Heavy Snow in Oregon, January 30 to 31, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
744 PM PST WED JAN 30 2008

.UPDATE...NEXT PACIFIC STORM IS MOVING INTO THE CASCADES THIS
EVENING. ON IR SATELLITE COLDEST CLOUD TOPS IN DESCHUTES COUNTY
AND SOUTH CENTRAL OREGON. RADAR INDICATES STEADY PRECIPITATION ON
WEST SIDE OF CASCADES WITH SOME SLOP OVER NEAR THE CREST AND
UPSLOPE SHOWERS DEVELOPING IN THE BLUES. SYSTEM SHOWS WESTERLY
TRACK THAT WILL KEEP PRECIPITATION SHADOW LIMITING PRECIPITATION
IN THE COLUMBIA BASIN. CURRENT FORECAST ON TRACK.  COONFIELD

&&

.PREV DISCUSSION... /ISSUED 220 PM PST WED JAN 30 2008/

SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...ANOTHER MOISTURE LADEN
PACIFIC STORM SYSTEM IS POISED TO MOVE INTO THE NORTHWEST TONIGHT.
SIGNIFICANT SNOW ACCUMULATIONS ARE EXPECTED ALONG THE EASTERN SLOPES
OF THE CASCADES...THE BLUE MOUNTAINS AND THE MOUNTAINS OF EASTERN
OREGON. WINTER WEATHER WARNINGS AND ADVISORIES HAVE BEEN ISSUED FOR
THESE AREAS. PLEASE REFER TO PRODUCT PDXWSWPDT FOR MORE INFORMATION.
IN ADDITION TO HEAVY SNOW...PRESSURE GRADIENTS WILL TIGHTEN AS THE
SYSTEM MOVES THROUGH THE AREA...CAUSING BREEZY TO WINDY CONDITIONS
ACROSS THE REGION THROUGH THURSDAY. THESE BREEZY CONDITIONS WILL
HELP TEMPERATURES IN THE LOWER COLUMBIA BASIN REMAIN AT OR ABOVE
FREEZING...DECREASING THE CHANCES FOR SNOWFALL. MOST OF THE
PRECIPITATION THAT DOES FALL IN THE LOWER ELEVATIONS SHOULD FALL IN
THE FORM OF RAIN.

ON FRIDAY...DRIER AIR AND HIGHER PRESSURE WILL MOVE INTO THE REGION.
ALTHOUGH THERE WILL STILL BE A CHANCE FOR SCATTERED SNOW SHOWERS IN
THE MOUNTAINS DUE TO UPSLOPE FLOW...DAYTIME TEMPERATURES WILL REMAIN
MILD IN THE 30S AND 40S.  CALDER

LONG TERM...SATURDAY THROUGH WEDNESDAY. A STORM OFF THE PACNW COAST
WILL APPROACH THE AREA THIS WEEKEND. SHOWERS ARE EXPECTED TO
DEVELOP OVER THE CASCADES SATURDAY AND MIGRATE EAST INTO THE ENTIRE
AREA SATURDAY NIGHT. COLD AIR REMAINS IN PLACE AND SNOW ACCUMULATION
IS EXPECTED ESPECIALLY OVER AREA MOUNTAINS. THE STORM IS FORECAST TO
MOVE SLOWLY ACROSS THE TWO STATE AREA SUNDAY WITH SHOWERS PERSISTING
BUT WITH DRIER AIR TRYING TO MOVE INTO THE REGION FROM THE WEST. AS
THE DRIER AIR FILTERS INTO MOST OF OR/WA SUNDAY NIGHT...SHOWERS
SHOULD LINGER OVER THE FAR EASTERN PORTIONS OF OUR AREA THAT
INCLUDES THE WALLOWA/BLUE MTNS. AS COLDER AIR MOVES INTO THE
AREA...A RIDGE OF HIGH PRESSURE BUILDS INTO THE PACNW MONDAY. THIS
DRY SPELL SHOULD LAST FOR ONLY A DAY AS ANOTHER STORM SYSTEM TAKES
AIM ON THE TWO STATE AREA TUESDAY WITH ANOTHER ROUND OF SHOWERS
LIKELY THROUGH MIDWEEK.

