Heavy Snow in Oregon, December 8, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
920 AM PST SAT DEC 8 2012

.UPDATE...A COLD MOIST NORTHWEST FLOW WILL CONTINUE TO PRODUCE SNOW
OVER THE NORTHEAST OREGON MOUNTAINS TODAY. UPSLOPE FLOW WILL BRING
THE HEAVIEST SNOW TO THE BLUES WHERE ADDITIONAL ACCUMULATIONS ARE
LIKELY TODAY. ADVISORIES AND WARNINGS REMAIN IN EFFECT THROUGH THE
EVENING. THE CASCADES WILL ALSO HAVE SNOW TODAY HOWEVER AS THE FLOW
ALOFT BECOMES MORE NORTHERLY THESE AREAS WILL HAVE LESS OF AN
UPSLOPE COMPONENT SO LOWER ACCUMULATIONS. A COLD FRONT MOVED THROUGH
THE AREA YESTERDAY EVENING. AS A RESULT HIGH TEMPERATURES TODAY WILL
ONLY BE IN THE 30S TO LOWER 40S. MUCH LESS WIND TODAY COMPARED TO
YESTERDAY AS WELL.  94

&&

.AVIATION...18Z TAFS...VFR CONDITIONS TO PREVAIL THROUGH 18Z SUNDAY.
EXPECT SCT-BKN CONDITIONS AT 5-6 THOUSAND FEET AND BKN-OVC AT AROUND
12000 FEET TODAY. THERE COULD BE SOME LOWER CLOUDS DEVELOPING
TONIGHT AT KDLS...KBDN...AND KRDM. FOR NOW INTRODUCED SOME SCT
CONDITIONS AT TWO THOUSAND FEET OVERNIGHT AND WILL EVALUATE FURTHER
DURING THE DAY. WINDS WILL GENERALLY BE LESS THAN 15KT FROM THE WEST
THIS AFTERNOON AND LIGHT TONIGHT. ANY SNOW SHOWERS SHOULD REMAIN
MOSTLY OVER THE MOUNTAINS. 78

&&

.PREV DISCUSSION... /ISSUED 240 AM PST SAT DEC 8 2012/

SHORT TERM...TODAY THROUGH SUNDAY NIGHT...A COOL NORTHWEST FLOW
WILL PREVAIL OVER THE REGION AND FORECAST AREA. THERE WILL BE A
COUPLE WEATHER DISTURBANCES IN THE FLOW WHICH WILL MOVE SOUTHEAST
FROM WESTERN CANADA INTO THE PACIFIC NORTHWEST. THE MAIN EFFECT FROM
THESE DISTURBANCES WILL BE CONTINUING SNOW SHOWERS OVER THE
NORTHEAST OREGON AND SOUTHEAST WASHINGTON MOUNTAINS. THE FIRST
SYSTEM WILL MOVE ACROSS THE FORECAST AREA TODAY WITH A SURGE OF
MOISTURE THAT WILL BRING MORE SNOW TO THE BLUE MOUNTAINS...WALLOWA
COUNTY AND THE GRANDE RONDE VALLEY. THIS WILL ADD EXTENSION TO THE
ALREADY EXISTING WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES
FOR THESE AREAS. THE SNOW SHOWERS WILL DECREASE OVER THE SOUTHERN
BLUES BY LATE MORNING BUT WILL CONTINUE IN THE OTHER AREAS MENTIONED
THROUGH EARLY THIS EVENING FOR SEVERAL MORE INCHES OF SNOW EXPECTED.
THERE MAY EVEN BE A FEW FLURRIES OR MIXED RAIN AND SNOW SHOWERS OVER
THE HIGHER ELEVATIONS OF THE BLUE MOUNTAIN FOOTHILLS THIS
MORNING...BUT AM NOT EXPECTING ANY ACCUMULATION. ELSEWHERE THERE
WILL BE A FEW MORE SNOW SHOWERS OVER THE CASCADES BUT WITH LITTLE IF
ANY ACCUMULATION EXPECTED. IT WILL BE DRY IN THE LOWER COLUMBIA
BASIN AND ADJACENT VALLEYS TO THE BASIN AND THE FLAT AREAS IN THE
LEE OF THE CASCADES OF OREGON. HIGH TEMPERATURES WILL BE QUITE COOL
TODAY WITH READINGS ONLY IN THE 40S IN THE LOWER ELEVATIONS AND 20S
TO LOWER 30S IN THE MOUNTAINS. THERE WILL BE A BREAK IN THE WEATHER
WITH CONDITIONS DRYING OUT TONIGHT AND SUNDAY. THE NEXT WEATHER
DISTURBANCE...WITH A WARM FRONT...WILL MOVE ACROSS THE REGION BY
SUNDAY NIGHT. THE JET STREAM WILL BE LIFTING BACK TO THE NORTH WITH
OVERRUNNING RAIN AND SNOW SHOWERS OVER THE MOUNTAINS SUNDAY NIGHT.
THIS WILL BE FOLLOWED BY A HIGH PRESSURE RIDGE. IT WILL REMAIN DRY
IN THE LOWER ELEVATIONS AS WELL AS NORTH CENTRAL OREGON AND THE JOHN
DAY BASIN. AM EXPECTING VERY LITTLE IF ANY PRECIPITATION
ACCUMULATION FROM THIS DISTURBANCE. SNOW LEVELS WILL RISE THROUGH
THE NIGHT BUT WILL REMAIN COLD ENOUGH FOR SNOW IN THE MOUNTAINS. 88

