369
FXUS66 KOTX 060005
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
405 PM PST Fri Dec 5 2025

.KEY MESSAGES...

- Moderate to heavy mountain snow through Saturday at the
  Cascade crest and the Idaho Panhandle mountains. 50% chance
  for 12+ inches at Stevens and Lookout Passes.

- Strong, potentially damaging winds in portions of Central
  Washington Friday night. Gusty winds in southeast Washington.

- Increased potential for rock slides next week with a mild and
  wet weather pattern.

&&

.SYNOPSIS...
A unsettled and complex weather pattern through the weekend and
into next week. Gusty winds developing Friday night.
Temperatures will modify and warm above normal with mid and wet
weather continuing through the weekend and into next week.

&&

.DISCUSSION...
Today and tomorrow: A shortwave trough and associated low
pressure system are driving wintry weather and windy
conditions across the Inland Northwest today and into tonight.
Details for each hazard below:

Snow: A warm front has generated a band of snow over northeast
Washington and the northern Panhandle. Low level wet bulb
temperatures have remained at or below 0C through early
afternoon, particularly near the Canadian border leading to all
snow. Total accumulations will be around 1-3. This will persist
for the next couple hours until a cold front sweeps through
around sunset. By this evening, precipitation will be limited to
the Cascades, extreme eastern Washington, and the Panhandle.
However, snow intensities will greatly increase for Stevens Pass
around 8 to 10 PM this evening as lapse rates steepen behind
the front with strong lift in the saturated dendritic layer on
the west slopes of the Cascades. The morning hi-res models
showed a massive uptrend in the snow amounts at Stevens Pass.
They indicate a 90% chance for 1/hr snowfall rates and a 40%
chance for 2" per hour snowfall rates from 10 PM this evening
through 5 AM Saturday. Strong winds will also contribute to a
minor risk for blowing snow and reduced visibility from the
surrounding peaks. Overall, expecting around 10-18 inches of
heavy wet snow at the pass level when all is set and done
Saturday evening. Expecting a similar story but less intense
snowfall rates for Lookout pass with similar accumulations by
Saturday evening. There is a 50% chance of 1/hr snowfall rates
from now through 11 PM this evening.

Winds: Winds get very interesting this evening in the east
slopes of the Cascades as strong flow perpendicular to the
Cascades behind the cold front leads to mountain wave formation.
Of particular concern is 60-70 kt flow about 3000-6000 feet
above sea level late tonight into Saturday. Confidence still is
not very high whether these winds will make it to the valley
floors, but there is moderate-high confidence of strong winds in
the mountains. The 3 PM observation at Mission Ridge Summit
already shows a peak gust to 78 mph. White Pass Summit has
already gusted up to 83 mph as well. Higher end model solutions
are already panning out in the mountains. The best chances
(40-60%) for 60 mph gusts tonight are on the higher benches of
the Wenatchee area and the southern Waterville Plateau so high
wind warnings remain in place. Southeast Washington in the
Clarkston Valley and the Palouse will be breezy too this evening
and tonight with southwest winds around 20-30 mph with gusts up
to 55 mph. Bumped up the timing of the wind advisory to start
now as Alpowa summit is gusting to 55 mph. Winds will decrease
after sunrise but stay breezy through much of the day tomorrow
gusting around 25-40 mph.

Sunday through Thursday: Several atmospheric rivers take aim at
the region resulting in a very wet period for the Inland
Northwest. The first one is the weakest arriving Sunday with
precipitable water increasing to 150-175% of normal. Snow levels
are around 2500-4500 feet so most of the precipitation in the
valleys will be rain. One area of uncertainty is the northern
valleys near the Canadian border where models still have some
cooler pockets of air. More significant atmospheric rivers
arrive Monday and Tuesday bringing a lot of precipitation to the
region. The ECMWF ensemble mean QPF from 4 AM Sunday to 4 AM
Thursday shows around 5-7.5 of precipitation at the Cascade
crest, 2-4 for the east slopes of the Cascades, 0.75-1.75 in
central WA valleys and eastern WA, and 1.5-3 for the ID
Panhandle. These rain amounts combined with snowmelt will lead
to significant rises on rivers and streams. Currently no rivers
are forecast to reach flood stage, but this will be monitored
closely in the coming days. This will also bring an increased
risk for mud and rock slides in areas of steep, snow-free
terrain and recently burned areas. DB

&&

.AVIATION...
00Z TAFs: Fluctuating conditions are anticipated through
tonight. Precip chances decreasing overnight, but winds will
increase. Low level wind shear is shown in model soundings for
KEAT/KMWH/KLWS/KPUW thru 06Z as winds around 2k feet AGL
increase to around 40-50 kts, locally stronger at KEAT. Stronger
gusts may occasional mix down to the surface in areas of
Central WA around Chelan, Wenatchee, Ephrata, and Vantage. The
increased winds likely to bring bring improvement to the
persistent stratus except far NE WA and N ID.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence for increase winds and low-level wind shear.
Confidence is low where and when the strongest winds gusts will
surface, especially in Central WA. Strong turbulence expected as
the jet crosses the mountain barriers.

-----------------------

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:/www.weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        35  44  35  43  38  49 /  50  30  20  80  60  80
Coeur d`Alene  35  43  35  43  38  47 /  80  70  50  90  80  90
Pullman        38  44  37  43  40  48 /  70  60  60  80  80  80
Lewiston       41  51  40  47  43  52 /  70  50  40  70  70  70
Colville       33  41  28  39  33  44 /  40  40  20  90  50  80
Sandpoint      33  39  34  39  37  43 /  80  90  80 100  90 100
Kellogg        35  39  37  41  40  46 / 100 100  90 100 100 100
Moses Lake     36  50  35  45  38  50 /  10  10   0  60  10  50
Wenatchee      38  49  37  45  39  47 /  60  30  20  70  30  70
Omak           34  43  32  40  34  42 /  40  20  10  60  20  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 7 AM PST Saturday for Lower Garfield and
     Asotin Counties-Washington Palouse.
     High Wind Warning from 7 PM this evening to 7 AM PST Saturday
     for Moses Lake Area-Waterville Plateau-Wenatchee Area.
     Winter Storm Warning from 7 PM this evening to 10 PM PST
     Saturday for Western Chelan County.
ID...Wind Advisory until 7 AM PST Saturday for Idaho Palouse.
     Winter Storm Warning until 4 PM PST Saturday for Central
     Panhandle Mountains.

&&

$$