Heavy Snow in Oregon, April 2, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
230 AM PDT FRI APR 2 2010

.SHORT TERM...TODAY THROUGH SATURDAY...A WARM FRONT IS MOVING TOWARD
THE COAST...BRINGING RAIN AND SNOW TO THE CASCADES. THE RAIN AND
SNOW WILL SPREAD EAST OVER THE AREA TODAY. THIS SYSTEM HAS LOTS OF
MOISTURE. THE HARD PART IS HOW MUCH SNOW WILL MELT WITH THE WARMER
AIR ALOFT BEFORE THE COLD FRONT MOVES THROUGH THIS AFTERNOON OR
EVENING AND CHANGES THE PRECIPITATION BACK TO SNOW. THE
PRECIPITATION WILL BEGIN AS SNOW IN THE MOUNTAINS...BUT STRONG WARM
ADVECTION WILL OCCUR AHEAD OF THE WARM FRONT. THE WARM SOUTHERLY
FLOW WILL LIMIT SNOW ACCUMULATION TODAY EVEN THOUGH THE SNOW LEVEL
ALONG THE EAST SLOPES OF THE CASCADES WILL BE 2000-3000 FEET. IN THE
BLUE MOUNTAINS BELOW 4000 FEET THE PRECIPITATION WILL CHANGE TO RAIN
THE AFTERNOON...THEN BACK TO SNOW AFTER THE WARM FRONT PASSES LATE
IN THE AFTERNOON. THIS WILL BE A MOIST SYSTEM WITH SNOW PERSISTING
IN THE MOUNTAINS THROUGH SATURDAY MORNING. VARIOUS WINTER SNOW
WARNINGS AND ADVISORIES HAVE BEEN ISSUED.

HIGHER WINDS ALOFT WILL MIX TO THE SURFACE AT TIMES ON
RIDGETOPS...THE DESCHUTES PLATEAU...AND THE WALLOWA VALLEY.
FUNNELING WILL ALSO INCREASE THE WINDS IN THE GRANDE RONDE VALLEY
AND THE NORTH-SOUTH PART OF THE JOHN DAY VALLEY. THE COLD FRONT WILL
MOVE ACROSS EASTERN WASHINGTON AND OREGON LATE FRIDAY AFTERNOON AND
EARLY EVENING. STRONG WESTERLY WINDS WILL DEVELOP IN THE TIGHTER
GRADIENT BEHIND THE COLD FRONT...AIDED BY HIGHER WINDS ALOFT MIXING
TO THE SURFACE. WIND ADVISORIES HAVE BEEN ISSUED FOR THE GRANDE
RONDE VALLEY...WALLOWA VALLEY...AND FOOTHILLS OF THE BLUE MOUNTAINS
FOR TODAY AND THIS EVENING...AND THE COLUMBIA BASIN FOR THIS
AFTERNOON AND EVENING. COONFIELD

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...RAIN AND SNOW SHOWERS
WILL CONTINUE THROUGH SATURDAY EVENING BUT WILL DIMINISH BY SUNDAY
MORNING. ANOTHER COMPLEX STORM SYSTEM WILL MOVE INTO THE AREA LATE
SUNDAY...WITH PERIODS OF SNOW AND LOW ELEVATION RAIN PERSISTING
THROUGH TUESDAY. WHILE IT IS STILL TOO EARLY TO PIN DOWN SPECIFIC
SNOW ACCUMULATIONS WITH A HIGH DEGREE OF CERTAINTY...THERE IS A GOOD
CHANCE THAT LOCATIONS ABOVE 3500 FEET WILL SEE SEVERAL INCHES OF
SNOW BEFORE THE TROUGH EXITS THE REGION ON TUESDAY NIGHT. DRIER
CONDITIONS CAN THEN BE EXPECTED ON WEDNESDAY AS A RIDGE OF HIGH
PRESSURE BUILDS OVER THE AREA. HOWEVER...ISOLATED TO SCATTERED
SHOWERS WILL REMAIN POSSIBLE IN THE NORTHEAST MOUNTAINS DUE TO
NORTHWESTERLY FLOW ON THE BACK SIDE OF THE TROUGH. THERE ARE
CONSIDERABLE MODEL DIFFERENCES FROM WEDNESDAY NIGHT ONWARD...BUT
BOTH THE 00Z GFS AND THE 00Z ECMWF DEPICT SOME FORM OF A SHORTWAVE
MOVING THROUGH THE PACIFIC NORTHWEST ON THURSDAY...FOLLOWED BY A
STRONGER DISTURBANCE ON FRIDAY OR FRIDAY NIGHT. THEREFORE...HAVE
LEFT CLIMO POPS IN THE FORECAST FOR THE END OF THE WEEK.
TEMPERATURES WILL GRADUALLY RISE WEDNESDAY THROUGH FRIDAY AS
SOUTHWESTERLY FLOW REESTABLISHES ITSELF.  82

