Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 210942
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
142 AM PST SUN DEC 21 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT...ACTIVE WEATHER PATTERN
CONTINUES OVER THE REGION THIS MORNING. A STRONG JET STREAM
CONTINUES TO PUSH PACIFIC MOISTURE INTO OREGON AND WASHINGTON. MUCH
OF THE PRECIP IS BEING SQUEEZED OUT OVER THE CASCADES...BUT THERE IS
ALSO SOME SIGNIFICANT RAINFALL OVER THE BLUE MOUNTAINS AS A WARM
FRONT LIFTS NORTHWARD ACROSS THE CWA. THE STEADY RAIN HAS BECOME
MORE SHOWERY DURING THE PAST FEW HOURS INDICATING AN INCREASE IN
WESTERLY WINDS ALONG THE CASCADES WHICH IS CREATING A MOUNTAIN WAVE
EFFECT. DUE TO THE SIGNIFICANT PRECIPITATION AN AREAL FLOOD WATCH
CONTINUES IN EFFECT FOR THE ENTIRE CWA EXCEPT FOR THE LOWER COLUMBIA
BASIN ZONES WHERE RAINFALL AMOUNTS ARE MUCH LESS. THE WATCH IS IN
EFFECT THROUGH 4 PM MONDAY. STILL EXPECTING WINDS TO INCREASE EARLY
THIS MORNING WITH VARIOUS HIGH WIND WARNINGS AND ADVISORIES. A HIGH
WIND WARNING IS CURRENTLY IN EFFECT FOR CENTRAL OREGON...NORTH
CENTRAL OREGON...THE SIMCOE HIGHLANDS AND THE FOOTHILLS OF THE
SOUTHERN BLUE MOUNTAINS. SEVERAL REPORTING STATIONS HAVE REACHED
HIGH WIND WARNING CRITERIA SO FAR. A WIND ADVISORY IS IN EFFECT FOR
THE LOWER COLUMBIA BASIN...NORTHERN BLUE MOUNTAIN FOOTHILLS OF
OREGON AND WASHINGTON AND THE YAKIMA VALLEY. IN THE YAKIMA VALLEY
THE STRONGEST WINDS WILL LIKELY BE AT THE SOUTH END OF THE VALLEY AT
THE BASE OF THE SIMCOE HIGHLANDS. ELSEWHERE IT WILL BE BREEZY TO
WINDY BUT WINDS NOT REACHING ADVISORY CRITERIA. TEMPERATURES TODAY
WILL BE QUITE MILD WITH MAXIMUM READINGS IN THE MID 40S MOUNTAINS TO
THE MID AND UPPER 50S IN THE LOWER ELEVATIONS. SOME OF THESE HIGH
TEMPERATURES HAVE ALREADY OCCURRED SINCE MIDNIGHT. THE WARMEST
TEMPERATURES ARE CURRENTLY ALONG THE BLUE MOUNTAIN FOOTHILLS AND THE
LOWER COLUMBIA BASIN WHERE DOWNSLOPE WARMING IS TAKING PLACE DUE TO
THE SOUTHWEST WINDS ACROSS THE CWA. THIS SYSTEM WILL BEGIN TO MOVE
OUT OF THE REGION TONIGHT BUT THERE WILL STILL LIKELY BE RAIN OVER
THE NORTHEAST MOUNTAINS AND NEAR THE CASCADE CREST...THOUGH NOT AS
STEADY OR AS HEAVY. MORE SIGNIFICANT DRYING WILL TAKE PLACE DURING
THE DAY MONDAY WITH THE PRECIPITATION BECOMING CONFINED ONLY TO THE
MOUNTAINS WITH DRY CONDITIONS ELSEWHERE. THE CWA WILL BE MOSTLY
PRECIPITATION FREE MONDAY NIGHT WITH CLEARING SKIES AND COOLER
TEMPERATURES. 88

