Area Forecast Discussion
Issued by NWS Spokane, WA

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235
FXUS66 KOTX 161734
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1034 AM PDT Wed Aug 16 2017

.SYNOPSIS...
Dry and seasonably warm temperatures can be expected this week.
Wildfire smoke will linger over north central Washington to north
Idaho through Thursday. Locally breezy conditions will be possible
late today and again on late Friday with the passage of a pair of
weak frontal systems.

&&

.DISCUSSION...
Today through Thursday night...A dry northwest flow will persist
with mostly clear skies and near normal temperatures. A weak wave
will track into British Columbia today with the main impact from
this being an increase in westerly winds through the cascade gaps
(Ellensburg, Wenatchee) and the ridges along the East Slopes of
the Cascades. Breezy winds combined with relative humidity near 20
percent this afternoon and early evening will elevate concerns
for fire spread with any new fire starts in the Cascade
valleys...and may also resulted in increase fire activity with
existing wildfires in the Cascades. At this time red flag
conditions are marginal and only expected to be achieved in
isolated areas and only for a short duration. Will continue to
monitor but no fire highlights planned at this time. This wave
drops into NE Montana on Thursday with a flat ridge moving over
the Inland NW. JW

Friday: Warm and dry winds on Friday will raise concerns for
wildfires. The medium range models continue to forecast a broad
500mb trough moving across British Columbia on Friday. As on-shore
flow increases throughout the day, a west to east pressure
gradient will cause west or southwest winds in the 10 to 15 mph
range over much of the Inland Northwest. At this time it looks
like the breeziest conditions will occur from late afternoon
through mid evening with the strongest gusts through the Cascade
Gaps. This type of pattern frequently produces gusts of 25 to 30
mph in places like Wenatchee, Waterville, and Vantage. With
high temperatures around 90 degrees along the East Slopes and
humidity levels in the 15 to 20 percent range, conditions will be
favorable for rapid spread of fires.

Saturday and Sunday: The weather pattern for the weekend looks
dry with seasonably warm temperatures. The pressure gradient will
relax on Saturday behind Friday`s cold front. At this time, it
looks like winds will become north or northwest over north central
and northeast Washington late Friday night into Saturday. Canadian
wildfire smoke will likely return for our counties bordering
British Columbia by Saturday morning. The concentration of smoke
will be determined by the localized activity of the fires. Some of
the BC fires could receive a bit of rain over the weekend and
cooler temps Friday night and Saturday may slow them a bit. Any
smoke that enters Washington on Sat will have a good shot of
sticking around for Sunday with relatively light northerly
pressure gradient into the afternoon.

Monday: Eclipse day. The medium range models continue to look good
over Idaho, Oregon, and eastern Washington for viewing the
eclipse. Monsoonal moisture is expected to remain well south of
our region as a high pressure ridge builds over the northern
Rockies. The translation is...our region should be free of clouds.
Wildfire smoke could be the wildcard particularly over north
central and northeast Washington.

Tuesday: The medium range models begin to diverge Tuesday and
Wednesday with monsoonal moisture and the strength of the ridge
over the northern Rockies. Slight chances for showers and
thunderstorms have been retained for the Cascades, portions of
southeast Washington and the southern Panhandle late in the day
Tuesday. Convective chances may need to be increased Tue night
into Wed depending on the interaction of moisture from the south
and the approaching Pacific trough. /GKoch

&&

.AVIATION...
18Z TAFS: High pressure will prevail over the region with VFR
conditons at all TAF sites through 18Z Thursday. Pockets of smoke
in northern valleys will locally reduce visibilities during the
period. /MJF

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        83  56  83  59  86  58 /   0   0   0   0   0   0
Coeur d`Alene  83  54  83  54  85  54 /   0   0   0   0   0   0
Pullman        82  53  81  53  85  55 /   0   0   0   0   0   0
Lewiston       90  61  89  60  93  62 /   0   0   0   0   0   0
Colville       86  52  87  51  89  52 /   0   0   0   0   0   0
Sandpoint      82  48  82  47  84  49 /   0   0   0   0   0   0
Kellogg        80  51  80  51  83  52 /   0   0   0   0   0   0
Moses Lake     90  56  88  55  91  58 /   0   0   0   0   0   0
Wenatchee      88  62  88  62  90  63 /   0   0   0   0   0  10
Omak           91  59  91  59  90  59 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&

$$



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