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Area forecast discussion 
National Weather Service Spokane Washington
213 am PDT sun Aug 30 2015

Synopsis...
a vigorous upper level disturbance will bring the inland
northwest some much needed rain today. Area wildfires will have a
good chance of a tenth to a quarter inch of rain. A cool,
occasionally breezy and showery weather pattern is expected much
of next week.

&&

Discussion...

Today and tonight...longwave trof hanging over a good portion of
the western US allows a wet cold front to pass through it today.
Pops remain high with such a scenario given the favorable long-
wave trof placement and a somewhat well maintained moisture feed
extending into it from the south/southwest overcoming the Lee side
rain-shadow of the Cascades. 0-6km above ground level winds suggest storm motion
to the northeast and east at about 25 to 35 mph today. This storm
motion is fast enough to continue to note that flash flooding on
area burn scars is not likely with today's rainfall. The -20 to
-22 deg celsius 500mb cold pool contained in the trof is on the
order of two Standard deviations on the cols side of what would be
considered normal for this time of year, therefore a mention of
thunder seems reasonable given the resulting instability of having
this cold pool aloft. Forecast temperatures on the cool side of
normal a given due to this trof and the resulting rainfall keeping
the daytime high on the cold side while more effective radiational
cooling is likely tonight under this trof. Robust winds from the
southwest remain as well today that will decrease a bit tonight
but likely not go calm given the dynamic nature of the the above
scenario. /Pelatti

Monday through Saturday...model agreement is pretty good between
the latest GFS and ec runs with details and run to run
consistency is very good regarding the overall concept of a
persistently troffy pattern enveloping the region through the work
week. A huge parent trough over western Canada will promote a
series of disturbances brushing or enveloping the forecast area
during the week. A well directed fetch of Pacific moisture will
probably benefit from some isentropic and orographic enhancement
into the Cascades and northern mountains on Monday. Tuesday may be
a relatively dry day with a few degrees of warming before the next
trough carves into the region with another cold front on or about
Wednesday with the actual trough lingering over the region through
Friday. This argues strongly for a period of cooler than normal
temperatures...occasional periods of showers mostly on the
mountains but with a few opportunities for basin precipitation as
well. All this will be good news for the fire fighting
efforts...but The Fly in the ointment will be the propensity for
breezy and occasionally gusty conditions across the basin
especially but also on the mid-slopes and ridges of the mountains
surrounding the basin...which may hamper firefighting. Monday and
especially Wednesday look like the breeziest days...with Wednesday
in particular shaping up to be quite windy and gusty in the wake
of an early day cold front passage.

Way out on or about Saturday the models suggest a pattern shift
back to a drying and warming weak ridge rebound over the region.
/Fugazzi

&&

Aviation...
06z tafs: a narrow band of showers and isolated thunderstorms
will track in the vicinity of klws through 08z. A more substantial
area of showers will continue to slowly push east of the Cascade
crest tonight, moving across eastern Washington and north Idaho overnight and
Sunday as an upper level trough pivots across the region over the
next 24 hours. Winds have diminished this evening but will
increase and start to become gusty again after 15z Sunday morning.
All taf sites will likely be affected by -shra at some point with
the most likely time period between 14z- 20z with the passage of
the cold pool aloft. Confidence is low that any taf site will see
thunderstorms but the more favorable site is kcoe after 18z
Sunday. Smoke may again affect the region if area wildfires flare
up again but confidence remains low on timing and location of
smoke plumes. Gusty afternoon winds will diminish after sunset
Sunday. /Ek

&&

Preliminary point temps/pops...
Spokane 66 50 71 53 72 53 / 80 10 20 10 10 20
Coeur D'Alene 63 48 70 51 72 51 / 80 10 20 10 10 30
Pullman 65 48 72 51 73 49 / 60 10 10 10 10 30
Lewiston 72 53 81 57 81 58 / 70 10 10 10 10 20
Colville 68 49 67 50 73 49 / 90 10 40 20 20 40
Sandpoint 61 47 66 49 71 49 / 90 20 40 20 20 50
Kellogg 60 45 69 48 70 49 / 90 20 20 10 10 50
Moses Lake 75 53 77 55 77 53 / 80 10 10 10 10 10
Wenatchee 74 53 74 55 74 56 / 40 10 20 20 10 20
Omak 74 50 70 51 74 50 / 50 10 30 30 20 20

&&

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

$$

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