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Area forecast discussion 
National Weather Service Spokane Washington
423 PM PDT Monday Jun 1 2015

Synopsis...

It will be quite stormy this evening into the overnight hours as a
vigorous Spring storm system moves into the inland northwest. Some
storms will be capable of hail and torrential rains this evening.
Showers and isolated thunderstorms will linger into Tuesday.
Temperatures Tuesday and Wednesday will be relatively cool. Much
warmer weather is expected Friday through the weekend with high
temperatures in the mid 80s to low 90s.



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Discussion...
tonight: active weather will continue tonight as a negatively
tilted trough lifts into Washington, guided by a strong shortwave
and surface front. Moderate instability and marginal shear exists
across southeast Washington into southern Idaho Panhandle by mid afternoon and into
the evening with the main threat being large hail and very heavy
rain. Pwats of near three quarters of an inch will be over the
region through the night. The weather threat will change to heavy
rain as the convection develops into a slow moving line that
stalls out over the northern zones. Could see rainfall amounts of
up to half inch in less than 6 hours. A Flash Flood Watch remains
in effect through the night across much of eastern Washington and
north Idaho. /Rfox

Tuesday through Thursday night...the upper level low and associated
cold pool aloft will settle over the inland northwest through at
least Wednesday. This will keep the threat of showers and afternoon
thunderstorms elevated for the higher terrain surrounding the
Columbia Basin with a lower threat for the Basin. A surface low will
form over eastern Washington that will direct moisture into the
northern and eastern zones while the cold pool aloft settles over
the forecast area and a multitude of shortwave impulses pivot around
the upper low. This will provide the moisture, lift and instability
for scattered to numerous showers through Wednesday along with some
thunderstorm activity during peak daytime heating. By Wednesday
night the upper low will start to weaken and the areal coverage of
showers will diminish from south to north and mainly be confined to
the higher terrain along our northern border. By Thursday night the
trough continues to weaken and will finally move off to the east.
This will bring an end to the showers and usher in a dry period just
in time for the weekend. Daytime temperatures will start out rather
cool for Tuesday then trend warmer as showers diminish and the low
moves out of the area. /Kelch

Friday through monday: there is good agreement between the
morning runs of the medium range models. Forecast confidence is
pretty high that we will see a return of Summer-like temperatures
this weekend. The GFS, ECMWF, Canadian and the ensembles all point
to a return to split flow Friday with the southern branch carving
another big trough into California. Good news for the Golden
state. There should be more showers this weekend in California,
Nevada and Arizona...but not enough to bring any long term drought
relief. For Washington and Idaho, a blocking ridge will set up
shop pushing our 850mb temperatures above 20c this weekend. High
temperatures in the mid 80s to low 90s will be a good bet Saturday
through at least Monday. /Gkoch

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Aviation...
00z tafs: showers and thunderstorms will increase in areal
coverage this afternoon and spread north across eastern Washington and north
Idaho. The strongest thunderstorms in the region are expected to
be across southeast Washington and up into the central Idaho Panhandle, with
large hail and heavy downpours the main threats. Taf sites that
may be impacted by these stronger thunderstorms include kgeg,
ksff, kcoe, kpuw and klws with a smaller threat possible at keat
and kwmh as well. Torrential rainfall with thunderstorms may also
result in MVFR vis and cigs at times. /Ek



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Preliminary point temps/pops...
Spokane 54 67 50 69 50 73 / 90 60 30 20 20 20
Coeur D'Alene 53 65 49 68 48 73 / 90 70 60 30 30 20
Pullman 50 65 45 67 44 71 / 70 50 40 20 20 20
Lewiston 56 72 52 74 52 78 / 70 60 50 30 20 20
Colville 56 67 50 70 48 76 / 90 90 80 40 40 30
Sandpoint 54 64 49 67 47 73 / 90 90 80 60 40 30
Kellogg 51 64 45 67 44 72 / 100 80 70 40 30 20
Moses Lake 56 74 51 75 51 79 / 50 30 20 20 10 10
Wenatchee 58 71 54 73 55 79 / 60 40 20 20 10 10
Omak 56 69 50 71 49 79 / 80 80 50 40 30 20

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Otx watches/warnings/advisories...
Idaho...Flash Flood Watch through late tonight for central Panhandle
mountains-Coeur D'Alene area-Idaho Palouse-northern
Panhandle.

Washington...Flash Flood Watch through late tonight for east slopes northern
Cascades-northeast mountains-Okanogan Highlands-Okanogan
Valley-Spokane area-upper Columbia Basin-Waterville Plateau-
Wenatchee area.

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