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Area forecast discussion 
National Weather Service Spokane Washington
435 am PDT Sat Apr 25 2015

Synopsis...
showery, cool conditions will linger through today, as an upper
low edges across the inland northwest. This is followed by high
pressure, with warmer temperatures and dry conditions, for the
beginning of next week. The threat for showers will increase
beginning Wednesday, lasting through the end of the week returns
late next week.

&&

Discussion...

Today through Sunday...upper level area of low pressure moves
through the region today allowing cool and showery conditions to
linger on through the day and evening. There remains enough
instability, moisture, and lift to keep a minor mention of
afternoon and evening thunderstorms in addition to showers.
Expectation is that with the shallow cape available from the
positioning of the cold low overhead any thunderstorms should be
weak pulse type with a slow storm motion to the north/northeast at
15 mph or less. A quick look at available short term mesoscale
models shows that the potential for thunderstorms remains low but
still worthy of a mention. The large trof that the upper level low
is nested in along with the small low itself all move east and
away from the area tonight which allows a ridge of high pressure
to nose in from the west/southwest bringing with it a drier and
warmer Sunday in comparison to Saturday. /Pelatti

Sunday night through Friday...high pressure over the region will
linger over the region through early Tuesday, while an upper
level trough dumbbells around a deep upper level low in the Gulf
of Alaska. This puts the inland northwest in a warm southwesterly
flow. The ridge axis is such that any sub-tropical moisture that
moves up from the south will be shunted to the north of the
forecast area west of the Cascades. However there will still be
some low end chances for light precipitation near the Cascade
crest Sunday night and Monday. Otherwise warm and dry.
Temperatures will climb into the 60 and 70s on Monday and 70s to
lower 80s on Tuesday. There are still some timing differences on
just how fast the upper trough moves into the region on Tuesday
and I wouldn't be surprised to see the chances for light
precipitation to get pushed a little further eastward by Tuesday
afternoon and evening.

From Tuesday night forward model differences become quite large
and confidence in the forecast begins to falter. Looking at
ensembles it makes sense to follow a solution that has multiple
waves with less amplitude that move through the Pacific northwest
Tuesday night through Friday...instead of what some models
indicate of a very deep and slow moving low moving through the
region Thursday and Friday. Difficult at this time to pin down
exact timing of each wave but expect increasing chances for rain
and high elevation snow showers each afternoon through Friday.
These showers will be spotty with the best chances hugging the
terrain. Also expect some of these showers to be strong enough to
contain brief heavy rain and possibly some small hail.
Temperatures will cool back down into the 60s with a few scattered
70s for our warmer locations. Southwest winds will be gusty at
times as these individual waves move through the region. Tobin

&&

Aviation...
12z tafs: an upper low moving over eastern Washington today will keep
showers in the forecast for much of the day. Isolated thunderstorms
are possible during the afternoon/evening hours. Expectation
remains that VFR conditions should prevail with brief MVFR
conditiosn near the more intense showers. /Pelatti

&&

Preliminary point temps/pops...
Spokane 53 36 60 39 67 45 / 40 30 10 0 0 0
Coeur D'Alene 52 34 59 36 67 40 / 60 30 10 10 0 0
Pullman 51 34 57 37 67 43 / 60 30 10 0 0 0
Lewiston 56 39 64 41 71 44 / 60 30 10 0 0 0
Colville 55 33 63 39 71 41 / 50 40 10 10 10 0
Sandpoint 52 32 58 34 66 37 / 70 40 10 10 10 0
Kellogg 49 35 56 35 66 38 / 70 50 20 10 10 0
Moses Lake 59 35 65 41 73 45 / 20 10 0 10 0 0
Wenatchee 58 40 65 45 75 48 / 20 10 10 10 10 0
Omak 56 32 65 40 72 42 / 30 30 10 10 10 0

&&

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

$$

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