Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 261109 CCA
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
300 AM PST MON JAN 26 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY AFTERNOON...STAGNANT PRESSURE
PATTERN AT THE SURFACE AND AT MID/UPPER LEVELS OF THE ATMOSPHERE
WILL CONTINUE THROUGH THE PERIOD THUS PRODUCING DRY CONDITIONS.

A PERSISTENT MID/HIGH LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN OVER
THE INTERIOR PACIFIC NORTHWEST THROUGH WEDNESDAY AFTERNOON. THE
LATEST MODEL RUNS HAVE CONSIDERABLY WEAKENED THE PACIFIC SHORT WAVE
THAT THE MODELS YESTERDAY HAD SHOWN MOVING ACROSS THE FORECAST AREA
AND BRINGING A CHANCE OF RAIN TO THE BLUE MOUNTAINS LATE TUESDAY
NIGHT AND WEDNESDAY, TO THE POINT THAT AT BEST IT WILL YIELD JUST A
LOW CHANCE OF RAIN NEAR THE CRESTS OF THE CENTRAL WASHINGTON
CASCADES. SUBSIDENCE ALOFT ASSOCIATED WITH THE RIDGE WILL CONTINUE
TO TRAP MOISTURE IN THE BOUNDARY LAYER THUS PRODUCING LOW STRATUS
CLOUDS ACROSS THE LOWER COLUMBIA BASIN AND ADJACENT VALLEYS. PATCHY
FOG WILL OCCUR IN ASSOCIATION WITH THE LOW CLOUDS WITH FOG BECOMING
THICKER OVERNIGHT FOR EACH DAY. A DENSE FOG ADVISORY REMAINS IN
EFFECT UNTIL 11 AM THIS MORNING FOR THE KITTITAS AND YAKIMA VALLEYS,
THE LOWER COLUMBIA BASIN, THE EASTERN COLUMBIA GORGE AND THE
NORTHERN BLUE MOUNTAIN FOOTHILLS OF WASHINGTON AND OREGON. A WIND
ADVISORY REMAINS IN EFFECT UNTIL 3 PM PST THIS AFTERNOON FOR THE
GRANDE RONDE VALLEY.  POLAN

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY. A WEAK UPPER LEVEL
SYSTEM WILL BE MOVING ACROSS THE REGION WEDNESDAY NIGHT AND
THURSDAY. EXPECT MOSTLY CLOUDY SKIES WITH JUST A CHANCE OF
SHOWERS...MAINLY OVER THE MOUNTAINS. THE UPPER RIDGE BUILDS BACK
INTO THE AREA THURSDAY THROUGH SATURDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER WITH PARTLY CLOUDY SKIES. 850MB TEMPERATURES MUCH COOLER
THAN WHAT WE HAVE SEEN THE PAST FEW DAYS SO TEMPS WILL BE CLOSER TO
NORMAL. HIGHS MOSTLY IN THE 40S TO LOWER 50S. LOW LEVEL INVERSION
OVER THE COLUMBIA BASIN AND ADJACENT VALLEYS WILL LIKELY RESULT IN
AREAS OF STRATUS AND FOG WITH COOLER TEMPERATURES. MODELS ARE IN
GOOD AGREEMENT UP THROUGH THIS POINT WITH THE STRONG UPPER RIDGE
OVER THE PACIFIC NORTHWEST. THEY DIVERGE SOME ON SUNDAY WITH THE GFS
FASTER TO BRING THE NEXT UPPER TROUGH THROUGH. WILL BLEND THE GFS
AND EURO AND GO WITH CHANCE POPS SUNDAY. 94

&&

.AVIATION...06Z TAFS...EXPECT MVFR/IFR CONDITIONS AT ALL TAF SITES
EXCEPT AT KPDT...KRDM AND KBDN DUE TO FOG AND LOW CLOUDS. THE FOG
WILL LIFT AND/OR BURN OFF BY NOON MONDAY. WINDS WILL REMAIN MOSTLY
LIGHT AND VARIABLE THROUGH THE NEXT 24 HOURS. 88

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  58  35  48  39 /   0   0   0  10
ALW  40  37  42  39 /   0   0   0  10
PSC  42  34  41  33 /   0   0   0  10
YKM  41  32  44  31 /   0   0   0  10
HRI  46  31  43  34 /   0   0   0  10
ELN  43  34  46  34 /   0   0  10  10
RDM  64  36  56  38 /   0   0  10  10
LGD  48  34  48  35 /   0   0  10  10
GCD  57  34  51  37 /   0   0  10  10
DLS  51  38  48  39 /  10  10  10  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...DENSE FOG ADVISORY UNTIL NOON PST TODAY ORZ041-044-507.

     WIND ADVISORY UNTIL 3 PM PST THIS AFTERNOON ORZ049.

WA...DENSE FOG ADVISORY UNTIL NOON PST TODAY WAZ024-026>029.

&&

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

$$

99/94/94










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