&&

.AVIATION...06Z TAFS...CLOUD COVER WILL INCREASE AND LOWER TONIGHT
AS A STRONG LATE SEASON BRINGS RAIN AND SNOW TO THE AREA TOMORROW
ALONG WITH STRONG WINDS. PRECIPITATION WILL BEGIN AROUND SUNRISE
NEAR THE CASCADES AFFECTING KRDM...KDLS AND KYKM. SNOW MAY LOWER
VISIBILITIES AT KRDM TO MVFR LEVELS UNTIL IT SWITCHES OVER TO RAIN
LATE IN THE MORNING. RAIN AND MOUNTAIN SNOW WILL CROSS THE AREA
DURING THE DAY THOUGH SOUTH WINDS MAY DELAY THE ONSET AT KPDT AND
KALW UNTIL THE AFTERNOON. WITH THE HEAVIER PRECIPITATION PERIODS OF
MVFR AND IFR CEILINGS AND VISIBILITIES ARE POSSIBLE. PRECIPITATION
WILL BECOME MORE SHOWERY AFTER THE FRONT PASSES IN THE LATE
AFTERNOON. SURFACE WINDS WILL PICK UP THIS MORNING WITH KALW...KPSC
AND KPDT HAVING SOUTH WINDS OF 15 TO 25 KTS WITH GUSTS TO 35 KTS AND
INCREASING TO 25 TO 35 KTS WITH GUSTS TO 45 KTS THIS AFTERNOON AND
EARLY EVENING BEFORE BEGINNING TO DIMINISH  IN THE LATE EVENING.
OTHER TAF LOCATIONS WILL HAVE 10 TO 20 KTS WITH GUSTS TO 30 KTS
INCREASING TO 20 TO 30 KTS WITH GUSTS TO 40 KTS THIS AFTERNOON
BEFORE DECREASING AFTER 03/02Z. PERRY

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  48  31  51  31 /  90  40  30  20
ALW  50  36  51  35 /  90  40  30  20
PSC  53  36  57  32 /  90  10  30  20
YKM  48  31  55  28 / 100  10  20  10
HRI  52  32  55  31 /  90  20  20  20
ELN  46  33  51  28 / 100  20  30  20
RDM  46  20  43  19 /  90  30  30  30
LGD  44  30  45  27 /  90  60  30  20
GCD  45  27  43  29 /  90  50  30  20
DLS  51  34  53  32 / 100  30  30  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY FROM 8 AM THIS MORNING TO 8 PM PDT THIS EVENING
     ORZ049-050.

     WINTER STORM WATCH FROM 2 PM PDT THIS AFTERNOON THROUGH SATURDAY
     MORNING ABOVE 3500 FEET FOR THE ORZ050.

     WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM PDT
     SATURDAY ORZ506.

     WINTER STORM WARNING FROM 6 AM THIS MORNING TO 11 PM PDT THIS
     EVENING ORZ043.

     WINTER STORM WARNING FROM 6 AM THIS MORNING TO 6 AM PDT SATURDAY
     ORZ502.

     WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM PDT
     SATURDAY ORZ503.

     WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS EVENING
     ORZ044.

     WIND ADVISORY FROM 8 AM THIS MORNING TO 8 PM PDT THIS EVENING
     ORZ501-504.

WA...WINTER STORM WARNING FROM 6 AM THIS MORNING TO 6 AM PDT SATURDAY
     ABOVE 2000 FEET FOR THE WAZ501.

     WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM PDT
     SATURDAY ABOVE 2000 FEET FOR THE WAZ502.

     WINTER STORM WARNING FROM 6 AM THIS MORNING TO 6 AM PDT SATURDAY
     WAZ030.

     WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS EVENING
     WAZ028.

     WIND ADVISORY FROM 8 AM THIS MORNING TO 8 PM PDT THIS EVENING
     WAZ029.

     WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 5 PM PDT THIS
     AFTERNOON ABOVE 1500 FEET FOR THE WAZ026.

&&

THREAT INDEX
TODAY : RED
SATURDAY : YELLOW
SUNDAY : 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

76/82/82

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1015 PM PDT THU APR 1 2010

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-021415-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
CENTRAL OREGON-LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-
WALLOWA COUNTY-FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-
NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-
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 CENTRAL CASCADES OF WASHINGTON-
EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON-
1015 PM PDT THU APR 1 2010

UPDATED FOR KITTITAS SNOW ADVISORY AND WIND ADVISORIES

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

.DAY ONE...TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

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

STRONG WIND FRIDAY
     FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON, GRANDE RONDE
     VALLEY, FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON, NORTHERN
     WHEELER AND SOUTHERN GILLIAM COUNTIES

SNOW SATURDAY
     WALLOWA COUNTY

A LATE SEASON COLD FRONT WILL SWEEP INTO THE REGION ON FRIDAY
BRINGING RAIN AND SNOW. SNOW LEVELS WILL LOWER FRIDAY NIGHT. SEE
LATEST PDXWSWPDT PRODUCT FOR MORE DETAILS OF ADVISORIES AND WARNINGS
THAT ARE IN EFFECT.

STRONG SOUTHERLY WINDS WILL PRECEDE THE COLD FRONT THEN SWITCH TO
WESTERLY FRIDAY AFTERNOON AND OVERNIGHT. WIND ADVISORIES HAVE BEEN
ISSUED. SEE LATEST PDXNPWPDT PRODUCT FOR LATEST DETAILS.

.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.