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Area forecast discussion 
National Weather Service Spokane Washington
431 PM PDT sun Sep 14 2014

Synopsis...
dry and warm weather is expected to continue over the inland
northwest through at least Tuesday as a ridge of high pressure
builds over the region. A cold front will brush the region
Wednesday night into Thursday. This will result in a chance of
rain showers and possibly a thunderstorm or two. The second half
of the week may become breezy with temperatures cooling toward
normal. The ridge will rebuild for the weekend with dry conditions
and warming temperatures.



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Discussion...
tonight through Wednesday night...high pressure will remain strong
over the Pacific northwest tonight through Tuesday. The ridge
does begin to push eastward as a weak wave runs up the backside of
the ridge Monday night. A much stronger...but splitting trough is
expected to move into the West Coast late in the day Wednesday.

Tonight through Tuesday...continued warm and dry with temperatures
climbing into the low to mid 80s. This is 10-12 degrees above
seasonal averages. In addition a weak northeast-east surface
gradient will keep light northeast winds in the region through
Tuesday. The weak wave that moves north just off the Washington
coast will have little effect on the inland northwest save for
possibly increased clouds over the Cascades.

Tuesday night...the flow turns southwest and will tap into deeper
Pacific moisture. The NAM and GFS are showing some moisture
advection and weak instability around 10k feet moving through the
Blue Mountains and Camas Prairie. The only thing that is lacking
is a decent wave to kick parcel high enough into the atmosphere to
tap into the mid level instability. Pops were bumped up a little
bit but the weather was kept as showers and held off on
thunderstorms overnight. It may end up just being some increased
mid level clouds. Any precipitation that does fall will be very
light or virga as the sub-cloud layer is extremely dry.

Wednesday and Wednesday night there will be a better chance for
showers and again possible thunderstorms. The models are showing
the trough splitting...with the best forcing going north into b.C.
And a secondary area remaining south in Oregon. Southwest flow
will definitely pump up enough moisture to sustain showers for the
mountains surrounding the Columbia Basin and Palouse.
Precipitation for the mountains should stay below a tenth of an
inch. The front or what resembles a front will just sag into the
region and while southwest winds will be on the increase they
should remain 10-15 mph or less. Temperatures will be on the
decline Wednesday but remain on the warm side of normal. /Tobin

Thursday through Sunday...unsettled weather will affect portions
of the inland northwest Thursday into Thursday night as a trough
of low pressure moves through the region. Medium range models are
in better agreement on split flow with the trough, keeping most of
the energy in the base of the trough that will slide down the
Oregon and California coasts. There will still be a good chance of
some precipitation for the higher elevations across the forecast
area but with the flow looking more westerly, the basin and east
slopes may get rain-shadowed. Once the trough axis moves east
Friday morning, a drying and warming trend will commence. How warm
it gets over the weekend will depend on the strength of the ridge.
The European model (ecmwf) is more bullish with the ridge and warming temperatures
than the GFS. /Kelch

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Aviation...
00z tafs: high pressure will remain over the inland northwest
tonight and Monday for VFR conditions at all taf. Winds will be
light northeast to east with clear skies. /Tobin





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Preliminary point temps/pops...
Spokane 47 82 52 85 57 82 / 0 0 0 10 10 10
Coeur D'Alene 46 81 48 85 53 82 / 0 0 0 10 10 10
Pullman 39 84 48 86 53 83 / 0 0 0 10 10 10
Lewiston 51 89 57 92 61 89 / 0 0 0 10 10 10
Colville 41 84 44 87 51 83 / 0 0 0 0 0 10
Sandpoint 36 77 40 80 48 79 / 0 0 0 10 10 10
Kellogg 44 79 49 83 53 80 / 0 0 0 10 20 10
Moses Lake 45 86 51 87 56 85 / 0 0 0 0 10 10
Wenatchee 52 85 56 87 60 84 / 0 0 0 0 10 10
Omak 46 86 47 88 55 83 / 0 0 0 0 10 20

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Otx watches/warnings/advisories...
Idaho...none.
Washington...none.
&&

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