Heavy Snow in Oregon, February 14 to 16, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
925 PM PST MON FEB 14 2011

.UPDATE...A COLD FRONT WAS SLOWLY MOVG INLAND WITH SHOWERS SPREADING
ALONG AND AHEAD OF THE FRONT. THE SHOWERS WERE DEVELOPING EVEN MORE
SO ACROSS THE AREA AND THIS IS EXPECTED TO INCREASE THROUGHOUT THE
NIGHT. AS THE COLDER AIR FILTERS INTO THE REGION...SNOW SHOULD
CONTINUE DEVELOPING ALONG THE JOHN DAY HIGHLANDS AND SURROUNDINGS
AREAS WHERE A WINTER WEATHER ADVISORY IS IN EFFECT. OTHERWISE THE
REMAINDER OF THE SHORT TERM FORECAST APPEARS ON TRACK FOR NOW.

&&

.AVIATION...VFR CONDITIONS WILL DETERIORATE TO AREAS OF MVFR
CEILINGS AND VSBY TONIGHT ACROSS ALL TAF SITES. SHOWERS WILL
CONTINUE DEVELOPING ACROSS THE AREA AND LCL IFR CONDITIONS IN THE
HEAVIER SHOWERS ARE POSSIBLE THROUGH TOMORROW.

&&

.PREV DISCUSSION... /ISSUED 342 PM PST MON FEB 14 2011/

UPDATE...THE WINDS IN AND AROUND THE BEND OREGON AREA HAVE BEEN IN
THE ADVISORY CRITERIA AND HAVE ISSUED A WIND ADVISORY FOR THE NEXT
SEVERAL HOURS. OTHERWISE THE REMAINDER OF THE FORECAST APPEARS ON
TRACK.

PREV DISCUSSION... /ISSUED 240 PM PST MON FEB 14 2011/

SHORT TERM...TONIGHT THROUGH THURSDAY...AN UPPER LEVEL TROUGH OF
LOW PRESSURE IN THE EASTERN PACIFIC IS BEGINNING TO PUSHES INLAND
AND WILL CONTINUE TO DO SO OVER THE NEXT THREE DAYS EVENTUALLY
SETTING UP OVER THE PACIFIC NORTHWEST. THIS WILL LEAD TO AN
INCREASINGLY UNSETTLED AND COOLER WEATHER PATTERN FOR THE FORECAST
AREA. A STRONG UPPER LEVEL JET IS CURRENTLY OVER THE REGION AS A
BOUNDARY BETWEEN THE DEPARTING RIDGE OF HIGH PRESSURE AND THE
APPROACHING TROUGH. THESE WINDS ARE MIXING DOWN TO THE SURFACE
MAINLY ACROSS THE OREGON PORTION OF THE FORECAST AREA CAUSING SOME
VERY WINDY LOCATIONS. THE WIND IS INTERACTING WITH THE TERRAIN TO
CAUSE SOME LOCALLY ENHANCED WINDS. THESE WINDS WILL CONTINUE INTO
THE EVENING THEN DECREASE OVERNIGHT. ANOTHER PASSING UPPER LEVEL JET
AND SURFACE LOW ON TUESDAY WILL BRING A RETURN OF SOME VERY WINDY
CONDITIONS TO THE SOUTH AND EASTERN PORTIONS OF THE FORECAST AREA.
WIND ADVISORIES ARE CURRENTLY IN EFFECT UNTIL 6 PM AND MAY NEED TO
BE EXTENDED A FEW MORE HOURS BUT I'LL LEAVE THAT TO THE EVENING
SHIFT TO DECIDE. SNOW LEVELS CURRENTLY ARE IN THE 4-5 THOUSAND FOOT
RANGE BUT THIS WILL BEGIN LOWERING OVERNIGHT AS COOLER AIR BEGINS
FILTERING INTO THE REGION. SNOW LEVELS BY TUESDAY MORNING WILL RANGE
FROM 2500 FEET NEAR THE CASCADES TO 4000 FEET IN THE EAST. THERE
WILL BE SOME LIGHT SNOW OVERNIGHT IN THE HIGHER ELEVATIONS AND A
COUPLE OF SNOW ADVISORIES HAVE BEEN ISSUED WHICH MAY OR MAY NOT
REACH CRITERIA BUT WILL LET THEM CONTINUE AS IS. COOLER AND SHOWERY
WEATHER WILL PERSIST TUESDAY THROUGH THURSDAY WITH SNOW LEVELS
EVENTUALLY GETTING DOWN TO AROUND 1000 FEET. COULD EVEN SEE SOME
LIGHT SNOW SHOWERS IN THE COLUMBIA BASIN BY MIDWEEK IN THE OVERNIGHT
PERIODS BUT NOT EXPECTING ANY SIGNIFICANT ACCUMULATIONS. WILL NEED
TO KEEP WATCH ON THE MOUNTAINS FOR POSSIBLE SNOW EVENTS BUT FOR NOW
IT LOOKS LIKE SNOW SHOWERS WILL BE SPREAD OUT OVER TIME AND IN
DURATION SO NOT LOOKING AT ANY HIGHLIGHTS AT THIS TIME.

