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Area forecast discussion...updated aviation discussion 
National Weather Service Pendleton or
930 am PST Friday Dec 26 2014

Short term...northwest flow aloft today. Satellite showing mainly
clear skies over the Columbia Basin. Upslope flow into the northeast
Oregon mountains producing mostly cloudy skies. Will likely see
increasing high level clouds in the afternoon from the next
approaching system. Temperatures today close to normal levels with
30s to lower 40s. Light winds. 12z models continue to indicate rain
and snow overspreading the region Saturday along with increasing
winds. Still appears the best snow accumulations will be over the
Cascades and northeast Oregon mountains through Sunday morning. 94

&&

Previous disc... /issued 320 am PST Friday Dec 26 2014/

Short term...today through Saturday...a weak disturbance will
swing across our eastern most zones early this morning resulting in
light snow with minimal accumulations. A few snow showers will also
continue to drift off the Cascade crest into the adjacent east
slopes this morning. Otherwise expect fair conditions with a few
passing clouds due to a persistent northwest upper level flow. Winds
will be generally 10 miles per hour or less. High temperatures will be a bit cooler
than yesterday due to cooler starts this morning. The next Pacific
system will begin to move into the Pacific northwest late tonight.
The system's surface low will reach extreme southwest British
Columbia by late afternoon Saturday. This surface low will cause
winds to increase from the south and southwest across our Oregon
zones and into portions of southeast Washington Saturday afternoon.
Thus will see snow levels rise to between 2500 and 3500 feet across
our Oregon zones. Snow levels will be lower across Washington,
especially over Yakima and Kittitas counties. Starting Saturday,
precipitation amounts over the Washington Cascade east slopes, the Blue
Mountains and into Wallowa County look to be rather decent. As such
will continue the Winter Storm Watch in the Washington Cascade east
slopes. Have added winter storm watches to the Blue Mountains
(northern Oregon and northwest washington) and Wallowa County. 90

Long term...Saturday night through Friday...the low will move north
of the area on Saturday night with moderate precipitation continuing
into Sunday. Several inches of snow will fall over the mountains
while elevations below 3000 feet will see mostly rain. Breezy
westerly winds can also be expected which may cause some
rain-shadowing east of the Cascades. As a result...central Oregon
and the Yakima and Kittitas valleys will see minimal rain and snow
amounts. Another low will move down from the north on Sunday night
and Monday with widespread showers. Snow levels will fall during
this period to near zero by Monday morning. Therefore...even the
lower Columbia Basin could see some light snow accumulations. A much
colder and drier northerly flow will be over the region Tuesday
through Thursday. The coldest day will be Tuesday with daytime high
temperatures only in the teens and 20s and overnight lows in the
single digits to middle teens. Temperatures will then gradually warm
through the end of the week. The Pacific Ridge will weaken on Friday
and another weather disturbance will move through the area with a
chance of rain and snow. Lower elevation temperatures could warm
into the middle 30s on Friday. Cobb

Aviation...18z tafs...VFR conditions with mostly clear skies will
prevail over the area today. Middle and high level clouds will begin to
increase overnight as another low pressure system approaches with
some MVFR ceilings and light rain at kykm...kpsc...kalw and kpdt
after 12z. Winds will remain light below 10 kts. 93

&&

Preliminary point temps/pops...
PDT 39 29 44 32 / 10 10 70 60
alw 39 31 45 32 / 10 10 80 70
psc 41 29 43 32 / 0 10 30 30
ykm 39 28 39 28 / 0 10 20 30
hri 41 28 44 34 / 10 0 50 30
eln 39 25 36 27 / 10 10 40 30
rdm 39 21 44 25 / 10 0 20 30
lgd 36 23 36 30 / 10 10 70 90
gcd 38 22 41 30 / 10 0 40 80
dls 47 33 45 34 / 10 10 30 40

&&

PDT watches/warnings/advisories...
or...Winter Storm Watch from late tonight through late Saturday night
orz050-502.

Washington...Winter Storm Watch from late tonight through late Saturday night
waz030.

Winter Storm Watch from late tonight through late Saturday night
waz520.

&&

For additional weather information, check our web site at...
www.Weather.Gov/Pendleton

$$

94

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