Heavy Snow in Oregon, January 24, 2010

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
335 AM PST SUN JAN 24 2010

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH MONDAY NIGHT...A WEAK RIDGE OVER THE
AREA WILL BE PUSHED OFF TO THE EAST TODAY AS ANOTHER PACIFIC STORM
BEGINS TO MOVE INTO THE AREA. AM ALREADY BEGINNING TO SEE RADAR
RETURNS ALONG THE COAST AND EXPECT THAT SNOW SHOWERS WILL BEGIN TO
MOVE INTO CENTRAL OREGON AN HOUR OR TWO AFTER SUNRISE. CENTRAL AND
NORTH CENTRAL OREGON SHOULD SEE A QUICK BURST OF SNOWFALL WITH THE
SYSTEM THIS MORNING. AS IT MOVES ACROSS THE AREA TODAY SNOW LEVELS
WILL RISE FROM 2000 TO 2500 FEET NOW TO 3500 FEET BY TONIGHT. THIS
WILL HAVE SNOW CHANGE OVER TO RAIN IN MOST LOCATIONS BUT AM
CONCERNED THAT SNOW WILL HANG ON LONG ENOUGH TO REACH ADVISORY
LEVELS ABOVE 4000 FEET. SNOW AMOUNTS ARE MARGINAL FOR AN ADVISORY
BUT WILL ISSUE ONE FOR CENTRAL OREGON...NORTH CENTRAL OREGON AND THE
OCHOCO-JOHN DAY HIGHLANDS THROUGH TOMORROW MORNING. MAY ALSO NEED
ADVISORIES FOR THE WASHINGTON CASCADES ZONES BUT WILL HOLD OFF FOR
NOW. MODEL PRECIPITATION AMOUNTS ARE IN SOME DISAGREEMENT AND WILL
LET DAY SHIFT SEE WHICH MODEL IS HANDLING THIS SYSTEM THE BEST.
TEMPERATURES WILL GENERALLY BE IN THE 30S BUT SOUTHERLY WINDS AHEAD
OF THE FRONT SHOULD ALLOW THE COLUMBIA BASIN AND BLUE MOUNTAIN
FOOTHILLS TO WARM INTO THE LOWER TO MID 40S.

BY THE AFTERNOON THE PRECIPITATION SHOULD REACH FROM YAKIMA TO
HEPPNER TO UKIAH AND TONIGHT IT WILL SPREAD TO THE REST OF THE AREA.
PRECIPITATION AMOUNTS SHOULD BE FAIRLY GENEROUS WITH THIS SYSTEM
WITH MOST LOWLAND LOCATIONS SEEING A COUPLE OF TENTHS OF LIQUID
PRECIPITATION. THE YAKIMA AND KITTITAS VALLEY COULD SEE A COUPLE OF
INCHES OF SNOW BUT BELIEVE THEY WILL STAY BELOW ADVISORY LEVELS. ON
MONDAY...ACTIVITY WILL TAPER OFF BUT THE AREA WILL STILL HAVE A
CHANCE OF MAINLY RAIN WITH SNOW ABOVE 3500 TO 4000 FEET.
TEMPERATURES WILL BE IN THE MID 30S TO MID 40S. MONDAY NIGHT WILL
SEE A FEW ADDITIONAL IMPULSES FOR A CHANCE OF SNOW IN THE MOUNTAINS
WITH THE LOWER ELEVATIONS DRYING OUT. PERRY

.LONG TERM...TUESDAY THROUGH SUNDAY...RAIN AND SNOW SHOWERS WILL
CONTINUE ON TUESDAY AS A WEAK TROUGH PASSES OVER THE AREA. A RIDGE
OF HIGH PRESSURE WILL BUILD INTO THE REGION ON WEDNESDAY...ALLOWING
THE SHOWERS TO TAPER OFF BY WEDNESDAY AFTERNOON. MOSTLY DRY
CONDITIONS WILL CONTINUE ON THURSDAY. HOWEVER...ANOTHER STORM SYSTEM
APPROACHING THE PACIFIC COAST COULD SEND A ENOUGH MOISTURE OVER THE
CASCADES FOR RAIN AND SNOW ALONG THE EASTERN SLOPES. BY FRIDAY AND
SATURDAY...ALL AREAS SHOULD SEE A CHANCE OF PRECIPITATION...BUT SNOW
LEVELS WILL LIKELY REMAIN HIGH ENOUGH TO PRECLUDE SIGNIFICANT LOW
LEVEL SNOW ACCUMULATIONS. ANOTHER RIDGE IS THEN FORECAST TO DEVELOP
ON SUNDAY...WHICH WILL CAUSE SHOWERS TO DISSIPATE.  82