LONG TERM...MONDAY THROUGH FRIDAY NIGHT...A RIDGE OF HIGH PRESSURE
WILL BE OVER THE EASTERN PACIFIC AT THE START OF THE WEEK. THIS WILL
LEAVE THE AREA IN A NORTHWEST TO NORTHERLY FLOW. WITH THE POTENTIAL
OF RESIDUAL MOISTURE AND UPSLOPE SHOWERS...HAVE KEPT A SLIGHT CHANCE
TO CHANCE OF PRECIPITATION ALONG THE CASCADE CREST AND IN THE
NORTHEAST MOUNTAINS. MODELS INDICATE THAT A TROUGH OF LOW PRESSURE
WILL REPLACE THE RIDGE ON TUESDAY NIGHT INTO WEDNESDAY. MODELS SEEM
TO BE SLOWING THIS SYSTEM DOWN A LITTLE AND THEREFORE HAVE KEPT A
SLIGHT CHANCE OF PRECIPITATION IN THE NORTHEAST MOUNTAINS ON TUESDAY
WITH HIGHER CHANCES ON TUESDAY NIGHT AND WEDNESDAY WITH THE TROUGH
PASSAGE. COLDER AIR WILL MOVE IN WITH THE TROUGH LEADING TO LOWERING
SNOW LEVELS AND THE POTENTIAL FOR SNOW DOWN TO THE BASIN. AFTER
WEDNESDAY...THE MODELS DISAGREE ON THE DETAILS BUT SEEM TO AGREE ON
THE BASIC IDEA THAT INDIVIDUAL DISTURBANCES WILL MOVE THROUGH THE
FLOW. THE GFS TRIES TO KEEP MORE OF A RIDGE PATTERN WITH WEAKER
DISTURBANCES WILL THE EUROPEAN MODEL IS MORE ACTIVE AND STRONGER
WITH THE DISTURBANCES. HAVE KEPT A SLIGHT CHANCE TO CHANCE THROUGH
THE END OF THE WEEK...BUT CONFIDENCE IN TIMING AND PRECIPITATION
CHANCES ARE LOWER AFTER WEDNESDAY FOR THE EXTENDED. DMH

AVIATION...12Z TAFS...SURFACE WINDS WILL BE GUSTY THROUGH THE
MORNING AND AFTERNOON BEFORE DECREASING OVERNIGHT. UPSLOPE FLOW INTO
THE BLUE MOUNTAINS WILL KEEP SHOWERS GOING WITH VICINITY SHOWERS
POSSIBLE NEAR KPDT AND KALW IN THE AFTERNOON. VFR CONDITIONS ARE
EXPECTED TO PREVAIL AT ALL TAF SITES. DMH

