Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Spokane Washington
230 PM PDT Sat Apr 19 2014

Synopsis...
a storm system will bring windy conditions this afternoon and
tonight with some showers mainly for the mountain zones. Easter
Sunday should be mild and mainly dry. After a warm and dry Monday,
a cool and unsettled weather pattern will return Tuesday and
linger through much of the week.



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Discussion...



Sunday night through tuesday: the upper level ridge will begin to
shift east Sunday night as an elongated upper level trough nears
the West Coast. The trough will begin to move onshore Monday night
and swing into the inland northwest Tuesday for an increased
chance of precipitation. While most of the energy associated with
the trough will dig south into California, there is still decent
dynamics across our area on Tuesday as the trough becomes
negatively tilted.

Have kept the forecast dry Sunday night. Monday keep the chance of
precip mostly along the Cascade mountains. Monday night
precipitation starts to move east across the state, and by Tuesday
most locations will be receiving rain. Rain amounts will generally
range from 0.10 or less across The East Slope valleys and Columbia
Basin to 0.30 along the Cascade crest and mountains of northern Washington
and north Idaho. Models are showing decent instability Tuesday
afternoon across north-central Washington and have therefore added a
slight chance of thunderstorms. Clouds will be on the increase
Monday into Tuesday. Monday temps will be 5-10 degrees above
average for this time of the year and then Tuesday with the trough
passage temps will drop down to about 5 degrees below average for
this time of the year. /Nisbet

Tuesday night through Saturday...an upper level trough will keep
cool and unsettled conditions across the region Tuesday night and
Wednesday. Post frontal gusty winds will keep temperatures from
falling below freezing for most valley locations. Daytime
temperatures will be on the cool side of normal while the cold
upper trough remains overhead, especially for the eastern zones
where instability showers will be more numerous in westerly
upslope flow. Brief ridging Wednesday night will be shunted east
by the next Pacific trough. This system will be slow to transition
east so the region will be in very moist and energetic flow aloft
for the rest of the work week and into next weekend. This will
bring a good chance of precipitation each day along with
temperatures near seasonal normals. /Kelch

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Aviation...
12z tafs: VFR conditions expected at all forecast sites through
18z sun. The main weather maker this period is a cold front which
is expected to move into the eat and mwh area between 20z-23z and
into the remaining sites between 22z-02z or so. As long as the
front is in the vicinity there will be a small chance of
showers...however there is also a significant amount of downslope
westerly flow to overcome. There will be a much better chance of a
substantial wind increase through the afternoon as the north to
east winds this morning transition to westerly flow later this
afternoon and into the evening. Timing the transition to the hour
will be tough...however feel confident it will occur at all sites
between 21z-01z. Wind gusts from 25-35 mph are expected. Winds
will slowly decrease overnight and into Sunday with clearing skies
expected. Fx



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Preliminary point temps/pops...
Spokane 35 58 39 67 44 54 / 20 0 0 0 50 70
Coeur D'Alene 35 57 37 68 46 54 / 30 0 0 0 40 70
Pullman 35 57 39 68 44 52 / 20 0 0 0 50 70
Lewiston 41 63 42 75 49 57 / 20 0 0 0 40 60
Colville 34 64 35 71 41 59 / 30 10 0 10 50 60
Sandpoint 35 57 35 67 43 53 / 50 10 0 0 20 70
Kellogg 36 55 35 68 41 51 / 40 20 0 0 20 80
Moses Lake 37 66 42 73 46 62 / 0 0 0 10 50 40
Wenatchee 41 67 46 70 48 60 / 0 0 0 10 50 40
Omak 33 66 39 70 44 60 / 10 0 0 20 50 40

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