129
FXUS66 KOTX 072337
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
337 PM PST Sun Dec 7 2025

.KEY MESSAGES...

- Strong west to southwest winds Monday evening into early
  Tuesday morning may result in downed trees and power outages.

- Heavy mountain rain will bring a risk for flooding  in the
  Cascades and the Idaho Panhandle.

&&

.SYNOPSIS...
An active weather pattern will impact the area through the week.
A series of warm and wet weather systems will result in periods
of heavy mountain rain, lowland rain, high mountain snow, and
gusty winds. Widespread strong wind gusts are expected Monday
night into Tuesday which may result in downed trees and power
outages.

&&

.DISCUSSION...
Sunday Night: Light precipitation associated with the warm
front lifting across the Inland Northwest will taper over the
next couple of hours as the front occludes and shifts east.
Satellite imagery shows the back edge of the cloud shield
pushing through central Washington with brief clearing following
behind. This break will be short-lived as clouds advance ahead
of the next surge of subtropical moisture arriving tonight.
Southwest winds will remain elevated into the evening with gusts
of 20 to 35 mph from the Columbia Basin into far eastern
Washington. Showers will linger over the Cascades and Idaho
Panhandle as moist upslope flow persists into these areas.

Monday through Tuesday Morning: This will be the first of two
impactful periods this week with high confidence in heavy
mountain rain and strong winds across the Inland Northwest. A
strong 976980 mb surface low, supported by a 160+ kt upper-
level jet, will move into the Gulf of Alaska. With high pressure
off the California coast and strong zonal flow across the
Pacific Northwest, a highly anomalous atmospheric river will be
directed into the region. As the upper-level jet penetrates
farther inland Monday afternoon and evening, a low will deepen
on the lee side of the southern Alberta Rockies, tightening the
pressure gradient and increasing winds Monday night into
Tuesday.

Rain: Precipitable water values are expected to climb to
between 0.75 and 1.00 inches, ranking in the 99.5th percentile
climatologically. Strong west winds will support heavy
precipitation over the Cascades and create a pronounced rain
shadow across the Columbia Basin. Confidence is high for 24-hour
rain totals exceeding 2 inches into central Chelan County,
including Leavenworth, while chances remain lower across the
Basin and Okanogan Valley with around a 30 percent chance of a
quarter inch of rain. Across far eastern Washington and the
Idaho Panhandle, ensembles show an 80 percent chance of a
quarter inch and around a 50 percent chance of a half inch of
rain. Orographic enhancement will likely bring around an inch to
the Panhandle mountains. Snow levels may briefly lower behind
the cold front early Tuesday morning, allowing precipitation to
mix with or change back to snow over Stevens Pass with a 50%
chance for 4 inches of snow.

Impacts: These rainfall totals combined with low to mid-
elevation snowmelt will lead to rises on small creeks and
streams and an elevated risk of mud and rock slides across
steep, snow-free terrain. Burn scars including Labor Mountain,
Lower Sugarloaf, and Pioneer will be especially vulnerable.
Similar concerns exist for smaller streams across north Idaho.

Winds: Winds will become a second hazard. Models show strong
consensus for a deepening Alberta low to increase the pressure
gradient between Yakima and Lethbridge to +15 to +20 mb Monday
evening. Winds aloft strengthen as 850 mb winds increase above
50 kt. Cooling aloft with the cold front later Monday into
Tuesday should allow stronger gusts to mix down, and the NBM
indicates an 80 percent chance for gusts exceeding 45 mph from
the Columbia Basin through the Spokane area and the Palouse.
While there remains some uncertainty in mixing efficiency,
forecast soundings support at least advisory-level winds.

Impacts: A Wind Advisory has been issued from 7 PM to 7 AM for
far eastern Washington and the central and northern Idaho
Panhandle. Even where gusts fall just short of advisory
criteria, saturated and unfrozen soils across northeast
Washington and the Panhandle will increase the risk of downed
trees and power outages.

Tuesday through Thursday: A brief break in precipitation is
expected Tuesday morning as the moisture plume sags south into
Oregon behind the front. The second impactful period arrives
Tuesday afternoon into Wednesday as the plume shifts back
northward with the next system approaching British Columbia. A
warm front lifting across the region will bring more widespread
rain, including areas shadowed on Monday. Confidence remains
high for another round of significant mountain precipitation,
with snow levels initially low enough for mountain pass snow
before rising Tuesday evening. There is around a 50 percent
chance of 4 inches of snow at Stevens Pass before the changeover
to rain. Hydrologic concerns will persist through mid-week as
soils become increasingly saturated and additional runoff
develops.

Friday and Saturday: Model ensembles continue to suggest the
moisture plume remains directed into the Pacific Northwest
through at least early Friday, sustaining mountain
precipitation. By Saturday, most ensemble members favor an
amplifying ridge shifting inland, which would help push the
plume north and provide a break in the active weather pattern,
though some uncertainty remains with timing and the degree of
drying. /vmt

&&

.AVIATION...
18Z TAFs: MVFR/IFR conditions expected at KGEG-KSFF-KCOE for
the remainder of the day. KPUW-KLWS will trend towards MVFR as
rain moves in early this afternoon. A cold front passage will
lead to improved conditions across the board this evening but
but breezy southwest winds in eastern WA and north ID. A
strengthening low will bring LLWS tomorrow afternoon and
eventually strong southwest winds.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence in MVFR/IFR conditions for eastern WA and north
ID. Moderate confidence in improvements as a cold front sweeps
through this evening.

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

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        39  50  42  47  38  49 /  30  90  80  50  90  80
Coeur d`Alene  38  49  42  46  38  47 /  60 100 100  60  90  90
Pullman        40  50  42  48  40  50 /  50 100  90  80 100  90
Lewiston       42  54  49  54  46  56 /  50  90  90  90 100  90
Colville       32  46  34  45  32  44 /  30 100  80  30  90  70
Sandpoint      36  46  39  45  35  43 /  80 100 100  60  90  90
Kellogg        39  47  41  46  38  47 /  90 100 100  80 100 100
Moses Lake     37  53  42  49  39  53 /  10  70  40  40  80  60
Wenatchee      38  50  41  47  40  50 /  20  90  80  50  90  80
Omak           34  46  35  45  35  44 /  20  80  70  20  80  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 7 PM Monday to 7 AM PST Tuesday for Lower
     Garfield and Asotin Counties-Northeast Mountains-Spokane
     Area-Upper Columbia Basin-Washington Palouse.
     Flood Watch from Monday morning through late Monday night for
     Central Chelan County-Wenatchee Area-Western Chelan
     County.
ID...Wind Advisory from 7 PM Monday to 7 AM PST Tuesday for Central
     Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
     Lewiston Area-Northern Panhandle.

&&

$$