Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 152150

Area Forecast Discussion
National Weather Service Spokane WA
250 PM PDT Wed Aug 15 2018

Generally dry conditions will continue through this week. Haze and
smoke will continue over most of the area from time to time.
Temperatures will warm back above average through the week, but
not as hot as last week. Thursday and Friday, a small chance of
thunderstorms will develop over southeast Washington and the Idaho


Tonight through Friday...Satellite reveals a fetch of mid and
upper level monsoonal moisture welling up into the forecast area
as a weak upper level trough forms off the coast and directs the
increasingly southerly flow into the region. Models are in
general agreement in shunting this moisture off to the eastern
third of the forecast area tonight...and while the moisture is
present along with some weak mid level instability...dynamic
forcing is lacking so there is guarded optimism that nothing will
come of ...or out of...this mid level ACCAS deck as it transits
the region overnight tonight. Meanwhile in the lower levels very
little will change with the smoke and haze issue with weak low
level winds feeding into the surface thermal trough axis in the
Columbia Basin.

Thursday will be another warm day with temperatures peaking for
the week solidly in the 90s...with little relief form the
ubiquitous smoke and haze...and in fact after consultation with
regional air quality authorities...the general Air Quality Alert
has been extended through Friday when the situation will be re-

Thursday afternoon and overnight into Friday things will get a
bit more active around the area. The weak upper trough off the
coast will begin to eject inland. The thermal trough will shift to
the east overnight. First this will translate into a weak Marine
Push through the Cascade gaps...and for a few hours during the
evening recovery period it is possible a short period of Red Flag
conditions may exist near gaps. The other issue will be another
surge of monsoonal moisture ahead of the trough...and this time
there may be sufficient forcing to create a nocturnal dry
thunderstorm threat overnight over far eastern Washington and the
Idaho Panhandle. This is not a sure bet...but the confidence level
of at least some lightning is high enough to warrant a Fire
Weather Watch for the overnight period and into the morning hours.

Friday will bring some moderation in temperatures behind the
weak cold front...perhaps 3 to 5 degrees in general...otherwise
dry and marginally breezy over the exposed terrain of the basin.
This may provide some temporary improvement of the smoke situation
at least south of Highway 2...but it may be fleeting before
deteriorating again as things clam down. The other main issue for
Friday will be an all day increasingly wet thunderstorm threat
over the southeastern zones as the trough transits the
region...with these zones closest to the trough base forcing as it
passes. The northeastern zones may see a lingering mountains
thunderstorm threat in the afternoon. /Fugazzi

Friday night through Wednesday: Warm temperature and continued
smoke and haze marks this period, along with periodic breezy
conditions and limited precipitation chances. First Friday night
an upper trough exits to the east. Shower/t-storm chances will
linger from the Blue Mountains and Camas Prairie into the central
Panhandle in the evening, before ending. Otherwise expect filtered
sunshine/moonlight through the smoke and haze. Another shortwave
drops in from the northwest late Sunday into Monday. This will
carry limited shower and t-storm chances to north Idaho late
Sunday. Some risk may also expand to far southeast WA and the
central/southern ID Panhandle Monday. With this feature an
increased northerly flow develops, with some breezy conditions.
The area that will monitored most will be down the Okanogan
Valley, where some critical fire conditions will be possible. At
this time, however, the stronger winds do not appear to sync up
with the lowest afternoon humidity. Models start to diverge for
Tuesday and Wednesday. Models suggest a trough somewhere in the
region, but vary over whether it will be. A limited shower/t-storm
threat is possible over the far southeast CWA but confidence is
low. /Cote`


18Z TAFS: Haze and smoke will remain the biggest impact to TAF
sites, with MVFR/isolated VFR visibility. Some variation in
conditions is expected the remainder moderate uncertainty in
details. Some middle to high clouds are expected late today into
Thursday, with cigs around 10-15kft. /Cote`


Spokane        66  95  67  89  61  87 /   0   0  10  20   0   0
Coeur d`Alene  60  95  62  88  58  87 /   0   0  20  20   0   0
Pullman        63  93  63  86  55  85 /  10  20  20  30  10   0
Lewiston       69 101  69  93  63  92 /  10  10  20  40  10   0
Colville       55  97  56  93  54  91 /   0   0   0  10  10   0
Sandpoint      51  90  53  87  51  85 /   0   0  10  20  10   0
Kellogg        57  92  58  86  55  84 /   0  10  10  20  10   0
Moses Lake     61  98  62  93  58  91 /   0   0   0  10   0   0
Wenatchee      67  95  66  91  64  90 /   0   0   0   0   0   0
Omak           63  98  63  95  62  93 /   0   0   0  10   0   0


ID...Fire Weather Watch from Thursday evening through Friday morning
     for Northern and Central Idaho Panhandle (Zone 101).

WA...Fire Weather Watch from Thursday evening through Friday morning
     for East Washington Palouse and Spokane Area (Zone 674).


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