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fxus66 kotx 231820 
afdotx

Area forecast discussion
National Weather Service Spokane Washington
1120 am PDT Tue may 23 2017

Synopsis...
today will be warm with continued rises expected on local rivers
and streams in the Cascades and across the northern mountains of
Washington and Idaho. A strong cold front will plow through the
region this evening bringing gusty winds. Breezy winds will usher
the cooler air into the region Wednesday knocking temperatures
down almost twenty degrees from those expected today. Cooler and
unsettled weather will likely persist through the end of the week
with a warming trend for the weekend.

&&

Discussion...

The evening timing of a strong cold front still looks on track.
Satellite trends as of 11 am show the cold front nearing the
western tip of Vancouver Island. The morning runs of the NAM and
GFS show increasing on-shore flow through the afternoon with a bit
of cooler marine air spilling through the Cascade gaps by late
afternoon. However, the brunt of the deep cold advection with the
front won't arrive until mid evening causing an abrupt increase in
west winds across the Columbia Basin into eastern Washington and
north Idaho. Gusts of 40 mph will likely occur around Wenatchee,
Chelan, and over the Waterville Plateau. We may be close to Wind
Advisory criteria for areas prone to Cascade Gap winds, and it
may be considered this afternoon for the aforementioned areas.
Further east, the strongest pressure gradient and strongest cold
advection will occur during the late evening and early morning
hours, the time of night that is the least efficient for low level
mixing. The strength of this front will certainly produce gusty
winds, but places like Ritzville, Spokane, Pullman, and Lewiston
will probably fall short of Wind Advisory criteria (sustained
30 mph or gusts over 45 mph). /Gkoch

&&

Aviation...
18z tafs: the passage of a dry cold front this evening will
produce a sharp increase in west winds for the inland northwest.
The timing and strength of the winds will be the biggest challenge
for the tafs. It is often difficult for strong and gusty winds to
persist all night long, but tonight's cold front is particularly
strong. The strongest gusts will likely occur at the Wenatchee and
Chelan airports (up to 35kts early this evening) with the
contribution of gap winds accelerating through the Wenatchee
valley and Down Lake Chelan. Further east, places like Spokane,
Coeur D'Alene, Pullman, and Lewiston will experience the tightest
pressure gradient and strongest 850mb winds between mid evening
and early morning which is the toughest time for efficient low
level mixing. /Gkoch

&&

Preliminary point temps/pops...
Spokane 84 48 64 46 65 47 / 0 0 10 10 30 20
Coeur D'Alene 83 47 63 44 63 44 / 0 0 10 10 30 30
Pullman 83 49 63 44 62 44 / 0 0 0 20 30 30
Lewiston 90 53 68 48 68 48 / 0 0 0 20 40 20
Colville 86 48 67 46 68 46 / 0 0 10 10 30 20
Sandpoint 81 44 61 42 63 42 / 0 0 20 10 50 30
Kellogg 81 43 60 42 60 41 / 0 10 20 20 50 30
Moses Lake 92 51 72 47 73 49 / 0 0 0 10 10 10
Wenatchee 90 50 69 48 73 51 / 0 0 0 10 10 10
Omak 88 49 70 47 72 49 / 0 0 10 10 10 10

&&

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

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