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fxus66 kotx 140548 
afdotx

Area forecast discussion
National Weather Service Spokane Washington
948 PM PST Wed Dec 13 2017

Synopsis...
many of The Lowlands across eastern Washington and north Idaho
will continue to be covered by low clouds. Chances for light
precipitation increase Friday with snow over northeast Washington
and north Idaho and a chance of a wintry mix in the Cascade
valleys and Columbia Basin. Drier weather returns over the weekend
before the next system arrives next Tuesday.



&&

Discussion...
tonight: the wave that brought some light snow amounts this
morning has moved off into Wyoming this afternoon. Portions of the
east slopes of the Cascades into the Columbia Basin have cleared
out this afternoon. Satellite shows the stratus is trying to thin
across portions of eastern Washington. There may be some brief clearning
before our early sunset. Low clouds and fog is expected to
redevelop this evening and overnight. The upper level ridge is
building back into the area. As the ridge axis moves east
overnight a weak wave currently located off the Washington coast will move
through the ridge overnight. The potential exists for some very
light freezing rain or flurries overnight into thur morning across
The East Slope valleys, Okanogan Valley, Wenatchee area,
Waterville Plateau and into portions of the Columbia Basin as that
wave moves through. Confidence is low, but given we have had
reports the last 2 mornings of snow or freezing precip falling out
of the stratus, think the potential is there to at least mention
it.

Thursday: ridge remains with that weak wave exiting in the
afternoon. Low clouds and fog will continue to plague The
Lowlands. Most valley locations will struggle to reach above
freezing temperatures. /Nisbet

Thursday night through Saturday...the ridge of high pressure will
break down Thursday night and Friday in response to an incoming
weather disturbance that will drop south out of the Gulf of Alaska
and continue to move south and east through the forecast area.
This will bring the next chance of precipitation to the region
mainly Friday and Friday night. Showers will linger across the
Cascades, the Panhandle and across the southeast zones through
Saturday. The cold front should provide enough lift and mixing to
clear out the strong inversion and stubborn stratus/fog that has
been around the last several days. Precipitation amounts with this
pattern will be low with most areas east of a line from Northport
south to Othello seeing just a few hundredths, with up to a tenth
across the Southeast Lowlands and possibly two tenths for the
Panhandle mountains and the Cascade crest. Snow levels will be
near the surface with precipitation as mainly light snow.
Accumulations of less than an inch will be possible across the
eastern third of the forecast area, with the mountains receiving
1-3 inches.

Model guidance is showing the potential of a few hours hours of
freezing rain and sleet in the vicinity of Moses Lake, Warden,
Othello, and Lind. Not much in the way of precipitation is
expected in this area, but there is the possibility of around 0.01
of freezing rain between 10 am and 100 PM. Another area of
concern will be along Highway 2 and Highway 209 from Peshastin to
Telma. Confidence in freezing precipitation is much less than in
the basin, but again light amounts may be possible 1000 am to 100
PM. Temperatures will rise into the lower 30s which is very close
to seasonal normals.



Sunday through Wednesday...the flow will be come westerly Sunday
and Monday as the storms system drops out of the area. This will
keep low end chances for rain and snow showers for areas outside
of the deep basin. By Tuesday and Wednesday weak high pressure
will build back into the region pushing to best chances for
precipitation into the northern mountains. Temperatures will rise
to a couple of degrees above normal through the middle of next
week. Tobin

&&

Aviation...
06 tafs: fog and low stratus will remain across most taf sites
today with the exception of keat which saw clearing yesterday and
will likely stay clear save for some high clouds. A weak
disturbance will bring a slight chance for some flurries or light
freezing rain early Thursday morning but should stay south of any
taf sites. Klws and kmwh are expected to break out of the stratus
this afternoon but most sites will stay socked in. /Bw

&&

Preliminary point temps/pops...
Spokane 24 31 26 33 25 32 / 0 0 0 60 20 10
Coeur D'Alene 24 32 26 34 25 32 / 0 0 0 60 30 10
Pullman 24 32 27 35 26 33 / 0 0 0 60 50 10
Lewiston 27 34 29 39 30 38 / 0 0 0 60 50 10
Colville 27 32 27 33 26 34 / 0 0 0 30 10 10
Sandpoint 25 32 26 34 26 33 / 0 0 0 60 30 10
Kellogg 25 28 26 34 25 29 / 0 0 0 80 60 20
Moses Lake 27 32 26 33 26 36 / 10 10 0 10 10 10
Wenatchee 28 32 28 36 29 38 / 10 10 0 10 10 10
Omak 28 33 28 34 27 34 / 10 10 0 10 10 10

&&

Otx watches/warnings/advisories...
Idaho...air stagnation advisory until 10 am PST Friday for central
Panhandle mountains-Coeur D'Alene area-Idaho Palouse-Lewis
and southern Nez Perce counties-Lewiston area-northern
Panhandle.

Washington...air stagnation advisory until 10 am PST Friday for east slopes
northern Cascades-lower Garfield and Asotin counties-Moses
Lake area-northeast Blue Mountains-northeast mountains-
Okanogan Highlands-Okanogan Valley-Spokane area-upper
Columbia Basin-Washington Palouse-Waterville Plateau-
Wenatchee area.

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