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Area forecast discussion 
National Weather Service Spokane Washington
358 am PST Wednesday Nov 25 2015

blustery dry winds will continue today. Expect north winds of 20
to 30 mph this morning, contributing to wind chills in the single
digits over much of the inland northwest. Winds will decrease on
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 possible chance of precipitation will be by
middle of next week.



..gusty north winds and cold wind chills today...

Today and tonight: a biting north wind will be the primary weather
hazard today. Much of central Washington, the upper Columbia
Basin, and the Sandpoint area/Rathdrum Prairie will experience
sustained winds of 20 to 25 mph for much of the day. Gusts as high
as 40-45mph will be possible in the mid to late morning hours
through the Okanogan Valley onto the Waterville Plateau. The
communities of Omak, Waterville, Mansfield, Coulee City, Ephrata
and Moses Lake is under a Wind Advisory through through noon

The surface pressure gradient between Arctic high pressure sliding
down the Canadian rockies and low pressure in the Great Basin is
the culprit for our blustery north/northeast winds. Prior to
midnight, gusts in the 40 to 45 mph range were measured from the
Omak Airport to Mansfield to Ephrata. As of 2 am, gusts have
diminished into the 30 to 35 mph range, but we may see a
resurgence in the gusts in the mid to late morning hours with a
bit of surface warming. By afternoon, the surface pressure
gradient is expected to decrease as the low in the Great Basin
digs southeast causing our northerly gradient to relax a bit.
Through 9am, blustery north winds will produce wind chills between
10 and 20 degrees with portions of the north Idaho Panhandle into
the Spokane Metro area in the single digits. By mid afternoon,
sunshine combined with high temperatures in the 30s will help take
the bite out of our wind chills as gusts gradually decrease late
in the day.

Thursday and friday: strong upper level high pressure will build
over British Columbia and Washington Thursday and Friday. We will
receive a glancing blow of modified Arctic air over the next 24 to
36 hours with the brunt of the Arctic spilling down the east side
of The Rockies. The air mass we receive will be very dry with
surface dewpoints plummeting into the teens. It is unlikely that
we will see much fog or low clouds Thursday or Friday since our
humidity levels will be so dry. Overnight low temperatures will be
the coldest that we have seen so far this fall. With snow on the
ground, the dry air mass and light winds will allow some spots
like Deer Park, Republic, Springdale, and Priest Lake to flirt
with single digit lows Thursday and Friday morning. /Gkoch

Friday night through tuesday: benign, dry and cold weather can be
expected for the weekend and into early next week. The upper
level pattern will consist of a blocking ridge of high pressure
that Will Park over the Pacific northwest while an upper level low sits
over California. This stable Rex block will keep the storm track
south of the region and bring drier north to east flow into the
inland northwest. This pattern will bring light winds, little
mixing and increase the low level inversions across the region.
Will even have to introduce low clouds and patchy fog in sheltered
valleys and across the Columbia Basin where wind directions are
favorable for Friday night into Saturday. Then winds shift and
become more southerly by Saturday afternoon, setting the stage for
valley fog and low clouds in the northern valleys. There is the
possibility of a weather disturbance will rotate around the upper
level low by Sunday and brush the region of some high level clouds
from the east, but the threat of any precipitation is very low.
The medium range models show the upper level low to migrate
northeast into Montana and even the Dakotas by Monday, keeping
high pressure over the region. The northern Pacific jet stream
will strengthen early next week and potentially kick a disturbance
toward the West Coast by Tuesday. Confidence on the timing and
placement of this disturbance and future disturbances are low with
the GFS and Canadian eager to push this feature inland, while the
European model (ecmwf) strengthens the ridge, splits the flow and pushes this
disturbance further south. The GFS has been showing this feature
for the past several runs, but it has been speeding up. Opted to
follow a blended forecast and introduce low chance probability of precipitation for
Tuesday night into Wednesday, most likely light snow. Temperatures
will be cold, and nudged forecast to the colder models. But even
with that, anticipate a gradual moderation of temperatures through
the period. /Rfox


12z tafs: north or northeast winds will gust as high as 30-35kts
at the Spokane, Coeur D'Alene, Sandpoint, Moses Lake and Ephrata
airports through 21z today. Strong cold/dry air advection will
erode clouds over the region with the 4000 to 6000 foot deck
around Pullman and Lewiston dispersing between 14z-17z. VFR
conditions are expected through 12z Thursday with decreasing winds
late this afternoon into the evening. /Gkoch


Preliminary point temps/pops...
Spokane 33 15 29 16 31 19 / 0 0 0 0 0 0
Coeur D'Alene 34 15 30 15 32 19 / 0 0 0 0 0 0
Pullman 33 14 29 13 31 20 / 0 0 0 0 0 0
Lewiston 39 20 33 18 32 20 / 10 0 0 0 0 0
Colville 37 13 33 14 33 18 / 0 0 0 0 0 0
Sandpoint 33 17 29 16 32 20 / 0 0 0 0 0 0
Kellogg 29 13 28 14 32 18 / 0 0 0 0 0 0
Moses Lake 41 15 35 13 33 17 / 0 0 0 0 0 0
Wenatchee 39 19 35 19 34 22 / 0 0 0 0 0 0
Omak 37 16 33 16 33 20 / 0 0 0 0 0 0


Otx watches/warnings/advisories...
Washington...Wind Advisory until noon PST today for Moses Lake area-Okanogan
Valley-Waterville Plateau.



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