AVIATION...VFR CONDITIONS WILL PERSIST AT ALL TAF SITES EXCEPT FOR
KDLS AND KRDM WHERE MVFR CONDITIONS MAY OCCUR DUE TO LOWERING
CEILINGS AND VSBY IN SHOWERS. THEN ALL TAF SITES MAY EXPERIENCE
SHOWERS THAT MAY PRODUCE MVFR/IFR CONDITIONS AFTER 02Z WITH EVEN
GREATER CHANCES FOR THIS TO OCCUR AFTER 12Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  32  40  31  39 /  40  40  20  20
ALW  33  41  32  41 /  50  50  20  20
PSC  34  43  31  43 /  30  50  10  10
YKM  25  40  25  39 /  30  50  10  20
HRI  33  42  30  43 /  30  50  10  10
ELN  23  36  22  36 /  40  60  20  20
RDM  27  42  23  38 /  50  70  40  40
LGD  29  37  27  35 /  30  70  40  30
GCD  26  39  24  34 /  50  80  50  30
DLS  32  42  32  42 /  50  50  20  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WARNING UNTIL 10 PM PST THURSDAY FOR ORZ042-043.

     SNOW AND BLOWING SNOW ADVISORY FROM 4 AM TO 10 PM PST THURSDAY
     FOR ORZ049-050.

     WINTER STORM WARNING UNTIL 10 PM PST THURSDAY FOR ORZ502.

     SNOW ADVISORY UNTIL 10 PM PST THIS EVENING FOR ORZ502.

     SNOW AND BLOWING SNOW ADVISORY UNTIL 10 PM PST THURSDAY FOR
     ORZ503-506.

WA...WINTER STORM WARNING UNTIL 10 PM PST THURSDAY FOR WAZ501-502.

     WINTER STORM WARNING UNTIL 10 PM PST THURSDAY FOR WAZ030.

     SNOW ADVISORY UNTIL 10 PM PST THIS EVENING FOR WAZ030.

&&

TI:YYG
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
76/76/76

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
140 PM PST WED JAN 30 2008

UPDATED FOR WARNINGS AND ADVISORIES

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-311415-
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-
EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON-
EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON-
140 PM PST WED JAN 30 2008

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

.DAY ONE...THE REST OF TODAY AND TONIGHT.

SNOW
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, NORTHWEST BLUE
     MOUNTAINS, NORTH CENTRAL OREGON, CENTRAL OREGON, NORTHERN BLUE
     MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON

SNOW SHOWERS ARE EXPECTED OVER THE MOUNTAINS TODAY...ESPECIALLY THE
CASCADES AND BLUES. A STORM APPROACHING THE PACIFIC NORTHWEST WILL
BRING INCREASING SNOW AND WIND LATER TONIGHT INTO THURSDAY. WINTER
WEATHER WARNINGS AND ADVISORIES HAVE BEEN ISSUED. PLEASE REFER TO
PRODUCT PDXWSWPDT FOR FURTHER DETAILS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

SNOW THURSDAY
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, NORTHWEST BLUE
     MOUNTAINS, 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

SIGNIFICANT MOUNTAIN SNOW ACCUMULATIONS WILL CONTINUE THROUGH
THURSDAY. THE COLUMBIA BASIN WILL BE WARM ENOUGH FOR MOSTLY RAIN
WITH THIS EVENT. LOCALLY WINDY CONDITIONS ARE ALSO EXPECTED. AN
ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THE WEEKEND. THIS WILL
RESULT IN PERIODS OF MOUNTAIN SNOW...VALLEY RAIN AND GUSTY WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY.

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...EXCEPT THE H IN
CURRENTHAZARDS.