Heavy Snow in Oregon, December 29 to 30, 2002

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
830 PM PST SUN DEC 29 2002

SATELLITE SHOWS NEXT SYSTEM MOVING ONTO THE COAST AT THIS TIME.
HOWEVER AS IT MOVES INLAND IT WILL WEAKEN AND STRETCH DUE TO MAIN
LOW CENTER REMAINING OFF THE BC COAST. BEST SHOT AT PRECIP COMES
AFTER MIDNIGHT THROUGH MONDAY MORNING BEFORE WESTERLY FLOW CUTS
ACROSS NORTHERN HALF OF FORECAST AREA CREATING RAIN SHADOW FROM THE
EAST SLOPES OF CASCADES TO EASTERN PORTION OF THE LOWER COLUMBIA
BASIN. WEST FLOW WILL AIDE IN SOME MORNING UPSLOPE FROM THE BLUE
MOUNTAIN FOOTHILLS EASTWARD.  SOUTHERN PORTION OF FORECAST AREA WILL
REMAIN UNDER A BAROCLINIC BAND THAT WILL INTENSIFY AS A WAVE FORMS
OFF THE COAST MONDAY. THIS WAVE WILL MOVE ONTO THE COAST MONDAY
AFTERNOON PLACING SOUTHERN FORECAST ZONES UNDER WARM AIR ADVECTION
MONDAY AFTERNOON AND EVENING (GOOD PRECIP PATTERN). NORTHERN ZONES
WILL COME UNDER THE INFLUENCE OF THE WARM AIR ADVECTION MONDAY NIGHT
WITH A GOOD CHANCE OF PRECIP THEN. SNOW LEVELS WILL RISE TO AROUND
5000 FEET IN THE SOUTH AND TO 3000 FEET FAR NORTH ZONES. CURRENT
SNOW ADVISORY FOR CENTRAL OREGON ZONES MONDAY ABOVE 4000 FEET LOOKS
OKAY BUT MAY NEED TO ADD SOME NORTHEAST MOUNTAIN ZONES AS WELL AS
EAST SLOPES OF WASHINGTON CASCADES FOR THE MONDAY AFTERNOON AND
NIGHT PERIODS. WILL LET MID SHIFT COORDINATE THIS WILL SURROUNDING
OFFICES.

WILL ISSUE AN UPDATED ZONE PACKAGE TO MAKE SOME TIMING CHANGES TO
TONIGHT AND EARLY MONDAY PERIODS.  SOLOMON

PDT 4644  ALW 4644  PSC 3444  YKM 3444

.KPDT...SNOW ADVISORY FOR CENTRAL AND NORTH CENTRAL OREGON (OREGON
        ZONE 42 AND 43) AND THE JOHN DAY HIGHLANDS (OREGON ZONE 48)
        FOR MONDAY AND MONDAY NIGHT