Winter Storm in Washington, December 16 to 17, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
147 PM PST SUN DEC 16 2012

.SHORT TERM...TONIGHT THROUGH WEDNESDAY...A MAJOR WINTER STORM WILL
BE IMPACTING THE FORECAST AREA OVERNIGHT AND INTO MONDAY. THIS STORM
WILL PACK A ONE-TWO PUNCH OF STRONG WINDS AND SIGNIFICANT SNOW FOR
SOME AREAS. THIS STORM IS CURRENTLY SENDING A WARM FRONT NORTHWARD
ACROSS OREGON WHICH WILL INCREASE PRECIPITATION ACROSS THE FORECAST
AREA LATE THIS AFTERNOON AND INTO THE NIGHT. STRONG SOUTHERLY WINDS
WILL FOLLOW THE WARM FRONTAL PASSAGE WHICH WILL RAISE SNOW LEVELS
OVERNIGHT. THEN LATE TONIGHT AND EARLY MONDAY THE ASSOCIATED COLD
FRONT WILL SWEEP THROUGH THE REGION LOWERING SNOW LEVELS. THE COLD
FRONT WILL ALSO SWITCH THE WINDS TO WESTERLY. NUMEROUS WINTER STORM
AND HIGH WIND PRODUCTS (PDXWSWPDT AND PDXNPWPDT) HAVE BEEN ISSUED
FOR THIS EVENT. SEE THESE PRODUCTS FOR MORE DETAILED INFORMATION.

PRECIPITATION WILL BEGIN TO TAPER OFF ON MONDAY EXCEPT FOR THE
ONGOING UPSLOPE PRECIPITATION IMPACTING THE CASCADE CREST REGION AND
THE EASTERN MOUNTAINS. ALL OTHER AREAS WILL SEE DECREASING SHOWERS
AND VERY WINDY CONDITIONS MONDAY. WINDS WILL TAPER OFF LATE MONDAY
THROUGH MONDAY NIGHT. FORECAST AREA WILL REMAIN UNDER A COLD
WESTERLY FLOW INTO TUESDAY WITH SOME INSTABILITY SHOWERS MAINLY IN
THE AFTERNOON AND DECREASING BY EARLY TUESDAY EVENING.

ANOTHER STORM SYSTEM IS EXPECTED TO ARRIVE ON WEDNESDAY. THIS SYSTEM
WILL ALSO BE ACCOMPANIED BY INCREASING SOUTHERLY WINDS MAINLY OVER
OREGON. SNOW LEVELS WILL RISE BUT STILL EXPECT POSSIBLE ACCUMULATING
SNOW IN THE HIGHER ELEVATIONS AND ALONG THE EAST SLOPES OF THE
CASCADES OF WASHINGTON.

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...THE REGION WILL BE
UNDER SW FLOW ALOFT THROUGH THE PERIOD WITH PERIODIC IMPULSES MOVING
THROUGH THE FLOW. THIS WILL KEEP UNSETTLED WEATHER OVER THE AREA AND
AT LEAST LOW CHANCES FOR PRECIPITATION. AT THE SURFACE IT APPEARS
THAT IT MAY BECOME INCREASINGLY COLDER AS A COLD CONTINENTAL AIRMASS
SPILLS OVER THE ROCKIES INTO THE INTERIOR NW. THIS WILL RESULT IN
SNOW LEVELS DOWN TO THE COLUMBIA BASIN FLOOR BY THEN END OF THE
WEEK...WITH ALL LOCATIONS SEEING SNOW AS THE PREDOMINANT
PRECIPITATION TYPE. HOWEVER...AS OF NOW IT DOES NOT APPEAR THAT A
MAJOR STORM WILL IMPACT THE AREA THROUGH THE PERIOD.

&&

.AVIATION...00Z TAFS...WIDESPREAD IFR CONDITIONS ARE EXPECTED
TONIGHT AS PRECIPITATION SPREADS OVER THE AREA. IT WILL FALL MOSTLY
AS RAIN WITH SNOW AT KYKM AND A RAIN SNOW MIX AT KBDN. WINDS WILL
BECOME AN INCREASING CONCERN AT MOST OF THE TAF SITES ESPECIALLY
AFTER 06Z. GUSTS COULD BE AS HIGH AS 45KT THROUGH MONDAY MORNING AT
KPDT AND KPSC. CONDITIONS WILL SLOWLY IMPROVE MONDAY AFTERNOON WITH
SLOWLY DIMINISHING WINDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  38  41  29  33 /  80  40  20  30
ALW  38  42  29  35 /  80  40  20  40
PSC  37  44  29  36 / 100  20  10  20
YKM  30  36  23  30 / 100  20  10  20
HRI  37  43  28  36 /  80  20  10  20
ELN  29  35  23  29 / 100  30  10  20
RDM  33  35  18  31 /  70  50  20  30
LGD  32  35  22  28 /  90  70  40  50
GCD  32  29  23  26 /  80  70  30  50
DLS  36  41  31  38 / 100  60  20  30

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...BLIZZARD WARNING FROM 4 PM THIS AFTERNOON TO 1 PM PST MONDAY
     ORZ050-502-503-506.

     WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM PST MONDAY
     ORZ042-044-507-508.

     HIGH WIND WARNING UNTIL 1 PM PST MONDAY ORZ049-505-509.

     BLIZZARD WARNING UNTIL 1 PM PST MONDAY ORZ509.

WA...BLIZZARD WARNING FROM 4 PM THIS AFTERNOON TO 1 PM PST MONDAY
     WAZ030.

     WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM PST MONDAY
     WAZ028-029-521.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT PST TONIGHT WAZ027.

     WINTER WEATHER ADVISORY UNTIL 4 AM PST MONDAY WAZ521.

     WINTER STORM WARNING UNTIL 1 PM PST MONDAY WAZ520.

     WINTER STORM WARNING UNTIL 10 AM PST MONDAY WAZ026.

&&

THREAT INDEX
MONDAY : RED
TUESDAY : GREEN
WEDNESDAY : 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

91/78/78

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
940 AM PST SUN DEC 16 2012

UPDATED FOR EXPANDED HEADLINE COVERAGE

ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
171245-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-WALLOWA COUNTY-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-JOHN DAY BASIN-OCHOCO-
JOHN DAY HIGHLANDS-
FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON-
FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON-
EAST SLOPES OF THE OREGON CASCADES-
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 WASHINGTON CASCADES-SIMCOE HIGHLANDS-
940 AM PST SUN DEC 16 2012

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 WASHINGTON CASCADES, KITTITAS VALLEY,
     NORTHWEST BLUE MOUNTAINS OF WASHINGTON, WALLOWA COUNTY,
     NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS
     OF OREGON, OCHOCO-JOHN DAY HIGHLANDS, YAKIMA VALLEY, SIMCOE
     HIGHLANDS, EAST SLOPES OF THE OREGON CASCADES

STRONG WIND
     SIMCOE HIGHLANDS, LOWER COLUMBIA BASIN OF WASHINGTON,
     FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON, NORTH CENTRAL
     OREGON, EAST SLOPES OF THE OREGON CASCADES, LOWER COLUMBIA
     BASIN OF OREGON, GRANDE RONDE VALLEY, FOOTHILLS OF THE
     NORTHERN BLUE MOUNTAINS OF OREGON, FOOTHILLS OF THE SOUTHERN
     BLUE MOUNTAINS OF OREGON, JOHN DAY BASIN

A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE PACIFIC NORTHWEST
LATER TODAY INTO TONIGHT. WINDS WILL BE INCREASING DURING THE
AFTERNOON BECOMING STRONG IN MANY LOCATIONS OVERNIGHT. HIGH WIND
WARNINGS AND ADVISORIES ARE IN EFFECT. SNOW MIXED WITH RAIN AT THE
LOWER ELEVATIONS WILL OVERSPREAD THE REGION TODAY AND WILL ALSO
CONTINUE INTO TONIGHT. WINTER STORM WARNINGS ARE IN EFFECT FOR SOME
LOCATIONS. SEE FORECASTS AND WARNING PRODUCTS FOR DETAILS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SNOW MONDAY
     EAST SLOPES OF THE WASHINGTON CASCADES, KITTITAS VALLEY,
     NORTHWEST BLUE MOUNTAINS OF WASHINGTON, WALLOWA COUNTY,
     NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS
     OF OREGON, OCHOCO-JOHN DAY HIGHLANDS, EAST SLOPES OF THE OREGON
     CASCADES

STRONG WIND MONDAY
     SIMCOE HIGHLANDS, LOWER COLUMBIA BASIN OF WASHINGTON,
     FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON, NORTH CENTRAL
     OREGON, EAST SLOPES OF THE OREGON CASCADES, LOWER COLUMBIA
     BASIN OF OREGON, GRANDE RONDE VALLEY, FOOTHILLS OF THE
     NORTHERN BLUE MOUNTAINS OF OREGON, FOOTHILLS OF THE SOUTHERN
     BLUE MOUNTAINS OF OREGON, JOHN DAY BASIN

THE LOW PRESSURE SYSTEM WILL BE EXITING THE AREA LATE MONDAY. STRONG
WINDS AND SNOW WILL CONTINUE INTO THE AFTERNOON THEN DIMINISH IN THE
EVENING. WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH
MONDAY AFTERNOON. AN ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH
THE WEEK WITH RAIN/SNOW AND PERIODS OF WIND.

.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.