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Area forecast discussion 
National Weather Service Spokane Washington
507 PM PDT Mon Jul 25 2016

a warm, summery and mostly dry Summer pattern will continue
through the work week. However, there will be a chance for showers
and thunderstorms near the Canadian border through Wednesday.
High temperatures in the 90s will be common for nearly all towns
this week with a cool down expected next Sunday. Gusty winds will
accompany this cool down...especially across the Columbia Basin
and Cascade gaps.


minor update to expand the area of early evening thunderstorms to
include the Methow and northern portions of the Okanogan Valley,
as well as a slight expansion around the Blewett Pass area. Radar
shows storms developing in these areas. See previous discussion
below for more forecast details. Jw


00z tafs: isolated thunderstorms along the east slopes of the
Cascades are expected to dissipate this evening with the loss of
daytime heating but elevated showers may linger tonight over the
northern mountains near the Canadian border. Storms are not
expected to impact any of the taf sites but will be watching keat
given close proximity to the Cascades. Scattered showers and
thunderstorms will redevelop Tuesday afternoon over the northern
mountains...mainly near the Canadian border. Jw


Previous discussion... /issued 436 PM PDT Mon Jul 25 2016/

Tonight through Wednesday evening: hot and dry weather can be
expected for the first half of the work week - Summer weather will
finally arrive. An upper level ridge of high pressure will
building over The Four Corners region of the SW. Although the
storm track over the southern Canadian providences will keep the
ridge flattened to a westerly flow aloft. This will allow weak
impulses in the flow to enhance surface based convection, for each
of the next several afternoons. The prime area seems to be near
the Canadian border, where surface based CAPES will rise to
500-1000 j/kg each afternoon, although the cap will need to be
broken to allow the convection to develop. This afternoon is a
prime example of a strong cap or cin, which spans across much of
the northern Cascades. The hrrr and other mesoscale models show
the best development over this area. Cumulus is developing on the
mountains but seems a bit slow to get-going. A weak impulse aloft
will help fire off this convection, but looks to be late this
afternoon into early evening, mainly across the paysten wilderness
area and north of any recent fire locations. Surface analysis
shows the low level surface pressure trough extending across the
western Columbia Basin and pointing up the Okanogan Valley.
Localized westerly gap winds will develop near Wenatchee this
evening with gusts to 20 mph. The threats from the convection are
expected to be on the low end with brief downpours and gusty
winds. Meanwhile the weak impulse aloft will slowly slide along
the Canadian border this evening and keep the potential for
showers going through the night. By Tuesday, expect more surface
based convection to fire with better instability and lift from
above. The area of concern will be east of Republic across the
mountains of northeast Washington and north Idaho for Tuesday
afternoon, while the surface pressure trough slides east and sets
up over extreme eastern Washington. The higher cape values for
Tuesday and less of a cap will lean to a better chance of
thunderstorms with the threats being heavy downpours, small hail
and gusty winds. This convection will decrease Tuesday evening.
More westerly gap winds will develop in the Cascade valleys and
into the western Columbia Basin by Tuesday evening. On Wednesday,
still another weak impulse will arrive to the region by afternoon
and help enhance another round of isolated thunderstorms along the
Canadian border into the evening hours. Temperatures will be the
main story this week with widespread 90s across the region,
pushing values above normal for late July. /Rfox.

Wednesday night through friday: the weak trough will pass to our
east Wednesday night and we will be in a west to northwest flow
through the remainder of the work week. Cascade Gap winds as well
as winds down the Okanogan Valley and into the Waterville Plateau
can be expected through the period. 850 mb temperatures continue
to rise with Friday looking to be the warmest day in the 7 day
forecast. Valley temps will Max out in the 90s with 99 to 102 for
the Moses Lake/dessert aire areas as well as the lc/Snake River

Saturday through monday: there are still model discrepancies on
the timing/strength of the trough for the weekend. Currently it
looks as though the cold front will pass through the area Saturday
night into Sunday. Winds will increas through the day on Saturday
and then continue into the night and through Sunday as well. The
Cascade gaps, Columbia Basin, Okanogan Valley and Spokane area, Washington
Palouse could see sustained winds 10-20 mph with gusts as high as
30 mph. Relative humidities will remain low as drier air moves in
behind the trough and therefore there could be some fire weather
concerns with low relative humidity values and strong winds. Temperatures will
cool down Sunday into the 80s, or about 3 to 5 degrees below
average for this time of the year. Monday will likely remain on
the cooler side of average for US with dry conditions. /Nisbet


Preliminary point temps/pops...
Spokane 64 91 63 90 63 91 / 0 0 10 0 0 0
Coeur D'Alene 59 89 59 89 59 91 / 0 0 10 0 0 0
Pullman 54 90 53 89 53 91 / 0 0 0 0 0 0
Lewiston 66 97 65 96 67 97 / 0 0 0 0 0 0
Colville 56 92 56 92 57 93 / 10 20 20 10 10 0
Sandpoint 53 86 54 85 53 87 / 0 10 20 10 10 0
Kellogg 56 87 54 87 55 87 / 0 10 10 0 0 0
Moses Lake 63 95 61 95 63 97 / 0 0 0 0 0 0
Wenatchee 68 93 66 93 68 97 / 10 0 0 0 0 0
Omak 66 94 66 94 66 95 / 10 10 10 10 10 0


Otx watches/warnings/advisories...


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