Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 210549
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
949 PM PST Mon Nov 20 2017

.SYNOPSIS...
Expect wet and mild weather as a series of storm systems brings
several rounds of precipitation this week. Snow levels will be
quite high Tuesday, Wednesday, and Thursday allowing motorists to
travel over mountain passes on wet pavement. Snow levels will
begin to lower just as travelers are heading home Friday into the
weekend.

&&

.DISCUSSION...
Evening update: Minor updates made to the forecast for tonight and
Tuesday morning. Radar shows showers have dwindled this evening
with an exiting mid level wave into Montana with just a few
showers lingering over the Central Panhandle Mountains. In the
wake of this wave an abundance of lower level moisture exists over
NE Washington into the North Idaho Panhandle with an abundance of
stratus. This should keep low temperatures a few degrees warmer
than previously thought in places like Colville and Sandpoint.
Patchy fog is still expected to gradually develop for the valleys
along the East Slopes of the Cascades into the Columbia Basin with
relative humidities near 100 percent and areas of clearing.
Breaks in the stratus are also expected for the Spokane area
tonight which may allow patchy fog to develop.

Attention then turns to the next system that will spread
precipitation from west to east into the area on Tuesday. Timing
will reach the East Slopes early Tuesday morning. The GFS and
ECMWF suggest snow for the Methow Valley in the morning changing
to a mix of snow...sleet...and possible brief freezing rain by
early afternoon and then all rain. Overall confidence is low of
significant impacts from sleet/freezing rain as temperatures will
be near the freezing mark. The NAM is faster to bring in the
warmer air aloft with a better chance of freezing rain in and
around the Methow Valley in the morning. Previous cases have
proven the NAM can be too aggressive with the warm air aloft so
will go with the GFS/ECMWF solutions which again supports snow in
the morning for the Methow Valley. Further south in Chelan county
model soundings suggest Plain and Leavenworth likely just above
freezing with rain...with the mountains starting as snow but
quickly changing to rain with pockets of freezing rain possible.
Again with surface temperatures in the mountains near freezing
confidence is low of significant impacts. Thus...no highlights are
expected at this time. JW

&&

.AVIATION...
06Z TAFs: Areas of clearing in the Columbia Basin and Spokane area
will promote stratus and patchy fog tonight. Exact restrictions
at any given airport carry low confidence as increasing mid and
high clouds will limit widespread development. A moist laden warm
front lifts into the area after 17z with top- down saturation,
widespread rain at the terminals, and mountain obscrns. There may
be a wintry mix for the Cascade East Slopes Tuesday morning into
the early afternoon including the Methow Valley Airport.  JW

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        34  46  41  53  45  57 /   0 100 100  70  50  60
Coeur d`Alene  34  45  40  53  44  56 /  10 100 100  70  50  70
Pullman        37  49  44  56  47  59 /   0 100 100  70  30  70
Lewiston       39  53  46  59  48  62 /   0  80  80  70  20  50
Colville       35  41  36  47  40  53 /  10 100 100  60  40  70
Sandpoint      33  41  37  47  41  52 /  20 100 100  70  70  90
Kellogg        32  42  39  49  43  51 /  10 100 100  80  40  90
Moses Lake     33  44  38  52  42  60 /   0 100  80  60  40  30
Wenatchee      33  40  36  48  40  55 /  10 100  40  60  30  50
Omak           33  42  36  47  42  54 /   0 100  70  50  40  70

&&

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

&&

$$


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