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  40  25  39  33 /  20  20  10  10
ALW  40  26  41  34 /  20  20  10  10
PSC  42  28  38  32 /  10  10  10  10
YKM  40  26  38  28 /  10  10  10  10
HRI  42  28  40  32 /  10  10  10  10
ELN  37  25  39  28 /  30  10  10  10
RDM  38  26  42  30 /  10  10  10  10
LGD  34  21  37  33 /  70  30  10  20
GCD  34  23  37  29 /  20  20  10  10
DLS  44  32  45  35 /  30  10  10  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WARNING UNTIL 6 PM PST THIS EVENING ORZ502.

     WINTER WEATHER ADVISORY UNTIL 6 PM PST THIS EVENING ORZ503.

     WINTER WEATHER ADVISORY UNTIL 6 PM PST THIS EVENING ORZ049-050.

WA...WINTER STORM WARNING UNTIL 6 PM PST THIS EVENING WAZ030.

&&

THREAT INDEX
TODAY : YELLOW
SUNDAY : GREEN
MONDAY : 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

94/78/78

HAZARDOUS WEATHER OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
930 AM PST SAT DEC 8 2012

ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
091230-
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-
930 AM PST SAT DEC 8 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
     NORTHWEST BLUE MOUNTAINS OF WASHINGTON, WALLOWA COUNTY,
     NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF
     OREGON

ANOTHER WEATHER SYSTEM WILL MOVE ACROSS NORTHEAST OREGON AND
SOUTHEAST WASHINGTON TODAY BRINGING MORE SNOW TO THE AREA. A WINTER
STORM WARNING REMAINS IN EFFECT UNTIL 6 PM FOR THE NORTHERN BLUE
MOUNTAINS. A WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM
FOR THE GRANDE RONDE VALLEY WALLOWA COUNTY AND THE SOUTHERN BLUE
MOUNTAINS. PLEASE REFER TO NWS PRODUCT ID PDXWSWPDT FOR MORE DETAILS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

A WARM FRONT WILL MOVE ACROSS THE REGION SUNDAY NIGHT INTO MONDAY AS
THE JET STREAM LIFTS BACK TO THE NORTH AND EAST. AFTER THAT HIGH
PRESSURE WITH MOSTLY DRY CONDITIONS WILL BE OVER THE FORECAST AREA
THROUGH TUESDAY MORNING. THEN A SERIES OF WEATHER SYSTEMS WILL MOVE
ACROSS THE REGION FROM THE NORTH LATE TUESDAY THROUGH FRIDAY WITH
EACH BRINGING A CHANCE OF LOW ELEVATION RAIN AND MOUNTAIN SNOW.

.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.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1134 AM PST SAT DEC 08 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0830 AM     HEAVY SNOW       SKI BLUEWOOD            46.08N 117.84W
12/08/2012  M24.0 INCH       COLUMBIA           WA   PUBLIC

            48 HR TOTAL AT THE BASE 25 INCHES AT THE SUMMIT.

&&

MVESCIO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
1231 PM PST SAT DEC 08 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0830 AM     HEAVY SNOW       MEACHAM                 45.51N 118.42W
12/08/2012  E0.0 INCH        UMATILLA           OR   DEPT OF HIGHWAYS

            INTERSTATE-84 CLOSED DUE TO HEAVY SNOW NEAR MEACHAM.

&&

MVESCIO

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE PENDLETON OR
1241 PM PST SAT DEC 08 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0830 AM     HEAVY SNOW       MEACHAM                 45.51N 118.42W
12/08/2012  U0.0 INCH        UMATILLA           OR   DEPT OF HIGHWAYS

            INTERSTATE-84 CLOSED DUE TO HEAVY SNOW NEAR MEACHAM AND
            CAR ACCIDENTS. SINCE REOPENED.

&&

MVESCIO