Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 081736 AAA
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
929 AM PST MON FEB 8 2016

UPDATED THE AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH WEDNESDAY...HIGH PRESSURE WILL BE
DOMINATING THE WEATHER PATTERN THROUGH MIDWEEK PROVIDING DRY
CONDITIONS. THIS WILL ALSO PROVIDE ABOVE NORMAL TEMPERATURES AND
POSSIBLE NEAR RECORD HIGHS ESPECIALLY ABOVE THE STRENGTHENING
INVERSION. BELOW THE INVERSION WE WILL SEE DEVELOPING FOG AND
LOW CLOUDS AND COOLER TEMPERATURES.

&&

.AVIATION...VFR CONDITIONS WILL PERSIST FOR THE NEXT 24 HOURS AT ALL
TAF SITES. HOWEVER THE VSBY COULD FALL TO NEAR 5SM AND LCL MVFR
CONDITIONS COULD BE APPROACHED BETWEEN 10Z-14Z IN PATCHY FOG.

&&

.PREV DISCUSSION... /ISSUED 240 AM PST MON FEB 8 2016/

SHORT TERM...TODAY THROUGH WEDNESDAY...MODELS ARE IN GOOD AGREEMENT
FOR THE SHORT TERM.  A RIDGE OF HIGH PRESSURE WILL DOMINATE THE
INTERIOR PACIFIC NORTHWEST TODAY THROUGH WEDNESDAY.  PATCHY FOG MAY
RESULT ALONG THE COLUMBIA RIVER AND POSSIBLY PARTS OF THE YAKIMA AND
KITTITAS VALLEY.  RIGHT NOW ANY FOG THAT DEVELOPS SHOULD BURN OFF IN
THE AFTERNOON...AS WE SHOULD BE TO A POINT WHERE THE SUN ANGLE IS
GETTING HIGH ENOUGH TO BURN OFF ANY FOG THAT DEVELOPS.  BUT WE WILL
STILL MONITOR CERTAIN AREAS TO MAKE SURE PERSISTENT FOG DOES NOT
CONTINUE.

A SURFACE HIGH WILL SET UP ALONG THE SOUTHERN OR/ID
BORDER.  THIS WILL RESULT IN SLIGHTLY TIGHT PRESSURE GRADIENTS ALONG
THE GRANDE RONDE VALLEY.  BREEZY WINDS OUT OF THE SOUTHWEST ABOUT 15
TO 20 MPH...WITH SLIGHTLY HIGHER GUSTS ARE CURRENTLY IN THE
FORECAST.

TEMPERATURES ACROSS THE LOWER ELEVATIONS ARE EXPECTED TO BE IN THE
UPPER 40S TO MID 50S. HOWEVER...850MB TEMPERATURES ARE MUCH WARMER
THAN SUNDAY...AND IF THE MORNING INVERSION BREAKS
QUICKER...TEMPERATURES COULD CLIMB INTO THE MID 50S TO LOWER 60S.
EITHER WAY TODAY SHOULD BE MOSTLY SUNNY ACROSS ALL AREAS WITH
EXCEPTION OF ANY AREAS THAT START OUT A BIT FOGGY.  THIS WILL
CONTINUE THROUGH MID WEEK WITH TEMPERATURES EXPECTED TO BE WITHIN A
FEW DEGREES +/- OF THE PREVIOUS DAY.

MODELS DO HINT AT A WEAK DISTURBANCE TO MOVE OVER THE AREA TUESDAY
NIGHT INTO WEDNESDAY.  HOWEVER...IT DOES NOT LOOK LIKE IT WILL
PROVIDE MUCH OTHER THAN POSSIBLE INCREASED CLOUD COVER. WEBER

LONG TERM...TODAY THROUGH TUESDAY...THE STRONG UPPER RIDGE THAT IS
BRINGING VERY MILD TEMPERATURES AND DRY CONDITIONS THROUGH MID
WEEK...ESPECIALLY IN THE HIGHER ELEVATIONS...IS EXPECTED TO WEAKEN
THURSDAY NIGHT AND ALLOW MOISTURE TO RIDE UP AND OVER THE TOP OF THE
RIDGE. MODELS (GFS AND NAM) ARE IN GOOD AGREEMENT WITH THIS SCENARIO
AND THEY ARE INDICATING SOME LIGHT PRECIPITATION ALONG THE CASCADE
EAST SLOPES AND ADJACENT VALLEYS. SINCE SNOW LEVELS WILL BE QUITE
HIGH PRECIPITATION IS EXPECTED TO BE ALL RAIN AT PASS LEVELS AND
LOWER IN THE ENTIRE FORECAST AREA. HOWEVER ONLY LIGHT PRECIPITATION
IS EXPECTED ONLY ALONG THE CASCADE EAST SLOPES AND ADJACENT VALLEYS
(ESPECIALLY IN SOUTHERN WASHINGTON) WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT. AFTER THAT THE MODELS ARE STILL IN GOOD AGREEMENT THAT
MOISTURE AND PRECIPITATION WILL SPREAD EASTWARD TO COVER MOST OF THE
FORECAST AREA ON FRIDAY AS AN UPPER TROUGH OFF THE COAST BEGINS TO
MOVE INLAND...WITH A DEEP SOUTHERLY FLOW AHEAD OF IT. THIS UPPER
TROUGH WILL MOVE ACROSS THE CWA ON SATURDAY. THEREFORE INCREASED
POPS OVER MOST OF THE CWA ON FRIDAY AND THEN OVER THE ENTIRE CWA ON
SATURDAY. MODELS ARE STILL IN GOOD AGREEMENT FOR THE UPPER TROUGH
PASSAGE ON SATURDAY. AFTER THAT THE OVERALL FLOW BECOMES PROGRESSIVE
WITH MORE FREQUENT WEATHER SYSTEMS TO BRING OCCASIONAL PERIODS OF
PRECIPITATION. SNOW LEVELS WILL REMAIN QUITE HIGH THROUGH FRIDAY
NIGHT BUT THEN THEY BEGIN TO DROP TO ABOUT 3500 FEET NORTHWEST CWA
AND 6000 FEET IN THE SOUTHEAST CWA ON SATURDAY. THIS WILL ALLOW SOME
SNOW OVER THE HIGHER MOUNTAINS ON SATURDAY. SNOW LEVELS WILL RISE
AGAIN DUE TO THE UPPER RIDGE REDEVELOPING ON SUNDAY THROUGH THE
REMAINDER OF THE LONG TERM FORECAST PERIOD. THEREFORE PRECIPITATION
TYPE WILL AGAIN BE MAINLY RAIN EXCEPT FOR THE HIGHEST PEAKS (ABOVE
PASS LEVELS) THROUGH NEXT TUESDAY. 88

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  53  31  51  34 /   0   0   0   0
ALW  52  31  50  36 /   0   0   0   0
PSC  50  30  47  33 /   0   0   0   0
YKM  51  30  48  35 /   0   0   0   0
HRI  50  30  48  34 /   0   0   0   0
ELN  42  23  45  30 /   0   0   0   0
RDM  61  39  57  37 /   0   0   0   0
LGD  50  29  48  36 /   0   0   0   0
GCD  55  32  53  32 /   0   0   0   0
DLS  55  31  53  38 /   0   0   0   0

&&

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

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

$$

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