.LONG TERM...TUESDAY THROUGH SUNDAY...THE REGION WILL BE UNDER AN
UPPER LEVEL RIDGE ON TUESDAY WITH MOSTLY DRY CONDITIONS. THERE WILL
BE A CHANCE OF VALLEY FOG. A RATHER VIGOROUS SHORTWAVE TROUGH WILL
MOVE ACROSS THE REGION WEDNESDAY INTO EARLY CHRISTMAS DAY. SNOW
LEVELS WILL INITIALLY BE HIGH SO PRECIPITATION WILL BE MOSTLY RAIN
ON WEDNESDAY BELOW 4000 FEET. HOWEVER COLDER AIR WILL ARRIVE
WEDNESDAY NIGHT AND SNOW WILL BEGIN TO FALL BELOW PASS LEVEL FOR
SOME POTENTIAL TRAVEL IMPACTS. BY THE TIME THAT SNOW LEVELS DROP TO
THE VALLEY FLOORS THE PRECIPITATION SHOULD BE ABOUT OVER ON
CHRISTMAS DAY. FRIDAY AND SATURDAY LOOK TO BE MOSTLY DRY AND COLD.
MEDIUM RANGE MODELS DIFFER ON THE HANDLING OF THE WEATHER FOR SUNDAY
BUT IT APPEARS THAT SOME ARCTIC AIR MAY SPILL INTO THE REGION WITH
AT LEAST A SLIGHT CHANCE FOR SNOW. 78

&&

.AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH 12Z
MONDAY. WINDS WILL BE THE PRIMARY CONCERN ESPECIALLY THROUGH THE
MORNING HOURS WITH SOME WESTERLY GUSTS EXCEEDING 40 KT. WINDS WILL
SLOWLY DIMINISH THIS AFTERNOON AND EVENING. RAIN WILL BE MOSTLY
CONFINED TO THE MOUNTAINS TODAY. EXPECT AT LEAST A BKN LAYER AT 4-7
THOUSAND FEET AND AN OVC LAYER OF MID CLOUDS ABOVE FOR MUCH OF THE
PERIOD. SOME CIGS BELOW 3000 FEET AGL ARE POSSIBLE OVERNIGHT
TONIGHT. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  55  38  42  33 /  50  40  10  10
ALW  55  40  43  34 /  50  50  10  10
PSC  57  37  45  32 /  30  10  10  10
YKM  52  35  41  31 /  40  20  10  10
HRI  57  37  48  33 /  40  20  10  10
ELN  48  34  39  29 /  40  20  10  10
RDM  53  35  43  30 /  70  20  10  10
LGD  47  37  42  29 / 100  80  20  10
GCD  47  36  43  33 /  80  60  20  10
DLS  54  39  47  36 /  80  30  10  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FLOOD WATCH THROUGH MONDAY AFTERNOON ORZ041-509>511.

     FLOOD WATCH THROUGH MONDAY AFTERNOON ORZ049-050-502-503-505>508.

     WIND ADVISORY UNTIL NOON PST TODAY ORZ044.

     HIGH WIND WARNING UNTIL 7 AM PST THIS MORNING ORZ509.

     HIGH WIND WARNING UNTIL NOON PST TODAY ORZ510-511.

     WIND ADVISORY UNTIL NOON PST TODAY ORZ507.

     HIGH WIND WARNING UNTIL NOON PST TODAY ORZ508.

WA...FLOOD WATCH THROUGH MONDAY AFTERNOON WAZ024-026-027-520-521.

     FLOOD WATCH THROUGH MONDAY AFTERNOON WAZ029-030.

     WIND ADVISORY UNTIL NOON PST TODAY WAZ028.

     HIGH WIND WARNING UNTIL NOON PST TODAY WAZ521.

     WIND ADVISORY UNTIL NOON PST TODAY WAZ029.

     WIND ADVISORY UNTIL NOON PST TODAY WAZ027.

&&

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

$$

88/78/78




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