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Area forecast discussion 
National Weather Service Spokane Washington
517 am PDT Sat Aug 29 2015

Synopsis...
a cold front will push through the inland northwest today and
bring high winds to the region. This will create a situation for
blowing dust with reduced visibility. There is the potential for
toppled trees and downed power lines as well. A cooler and
occasionally breezy regime with some shower activity will persist
through the next week.

&&

Discussion...
today and tonight...numerous highlights in effect to address the
impacts resulting from the vigorous cold front passage today. A
red flag warning and a high wind watch for just about all of the
forecast area (with the exception of some portions of the
Washington cascades) is in effect for today and this evening. The
red flag warning will stay as is but the plan is for the high wind
watch to be upgraded between 7 and 8am PDT this morning for
optimal dissemination. An air quality alert message remains in
effect until further notice addressing the health impacts and
protective precautions that can be taken to protect oneself from
wildfire smoke and blowing dust. For brevity I won't repeat the
call to actions and other useful content contained in those
highlights here but encourage all reading this discussion to pull
them up and look them over (many of them will be noted in social
network posts and imagecasts).

As far as model differences, well I see good consistency as far
as timing and placement of the front with its passage today and
tonight. Of particular note is the ensemble situational awareness
tables noting some of the wind at 850mb (around 5000 feet msl)
over the area at 11am PDT today are on the order of 5 to 6
standardized anomalies above the mean climatology data between
1979-2009. That would signify these to be very rare and extreme
winds for this time of year which supports the current wind
forecast and resulting highlights.

Precipitation amounts will decrease substantially across the
crest due to the typical Lee side rain-shadow of the Washington Cascades.
Any convection that forms will be moving with a quick storm
motion to the northeast at 40 mph. This is too fast to allow
substantial precipitation to fall in one place so the amounts
expected remain on the light side.

/Pelatti

Sunday through Friday....models are in general agreement in
establishing and maintaining through the next week a huge closed
upper low over western Canada with a sprawling surface low
pressure underneath it. This pattern creates high confidence of a
continued active pattern featuring multiple spur troughs sweeping
through the region dragging cold fronts bearing occasional showers
and cooler than normal temperatures. The persistent southerly
gradient feeding onto the surface low will promote breezy
southwesterly winds much of the time especially over the exposed
terrain of the eastern basin. Rain showers and possibly even some
high elevation snow will be the feature of just about every day
through Friday in the mountains surrounding the basin...with a
chance of showers in the basin on those days where a spur trough
sweeps through...at this time almost definitely Sunday...again on
Tuesday or Wednesday depending on which model is used...and
possibly yet again on or about Thursday. /Fugazzi

&&

Aviation...
12z tafs: a vigorous cold front passage today will cause the winds
to increase and shift during the aviation period along with some
spells of low level wind shear this morning. When winds reach peak this afternoon
the mixing of the smoke will be replaced with some blowing dust
to impact visibilities (possibly down to IFR near kmwh this
afternoon). Showers (and some thunderstorms) that form will move
quickly to the northeast at 40 mph or more which won't allow much
precipitation to fall in one place. High wind watch remains in
place for today. Decrease in wind and blowing dust expected in
very late afternoon and early evening. /Pelatti

&&

Preliminary point temps/pops...
Spokane 82 53 68 52 71 53 / 30 20 70 10 10 10
Coeur D'Alene 83 52 64 49 71 52 / 40 20 70 10 20 20
Pullman 83 52 66 50 74 51 / 30 20 60 10 10 10
Lewiston 89 58 73 55 80 57 / 20 20 50 10 10 10
Colville 83 51 70 50 70 50 / 40 30 70 20 40 20
Sandpoint 83 50 62 48 69 49 / 40 20 80 20 40 40
Kellogg 83 49 60 47 71 48 / 30 30 80 20 20 20
Moses Lake 80 55 74 54 76 55 / 20 40 50 10 10 10
Wenatchee 77 56 71 55 74 55 / 30 50 30 10 20 20
Omak 78 52 72 51 73 52 / 40 70 50 20 20 30

&&

Otx watches/warnings/advisories...
Idaho...red flag warning from 11 am this morning to 7 PM PDT this
evening for northern and central Idaho Panhandle (zone 101).

High wind watch from 9 am PDT this morning through this evening
for central Panhandle mountains-Coeur D'Alene area-Idaho
Palouse-Lewis and southern Nez Perce counties-Lewiston area-
northern Panhandle.

Washington...red flag warning from 11 am this morning to 7 PM PDT this
evening for East Washington central Cascade valleys (zone
677)-East Washington northeast (zone 686)-East Washington
northern Columbia Basin (zone 673)-East Washington Okanogan
Highlands (zone 687)-East Washington Okanogan/Methow
valleys (zone 684)-East Washington Palouse and Spokane area
(zone 674).

High wind watch from 9 am PDT this morning through this evening
for 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.

&&

$$

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