FXUS66 KPDT 041801 AAA
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1000 AM PST FRI DEC 4 2009
.SHORT TERM...UPDATE...AN UPPER LOW...CURRENTLY OVER SOUTHEAST
BRITISH COLUMBIA...WILL MOVE SOUTH INTO WESTERN MONTANA BY LATE THIS
AFTERNOON. THE COLD FRONT ALOFT HAS MOVED THROUGH THE REGION ALREADY
WITH THE FIRST OF TWO SURFACE COLD FRONTS EXPECTED TO MOVE SOUTH
THROUGH THE AREA TODAY. MOST HIGHER LEVEL CLOUDS...ABOVE 8000 FT
MSL...HAVE CLEARED FROM THE AREA...BUT STRATUS AND FOG REMAINS
TRAPPED IN THE COLUMBIA BASIN...THE YAKIMA VALLEY AND THE KITTITAS
VALLEY. EXPECT THE SURFACE FRONT TO GRADUALLY PUSH THIS STRATUS/FOG
SOUTH INTO MORE OF EASTERN OREGON...WHILE GRADUALLY CLEARING IT OUT
OF WASHINGTON DURING THE NEXT 12 HOURS. THUS VISIBILITIES IN THE
BLUE MOUNTAIN FOOTHILLS SHOULD BE UP AND DOWN TODAY. WILL MAKE SOME
ADJUSTMENTS TO SKY COVER AND FOG PLACEMENT FOR TODAY. ALSO WILL
LOWER HIGH TEMPS AT MANY LOCATIONS UNDER THE STRATUS/FOG. GRADIENTS
REMAIN TIGHT ACROSS THE SOUTHERN END OF THE GRANDE RONDE VALLEY. AS
A RESULT WINDS REMAIN IN THE ADVISORY RANGE...ESPECIALLY THROUGH
LADD AND PYLES CANYONS. THUS WILL CONTINUE THE CURRENT ADVISORY
UNTIL 1 PM. 90
.LONG TERM...PREVIOUS DISCUSSION...AN UPPER LEVEL LOW WILL MOVE FROM
BRITISH COLUMBIA TO WESTERN OREGON SUNDAY. THIS WILL BRING A
WIDESPREAD CHANCE OF SNOW TO EASTERN WASHINGTON AND OREGON...WITH
SHOWERS LINGERING IN OREGON MONDAY. COLD NORTHERLY FLOW WILL REMAIN
OVER THE AREA TUESDAY. UPPER LEVEL FLOW WILL BECOME MORE NORTHWEST
WEDNESDAY AND THURSDAY WITH COLD AIR TRAPPED IN THE COLUMBIA BASIN.
A SERIES OF DISTURBANCES IN THE NORTHWEST FLOW WILL BRING VARYING
CHANCES OF WINTER PRECIPITATION WEDNESDAY AND THURSDAY.
&&
.AVIATION...MVFR AND OCCASIONAL IFR CONDITIONS ARE POSSIBLE ACROSS
MOST TAF SITES TODAY 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 31 17 33 18 / 10 20 20 30
ALW 34 20 36 18 / 10 20 20 30
PSC 36 18 38 18 / 10 10 10 20
YKM 37 16 37 21 / 10 10 10 20
HRI 35 15 35 18 / 10 10 10 20
ELN 36 18 37 15 / 10 10 10 20
RDM 42 10 36 11 / 10 20 20 20
LGD 36 20 31 17 / 10 30 30 40
GCD 39 18 33 12 / 10 20 20 40
DLS 39 22 40 19 / 10 20 20 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR ORZ049.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SATURDAY : GREEN
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
$$
90/76/97
