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Area forecast discussion 
National Weather Service Spokane Washington
327 PM PST Thursday Nov 26 2015

chilly temperatures and clear skies are expected through at least
Friday as strong high pressure builds over the Pacific northwest.
Light winds and a strengthening inversion will increase the
potential for air stagnation this weekend. We will also have the
potential for areas of fog and low clouds over the weekend into
early next week. The next chance of precipitation is expected next
Wednesday with the arrival of a frontal system.


tonight through Mon: the biggest challenge remains determining the
areal coverage of stratus (low clouds) and lake fog the next few
nights. We simply tried to re-introduce low clouds in the areas
that had coverage this morning... but modified slightly. The most
persistent stratus should be along the highways 2 and 95 corridor
in boundary and Bonner counties Idaho. Patchy low clouds were also
added to Priest Lake, and also kept patchy fog for Lake Chelan and
Lake Wenatchee. It's interesting that the NAM is producing light
amnts of pcpn mainly Sat nt and sun nt across the cntrl part of
the Columbia Basin. No other guidance is doing this. The NAM fcst
soundings also show a sufficiently deep saturated sfc lyr (with a
dry dendritic layer aloft) to produce snow grains for the above-
mentioned nights. We did not put any pcpn in the fcst attm.Bz

Monday night through Tuesday night: high pressure will continue to
dominate over the inland northwest. Little air movement and large
scale subsidence will result in stagnant conditions. There is a
good chance that little will change in air quality across the
region. Slightly higher dew point temperatures will result in a
higher probability for fog or low stratus early next week. Best
chances for fog will be in the mountain valleys and across the
western portion of the basin.

Wednesday through thursday: models show reasonable consistency in
showing the ridge breaking down around this time. Energy pushing in
off of the Pacific looks to split or weaken as it impinges upon
the upper level ridge of higher pressure. This will assuredly
result in light amounts of precip as lift will be weak, and models
also show little in the way of moisture. The main impact to watch
out for will be for the potential of a mixture of snow and freezing
precip. Temperatures will likely remain around freezing as the
first bit of moisture pushes in. With how weak the energy looks to
be, it will likely do little to mix up the lower atmosphere. Weak
easterly winds will result in better mixing potential for the
southeast portion of the region. Where mixing will have a harder
time occurring, and where mixed precip will be more likely, will
be over the western basin and into the valleys of the east slopes
of the northern Cascades and across the northern mountains. With
that said, confidence is still too low to add a mention of
freezing precip to the forecast, but best potential would be from
the Wednesday morning through the Thursday morning portion of the
extended forecast. /Svh


00z tafs: strong high pressure will produce clear skies over the
inland northwest for at least the next 24 to 36 hours. VFR
conditions are expected at all airports this Thanksgiving Holiday.


Preliminary point temps/pops...
Spokane 15 30 18 32 17 32 / 0 0 0 0 0 0
Coeur D'Alene 14 31 18 33 19 32 / 0 0 0 0 0 0
Pullman 15 31 17 32 18 33 / 0 0 0 0 0 0
Lewiston 18 33 20 33 22 33 / 0 0 0 0 0 0
Colville 12 34 13 37 16 34 / 0 0 0 0 0 0
Sandpoint 17 31 18 34 17 33 / 0 0 0 0 0 0
Kellogg 14 32 13 34 18 33 / 0 0 0 0 0 0
Moses Lake 14 32 17 33 18 33 / 0 0 0 0 0 0
Wenatchee 20 33 19 33 21 34 / 0 0 0 0 0 0
Omak 17 33 16 35 17 33 / 0 0 0 0 0 0


Otx watches/warnings/advisories...
Idaho...air stagnation advisory from 9 PM this evening to noon PST
Monday for central Panhandle mountains-Coeur D'Alene area-
Idaho Palouse-Lewis and southern Nez Perce counties-
Lewiston area-northern Panhandle.

Washington...air stagnation advisory from 9 PM this evening to noon PST
Monday 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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