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fxus66 kotx 242100 
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Area forecast discussion
National Weather Service Spokane Washington
200 PM PDT Sat Jun 24 2017

Synopsis...
warm and sunny weather will be in place this weekend with
widespread 90s expected by Sunday. Monday will also be warm
with increasing clouds and chance for showers and thunderstorms
late in the day. A return to cooler, more average temperatures
are expected by the middle of next week, with breezy conditions
possible late Monday through Tuesday.



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Discussion...
tonight through Monday night: this period will feature a
transition in the weather. Sunday will be about 6 or 7 degrees
warmer than today with just a smattering of cirrus clouds to
interrupt the Blue Sky. Meanwhile, a low pressure system well west
of California will slowly start to eject to the northeast. This
will fire off thunderstorms over Oregon Sunday night. At this
point it looks like this activity will remain south of our
forecast area. We will see the cloud remnants move into our area
by Monday morning and some computer models want to even give US
some rain from this. But the clouds should be rather high with
very dry lower levels, so rain will have a hard time making it to
the ground.

But even if there's no rain, we should see an increase in overall
atmospheric moisture, and this will help to destabilize the
atmosphere on Monday. It should be another hot one, although the
cloud cover will ultimately determine how hot it is. The
aforementioned low links up with a trough in BC, and these sweep
through the region on Monday. The Cascades and basin have the
lowest chance of thunderstorms, while the best location for them
will be southeast Washington and the southern Panhandle. Some of
these storms could be severe. To the north, isolated thunderstorms
are possible, but rainfall from them should be minimal. All of
this activity will sweep east into Montana on Monday night. Rj

Tuesday through saturday: the inland northwest will remain in a
progressive pattern, with limited shower chances and temperatures
closer to seasonal averages. Low pressure currently in the Gulf of
Alaska moves to Alberta by the start of this period before heading
toward the northern High Plains. Smaller scale shortwave
disturbances rounding its backside pivot by the inland northwest in the
west/northwest flow. These, plus some orographic enhancement, will
lead to the occasional threat of showers and afternoon
thunderstorms between Tuesday and Thursday around the northern
and eastern mountains. The threat will be highest Wednesday and
Thursday in the afternoon/early evening hours, but even then
coverage does not look extensive. A ridge briefly builds in
Thursday night into early Friday before another trough approaches
the coast end embedded shortwave disturbances slip in ahead of it.
This will provide additional shower/thunderstorm chances around
the mountains, from the Cascades to the Idaho Panhandle, with the
best risk on Saturday. Otherwise expect occasional middle to high
clouds and some afternoon cumulus fields. Winds will be
occasionally breezy in the afternoon/evening hours focused
especially around Tuesday and Wednesday. /J. Cote'



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Aviation...
18z tafs: sunny skies with light winds today. Thin cirrus will
approach the area from the west on Sunday morning. Rj

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Fire weather...
isolated to scattered thunderstorms are also possible on Monday.
But the majority of these will be over the mountains that have yet
to cure out their fuels. So aside from an outside chance of a
lightning strike in the basin where the fuels are dry enough to
burn, thunderstorms should not be a big fire weather impact.

The atmosphere will also be unusually unstable on Sunday and
Sunday night with widespread values of Haines 6 over the Columbia
Basin. But due to the current state of our fuels, no red flag will
be issued.

Gusty westerly winds will develop on Monday afternoon. At this
point it appears that winds will be around 15-20 mph, mainly from
Wenatchee and the Waterville Plateau across the basin and into
Spokane and Pullman. Meanwhile, humidities will be in the 15-20%
range. These conditions may require the issuance of a red flag
warning.

Cooler temperatures will arrive on Tuesday. But the combination
of continued breezy winds and low humidities could also cause
heightened fire danger over the basin. Rj

&&

Preliminary point temps/pops...
Spokane 61 93 66 93 61 82 / 0 0 0 20 20 10
Coeur D'Alene 55 91 59 90 57 79 / 0 0 0 20 20 10
Pullman 52 92 63 89 59 79 / 0 0 0 20 30 10
Lewiston 60 98 66 96 63 87 / 0 0 0 20 40 10
Colville 51 93 58 92 54 84 / 0 0 0 10 10 10
Sandpoint 46 88 55 87 54 79 / 0 0 0 20 20 10
Kellogg 53 90 60 88 55 77 / 0 0 0 20 40 10
Moses Lake 53 99 63 96 58 87 / 0 0 0 10 10 0
Wenatchee 59 96 69 95 61 84 / 0 0 10 10 0 0
Omak 55 95 62 94 55 85 / 0 0 10 10 10 0

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Otx watches/warnings/advisories...

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