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Area forecast discussion 
National Weather Service Spokane Washington
1123 am PDT Tuesday Apr 21 2015

Synopsis...

Today will likely be the warmest day in the next 7 to 10 days as
strong high pressure remains over the region for one last day. A
cold front will arrive Tuesday night bringing cooler weather and
breezy conditions into Wednesday. A cool upper trough is expected
to bring showery conditions Friday and Saturday. A stronger
weather disturbance will result in widespread and possibly
moderate precipitation Sunday and lingering into the new week.



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Discussion...
the morning model runs have come into better agreement with the
timing and strength of tonight's cold front and the trailing upper
trough during the day tomorrow (wednesday). The GFS continues to
be slower than the other models, but is more progressive than
previous runs. None of the models support much potential for
thunderstorms on Wednesday. The best instability will be shunted
east of the Idaho Panhandle by late morning. The NAM and GFS
forecast a bit of surface based cape along the Washington/Canada
border Wednesday afternoon, but the buoyancy on the sounding looks
to be too low in the thermal profile to get much charge
separation (or lightning). In general, this front looks to bring
a cool down, and bit of breeziness, and spotty light showers.
/Gkoch

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Aviation...
18z tafs: a high and thin cloud deck is expected through this
evening ahead of a cold front advancing toward the Pacific
northwest. The front will spill over the Cascades between 00z-03z
and reach the Idaho Panhandle around 06z. This front will largely
be a dry cold front. Scattered light rain showers are expected to
be on the increase after 15z on Wednesday with the arrival of a
trailing cold upper trough. Given the dry Post frontal air mass,
we are not anticipating ceiling or visibility restrictions on
Wednesday. The main aviation impact will be increasing west or
southwest winds gusting as high as 20kts on Wednesday. /Gkoch




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Preliminary point temps/pops...
Spokane 74 49 59 36 60 41 / 10 10 20 10 10 20
Coeur D'Alene 73 43 60 34 60 37 / 10 10 30 20 10 20
Pullman 72 45 57 34 60 39 / 10 10 30 10 10 10
Lewiston 79 50 64 38 66 44 / 0 10 30 10 10 10
Colville 77 47 63 37 63 39 / 10 10 50 30 10 20
Sandpoint 72 40 59 33 59 34 / 10 10 30 30 20 20
Kellogg 71 43 57 34 60 36 / 10 10 40 20 10 20
Moses Lake 79 49 66 37 65 40 / 0 10 10 0 10 10
Wenatchee 77 53 65 41 64 44 / 10 10 10 10 10 10
Omak 78 47 64 35 64 38 / 10 10 30 10 10 10

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

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