Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 242355

Area Forecast Discussion
National Weather Service Spokane WA
455 PM PDT Wed Aug 24 2016

Light northerly winds will continue into Thursday. Area wildfires
are not producing as much smoke as they were a few days ago. The
smaller smoke plumes from fires will be pushed into the Columbia
Basin and the southern Idaho Panhandle. A strong cold front is
expected to bring gusty west winds Saturday and heighten wildfire
concerns once again. Seasonal temperatures return next week with
an increase chance for showers across the northern mountains.



Today through Friday: The region will remain under a Northerly flow
pattern this period. Dry conditions are expected for the region
except in Northern Idaho along the Canadian border. With CAPE
values of a couple hundred, an isolated shower could pop up in
that area and produce lightning through the early hours on
Wednesday and Thursday. Late Friday the influence of an incoming
Low will switch the winds from the north to the a southwest flow.
This will also increase winds across the Columbia Basin. Winds
will be around 10 MPH with gusts near 15. Temperatures for the
period will mainly be in the 80s for highs and 50s for lows. /JDC

...Gusty winds and dry conditions Saturday...

Saturday: Saturday will bring the next bout of winds across the
region and elevated concerns for spreading wildfires. This has
been a consistent message amongst the forecast models and
confidence continues to increase. A shortwave trof will be
swinging through southern BC and ejecting to the east late
Saturday. Look for an increase in southerly winds early Saturday
morning then becoming southwest just prior to midday as a surface
low materializes over southern Alberta. Unlike last Sunday, this
wind event will be driven more on pressure gradients than a strong
punch of cold air advection and high momentum air aloft.
Consequently, winds speeds will be not be as strong but still
problematic in regards to fire weather concerns. To give some
perspective...the air mass cooled near 10C at 850mb during the
Sunday-Monday time-frame of the last wind event. This Saturday,
the air mass is only expected to cool on the order of 5C between
Saturday and Sunday mornings. Peak wind speeds with this event
will range between 15-22 mph with gusts 25-30 mph. Looking at
humidity or dryness levels...models have trend drier with
afternoon levels and critical fire weather conditions will be
possible across the Columbia Basin, Palouse, West Plains/Spokane
Area, Idaho Panhandle, and into southern reaches of the northern
mountains. Remaining areas will also experience breezy to gusty
conditions but either speeds will be lower or humidity levels will
not be as dry unless forecast parameters continue to trend toward
this direction.

Other impacts from the winds will be choppy lakes, especially
locations like Rock Lake and other SW to NE oriented water bodies
in the open Basin and potential for localized blowing dust. We did
not track down any reports of blowing dust with the Sunday event
so will hold off on including it in this forecast package.

Sunday through Wednesday: Medium range models are in good agreement
regarding a large-scale pattern shift toward a more trough"e" Pac
NW but there remains some differences how fast this occurs and
where to place the best chances for precipitation. Saturday`s
shortwave will carve out the initial trof over the Pac NW but the
main upper-level front will stall from southwest to northeast
across northern Washington and just north of the Idaho/Canadian
border. Once this boundary becomes established, several more
shortwaves reloading the trof will ride along the boundary
squeezing out periods of showers and thunderstorms with general
consensus of a decent moisture influx along the boundary. This
will not be a widespread precipitation event but rather come in a
few waves with the best shot mainly north of a line from Stevens
Pass in the Cascades to Ione in Northeastern WA. The best chance
for isolated afternoon t-storms will be north of this boundary
while dry conditions persist across the Columbia Basin and points
south. It will not be until midweek when the trof possibly digs
deeper into the Northwest introducing the consideration of hit or
miss showers and t-storms in the Basin and eastern mountains. Run
to run model consistency has not been stellar so overall
confidence is low. The pattern does support near to slightly above
seasonal temps until midweek and above normal odds for breezy
winds early in the work week. /sb


00Z TAFS: Widely scattered showers over the southern Idaho
Panhandle and far northeast Washington should dissipate by early
evening (02z-04z) with the loss of daytime heating. At this time,
it does not appear that any of the TAF sites will experience
showers this evening. Wildfire activity has decreased over the
last couple of days. With less smoke in the area, it is doubtful
that there will be any visibility restrictions at the TAF sites
during the next 24 to 36 hours. /GKoch


Spokane        56  81  58  83  59  86 /   0   0   0   0   0   0
Coeur d`Alene  53  80  54  81  55  85 /   0   0   0   0   0   0
Pullman        50  81  50  82  53  87 /   0   0   0   0   0   0
Lewiston       59  87  59  88  61  94 /   0   0   0   0   0   0
Colville       51  84  52  85  53  87 /  10   0   0  10  10  10
Sandpoint      49  78  50  78  50  83 /  10   0  10  10   0  10
Kellogg        50  76  50  79  52  82 /   0   0  10  10   0   0
Moses Lake     56  88  57  89  58  92 /   0   0   0   0   0   0
Wenatchee      63  88  64  89  66  87 /   0   0   0   0   0   0
Omak           57  88  59  90  59  88 /   0   0   0   0   0  10



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