766
FXUS66 KOTX 122148
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
248 PM PDT Sun Oct 12 2025

.KEY MESSAGES...

- Moderate to heavy snow for the mountains tonight 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 into early next week with highs in
  the 50s. Low temperatures dropping into the 20s and 30s by
  Tuesday.

&&

.SYNOPSIS...
Heavy snow with winter conditions is expected in the Cascades
and northern mountains above 3000 feet through Monday. Monday
will also bring gusty north to northeast winds. Dry weather
with fall like temperatures are expected Tuesday through
Thursday. Wet weather and breezy winds looks to return next
weekend.

&&

.DISCUSSION...

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

Tonight into Monday: As advertised, a potent low pressure
system is digging south along the Washington coastline. The
center of the low is currently located right over the Olympic
Peninsula. Satellite imagery shows a good fetch of moisture
rotating around the upper level trough into the Inland Northwest
where stratiform precipitation is across much of the region.
Lift is primarily being generated along a convergence boundary
stretching west to east from the western Montana to the
Washington Cascades. This convergence boundary is being fueled
by strong southerly moisture transport and an advancing modified
Arctic boundary dropping southward across BC. Models have
trended toward higher precipitation amounts along the axis of
this boundary across North Idaho to the northern Washington
Cascades. Temperatures will drop with the setting sun and as
colder air advects in with the advancing Arctic front. This will
drive snow levels down from around 4,000 feet this afternoon
down to valley floors as moisture shifts south. Snow
accumulation will primarily be in the mountains above 3,000
feet and there is potential that we are underestimating
accumulations in the higher terrain. Snow in the valleys will
come at the tail end as drier air with the Arctic front begins
to win. This may result in some slushy accumulations on grassy
surfaces, but impacts from snow in the valleys is not expected.

Precipitaiton will become more focused across Chelan County by
Monday morning as the low sags further south and continues to
deepen as it does so. The effect of this is to generate good
up slope due to north-northeast winds. This will be especially
so along Mission Ridge where heavy mountain snow with rates of 1
to 2 inches per hour will be possible. This could result in a
snow piling up quick especially above 3000-4000 feet as the cold
air advects into this part of the region and snow levels crash.
Of all of our mountain passes, Blewett Pass may see the
heaviest snow with near a foot when all is said and done.

The current suite of winter highlights remain in valid with the
most highlighting snow in the mountains above 3,000 feet. The
winter weather advisory in the Central Panhandle Mountains
remains in effect above 4,000 feet mainly for light snow at
Lookout Pass. The rest are above 3,000 feet where some areas
above 4,000 feet will see heavy snow, including Sherman Pass,
Washington Pass, and Blewett Pass.

Winds will increase with the Arctic front pushing into the
region overnight. Winds look to gust between 25-35 mph down the
Okanogan Valley, Purcell Trench, and over the Columbia Basin.
Winds will be gusty in the mountains where wind chills in the
teens to low 20s is expected. Winds will be particularly gusty
in the mountains of northeast Washington and North Idaho where
wind chills in the single digits are expected.

Monday Night through Thursday: Model ensembles continue to show
a much more benign weather pattern with low pressure system push
south away from the region. Tuesday will continue to see breezy
north to northeast winds, but not as windy as Monday.
Temperatures will be chilly Monday night into Tuesday morning
with the northern valleys in the low 20s and the Columbia Basin
into the upper 20s to low 30s.

Friday and Sunday: The forecast is looking more unsettled
particularly for the weekend. Ensembles show a deep fetch of
moisture ahead of a low pressure trough for the latter half of
the weekend. Saturday may be a good day for fall outdoor
activities, but Sunday is trending wet. No reinforcement of
cold air with this trough. Snow levels will rise with
precipitation with mostly rain except for the higher mountain
peaks that look to see snow. Winds may be a bit breezy for
Sunday with a cold front passage. /SVH

&&

.AVIATION...
00Z TAFS: Low pressure drops south along the Washington
coastline tonight. A clash of moisture from the south into
colder Canadian air from the north will result in widespread
precipitation across the Inland Northwest today into tonight.
Widespread MVFR conditions is expected through the day tonight.
Airports across the region will mainly see rain with this low
pressure system. Cold air with increasing north to northeast
winds will make an impact tonight. This may result in a little
bit of snow mixing in with rain overnight including at KCOE and
KGEG. Northerly winds will be gusty through north Idaho, the
Okanogan Valley, and over the Columbia Basin overnight into
Monday with gusts of 20-30 kts common, and as strong as 35 kts
at KOMK/KSZT KCOE by the morning hours on Monday. IFR conditions
with lowering ceilings may occur overnight fore the boundary
layer dries out into Monday morning.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in CIGS lowering to at least MVFR for GEG/SFF/COE/PUW and
moderate confidence for MVFR conditions at LWS/MWH/EAT. Low
confidence for snow to mix in as temperatures cool late tonight
into Monday morning. Best chances would be at KGEG/KCOE/KEAT
with a probability of less than 10% chance. /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        35  51  31  56  33  58 /  90  10   0   0  10  10
Coeur d`Alene  34  52  31  58  35  57 /  90  10   0  10  10  10
Pullman        39  55  30  56  32  54 /  80  10   0  10  10  10
Lewiston       44  62  39  60  40  59 /  70  10  10  10  10  20
Colville       32  52  19  57  22  61 / 100  10   0   0  10   0
Sandpoint      32  48  26  54  31  56 / 100  10   0   0  10  10
Kellogg        32  47  32  55  36  55 / 100  20  10  10  20  20
Moses Lake     40  55  35  59  32  60 /  90  60   0   0  10   0
Wenatchee      37  52  37  58  40  62 /  90  80   0   0  10   0
Omak           37  54  33  61  33  62 /  90  20   0   0   0   0

&&

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

&&

$$