LONG TERM...THURSDAY NIGHT THROUGH SUNDAY NIGHT...TWO TROUGHS OF
LOW PRESSURE WILL INFLUENCE WEATHER IN THE PACIFIC NORTHWEST THROUGH
THE EXTENDED. THE FIRST TROUGH WILL SPLIT BY THE WEEKEND WITH MOST
OF THE ENERGY CLOSING OFF INTO A LOW PRESSURE CENTER OFF THE COAST
OF CALIFORNIA...AND THE NORTHERN PORTION OF THE TROUGH PASSING
THROUGH THE AREA BY SATURDAY. THIS WILL LEAD TO A DECREASE IN
PRECIPITATION OVER THE REGION AS MOST OF THE DISTURBANCES REMAIN
WEST OF THE CASCADES OR EAST OF THE REGION. FOR SATURDAY INTO
SUNDAY...THE REGION WILL BE UNDER A DRY NORTHWEST FLOW. A FEW
SHOWERS MAY BE POSSIBLE DUE TO UPSLOPE FLOW. BY SUNDAY...ANOTHER LOW
PRESSURE SYSTEM WILL DROP SOUTH OUT OF BRITISH COLUMBIA...BRINGING
COOLER TEMPERATURES AND AN INCREASE IN PRECIPITATION. FORECAST
MODELS AGREE IN THIS GENERAL PATTERN FROM THURSDAY NIGHT THROUGH THE
WEEKEND...BUT DETAILS OF INDIVIDUAL DISTURBANCES VARY BETWEEN
MODELS. HAVE KEPT SOME CHANCES OF PRECIPITATION THROUGH THE
PERIOD...PARTICULARLY FOR THE MOUNTAINS TO ACCOUNT FOR THIS
UNCERTAINTY...BUT SUNDAY AND SUNDAY NIGHT WILL BE THE NEXT BEST
CHANCE OF PRECIPITATION IN THE EXTENDED AS ALL MODELS INDICATE THIS.
WITH THE COLDER TEMPERATURES ALOFT WITH THIS LATE WEEKEND
SYSTEM...SNOW WILL BE THE PRIMARY PRECIPITATION TYPE FOR ALL
LOCATIONS DURING THE OVERNIGHT HOURS AND A MIX OF RAIN AND SNOW FOR
THE LOWER ELEVATIONS DURING THE DAY. DMH

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  43  49  35  42 /  40  60  50  50
ALW  43  50  38  45 /  50  60  60  50
PSC  42  51  36  48 /  20  50  20  20
YKM  36  46  32  43 /  20  40  20  20
HRI  41  50  37  48 /  20  60  30  20
ELN  35  44  30  41 /  20  50  20  30
RDM  38  46  31  36 /  60  70  70  60
LGD  39  47  34  37 /  60  70  80  70
GCD  39  46  34  37 /  60  60  80  70
DLS  40  50  36  45 /  30  60  40  40

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 9 AM PST TUESDAY ABOVE 4000 FEET
     FOR THE ORZ503-506.

WA...NONE.
&&

THREAT INDEX
TUESDAY : GREEN
WEDNESDAY : GREEN
THURSDAY : 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

97/99/76

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
900 PM PST MON FEB 14 2011

UPDATED TO REMOVE STRONG WINDS TONIGHT

ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
151415-
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-
900 PM PST MON FEB 14 2011

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

.DAY ONE...TONIGHT

SNOW
     SOUTHERN BLUE MOUNTAINS OF OREGON, OCHOCO-JOHN DAY HIGHLANDS

SOUTHERLY WINDS WILL CONTINUE AND DECREASE THIS EVENING AND
OVERNIGHT. THE STRONGEST WINDS WILL OCCUR WHERE WIND IS FUNNELED
THROUGH CANYONS AND CANYON EXITS FACING TO THE NORTH.

SNOW LEVELS WILL LOWER TO AROUND 4000 FEET OVERNIGHT IN THE SOUTHERN
BLUE MOUNTAINS AND JOHN DAY HIGHLANDS. THIS WILL ALLOW A FEW INCHES
OF SNOW TO ACCUMULATE IN THE HIGHER ELEVATIONS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

AN UPPER LEVEL TROUGH WILL MOVE INTO THE REGION AND CONTINUE TO
IMPACT THE REGION THROUGH THE REST OF THE SEVEN DAYS.

.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.