FXUS66 KPDT 050320
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
720 PM PST FRI DEC 4 2009
.UPDATE...VERY LIGHT SNOW SHOWERS ARE BEGINNING TO SHOW UP ON THE
DOPPLER RADAR OVER THE BLUE MOUNTAINS AND PORTIONS OF THE LOWER
COLUMBIA BASIN...BUT ANY GROUND ACCUMULATION IS EXPECTED TO BE
MINIMAL. AS THE COLD FRONT SAGS SOUTHWARD OVERNIGHT...THE
AREA OF PRECIPITATION WILL MOVE INTO NORTH CENTRAL OREGON AND
EVENTUALLY INTO CENTRAL AND EAST CENTRAL OREGON. BELOW NORMAL
TEMPERATURES WILL CONTINUE TO BE LIKELY. 82
&&
.PREV DISCUSSION... /ISSUED 233 PM PST FRI DEC 4 2009/
SHORT TERM...AN UPPER LOW CONTINUES TO MOVE SOUTH-SOUTHEAST TOWARDS
WESTERN MONTANA THIS AFTERNOON. THIS SYSTEM WILL DROP INTO SOUTHEAST
IDAHO BY SATURDAY AFTERNOON. BANDS OF LIGHT PRECIP WRAPPING AROUND
THE SYSTEM MAY BRING ISOLATED TO SCATTERED SNOW SHOWERS TO A FEW
AREAS TONIGHT AND ON SATURDAY. ANY ACCUMULATIONS WILL BE LIGHT...
GENERALLY 2 INCHES OR LESS WITH THE HIGHEST AMOUNTS OVER THE HIGHER
TERRAIN. THIS SYSTEM WILL ALSO BRING A GRADUAL AIR MASS CHANGE WHICH
SHOULD HELP TO SLOWLY MIX OUT THE LINGERING STRATUS AND FOG TRAPPED
IN THE COLUMBIA BASIN THROUGH THE NEXT 12 TO 24 HOURS. ANOTHER
DISTURBANCE WILL DROP SOUTH FROM WESTERN CANADA INTO THE PACIFIC
NORTHWEST SATURDAY NIGHT AND SUNDAY. THIS SYSTEM WILL BRING CHANCES
OF LIGHT SNOW FOR A GOOD PORTION OF THE AREA SATURDAY NIGHT AND
SUNDAY. AT THIS TIME THE BEST CHANCES FOR SNOW APPEAR TO BE ALONG
EAST FACING SLOPES OF THE BLUE AND WALLOWA MOUNTAINS...ALONG THE
EAST SLOPES OF THE CASCADES...THE YAKIMA AND KITTITAS VALLEYS...AND
INTO CENTRAL OREGON. SNOW AMOUNTS AT THIS TIME LOOK TO STAY BELOW
ADVISORY LEVELS. THIS SECOND SYSTEM WILL ALSO PULL IN A BATCH OF
EVEN COLDER AIR FROM CENTRAL CANADA WITH LOW TEMPS BY MONDAY MORNING
BEING 15 DEGREES OR COLDER REGION WIDE. 90
LONG TERM...MONDAY THROUGH FRIDAY. ON MONDAY A DEPARTING LOW
PRESSURE SYSTEM WILL KEEP CLOUDS AND SOME SHOWERS ACROSS THE AREA.
THE SHOWERS SHOULD REMAIN OVER THE SOUTHERN PORTIONS OF OUR REGION
THAT INCLUDES CENTRAL OREGON...JOHN DAY HIGHLANDS AND THE
BLUE/WALLOWA MTNS WHICH SHOULD LINGER INTO MONDAY NIGHT. SEVERAL
DISTURBANCES ARE EXPECTED TO CROSS THE TWO STATE AREA THROUGH THE
WEEK KEEPING SNOW SHOWERS ACROSS THE AREA MOUNTAINS. TEMPERATURES
WILL REMAIN UNSEASONABLY COLD THROUGH THE PERIOD.
AVIATION...00Z TAFS...MVFR AND OCCASIONAL IFR CONDITIONS ARE
POSSIBLE ACROSS MOST TAF SITES DUE TO LOWERING CEILINGS AND
DECREASING VSBY EXCEPT FOR KRDM WHICH WILL CONTINUE EXPERIENCING VFR
CONDITIONS. HOWEVER A COLD FRONT IS FORECAST TO SWEEP ACROSS THE
REGION TONIGHT KEEPING THE MVFR AND IFR CONDITIONS THROUGH TOMORROW
MORNING FOR ALL TAF SITES.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 20 31 19 26 / 20 20 40 40
ALW 23 32 22 28 / 10 20 40 30
PSC 21 35 16 30 / 20 10 20 20
YKM 17 34 16 30 / 10 10 60 20
HRI 22 34 18 30 / 20 10 30 20
ELN 19 33 15 28 / 10 10 60 20
RDM 16 34 11 26 / 20 10 20 40
LGD 19 30 18 27 / 20 20 40 30
GCD 20 33 15 27 / 20 20 30 40
DLS 25 35 21 31 / 20 10 50 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SATURDAY : GREEN
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
$$
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