Heavy Snow in Oregon, December 30 to 31, 2002

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
145 PM PST MON DEC 30 2002

GETTING REPORTS OF HEAVY SNOW IN CENTRAL OREGON AND IN THE BLUE
MOUNTAINS ALREADY...EXPECT THIS TO CONTINUE THROUGH THE EVENING
HOURS. HAVE ALREADY ISSUED HEAVY SNOW WARNING AND WILL BE EXTENDING
IT THROUGH THE OVERNIGHT HOURS WITH THE NEXT FORECAST PACKAGE.
LESSER AMOUNTS OF SNOW ARE STILL EXPECTED ACROSS OREGON ABOVE 3500
FEET WITH THE APPROACH OF THE SURFACE LOW ALONG THE UPPER TROUGH.
ANOTHER AREA OF CONCERN IS THE YAKIMA AND KITTITAS VALLEYS THIS
EVENING. AS SURFACE LOW MOVES ACROSS THE BASIN...THEY WILL HAVE
DECENT UPSLOPE FLOW AND COLD AIR DEEP ENOUGH TO SUPPORT SNOW.
THEREFORE...WILL BE ISSUING SNOW ADVISORY AND CONTINUING THE
ADVISORY ALONG THE EAST SLOPES OF THE WASHINGTON CASCADES. ON
TUESDAY MORNING...THE TRAILING COLD FRONT WILL MOVE
THROUGH...CREATING ANOTHER FORECAST PROBLEM OF TIMING OF COLD AIR
AND UPSLOPE PRECIP ALONG THE FOOTHILLS OF THE BLUES. THE AMOUNT OF
COLD AIR ADVECTION IS NOT VERY STRONG...WHICH WILL KEEP AIR OVER THE
FOOTHILLS WARM ENOUGH TO KEEP SNOW AMOUNTS BELOW ADVISORY CRITERIA.
THE WESTERLY FLOW THAT CREATES UPSLOPE IN THE BLUES WILL DRY OUT THE
REST OF THE FORECAST AREA SO MOST PEOPLE WILL SEE SOME BLUE SKY ON
TUESDAY. DRIER WEATHER WILL CONTINUE THROUGH WEDNESDAY UNDER HIGH
PRESSURE. JR

EXTENDED...THE PROGRESSIVE AND WET WEATHER PATTERN WILL CONTINUE
THROUGH MONDAY WITH VERY FEW BREAKS THAT WILL BE HARD TO TIME. THE
MOST IMPRESSIVE SYSTEM DURING THE EXTENDED WILL MOVE IN LATE
THURSDAY NIGHT AND INTO FRIDAY...HOPEFULLY BRINGING IN ANOTHER
IMPRESSIVE ROUND OF RAIN AND MOUNTAIN SNOW. FOLLOWING THIS
SYSTEM...THE UPPER LEVEL FLOW TRANSITIONS TO A MORE ZONAL
PATTERN...WITH A COUPLE OF WEAK WAVES THAT MOVE THROUGH IT.  BY
SATURDAY NIGHT...A RIDGE TRIES TO BUILD IN OVER THE PACIFIC
NORTHWEST.  HOWEVER...WE WILL REMAIN IN THE MOIST SOUTHWESTERLY
FLOW...KEEPING A CHANCE OF PRECIPITATION IN THE FORECAST THROUGH
MONDAY. PALMER

PDT 8633  ALW 8733  PSC 8422  YKM 8622

.KPDT...HEAVY SNOW WARNING FOR CENTRAL OREGON AND THE BLUE MOUNTAINS
        THROUGH TONIGHT.
     ...SNOW ADVISORY FOR NORTH CENTRAL OREGON...THE JOHN DAY
        HIGHLANDS...THE GRANDE RONDE VALLEY...WALLOWA COUNTY...EAST
        SLOPES OF THE SOUTHERN WASHINGTON CASCADES AND YAKIMA AND
        KITTITAS VALLEYS THROUGH TONIGHT

ORZ041>050-WAZ024>030-311400-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
600 AM PST MON DEC 30 2002

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

.DAY ONE...TODAY

A WINTER WEATHER SYSTEM WILL MOVE NORTHEAST AND INTO THE COLUMBIA
BASIN TONIGHT. AS IT DOES SO...MODERATE AMOUNTS OF SNOWFALL WILL
ACCUMULATE ACROSS CENTRAL OREGON...THE MOUNTAINS OF NORTHEAST OREGON
AND SOUTHEAST WASHINGTON...AND ALONG THE EAST SLOPES OF THE SOUTHERN
WASHINGTON CASCADES. SNOW ADVISORIES HAVE BEEN ISSUED FOR THE EAST
SLOPES OF THE SOUTHERN WASHINGTON CASCADES...ABOVE 4000 FEET IN
CENTRAL AND NORTH CENTRAL OREGON AND GRANT COUNTY...THE BLUE
MOUNTAINS AND THE JOHN DAY BASIN. ALL ADVISORIES ARE FOR TODAY AND
TONIGHT...EXCEPT FOR THE SNOW ADVISORY FOR THE JOHN DAY BASIN...
WHICH IS FOR TONIGHT ONLY. SEE THE LATEST SNOW ADVISORIES WWUS46
KPDT OR PDXWSWPDT FOR DETAILS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

POLAN