902
FXUS66 KOTX 070620
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1020 PM PST Sat Dec 6 2025

.KEY MESSAGES...

- Widespread precipitation on Sunday. Light snow for the
  northern valleys and mountains with rain elsewhere.

- Strong west to southwest winds Monday evening into early
  Tuesday morning.

- Increased potential for rises along small creeks and streams
  and rock slides next week due to a warm and wet weather
  pattern.

&&

.SYNOPSIS...
A series of very wet and warm systems will move through the
Inland Northwest through the middle of next week. This will
result in warmer than normal temperatures, periods of heavy
mountain rain, high mountain snow, and lowland rain. Strong west
to southwest winds are expected Monday evening into Tuesday.

&&

.DISCUSSION...
Saturday Night through Sunday: The Inland Northwest remains in
the wake of todays passing front, which brought drier conditions
and sunshine to much of the Inland Northwest. Breezy west to
southwest winds of 20-40 mph across the Basin, Spokane area, and
Palouse are the result of steep low-level lapse rates mixing
35-40 mph winds from 850 mb to the surface. Winds will ease this
evening after sunset.

A conditionally unstable airmass combined with moist upslope
flow continues to produce orographically enhanced showers over
the mountains, including snow at Stevens and Lookout Passes.
Temperatures near 32-34F are limiting road accumulations.

A series of weather systems begins early Sunday as the parent
surface low and its occlusion move into the central BC coast.
Guidance shows a secondary low developing off the WA coast,
lifting a warm front and a new moisture plume into the region
from the south. Snow levels will be high, favoring lowland rain
and high mountain snow. The exception will be across the
northern valleys where cold air remains trapped. The Methow
Valley has held near freezing all day today under persistent
low clouds, and warm-frontal precipitation may fall as snow,
which models typically handle poorly.

Monday through Thursday: A long-duration atmospheric river
targets the Pacific Northwest. From Monday into Tuesday, strong
westerly flow will focus precipitation over the mountains and
far eastern Washington. Ensemble agreement continues for a
deepening surface low tracking through southern BC. With
precipitable water 250350% of normal, expect heavy mountain
rain, increasing concerns for rises on small streams and
localized mud/rock slides on steep, snow-free slopes.

For eastern WA and north ID, the primary hazard Monday night
into Tuesday will be strong winds as the cold front pushes
through and the low deepens into southern Alberta. A tightening
southwest pressure gradient and 850 mb winds of 40-55 kt support
the following wind probabilities from the NBM for the Columbia
Basin, Blue Mountains, Palouse, and Spokane area: a 50-70%
chance of gusts greater than 45 mph and a 30-40% chance of gusts
greater than 55 mph.

A brief break in precipitation is expected early Tuesday as the
moisture plume sags south into Oregon. Beyond that, guidance
diverges Tuesday night through Thursday regarding the next lows
track into BC, which will dictate how far north the plume
returns. If the plume stays farther south, precipitation totals
would fall in the lower end of the spectrum, though a further
northward placement would continue to pile on the rain totals
into the mountains. This timing and placement will be refined in
the coming days.

Friday and Saturday: Ensembles begin to hint at a break in the
pattern Friday into the weekend with a majority of ensemble
guidance (~80% of GEFS/ECMWF/CMC members) favoring an amplifying
ridge building over the PNW. However, this comes with some
uncertainty as ~20% of solutions support a colder trough
instead. /vmt

&&

.AVIATION...
06Z TAFs: Wind gusts have decreased at all TAF sites but KPUW,
where they are anticipated to last through 10Z. Rain will begin
to move into the forecast area around 12-15Z with a front moving
in, with ceilings dropping around the same time. While most
sites will drop down to MVFR, KGEG/KSFF/KCOE have a chance of
dropping to IFR. NBM probabilities show those sites having a
30-50 percent chance of dropping to IFR. Currently, models are
showing wind gusts returning to the TAF sites around 23-00Z.
Apart from KMWH, rain will continue through 06Z tomorrow and
into the next forecast period.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Moderate to high confidence in the return of widespread MVFR/IFR
conditions by 12-15Z. Moderate to high confidence in rain
continuing into next period. Moderate confidence in wind gusts
returning tomorrow afternoon. /AS

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

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        44  34  44  39  50  41 /  40  10  90  50  90  90
Coeur d`Alene  40  34  43  39  48  41 /  70  30  90  80 100 100
Pullman        45  38  45  41  50  42 /  60  30  90  80 100 100
Lewiston       57  40  49  43  53  48 /  50  30  80  70  90 100
Colville       37  24  39  31  46  32 /  50  10 100  50  90  80
Sandpoint      39  31  41  36  45  38 /  90  40 100  90 100 100
Kellogg        40  36  41  39  47  41 / 100  80 100 100 100 100
Moses Lake     55  36  49  37  52  41 /  10  10  80  10  70  60
Wenatchee      53  38  46  39  51  41 /  20  30  90  30  80  80
Omak           40  31  41  34  44  34 /  20  10  90  20  70  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...None.
ID...None.

&&

$$