&&

.AVIATION...12Z TAFS...WINDS WILL BE LIGHT AND WILL GENERALLY RANGE
FROM 5 TO 10 KTS. PRECIPITATION WILL BEGIN TO AFFECT TAF KRDM
THIS MORNING WITH CONDITIONS DECREASING TO IFR OR MVFR IN LOWERED
CEILINGS AND VISIBILITY IN RAIN/SNOW. ELSEWHERE...VFR CONDITIONS
SHOULD PERSIST THROUGH THIS AFTERNOON EVEN THOUGH CLOUDS WILL
INCREASE AND THICKEN AND LOWER THROUGHOUT THE DAY. RAIN WILL BE
POSSIBLE AT KDLS BY 21Z...AND AT KYKM...KPSC...KALW AND KPDT AFTER
25/00Z. MVFR OR LOWER CONDITIONS WILL THEN BE POSSIBLE IN RAIN
THROUGH MONDAY MORNING.  82

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  45  33  44  33 /  10  60  50  20
ALW  46  36  46  35 /  10  60  50  30
PSC  45  33  45  32 /  10  70  40  10
YKM  40  30  41  30 /  20  80  50  20
HRI  44  33  45  33 /  10  60  40  10
ELN  39  30  40  29 /  20  80  60  20
RDM  38  31  42  26 /  60  70  40  30
LGD  39  33  41  30 /  10  60  50  30
GCD  40  34  43  32 /  40  70  40  40
DLS  41  33  43  33 /  50  80  60  20

&&

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

THREAT INDEX
TODAY : YELLOW
MONDAY : YELLOW
TUESDAY : 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

83/82/82

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
552 AM PST SUN JAN 24 2010

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-251330-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
CENTRAL OREGON-LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-
WALLOWA COUNTY-FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-
NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-KITTITAS VALLEY-
YAKIMA VALLEY-LOWER COLUMBIA BASIN OF WASHINGTON-
FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON-
NORTHWEST BLUE MOUNTAINS OF WASHINGTON-
EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON-
EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON-
523 AM PST SUN JAN 24 2010

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

.DAY ONE...TODAY AND TONIGHT

SNOW
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, KITTITAS VALLEY,
     YAKIMA VALLEY, NORTHWEST BLUE MOUNTAINS OF WASHINGTON, NORTH
     CENTRAL OREGON, CENTRAL OREGON, GRANDE RONDE VALLEY, WALLOWA
     COUNTY, NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE
     MOUNTAINS OF OREGON, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS

ANOTHER STORM SYSTEM WILL IMPACT THE AREA TODAY AND TONIGHT BRINGING
RAIN IN THE LOWER COLUMBIA BASIN AND BLUE MOUNTAIN FOOTHILLS AND
SNOW OR A RAIN/SNOW MIX ELSEWHERE. 2 TO 6 INCHES OF SNOW ABOVE 3500
FEET ARE EXPECTED IN CENTRAL AND NORTH CENTRAL OREGON AND THE
OCHOCO-JOHN DAY HIGHLANDS. A WINTER WEATHER ADVISORY HAS BEEN ISSUED
FOR THAT AREA. SEE PRODUCT PDXWSWPDT FOR MORE DETAILS. SEVERAL
INCHES OF SNOW ARE ALSO POSSIBLE TONIGHT ALONG THE EAST SLOPES OF
THE CENTRAL AND SOUTHERN WASHINGTON CASCADES AND THE KITTITAS AND
YAKIMA VALLEYS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SNOW MONDAY
     NORTHWEST BLUE MOUNTAINS OF WASHINGTON, GRANDE RONDE VALLEY,
     WALLOWA COUNTY, NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN
     BLUE MOUNTAINS OF OREGON, JOHN DAY BASIN, OCHOCO-JOHN DAY
     HIGHLANDS

RAIN AND SNOW FROM THE SYSTEM ARRIVING TODAY WILL LINGER ON MONDAY
AND BRING UP TO A COUPLE OF INCHES OF ADDITIONAL SNOW TO EASTERN
OREGON MOUNTAINS. UNSETTLED CONDITIONS WILL CONTINUE THROUGH TUESDAY
WITH LIGHT AMOUNTS OF RAIN AND SNOW EXPECTED. THE AREA WILL SEE A
BREAK WITH FAIR AND DRY CONDITIONS ON WEDNESDAY AND THURSDAY BEFORE
ANOTHER WEATHER SYSTEM BRINGS MORE RAIN AND SNOW FRIDAY AND
SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

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

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

WWW.WRH.NOAA.GOV/PDT/CURRENTHAZARDS/HWO.HTML

ALL LETTERS IN THE ABOVE URL ARE LOWER CASE.