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Area forecast discussion 
National Weather Service Pendleton or
300 am PST Wednesday Jan 28 2015

Short through Friday...a weak system continues to
drift across the region early this morning. This system will cause a
few showers near the Cascade crest today, with a few showers in
Wallowa County this morning. Also a few sprinkles of flurries will
be possible over The Blues this morning. This system has mixed out
the low level inversions across most of our Oregon zones. The
inversions in over some of our Washington zones persist with some
areas of dense fog having formed early this morning. Also areas of
dense fog have redeveloped in the Lower Basin in Oregon. Thus will
issue dense fog advisories for the Lower Basin in Oregon and
Washington, and the Yakima Valley in Washington for much of this
morning. Another weak system is expected to bring a few showers to
south-central Washington tonight into Thursday morning. Otherwise
expect dry conditions due to increasing upper level high pressure.
This upper level high pressure will cause low level inversions to
increase across the interior northwest. Thus will continue to
indicate an increase in fog coverage over our area tonight through
Friday. High temperatures will continue to be warmer above the inversions,
though not quite as warm as in recent days due to some cooling
aloft. High and low temperatures within foggy areas will see limited
diurnal changes, with high temperatures in the 30s to low 40s. 90

Long term...Friday night through Tuesday...high pressure ridge
remains over forecast area beginning Friday night for dry conditions
persisting through Saturday night. Sunday a warm front associated
with warm air advection in the middle levels Ushers in a chance of rain
during the day on Sunday. Then a Pacific middle/upper level short wave
and associated dynamic lift moves into the Pacific northwest Sunday
night for rain likely, except for a chance of rain in Benton and
Franklin counties Sunday night. Monday the upper level short wave
moves across forecast area for a chance of basin/valley rain and a
chance of snow in the mountains with snow level 4500-5500 feet
through Monday afternoon. Monday night a weak disturbance moves
through southern Oregon for a chance of rain in central and north
central Oregon, the Blue Mountains and the east slopes of the
Cascades. A middle/upper level ridge of high pressure builds over the
region on Tuesday. Polan


Aviation...12z tafs...yesterday a middle/upper level low southeast of
taf sites and a passing weak weather system has broken up low fog
and stratus deck except at kpsc and kykm. Cooler temperatures above
the inversion prevent fog from forming at other taf sites through
29/03z, but fog and stratus may start to form at kalw and kpdt after
29/03z while conditions worsen at kykm and kpsc as brief subsidence
occurs between weather systems. Another weather disturbance will
approach central Washington and bring a vicinity shower to kykm
after 29/03z. Polan


Preliminary point temps/pops...
PDT 49 33 40 32 / 10 10 10 0
alw 46 35 43 34 / 10 10 10 0
psc 41 35 44 34 / 0 10 10 0
ykm 41 33 42 32 / 10 20 20 0
hri 42 34 44 34 / 0 10 10 0
eln 49 33 42 32 / 10 20 20 0
rdm 56 29 46 28 / 10 10 10 0
lgd 50 29 47 29 / 10 10 10 0
gcd 52 33 50 32 / 10 10 10 0
dls 50 39 46 36 / 10 20 10 0


PDT watches/warnings/advisories...
or...dense fog advisory until 11 am PST this morning orz044.

Washington...dense fog advisory until 11 am PST this morning waz027-028.


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