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Area forecast discussion 
National Weather Service Spokane Washington
228 PM PDT Wed Jul 30 2014

Synopsis...
it will be partly cloudy and hot with isolated thunderstorms
through the end of the week and into the weekend. No significant
relief from the hot weather is forecast through the seven-day
forecast period. However, only a few spots may reach the 100-degree
mark. Isolated thunderstorms the next several days are not
expected to be strong or severe but could bring localized heavy
downpours.



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Discussion...tonight through Saturday night. The forecast area will be
located on the backside of an upper level ridge through Saturday
and will be influenced by a weak SW flow aloft. A few disturbances
in the flow may increase moisture and lift to a presently unstable
air mass...resulting in isolated thunderstorms. Due to a weak mid-level
shear and marginal instability...most storms will be garden
variety and diurnally driven. The main concern will be the slow
storm movement bringing heavy downpours. Today there have been a
few showers sitting near the northeast mountains with storm
movement less than 10 mph. Forecasters will need to keep a close
eye on storms that may develop near burn scars in steep terrain.
Thunderstorms will mainly be confined to central and northern
Idaho, but a slight chance of showers and thunderstorms was added
to all zones on Saturday. All models hint at a shortwave off the
coast edging inland that will steepen lapse rates across eastern
Washington on Saturday. Increasing clouds will keep temperatures
from climbing significantly during the afternoon thurs-Sat, but the
heat advisory for the Lewiston area will be extended through
Thursday evening as this area will have overnight lows around 70
and afternoon temperatures in the 100-105 degree range.

Sunday through Wednesday...no major changes are expected in the
weather pattern during the remainder of the period. The Pacific northwest
will be influenced by a broad upper level ridge and an inverted
surface thermal trough. Afternoon temperatures will remain in the
mid 80s to mid 90s. A slight chance of thunderstorms is forecast
for the afternoon and evening on Sunday and Monday...as weak
impulses pass through the region. Of course, any threat of
thunderstorms brings fire weather concerns but there does not
appear to be any organized waves to increase shear and enhance
lift for significant lightning strikes. Moisture is limited as
well. Monsoonal moisture advection will primarily be directed
east of The Rockies. I've kept thunderstorms out of the forecast
for most of the area Tuesday and Wednesday as the flow is more
westerly. Models are in general agreement so confidence in the
continued hot temperatures is high...but there is uncertainty in
the thunderstorm forecast...particularly where thunderstorms will
be located Sunday and Monday. Wister







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Aviation...
18z tafs: scattered mid/high level clouds will continue to
overspread most sites through the period. Isolated showers and
thunderstorms may develop across the far northern Cascades and NE
blue mts into the Idaho Panhandle this afternoon but confidence is
very low that convection will affect any taf site. Mcw





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Preliminary point temps/pops...
Spokane 67 96 66 93 65 92 / 10 0 0 10 10 20
Coeur D'Alene 62 94 59 92 62 90 / 10 10 10 10 20 20
Pullman 56 95 61 91 57 91 / 10 10 10 20 20 20
Lewiston 70 102 69 97 68 97 / 10 10 10 30 30 20
Colville 57 101 57 95 59 95 / 10 0 10 10 10 20
Sandpoint 54 92 52 89 56 87 / 10 0 10 10 20 30
Kellogg 61 93 57 90 62 87 / 20 10 10 20 20 20
Moses Lake 64 100 65 97 64 97 / 0 0 10 10 10 20
Wenatchee 71 100 67 96 71 97 / 0 0 10 10 10 20
Omak 65 100 63 98 68 97 / 0 0 0 10 10 20

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Otx watches/warnings/advisories...
Idaho...heat advisory until 8 PM PDT Thursday for Lewiston area.

Washington...heat advisory until 8 PM PDT this evening for Moses Lake area-
Okanogan Valley-upper Columbia Basin-Waterville Plateau-
Wenatchee area.

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