Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 170504
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1004 PM PDT Mon Oct 16 2017

.SYNOPSIS...
Strong winds will develop Tuesday afternoon. Gusts up to 50 mph
will be possible. This will be the start to a wetter and windier
weather pattern. Unsettled weather will continue Wednesday and
Thursday however with relatively mild temperatures for the season.
A cold front late in the week will cool the region down again to
more seasonal temperatures with the return of mountain snow.



&&

.DISCUSSION...
Evening update: After analyzing the 00z guidance, the GFS is a
touch weaker with the wind forecast vs its 18z run but only by 1
mb or few knots. This particular model appears to be under-
initializing the wave off the coast which is a bit deeper compared
to the 03z initialization/forecast. The NAM came in similar or
generally half a millibar stronger. Consequently, confidence
remains high for a windy day on Tuesday with sustained winds on
the order of 20-30 mph and gusts 40-50 mph.

The main changes to the forecast were to increase winds for areas
of Central WA including the Hwy 97 corridor from Wenatchee to
around Brewster...especially on the higher benches and Waterville
Plateau.

The potential for bust with this forecast will come in the form of
whether gusts 55-65 mph can mix down. The mixed layer on the bufkit
profiles for Wenatchee suggest mixing may be deep enough briefly
as the cold front presses through but it does not have support
from the hi-res OTX 1km, NAM 3km, and UW Wrf models. So at this
point...confidence remains lower for these speeds which are likely
to be very isolated and brief if they occur.

Patchy blowing dust was also added to the grids. Rainfall on
Friday was light and followed by two days of dry, sunny weather.
With little to no QPF coming with the Tue front and the strongest
winds of the season, thinking some dust will become lofted yet
confidence remains below normal for exact impacts. /sb


&&

.AVIATION...

...STRONG WINDS TUESDAY AFTERNOON AND EARLY EVENING...

00Z TAFS: A robust cold front will bring strong winds to the
aviation area Tuesday. A low-level jet develops ahead of the
front creating low-level wind shear roughly 15-18z then expect
sustained winds 20-30 mph accompanied by gusts 35-50 mph.
Isolated gusts between 22-00z may approach 50-60 mph at times
with the passage of the main cold front. There is some uncertainty
regarding when Lewiston transitions to westerly flow between
19-22Z. Winds may lead to areas of blowing dust and haze with
forecast favoring haze. Otherwise, the front to bring ceilings
arnd 6-8k ft AGL and brief pcpn to the terminals. /sb



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        43  59  41  59  47  59 /   0  60  20  50  50  70
Coeur d`Alene  42  60  39  59  45  60 /   0  70  20  60  50  70
Pullman        43  63  44  64  48  64 /   0  50  50  40  30  40
Lewiston       46  70  48  71  50  71 /   0  10  20  30  20  10
Colville       38  58  35  55  42  57 /  10  50  20  50  60  70
Sandpoint      36  55  34  54  41  56 /  10  80  30  60  70  80
Kellogg        40  58  39  55  43  59 /   0  60  60  60  50  50
Moses Lake     39  65  39  65  45  63 /   0  10  10  30  30  40
Wenatchee      45  62  40  61  47  59 /   0  20  10  30  40  40
Omak           40  63  34  60  42  59 /  10  20  10  40  60  70

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory from 1 PM to 8 PM PDT Tuesday for Central
     Panhandle Mountains-Northern Panhandle.

     Wind Advisory from 1 PM to 8 PM PDT Tuesday for Coeur d`Alene
     Area-Idaho Palouse.

WA...Wind Advisory from 1 PM to 8 PM PDT Tuesday for East Slopes
     Northern Cascades-Northeast Mountains-Okanogan Highlands-
     Okanogan Valley-Wenatchee Area.

     Wind Advisory from 1 PM to 8 PM PDT Tuesday for Lower Garfield
     and Asotin Counties-Moses Lake Area-Spokane Area-Upper
     Columbia Basin-Washington Palouse-Waterville Plateau.


&&

$$


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