805
FXUS66 KOTX 112341
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
441 PM PDT Sat Oct 11 2025

.KEY MESSAGES...

- Moderate to heavy snow for the mountains Sunday into Monday
  morning.

- Gusty north to northeast winds on Monday. Cold wind chills in
  the teens to single digits in the mountains.

- Below normal temperatures Sunday into early next week with
  highs in the 50s. Low temperatures dropping into the 20s and
  30s by Tuesday.

&&

.SYNOPSIS...
Rain will continue over much of extreme eastern Washington into
the Idaho Panhandle tonight. Heavy snow with winter conditions
is expected in the Cascades and northern mountains above 3000
feet Sunday into Monday. Dry weather with fall like temperatures
are expected Tuesday through Thursday.

&&

.DISCUSSION...

...EARLY SEASON WINTER STORM TO BRING MODERATE TO HEAVY SNOW TO THE
CASCADES, NORTHERN MOUNTAINS OF EASTERN WASHINGTON AND NORTH IDAHO...

Tonight: A trough of lower pressure pushing across the Inland
Northwest will bring light precipitation through tonight. Additional
energy diving south across BC will reinforce the moist isentropic
ascent across the eastern half or so of the forecast area tonight.
Snow levels will also begin to drop overnight down to between 3000-
4000 over the Cascades and the northern mountains. We will
start to see light snow for those higher elevations particularly
closer to the Cascade crest. The Idaho Panhandle will see up to
a quarter of an inch to up to a half of an inch of precipitation
for those more favored higher elevations where orographics help
generate lift. Expect low clouds and a damp morning on Sunday
especially for the eastern half of the forecast area. Winds will
remain breezy, but higher gusts will generally die off
overnight.

Sunday through Monday: Bigger impacts are anticipated with a second
upper level low that deepens across western Washington.
Models remain in good agreement with a surface low spinning up over
northwest Washington Sunday afternoon and continuing to deepen as it
tracks down the western Washington coastline. This will do two
things: (1) tighten the northerly pressure gradient with cold
Canadian air advancing into the region, and (2) draw moisture
northward across the region that overruns the advancing cold air.
Advection of colder Canadian air will drop snow levels further
Sunday night. Snow will accumulate further down in elevation through
the nigh on Sunday with the northern locations such as Republic,
Northport, Sandpoint, Bonners Ferry, Porthill, and Eastport
picking up at least a dusting. Warm road temperatures may make
it difficult for snow to accumulate initially, but these
temperatures are expected to drop overnight Sunday. Strong
dynamics and vertical lift in the snow growth zone may also push
snow levels down more so than models are letting on. The east
slopes of the Cascades will be favored for higher intensity
snowfall south of Lake Chelan with north-northeast winds
resulting in favorable upslope flow into this area. This will be
particularly so into Mission Ridge where burst of heavy snow is
possible. A big concern will be for any backcountry
recrationalists camping in the mountains this weekend. Weather
conditions will deteriorate rapidly particularly late on Sunday.
Expect winter conditions and cold temperatures. Mountain passes
will also see the potential for snow covered roads and heavy at
times for Washington Pass and Sherman Pass; however, Loup Loup
Pass, Stevens Pass, and Blewett Pass will also see the potential
for snow travel. Below are the probabilities for snowfall
thresholds of at least 2", 4", and 8" at our mountain passes:

Mountain Pass    Chance of 2+"    Chance of 4+"     Chance of 8+"
Washington       95%              90%               60%
Sherman          100%             85%               30%
Lookout          80%              45%                5%
Stevens          95%              80%               45%
Blewett          90%              70%               20%
Loup Loup        85%              50%                5%

North to northeast winds will also be gusty, especially down the
Okanogan Valley, Purcell Trench and across the Columbia Basin.
The ECMWF ensemble has a mean wind gust speed of 40 mph at
Sandpoint for Monday. The gusty winds and cold air is expected
to produce chilly wind chills in the single digits in the
mountains. Wind chills in the teens can be expected in the
mountains in the Cascades and across the northern mountains of
Eastern Washington. The combination of changing weather
conditions to snow and then add the bitterly cold wind will make
for dangerous winter conditions for anyone in the backcountry
that is prepared. The Winter Storm Watch has been upgraded to a
Winter Storm Warning in North Idaho above 3,000 feet. Snow
accumulations don`t look to meet warning criteria for the rest
of the higher terrain and Winter Weather Advisories have been
issued instead. There is potential for heavy snow accumulation
across the higher terrain of Chelan County especially as
temperatures cool and snow ratios increase early Monday morning,
but not confident enough that snow will be heavy enough to
warrant a winter storm warning. Wind gusts on Monday will range
from between 30-40 mph for the Okanogan Valley, Purcell Trench,
and Columbia Basin. /SVH

Monday Night through Thursday: A quieter pattern returns as the
low drops south over California and an upper ridge builds off
the coast providing a dry north to northwest flow over the
Inland Northwest. It will feel like fall as low temperatures
drop into the 20s and 30s for most of the region, and daytime
highs in the mid 50s to low 60s.

By Friday, 85% of the ensembles shows another system dropping
in from the northwest but differ with the strength. 40% show a
windy and wet scenario while 45% show a weaker trough. Forecast
currently leans towards the weaker scenario but this will
continue to be monitored in the coming days. JW

&&

.AVIATION...
00Z TAFS: Steady light rain through tonight into Sunday across
extreme Eastern Washington and the Idaho Panhandle. A moist
boundary layer fueled by the rain and upslope flow into the
Palouse (KPUW), Spokane-Coeur d`Alene corridor (KGEG/KSFF
KCOE), northeast Washington (KDEW/K63S) and Idaho Panhandle
(K65S/KSZT) will keep low stratus and MVFR conditions in place
through the night. Additional precipitation for the afternoon on
Sunday will keep ceilings low.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate
confidence for MVFR conditions to continue at KPUW/KGEG/KSFF
KCOE through the night tonight. There is some potential for
drier air to advect into the Spokane Area with VFR conditions
for KGEG/KSFF between 08-14Z before stratus fills back in. /SVH

-----------------------
Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane
airports, please refer to the Aviation Dashboard on our webpage:
https:/weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        41  48  35  49  31  55 /  80  90  90  20   0   0
Coeur d`Alene  41  47  34  49  31  55 /  90  90 100  10  10   0
Pullman        41  45  39  52  31  55 /  90  90  90  20  10  10
Lewiston       47  53  44  59  39  58 /  90  80  80  20  10  10
Colville       35  48  32  50  19  56 /  90  90 100  20   0   0
Sandpoint      40  45  32  46  25  53 / 100  90 100  10  10   0
Kellogg        40  45  32  46  32  53 / 100 100 100  20  10  10
Moses Lake     43  53  40  54  34  58 /  20  70  90  60   0   0
Wenatchee      44  51  37  50  36  57 /  40  80  90  80   0   0
Omak           42  51  37  55  33  59 /  60  80  90  30   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 5 PM Sunday to 5 AM PDT Monday
     for Northeast Mountains-Okanogan Highlands.
     Winter Weather Advisory from 8 AM Sunday to 11 AM PDT Monday
     for Central Chelan County-Western Chelan County-Western
     Okanogan County.
ID...Winter Storm Warning from 2 PM Sunday to 5 AM PDT Monday for
     Northern Panhandle.

&&

$$