Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 120622
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1015 PM PST THU FEB 11 2016

.SHORT TERM...WARM FRONT MOVING ACROSS THE NORTHERN PORTION OF THE
FORECAST AREA THIS EVENING WITH SOME LIGHT RAIN. SHOULD EXIT THE
REGION BY LATE EVENING. SATELLITE INDICATES PARTLY TO MOSTLY
CLOUDY SKIES FOR THE REMAINDER OF THE NIGHT. UPPER LEVEL TROUGH
AND COLD FRONT MOVE THROUGH ON FRIDAY WITH ADDITIONAL RAIN AND
MOUNTAIN SNOW. NEXT SYSTEM LOOKS FAIRLY STRONG AND WILL BRING
DECENT PRECIPITATION SATURDAY NIGHT INTO SUNDAY NIGHT. RAINFALL
AMOUNTS COMBINED WITH WARM AIRMASS WILL RESULT IN SIGNIFICANT
RIVER RISES SUNDAY THROUGH TUESDAY. 94

.AVIATION...06Z TAFS. RAIN ENDING ACROSS THE REGION AS WARM FRONT
MOVES NORTHWARD. CLEARING SKIES EVIDENT ON SATELLITE COMBINED WITH
HIGH DEW POINTS. EXPECT INCREASING COVERAGE OF FOG AND LOW CLOUDS
TONIGHT INTO FRIDAY MORNING. EXPECT SOME IFR CONDITIONS TO DEVELOP.
COLD FRONT MOVING ACROSS THE AREA FRIDAY WILL BRING A CHANCE OF
RAIN. 94

&&

.PREV DISCUSSION... /ISSUED 353 PM PST THU FEB 11 2016/

SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...A WARM FRONT
ASSOCIATED WITH THE NEXT PACIFIC SYSTEM IS CURRENTLY MOVING NORTH
ACROSS THE PACIFIC NORTHWEST. THIS FRONT WILL CONTINUE TO MOVE
THROUGH NORTHEAST OREGON AND SOUTHEAST WASHINGTON LATE THIS
AFTERNOON AND EARLY THIS EVENING. THUS WILL SEE LIGHT SHOWERS
GRADUALLY LIFT NORTH OUT OF MUCH OF THE AREA BY MID EVENING. A FEW
SHOWERS SHOULD LINGER OVER THE NORTHERN BLUES, NEAR THE OREGON
CASCADES AND OVER PORTIONS OF SOUTHEAST WASHINGTON OVERNIGHT. LOW
LEVEL INVERSIONS WILL CONTINUE OVER PORTIONS OF THE BASIN, AND SOME
PATCHY FOG WILL AGAIN BE POSSIBLE OVERNIGHT INTO FRIDAY MORNING.
THUS WILL ALSO CONTINUE THE CURRENT AIR STAGNATION ADVISORIES. THE
COLD FRONT ASSOCIATED WITH THIS NEXT SYSTEM WILL MOVE ACROSS THE
REGION FRIDAY AFTERNOON AND EVENING. THIS SYSTEM WILL SPREAD MORE
PRECIP ACROSS THE AREA. WILL SEE SNOW LEVELS LOWER BEHIND THE FRONT.
ALSO SHOULD SEE WINDS OVER PORTIONS OF THE AREA INCREASE BEHIND THE
FRONT. A FEW SHOWERS WILL LINGER SATURDAY OVER THE MOUNTAINS.
MEANWHILE SHOULD SEE BREEZIER WINDS AND BETTER MIXING AT MOST
LOCATIONS, THOUGH MIXING MAY REMAIN LIMITED IN THE YAKIMA AND
KITTITAS VALLEYS. ANOTHER WARM FRONT IS EXPECTED TO MOVE ACROSS THE
REGION SATURDAY NIGHT BRINGING ANOTHER ROUND OF PRECIP. SNOW LEVELS
SATURDAY NIGHT WILL RUN AROUND 4000 FEET. 90

