Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Spokane Washington
1003 am PDT Wednesday Apr 23 2014

Synopsis...
occasional precipitation chances, breezy conditions and relatively
cool temperatures dominate the weather pattern. Passing rain and
snow chances Wednesday are followed by steadier rain chances late
Wednesday night into Thursday, followed by a threat of more
scattered showers, and perhaps some thunder, Thursday afternoon.
Showers will remain a threat into the weekend, before a relative
lull comes for the start of the new work week.



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Discussion...
rest of today...the forecast area is underneath an upper level
trough today...and while there are no organized storm systems over
the area...a weak disturbance is tracking through the eastern
zones this morning. The air mass remains moist with moderate
instability owing to a cool pool aloft. Mid level flow is
westerly...producing a noticeable rain shadow in the Cascades Lee
area with scattered rain and mountain snow showers increasing in
areal coverage with the rising terrain over the east. This
situation will largely hold static through today with showers
common and frequent over the Idaho Panhandle...and merely isolated
over the deep basin. Instability due to the cool air over surface
diurnal heating will peak during the early afternoon with warming
aloft as the trough is replaced bu a weak ridge later today and
this evening. A random weak thunderstorm cannot be ruled out this
afternoon over the northeast mountains and north Idaho Panhandle
but the threat is not great. Temperatures will remain below
normal. /Fugazzi

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Aviation...
18z tafs: an upper level trough with an embedded weak disturbance
and moderate instability will promote showery conditions today.
The eastern taf sites will be subject to scattered -shra through
00-02z with occasional brief MVFR ceilings in shower cores.
Isolated thunderstorms are possible Manly over the northeast
Washington and north Idaho mountains...but some thunderstorms
may break out near the kgeg vicinity taf sites between 20z and
01z. The keat and kmwh taf sites will benefit from a rain shadow
fro only small chances of a brief shower. After 03z from west to
east a stronger Pacific storm system will bring lowering ceilings
and an increasing chance of rain with MVFR ceilings to all tafsites
by 12z Thursday. /Mjf

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Preliminary point temps/pops...
Spokane 51 39 55 38 54 37 / 50 70 100 40 40 20
Coeur D'Alene 50 38 53 37 53 37 / 60 60 100 70 50 20
Pullman 50 41 54 39 50 37 / 60 70 100 50 50 20
Lewiston 56 45 60 44 55 42 / 50 50 100 60 70 20
Colville 57 35 59 35 61 36 / 50 50 100 60 40 20
Sandpoint 49 36 51 36 54 37 / 60 50 100 80 50 30
Kellogg 45 36 50 36 52 36 / 80 60 100 70 70 40
Moses Lake 61 44 65 40 61 38 / 20 70 70 10 10 20
Wenatchee 60 45 64 43 61 41 / 20 60 70 10 10 20
Omak 59 39 62 36 62 35 / 20 50 80 10 20 20

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

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