN SNOW ON
THURSDAY AND FRIDAY.  POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 045 034 040 / 010 030 020
WALLA WALLA         044 035 041 / 020 030 020
TRI-CITIES          041 032 041 / 020 020 020
YAKIMA              041 028 037 / 020 030 020
HERMISTON           042 032 042 / 010 020 020
ELLENSBURG          040 028 037 / 030 030 030
REDMOND             048 029 037 / 010 040 050
LA GRANDE           043 032 039 / 010 030 030
JOHN DAY            045 030 040 / 010 030 030
THE DALLES          040 035 042 / 020 030 030
&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING FOR THE GRANDE RONDE VALLEY THROUGH 4 PM
TODAY.
WA...NONE.
&&

TI:YGG
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
96

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OREGON
335 PM PST FRI DEC 24 2004

ORZ041>050-WAZ024>030-251300-
NORTH CENTRAL OREGON-CENTRAL OREGON-LOWER COLUMBIA BASIN (OR)-
FOOTHILLS OF THE BLUE MOUNTAINS (OR)-BLUE MOUNTAINS-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-GRANDE RONDE VALLEY-WALLOWA COUNTY-
EASTERN COLUMBIA RIVER GORGE (WA)-
EAST SLOPES OF THE SOUTHERN CASCADES-KITTITAS VALLEY-YAKIMA VALLEY-
LOWER COLUMBIA BASIN (WA)-FOOTHILLS OF THE BLUE MOUNTAINS (WA)-
NORTHWEST BLUE MOUNTAINS-
335 PM PST FRI DEC 24 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND NORTHEAST OREGON
AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.

.DAY ONE...THIS AFTERNOON AND TONIGHT

STRONG WIND
     GRANDE RONDE VALLEY

STRENGTHENING PRESSURE GRADIENTS ACROSS THE GRANDE RONDE VALLEY WILL
LEAD TO VERY WINDY CONDITIONS TONIGHT. SOUTH WINDS OF 30 TO 35 MPH
WITH GUSTS FROM 45 TO 55 MPH CAN BE EXPECTED NEAR AND TO THE NORTH
OF LADD AND PYLES CANYONS. SEE THE LATEST PDXNPWPDT (WMO PRODUCT
HEADER WWUS76 KPDT) FOR MORE DETAILS.

HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER THROUGH TONIGHT
ALLOWING THE STRONG INVERSIONS OVER THE COLUMBIA BASIN TO PERSIST.
LOW CLOUDS AND FOG SHOULD REDEVELOP OVER THE LOWER COLUMBIA BASIN OF
WASHINGTON WHILE EXPANDING IN COVERAGE OVER THE LOWER COLUMBIA BASIN
OF OREGON.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

STRONG WIND SATURDAY
          GRANDE RONDE VALLEY

SOUTH WINDS OF 30 TO 35 MPH WITH GUSTS FROM 45 TO 55 MPH ARE
EXPECTED TO CONTINUE NEAR AND TO THE NORTH OF LADD AND PYLES CANYONS
CHRISTMAS DAY. THESE WINDS SHOULD SLOWLY DECREASE DURING THE LATE
AFTERNOON CHRISTMAS DAY. SEE THE LATEST PDXNPWPDT (WMO PRODUCT
HEADER WWUS76 KPDT) FOR MORE DETAILS.

A TROUGH OF LOW PRESSURE WILL MOVE SOUTHWARD ALONG THE COAST THROUGH
SUNDAY. A COLD FRONT ASSOCIATED WITH THE TROUGH WILL MOVE EAST OF
THE CASCADES LATE SATURDAY AFTERNOON AND SATURDAY NIGHT. THIS FRONT
WILL PRODUCE MOSTLY LIGHT AMOUNTS OF PRECIPITATION...THOUGH HEAVIER
AMOUNTS WILL FALL NEAR THE CASCADE CREST. UNSETTLED WEATHER WILL
LINGER THROUGH THE REMAINDER OF THE EXTENDED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

PROTOTYPE GRAPHICAL FORECASTS OF WEATHER HAZARDS OUT TO SEVEN DAYS
ARE DISPLAYED ON THE WORLD WIDE WEB AT:

WWW.WRH.NOAA.GOV/PENDLETON/FORECAST/HWOGRAPHICS/HWOGRAPHICS.PHP

ALL LETTERS IN THE ABOVE URL ARE LOWER CASE...EXCEPT THE G IN
HWOGRAPHICS AND THE G IN HWOGRAPHICS.PHP.