Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 132323 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
323 PM PST SAT FEB 13 2016

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH MONDAY...WEST-NORTHWEST FLOW ALOFT
WILL CONTINUE OVER THE PACIFIC NORTHWEST THROUGH TONIGHT. A
DISTURBANCE WITHIN THIS FLOW WILL SWING ACROSS THE REGION THIS
EVENING. THIS DISTURBANCE WILL BRING GOOD CHANCES OF PRECIP TO MUCH
OF THE AREA THIS EVENING. LIGHT SURFACE FLOW IN THE YAKIMA AND
KITTITAS VALLEYS WILL RESULT IN WEAK INVERSIONS STRENGTHENING ENOUGH
FOR MORE FOG DEVELOPMENT AND THE CONTINUED TRAPPING OF POLLUTANTS
LATE TONIGHT INTO SUNDAY MORNING. SNOW LEVELS WILL START OUT BETWEEN
3500 AND 4500 FEET THIS EVENING, BUT WILL RISE OVERNIGHT INTO SUNDAY
MORNING. AT THIS TIME SNOW ACCUMULATIONS ABOVE THESE LEVELS LOOK TO
REMAIN BELOW 7 INCHES IN THE BLUES AND BELOW 4 INCHES ELSEWHERE.

AN UPPER RIDGE CURRENTLY OVER THE EASTERN PACIFIC WILL BEGIN TO
BUILD ALONG THE WEST COAST LATE TONIGHT INTO SUNDAY. THIS WILL CAUSE
WARM AIR ADVECTION ALOFT. THIS WARM AIR ADVECTION WILL PROVIDE
ENERGY THAT WILL ACCESS THE MOIST AIR OVER THE REGION RESULTING IN
CONTINUED PRECIP ACROSS THE REGION SUNDAY AND SUNDAY NIGHT. BEST,
AND HEAVIEST, PRECIP WILL OCCUR NEAR THE CASCADE CREST AND OVER THE
INTERIOR MOUNTAINS. THERE IS THE POTENTIAL FOR SIGNIFICANT RISES OF
RIVER FLOWING THROUGH THE WASHINGTON CASCADE EAST SLOPES. ALSO WILL
SEE WINDS INCREASE ACROSS THE REGION SUNDAY AFTERNOON CAUSING A
WARMING OF AREA TEMPERATURES. THE WINDS WILL ALSO CAUSE BETTER
MIXING AREAWIDE. THE RIDGE WILL BUILD FURTHER ON MONDAY PUSHING THE
PRECIP THREAT NORTH, WITH ONLY LIGHT PRECIP NEAR THE CASCADES AND
OVER THE BLUES AND WALLOWAS EXPECTED. CONDITIONS WILL CONTINUE
LOCALLY BREEZY AND MILD. 90

.LONG TERM...A RIDGE OF HIGH PRESSURE REBUILDS OVER THE REGION
MONDAY NIGHT AND TUESDAY PUSHING MOST OF THE MOISTURE NORTH OF THE
AREA...BUT THERE MAY STILL BE SOME SHOWERS ALONG THE CASCADES...
ESPECIALLY IN WESTERN KITTITAS COUNTY. ANOTHER WEATHER SYSTEM WILL
APPROACH ON WEDNESDAY...AND THERE WILL BE A CHANCE OF MOSTLY RAIN
SHOWERS WITH SNOW LEVELS RANGING 5500 TO 7000 FEET. SNOW LEVELS WILL
THEN DECREASE ON WEDNESDAY NIGHT AND THURSDAY AS THE LOW PRESSURE
TROUGH MOVES INLAND...FALLING TO AROUND 4000 FEET. BESIDES RAIN AND
MOUNTAIN SNOW...BREEZY WINDS CAN ALSO BE EXPECTED ON THURSDAY. A
HIGH PRESSURE RIDGE THEN MOVES QUICKLY ACROSS THE REGION THURSDAY
NIGHT AND SHOWERS WILL DECREASE. THE MODELS CONTINUE TO BE IN
DISAGREEMENT FROM FRIDAY ONWARD AS THE ECMWF WANTS TO BRING ANOTHER
SYSTEM THROUGH THE AREA ON FRIDAY...WHILE THE GFS KEEPS THE MAIN
FRONT OFFSHORE UNTIL SATURDAY. HAVE THEREFORE KEPT A SLIGHT CHANCE
TO A CHANCE OF RAIN AND SNOW IN THE FORECAST THROUGH THIS PERIOD TO
ACCOUNT FOR UNCERTAINTY. TEMPERATURES WILL REMAIN ABOVE NORMAL
THROUGH NEXT WEEKEND. THE WARMEST DAYS WILL BE MONDAY AND TUESDAY
WITH HIGHS IN THE 50S AND 60S.  COBB

&&

.AVIATION...00Z TAFS...AS ANOTHER WEATHER SYSTEM MOVES INTO THE
REGION...RAIN WILL BECOME MORE PREVALENT ACROSS THE AREA. EXPECT
PERIODIC SHOWERS...ESPECIALLY AFTER 06Z. MVFR OR WORSE CONDITIONS
WILL BE POSSIBLE IN RAIN...WHICH WILL CONTINUE THROUGH SUNDAY.
SUSTAINED WINDS WILL GENERALLY BE LESS THAN 15 KTS...BUT COULD BE
GUSTY AT TIMES.  82

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  42  58  48  64 /  80  70  50  10
ALW  45  59  50  66 /  80  70  50  10
PSC  44  58  49  66 /  60  40  20  10
YKM  35  55  42  63 /  50  20  20  10
HRI  43  59  49  66 /  60  50  30  10
ELN  35  51  42  58 /  50  20  20  10
RDM  39  56  41  62 /  50  40  30  10
LGD  38  52  46  59 /  80  80  60  20
GCD  36  55  43  60 /  80  70  40  10
DLS  42  56  48  63 /  60  50  30  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...AIR STAGNATION ADVISORY UNTIL 10 AM PST SUNDAY FOR WAZ026-027.

&&

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

$$

90/82/82


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