Cold in Oregon, January 4 to 5, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
230 PM PST SUN JAN 4 2004

.SHORT TERM...CONCERN THIS PACKAGE IS WITH TEMPERATURES THROUGH
MIDWEEK ALONG WITH PRECIPITATION CHANCES AND ACCUMULATING SNOWS ON
TUESDAY WITH FREEZING RAIN POSSIBLE TUESDAY NIGHT.

ARCTIC AIR WAS POURING INTO THE TWO STATE AREA TODAY. SOME BREAKS IN
THE CLOUDS WERE OCCURRING ACROSS THE REGION AND WHERE THESE BREAKS
DEVELOP TONIGHT...OVERNIGHT LOWS WILL PLUMMET. MOST LOCATIONS BY
MONDAY MORNING WILL EXPERIENCE NEGATIVE DIGITS.

THE ARCTIC AIR WILL REMAIN IN PLACE TOMORROW AND AFTERNOON HIGHS WILL
STRUGGLE TO REACH THE TEENS. ABUNDANT MOISTURE OVER THE NORTHEAST
PACIFIC WILL MAKE ITS WAY TOWARD THE PACNW TOMORROW. THIS WILL
SPREAD INTO THE RDM AREA BY AFTERNOON WITH SOME SNOW SHOWERS
POSSIBLE. THE MOISTURE WILL EXPAND INTO THE REMAINDER OF THE AREA
MONDAY NIGHT WITH LIGHT SNOW DEVELOPING ACROSS MOST PORTIONS OF THE
REGION BY TUESDAY MORNING.

BY TUESDAY THE LOW LEVEL WINDS TURN INTO A WARMER AND MOIST SSW FLOW
AND OVERRUN THE ARCTIC COLD AIR IN PLACE OVER THE TWO STATE AREA.
WITH AN APPROACHING DISTURBANCE COMBINING WITH THE MOISTURE...SNOW
IS EXPECTED TO EXPAND IN COVERAGE AND INTENSITY TUESDAY WITH
SIGNIFICANT ACCUMULATIONS POSSIBLE. THIS HAS PROMPTED THE ISSUANCE
OF A WINTER STORM WATCH FOR THE ENTIRE AREA TUESDAY AND TUESDAY
NIGHT. THE INFLUX OF WARM AIR WILL ALSO POSE A CHALLENGE TO
TEMPERATURES. FORECAST SOUNDINGS INDICATE COLD AIR TRAPPED AT THE
SURFACE WITH MUCH WARMER AIR ALOFT. THIS MAY RESULT IN A CHANGE OVER
FROM SNOW TO FREEZING RAIN TUESDAY NIGHT MAKING TRAVEL EVEN MORE
TREACHEROUS. THIS CHANGEOVER MAY BE SLOWER TO OCCUR OVER THE BASIN
AND ALONG THE EAST SLOPES OF THE WASHINGTON CASCADES. VP

.LONG TERM...A MUCH WARMER BUT UNSETTLED WEATHER PATTERN WILL
PREVAIL THROUGHOUT THE EXTENDED PERIOD AS THE FLOW WILL BE MORE
SOUTHWEST FROM OFF THE PACIFIC.  THIS WILL DRAW IN FREQUENT PACIFIC
WEATHER SYSTEMS IN THE MOIST SOUTHWEST FLOW.  EACH SYSTEM WILL GO TO
THE NORTH OF THE FORECAST AREA CREATING A SOUTH TO SOUTHEAST
PRESSURE GRADIENT.  THIS WILL ENHANCE PRECIPITATION OVER THE
NORTHERN PORTIONS OF THE FORECAST AREA...MAINLY ALONG THE CASCADE
EAST SLOPES AND ADJACENT VALLEYS.  COLD AIR IS LIKELY TO STICK IN
THESE PLACES LONGER THAN THE REST OF THE REST OF THE FORECAST AREA
SO WILL KEEP A MENTION OF SNOW OR FREEZING RAIN IN ON WEDNESDAY.
AFTER THAT HOWEVER 850 MB TEMPERATURES WARM UP SIGNIFICANTLY WITH
EACH PASSING WEATHER SYSTEM UNTIL THE END OF NEXT WEEK WHEN EVEN THE
MOUNTAINS MAY SEE JUST RAIN BY NEXT WEEKEND.  THIS WILL POSE A
POSSIBLE FLOODING THREAT WITH RAPID SNOW MELT...ESPECIALLY IN THE
LOWER ELEVATIONS WHERE THERE IS CURRENTLY A MODERATE TO HEAVY
SNOWPACK.  EXPECT TEMPERATURES TO APPROACH THE 40S TO NEAR 50 BY
NEXT WEEKEND IN THE VALLEYS AND 30S TO 40S IN THE MOUNTAINS.  RSC.

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) -6 12 6 28 / 00 00 20 80
WALLA WALLA         -5 14 8 28 / 00 00 20 80
TRI-CITIES          -8 14 6 27 / 00 00 20 80
YAKIMA              -9 13 7 25 / 00 00 20 80
&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WATCH FOR TUESDAY AND TUESDAY NIGHT FOR THE ENTIRE
AREA.
WA...WINTER STORM WATCH FOR TUESDAY AND TUESDAY NIGHT FOR THE ENTIRE
AREA.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
500 AM PST SUN JAN 4 2004

ORZ041>050-WAZ024>030-051300-

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

.DAY ONE...

AN ARCTIC FRONT WILL CONTINUE TO DROP SOUTHWARD INTO CENTRAL OREGON
TODAY. SNOW CAN BE EXPECTED ALONG THE FRONT WITH ACCUMULATIONS OF 1
TO 3 INCHES ACROSS CENTRAL AND EASTERN OREGON. BEHIND THE FRONT ARE
VERY COLD CONDITIONS WITH WIND CHILL TEMPERATURES DROPPING BELOW
ZERO.

.DAYS TWO THROUGH SEVEN...

VERY COLD CONDITIONS WILL PERSIST INTO MONDAY. A NEW WEATHER SYSTEM
IS EXPECTED TO ARRIVE LATE MONDAY AND TUESDAY PRODUING WIDESPREAD
SNOW THEN CHANCING OVER TO A MIX OF PRECIPITATION LATE TUESDAY.
WARMER AND UNSETTLED CONDITIONS EXPECTED THROUGH THE REMAINDER OF THE
OUTLOOK PERIOD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY.

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