LONG TERM...SUNDAY THROUGH THURSDAY...A WEST TO NORTHWEST FLOW WILL
PROVIDE AMPLE MOISTURE AS A SERIES OF DISTURBANCES RIDE OVER AN
OFFSHORE RIDGE. THIS WILL LEAD TO A CHANCE FOR MAINLY RAIN SHOWERS
AT TIMES. SUNDAY WILL SEE A COLD FRONT CROSS THE AREA AS A RIDGE
BUILDS OFFSHORE. SNOW LEVELS WILL REMAIN AROUND 4000 FEET IN THE
MORNING THEN RISE TO 6000-7000 FEET IN THE AFTERNOON. THIS WILL GIVE
US A CHANCE OF RAIN ACROSS THE AREA AND THE MOUNTAINS WILL HAVE A
CHANCE OF OF UP TO AN INCH OR TWO OF SNOW IN THE MORNING. THE
STRENGTHENING OFFSHORE RIDGE WILL LIFT THE FRONT NORTH OUT OF THE
AREA SUNDAY NIGHT WITH A CONTINUED CHANCE OF RAIN IN THE MOUNTAINS
AND A SLIGHT CHANCE IN THE LOWER ELEVATIONS. MONDAY THROUGH TUESDAY
THE RIDGE WILL DEFLECT SYSTEMS TO OUR NORTH AND WE WILL BE DRY ASIDE
FROM A CHANCE OF SHOWERS ALONG THE CASCADE CREST AND A SLIGHT CHANCE
OF SHOWERS IN THE EASTERN MOUNTAINS. TUESDAY AND TUESDAY NIGHT AN
APPROACHING TROUGH WILL PUSH THE RIDGE ACROSS OUR AREA AND OFF TO
THE EAST. MODELS DIFFER AS TO WHEN A FRONT ASSOCIATED WITH THE
TROUGH WILL CROSS THE AREA. THE GFS BRINGS IT IN WEDNESDAY AND
WEDNESDAY NIGHT WITH THE TROUGH MOVING THROUGH BEHIND THE FRONT ON
THURSDAY. THE ECMWF HAS A STRONGER SYSTEM FURTHER SOUTH WITH IT
MOVING INTO THE AREA WEDNESDAY NIGHT AND THURSDAY. BOTH SITUATIONS
WOULD MEAN A CHANCE OF RAIN ACROSS THE AREA WITH SNOW LEVELS AROUND
6000-7000 FEET INITIALLY BEFORE DROPPING TO 3000-4000 FEET WITH THE
TROUGH PASSAGE. HAVE LEANED TOWARDS THE GFS TIMING AND HAVE A CHANCE
OF RAIN WEDNESDAY THROUGH THURSDAY WITH A CHANCE OF MOUNTAIN SNOW IN
ADDITION BY THURSDAY. TEMPERATURES SUNDAY WILL BE IN THE LOWER TO
MID 50S WITH MID 40S TO MID 50S IN THE MOUNTAINS. WITH THE INFLUENCE
OF THE OFFSHORE RIDGE TEMPERATURES WILL SOAR MONDAY AND TUESDAY TO
UPPER 50S TO MID 60S WITH UPPER 40S AND 50S IN THE MOUNTAINS. A FEW
PLACES MAY SEE RECORD HIGH TEMPERATURES ON THESE DAYS. WEDNESDAY AND
THURSDAY WILL DROP BACK THE 50S WITH MAINLY 40S IN THE MOUNTAINS.
PERRY

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  40  52  39  53 /  30  40  50  10
ALW  43  52  43  53 /  30  40  50  20
PSC  39  51  38  56 /  30  40  30  10
YKM  38  48  33  52 /  50  40  20  10
HRI  40  52  39  56 /  30  40  40  10
ELN  33  44  33  46 /  60  50  20  20
RDM  36  56  31  52 /  10  30  30  10
LGD  38  51  34  49 /  30  20  40  20
GCD  38  54  33  50 /  10  20  30  10
DLS  41  54  40  54 /  40  50  30  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST SATURDAY FOR ORZ041-044-
     050-505-507-508-510.

WA...AIR STAGNATION ADVISORY UNTIL 10 AM PST SATURDAY FOR WAZ024-
     026>029-520-521.

&&

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

$$

94


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