Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 012241
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
241 PM PST SUN FEB 1 2015

.SHORT TERM...TONIGHT THROUGH TUESDAY AFTERNOON...PERIODS OF RAIN
WILL CONTINUE ACROSS MUCH OF THE REGION THIS EVENING BEFORE TAPERING
OFF AND ENDING FROM NORTHWEST TO SOUTHEAST AFTER MIDNIGHT. SOME
LIGHT RAIN AND SNOW WILL LINGER IN THE BLUE MOUNTAINS AND WALLOWA
MTNS THROUGH DAYBREAK. POPS WERE INCREASED TO LIKELY/CATEGORICAL FOR
THIS AFTERNOON AND EVENING TO ACCOUNT FOR THE STEADY PRECIPITATION
THAT WAS AFFECTING THE AREA. ALSO INCREASED QPF AMOUNTS BY AROUND A
TENTH OF AN INCH OVER CENTRAL AND EASTERN PARTS OF THE CWA...KPDT
HAS ALREADY RECEIVED 0.11 INCHES OF PRECIP THROUGH 2PM. ALSO LOWERED
SNOW LEVELS IN THE WASHINGTON FOOTHILLS OF THE NORTHERN BLUES
MTNS...MAINLY NEAR DAYTON AS WE HAVE BEEN GETTING REPORTS OF SNOW
FALLING DOWN TO ABOUT 1500 FEET ABOVE MSL THIS AFTERNOON HERE.
ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT...GENERALLY UNDER ONE
INCH FOR ELEVATIONS BETWEEN 1500-2500 FEET. THE SNOW LEVELS WILL
LIKELY RISE CHANGING THE SNOW OVER TO RAIN AFTER 03Z THIS EVENING IN
THE DAYTON AREA. ADDED PATCHY FOG AND FREEZING FOG TO THE COLUMBIA
BASIN BELOW 1500 MSL AFTER 06Z TONIGHT THROUGH 15-18Z MONDAY. AFTER
A BRIEF BREAK IN THE PRECIPITATION FOR THE LOWER ELEVATIONS LATE
TONIGHT...EXPECT THE NEXT SYSTEM TO MOVE INTO THE AREA ON MONDAY.
RAIN WILL DEVELOP BY 12-15Z MONDAY IN CENTRAL OREGON AND PROGRESS
NORTHEASTWARD THROUGH THE DAY...REACHING THE LOWER COLUMBIA BASIN BY
18-21Z MONDAY. QPF AMOUNTS DURING THE DAY ON MONDAY ARE FORECAST TO
RANGE FROM 0.05 TO 0.10" IN THE COLUMBIA BASIN...WITH 0.10 TO 0.25"
FOR CENTRAL OREGON AND THE BLUE MOUNTAINS. LIGHT SCATTERED MOUNTAIN
RAIN AND SNOW SHOWERS THEN CONTINUE ON AND OFF FOR MONDAY
NIGHT...BEFORE YET ANOTHER SYSTEM MOVES IN FROM THE SOUTH DURING THE
DAY ON TUESDAY. BROUGHT POPS UP TO LIKELY/LOW END CATEGORICAL TO
ACCOUNT FOR THIS SYSTEM...AT THIS TIME THE HIGHEST POPS/QPF LOOK TO
STAY ALONG A LINE FROM THE DALLES TO PASCO AND DAYTON SOUTHWARD.
ALSO RAISED QPF AMOUNT TO 0.10 TO 0.50" SOUTH OF THE WASHINGTON
BORDER. SNOW LEVELS WILL RANGE FROM 3500 NORTH TO 5000 FEET SOUTH
DURING THE DAY ON TUESDAY...WITH A FEW INCHES OF SNOW ACCUMULATION
POSSIBLE ABOVE THESE LEVELS. 77

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...A MOIST SW FLOW ALOFT
WILL PERSIST ACROSS THE PACIFIC NW THROUGH THE FORECAST PERIOD.
NUMEROUS STORM SYSTEMS WILL IMPACT THE AREA WITH ABUNDANT RAINFALL
ESPECIALLY FROM THURSDAY ONWARD. RAINFALL AMOUNTS FROM THURSDAY
MORNING THROUGH SATURDAY AFTERNOON COULD REACH 2 INCHES IN THE BLUE
MOUNTAINS AND 2-4 INCHES ALONG THE EAST SLOPES OF THE WASHINGTON
CASCADES. SNOW LEVELS WILL BE MAINLY ABOVE 6000 FEET SO THIS WILL BE
MOSTLY AN ALL RAIN EVENT. AREA RIVERS ARE EXPECTED TO RISE SHARPLY
LATE IN THE WEEK AND NEXT WEEKEND. THE LATEST GFS IS HINTING AT A
POTENTIAL WINDY DAY ON FRIDAY AND FRIDAY NIGHT. GUSTY SOUTH WINDS
ARE POSSIBLE ALONG THE FOOTHILLS...SIMCOE HIGHLANDS...AND IN CENTRAL
OREGON WITH AT LEAST ADVISORY LEVEL WINDS POSSIBLE.

IN THE SHORTER TERM...FOR WEDNESDAY THE GFS AND ECMWF DISAGREE ON
PRECIPITATION POTENTIAL FOR WEDNESDAY. THE ECMWF IS WETTER WITH A
WARM FRONT LIFTING NORTH ACROSS THE REGION WHILE THE GFS IS DRY. THE
ECMWF HAS BEEN SHOWING A PRECIPITATION SHIELD OVER THE AREA FOR
SEVERAL DAYS WHILE THE GFS HAS BEEN FLIP FLOPPING. FOR NOW WENT WITH
CHANCE POPS WHICH IS A LEAN TOWARD THE WETTER ECMWF GIVEN ITS
CONSISTENCY. 78

&&

.PREVIOUS AVIATION DISCUSSION...18Z TAFS... LINGERING IFR/LIFR CIGS
AT KBDN...KRDM AND KPDT SHOULD LIFT TO MVFR BY 19-20Z TODAY AS A
SYSTEM MOVES IN MIXING OUT THE STUBBORN LOW CLOUDS. EXPECTING MAINLY
MVFR CIGS/VIS ALONG WITH LIGHT RAIN FOR ALL TAFS SITES THIS
AFTERNOON THROUGH ABOUT 06Z THIS EVENING BEFORE THE RAIN SHOWERS
TAPER OFF AND CIGS LIKELY SCATTER OUT. WATCHING FOR SOME SCT LOW
CLOUDS AND MVFR BR AFTER 02/10-12Z AT SEVERAL TAF SITES. THE NEXT
WEATHER SYSTEM WILL BEGIN AFFECTING KBDN AND KRDM AFTER 02/15Z BRING
STEADY LIGHT RAIN WITH BORDERLINE IFR CIGS ONCE AGAIN. 77

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  35  48  37  45 /  60  50  10  60
ALW  37  45  39  45 /  60  50  20  60
PSC  33  44  37  45 /  40  50  10  50
YKM  30  42  32  42 /  10  40  10  20
HRI  35  47  39  47 /  50  40  10  50
ELN  30  42  32  43 /  20  50  20  20
RDM  36  55  36  48 /  60  70  20  80
LGD  34  47  34  45 /  70  60  40  60
GCD  36  51  34  50 /  60  70  40  80
DLS  38  49  40  49 /  20  60  10  50

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&

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

$$

77/78/77








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