Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 090546 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
946 PM PST MON FEB 8 2016

UPDATED AVIATION FORECAST

.UPDATE...HIGH PRESSURE OVER THE PACIFIC NORTHWEST IS LEADING TO A
QUIET WEATHER NIGHT OVER THE FORECAST AREA. SKIES ARE GENERALLY
CLEAR ASIDE FROM SOME HIGH CIRRUS OVER THE NORTHERN HALF OF THE
AREA. WINDS ARE LIGHT AND TEMPERATURES REMAIN RELATIVELY WARM
THOUGH MANY LOCATIONS HAVE HAD RAPID RADIATIVE COOLING SINCE
SUNDOWN. A FEW PLACES WERE APPROACHING FORECAST LOW TEMPERATURE OR
HAD LOW DEW POINT TEMPERATURES WHICH WOULD ALLOW FURTHER COOLING
SO HAVE MADE SOME TEMPERATURE ADJUSTMENTS. WITH THE RADIATIVE
COOLING, PATCHY FOG REMAINS A POSSIBILITY LATE TONIGHT AND
TOMORROW MORNING IN THE COLUMBIA BASIN AND ADJACENT VALLEYS.
CURRENT FORECAST HAD A GOOD HANDLE ON THAT. HOWEVER, HAVE NOTICED
THAT MADRAS AIRPORT HAS 100 PERCENT HUMIDITY IN ITS LATEST
OBSERVATION AND HAD SOME FOG THIS MORNING SO HAVE ADDED PATCHY FOG
IN NORTH CENTRAL OREGON DOWN TO MADRAS. FORECAST UPDATE ALREADY
OUT. PERRY

&&

.AVIATION...06Z TAFS...VFR CONDITIONS WILL BE PREVALENT FOR THE NEXT
24 HOURS AT ALL TAF SITES. HOWEVER VISIBILITY COULD FALL TO 5-6SM
WITH LOCALIZED MVFR CONDITIONS AT COLUMBIA BASIN TAF SITES FROM 12Z
TO 18Z TOMORROW MORNING. HAVE INCLUDED 6SM BR AT MOST COLUMBIA BASIN
TAFS SITES TO COVER THAT POSSIBILITY. OTHERWISE EXPECT JUST SOME
HIGH CIRRUS AND SURFACE WINDS LESS THAN 10 KTS FOR THE NEXT 24
HOURS. PERRY

&&

.PREV DISCUSSION... /ISSUED 228 PM PST MON FEB 8 2016/

SHORT TERM...TONIGHT THROUGH THURSDAY...RIDGE OF HIGH PRESSURE WILL
CONTINUE TO DOMINATE THE WEATHER PATTERN THROUGH THE SHORT TERM. THE
RIDGE WILL BE AT ITS STRONGEST AND CENTERED OVER THE PACIFIC
NORTHWEST THROUGH TUESDAY AND THEN SHIFT SLIGHTLY EASTWARD AND
FLATTEN THROUGH MIDWEEK. THIS WILL ALLOW A MORE SOUTHWEST FLOW TO
INFLUENCE THE REGION WITH SOME MID AND HIGH LEVEL CLOUDS MIDWEEK.
THE STRENGTH OF THE RIDGE WILL KEEP A LOW LEVEL INVERSION IN PLACE
THROUGH THE SHORT TERM WHICH WILL TRAP SOME FOG AND LOW CLOUDS
BENEATH IT. DAYS ARE GETTING LONGER WITH RESULTING SOLAR RADIATION
HEATING THE GROUND INCREASING SO EXPECT SOME OF THE FOG TO BURN OFF
DURING THE DAYS ONLY TO REFORM AT NIGHT. TEMPERATURES WILL CONTINUE
TO RUN ABOVE NORMAL AND POSSIBLY NEAR RECORD LEVELS ABOVE THE
INVERSION.


LONG TERM...THURSDAY NIGHT THROUGH MONDAY. A RIDGE OF HIGH PRESSURE
WILL SLOWLY SHIFT EAST AND ALLOW A FEW SHOWERS TO DEVELOP ALONG THE
WA/OR CASCADES THURSDAY NIGHT. THE SHOWERS WILL MIGRATE EAST INTO
THE REMAINDER OF THE AREA FRIDAY AND FRIDAY NIGHT. A LOW PRESSURE
SYSTEM THAT IS RESPONSIBLE FOR THE PCPN IS EXPECTED TO MOVE ACROSS
OUR REGION SATURDAY AND SATURDAY EVENING AND THIS SHOULD KEEP THE
UNSETTLED WEATHER PATTERN INTO THE BEGINNING OF THE WEEKEND. AS THE
LOW PRESSURE MOVES AWAY FROM OUR AREA SATURDAY NIGHT...DRIER
CONDITIONS ARE SHOULD FILTER INTO OUR REGION FROM WEST TO EAST INTO
SUNDAY MORNING. ANOTHER RIDGE OF HIGH PRESSURE TRIES TO REBUILD INTO
THE REGION SUNDAY AND MONDAY BUT SOME SHOWERS ARE POSSIBLE EACH DAY
WITH THE BETTER CHANCE IN THE MOUNTAINS. TEMPERATURES WILL REMAIN
ABOVE NORMAL THROUGH THE PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  31  51  31  50 /   0   0   0   0
ALW  31  49  31  49 /   0   0   0   0
PSC  31  47  31  46 /   0   0   0   0
YKM  29  50  33  47 /   0   0   0   0
HRI  30  48  31  47 /   0   0   0   0
ELN  24  42  28  44 /   0   0   0   0
RDM  35  65  37  58 /   0   0   0   0
LGD  32  52  35  48 /   0   0   0   0
GCD  33  61  31  54 /   0   0   0   0
DLS  33  53  35  52 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST SATURDAY FOR ORZ041-044-
     050-502-503-505-507-508-510.

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

$$

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