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Area forecast discussion 
National Weather Service Spokane Washington
351 PM PST Wednesday Nov 25 2015

winds will decrease into Thanksgiving day, but temperatures will
be cold, with most areas only reaching the mid 20s to low 30s. It
will remain dry and chilly, with an increasing chance of fog and
low clouds starting this weekend. The next chance of precipitation
arrives by the middle of next week.


tonight through Fri: a very dry and cold northeasterly steering
flow will dominate the synoptic pattern the next couple days. This
will keep the fcst dry, cold and generally cloud-free. With
pressure gradients weakening this evening (following tight
gradients which produced very gusty winds today) low temps will be
roughly 10f below normal and high temps around 5-10f below normal.
Record low temps are not expected.

Stagnant air will become an issue by Friday under broad ridging,
moderate to strong inversions and light sfc winds. Bz

Friday night through wednesday: dry, cold conditions start the
period but some opportunity for precipitation returns next week.
Between Friday night and Monday the west will be under the
influence of a Rex block (a ridge of high pressure over the top of
a cut-off low). The inland northwest resides in the easterly flow between
these respective pressure centers through Sunday, before the low
shifts toward the northern High Plains and some energy starts to
approach from the Pacific. A few model runs show some showers may
swipe the lower Panhandle/far southeast Washington late Sunday into Monday
when that shift occurs. However average model consensus supports
keeping things dry. Yet there could be a few more clouds in this

As for temperatures: regional 850 mb temperatures warm under the
ridge. Yet with little mixing and strong low-level inversions the
surface temperatures are not likely to reach their full potential
in the valley/basin areas. Model guidance also indicates this
thinking. Tack on the potential for fog under these inversions and
we have temperatures that are expected to remain below normal.
This is a set-up where we could easily see temperatures warmer in
the mountains than in the valleys.

As for fog: looking where guidance places the main low level
moisture, fog will be a threat across the Columbia Basin and in
the sheltered valleys across North Washington and the Idaho Panhandle. For
now the fog will be worded as patchy due to a lack of confidence
in placement and coverage or how deep the available moisture will
be. Yet it may become more widespread and locally dense as things

Between Tuesday and Wednesday some threat of precipitation arrives.
A trough moving into the Gulf of Alaska during the early weekend stretches
and splits. The southern split tracks toward the West Coast,
sitting some 600-800 miles west of the California coast by Sunday night.
There is little confidence in where it tracks after that because
models take it in 3 or 4 varying paths. Of the four models, three
track it in a way that would bring at least some increased cloud
and snow/rain shower threat. The ECMWF, at this time, keeps it
south and the region remains dry. For now the forecast calls for
increasing clouds starting Tuesday. A threat of snow showers
starts into from the west to southwest Tuesday afternoon and
across a broader area Tuesday night into Wednesday. It is still
possible the system would miss the region entirely. /J. Cote'


00z tafs: expect VFR conditions for all sites, with the currently
gusty north and northeast winds decreasing significantly
this evening. The sky will remain clear with light winds through
at least 00z Fri.Bz


Preliminary point temps/pops...
Spokane 15 29 16 31 19 33 / 0 0 0 0 0 0
Coeur D'Alene 15 30 15 32 19 32 / 0 0 0 0 0 0
Pullman 14 29 13 31 20 30 / 0 0 0 0 0 0
Lewiston 20 33 18 32 20 30 / 0 0 0 0 0 0
Colville 13 33 14 33 18 32 / 0 0 0 0 0 0
Sandpoint 17 29 16 32 20 30 / 0 0 0 0 0 0
Kellogg 13 28 14 32 18 33 / 0 0 0 0 0 0
Moses Lake 15 35 13 33 17 33 / 0 0 0 0 0 0
Wenatchee 19 35 19 34 22 31 / 0 0 0 0 0 0
Omak 16 33 16 32 20 32 / 0 0 0 0 0 0


Otx watches/warnings/advisories...
Idaho...air stagnation advisory from 9 PM Thursday 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 Thursday 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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