Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 230607
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1007 PM PST Tue Jan 22 2019

.SYNOPSIS...
A strong weather system will bring moderate to heavy snow
accumulations tonight to much of the area with only the deeper
portions of the western Columbia Basin escaping with minor
overnight accumulations. Breezy and unsettled conditions will
continue through Wednesday. Expect generally dry weather with
occasional fog and seasonable temperatures from Thursday through
the weekend.



&&

.DISCUSSION...

Evening update: Light to moderate snow is falling across most
locations across the Inland NW this evening. Snow has been slower
to fill in across far N Idaho than expected but moved into
Sandpoint in the last hour and will be in the Bonners Ferry area
shortly. The heaviest activity is accompanying the 700mb warm
front which extends from roughly Tonasket to Wilbur to Moses Lake.
The front and higher precipitation intensities will begin to
track eastward in the next 3-6 hours and we should see snow really
pick up across the eastern third of WA and N ID. As of
8PM...precipitation has been predominantly snow for all locations
outside the lower Columbia Basin. It has been mainly rain for
Moses Lake, Ephrata and points southward. Reports suggest
rain/snow mix along the Snake River and northern Garfield County
but Ritzville has been moderate to heavy wet snow at 33F with 2.5
inches already on the ground.

Forecast has been updated to include the 00z guidance and this
has pushed snow amounts up some for locations across the Upper
Columbia Basin like Davenport, Airway Heights, and down into the
higher terrain of the Palouse from Rosalia to Pullman and into the
Central Idaho Panhandle around Cd`A...St Maries...and Moscow.
There is still moderate uncertainty with these amounts with some
wavering when the warmer air may switch pcpn to rain. It does
appear the column will warm and make the switch but it could also
come near the end of the heaviest precipitation after 3 to 6
inches.

Precipitation intensities will rapidly wane across the Columbia
from west to east after 1AM noted by rapid drying within the
dendritic layer but a west to east band of snow will continue to
impact the northern mountains on the northern periphery of the
surface low and under the cooler temperatures of the 700mb low
center and this period from roughly 3AM to 6AM could prove to be
the time when we see the heaviest snowfall rates from Sandpoint to
Republic and possibly into Oroville.  /sb

We are also continuing to closely monitor for isolated strong wind
gusts in the Central Cascades of southern Chelan County,
Waterville Plateau, and Vantage Area. Models did not change the
tone much so still thinking these winds of 50-75 mph will largely
remain on the exposed ridgetops but something we will be watching
from 1AM through 6AM.  /sb

&&

.AVIATION...
06z: Moderate snows will continue to impact KGEG/KSFF/KCOE/KPUW
through 10z...then we could see a transition to rain or rain/snow
mix. This is slower by about 2 hours than previous forecast and there
is a potential this does not switch at KGEG/KCOE. Precipitation
has been all rain at KMWH and mix of rain/snow at KEAT with brief
ice pellets or freezing rain. Precipitation will end by 10z near
KEAT/KMWH but then the focus will be on gusty winds near KEAT
with wind sheer after 10z while gusty winds look to reach the
surface from KPUW to KLWS. As precipitation wanes...areas of low
stratus will be likely with some clearing expected Wed afternoon.
After 00z...look for low clouds and fog to return to most sites
renewing the threat for restrictions. /sb


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  24  36  30  36 / 100  70   0  10   0   0
Coeur d`Alene  32  37  25  35  31  36 / 100  90   0  10  10   0
Pullman        30  39  29  39  31  38 / 100  60  10  10  10   0
Lewiston       36  48  36  45  35  45 / 100  60  10  10   0   0
Colville       31  39  22  39  25  40 / 100  80   0  10   0   0
Sandpoint      32  36  27  35  30  36 / 100  90   0  10  20  10
Kellogg        30  37  29  37  33  37 / 100 100  10  20  20  10
Moses Lake     34  44  29  42  29  42 / 100  10   0   0   0   0
Wenatchee      32  40  32  40  31  42 /  70  30   0   0   0   0
Omak           32  38  26  37  28  39 /  80  50   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Warning until 4 PM PST Wednesday for Central
     Panhandle Mountains.

     Winter Weather Advisory until 4 AM PST Wednesday for Lewis and
     Southern Nez Perce Counties.

     Winter Storm Warning until 4 AM PST Wednesday for Idaho Palouse.

     Winter Storm Warning until 10 AM PST Wednesday for Coeur d`Alene
     Area-Northern Panhandle.

WA...Winter Weather Advisory until midnight PST tonight for East
     Slopes Northern Cascades.

     Winter Weather Advisory until 4 AM PST Wednesday for Northeast
     Blue Mountains.

     Winter Storm Warning until 10 AM PST Wednesday for Northeast
     Mountains.

     Winter Weather Advisory until midnight PST tonight for Okanogan
     Highlands-Okanogan Valley-Upper Columbia Basin.

     Winter Weather Advisory until 4 AM PST Wednesday for Spokane
     Area-Washington Palouse.


&&

$$


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