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Area forecast discussion...updated 
National Weather Service Pendleton or
315 am PST Tue Dec 6 2016

Updated aviation discussion

Short through Wednesday night...the latest Pacific
storm system continues to move across the region early this morning.
The main upper low center is currently over southeastern Washington.
Light snow showers continue to develop along the south side of the
low and are swinging into the Blue Mountains and the adjacent
foothills. An area of showers is currently crossing the southern
Willamette Valley, and expect this area to move across central
Oregon in a few hours time. Bands of showers are also evident over
southern Union County and northern Grant County. Overall still
expect to see scattered to numerous showers over the advised zones
into mid morning. Will therefore continue the advisories, though
snow amounts will not be uniform across the affected zones. As the
upper low shifts into southern Idaho late this morning and this
afternoon, should continue to see light snow showers as moisture
wraps around the back side of the low. Favored areas for snow
showers will be The Blues and their adjacent foothills, the south
end of the Wallowa valley, and the area from Bend to Lava Butte.
Daytime heating, such as it will be, and solar insolation should
limit accumulations of snow this afternoon (especially on roadways).
The snow showers will end across the area this evening, and expect
dry but cold conditions Wednesday. The next Pacific system is still
on track to begin affecting the region some time Wednesday night.
Timing differences remain between the various data sets. For now
will continue to blend the various solutions, though this did result
in a slight slowing of the system arrival Wednesday night. 90

Long term...Thursday through Monday...Thursday an occluded front
will move into eastern or and Washington. Cold air will remain in place at
the surface so the precipitation will be snow. Light snow will
rapidly spread east Thursday morning. A wave will move along the
frontal boundary Thursday night with more snow likely. Snow levels
will be slow to rise...with precipitation remaining snow for most if
not all areas until Friday morning. The difficult part of the
forecast is how fast the overrunning warm air mixes to the surface
Friday. Freezing rain is possible in the lower Columbia Basin early
Friday. Snow levels will rise to 1500-2000 feet across the lower
elevations of southeast Washington Saturday...with snow levels 2500-3000 feet
across most of NE or. Showers will persist Friday through Monday,
especially in the mountains, as a series of disturbances move across
the area in westerly flow. Since the flow aloft will be westerly,
some precipitation shadowing will be likely across the lower
Columbia Basin. Coonfield


Aviation...12z tafs...MVFR/IFR ceilings and visibilities in -sn are likely
this morning at kpdt...kalw...kbdn and kpsc. Other taf sites will be
may see MVFR cigs/vsby this morning. Winds will be 10 kt or less. 76


Preliminary point temps/pops...
PDT 30 15 25 16 / 60 10 0 10
alw 31 20 25 19 / 60 20 0 10
psc 35 17 28 20 / 50 0 0 10
ykm 35 12 30 16 / 20 0 0 20
hri 35 15 28 18 / 50 10 0 10
eln 29 12 26 16 / 30 0 0 20
rdm 29 2 28 17 / 60 10 0 60
lgd 28 7 23 17 / 60 20 0 10
gcd 29 9 25 19 / 60 10 0 40
dls 37 20 33 23 / 20 0 0 40


PDT watches/warnings/advisories...
or...Winter Weather Advisory until 10 am PST this morning for orz044-

Washington...Winter Weather Advisory until 10 am PST this morning for waz028-




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