655
FXUS66 KOTX 092352
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
352 PM PST Tue Dec 9 2025

.KEY MESSAGES...

- Heavy mountain rain will bring a risk for flooding in the
  Cascades and the Idaho Panhandle. Potential for moderate to
  major flooding along the Entiat River and Wenatchee River in
  the Cascades.

- Strong winds across southeast Washington for Wednesday and
  Wednesday night.

&&

.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. Strong winds will occur on Wednesday into Wednesday
night. Drier conditions arrive Thursday night into weekend, but
showers at times will be possible with weaker weather systems
possible and quicker shots at additional precipitation.

&&

.DISCUSSION...

...STRONG LONG DURATION ATMOSPHERIC RIVER EVENT TO BRING MINOR
FLOODING, ROCK/MUD SLIDES, AS WELL AS STRONG WINDS TONIGHT THROUGH
WEDNESDAY NIGHT...

Tonight through Thursday: The next Atmospheric River (AR) moves into
the region tonight. This one will deliver another round of heavy
rain to the Cascades and Idaho Panhandle, and also a second round to
strong winds to portions of the Inland Northwest. The peak of the AR
magnitude will be similar to yesterday with an Integrated Vapor
Transport (IVT) between 500-600 kg/m*s into the interior portions of
the Inland Northwest, but the difference is that the sub-tropical
moisture plume will be longer lasting. The peak of the AR will be
the first 24 hours beginning this evening into tomorrow where
precipitation totals over the Cascade crest looks to be in the range
of 6-8 inches translating to around 2-5 inches for locations just
off of the crest like Leavenworth, Plain, and Stehekin. This all
falling within the first 24 hours. That is a lot of precipitation!
Snow levels in the Cascades will start out around 4500 feet south of
Lake Chelan and down to around 2000-3000 feet in the Methow Valley
where colder will be trapped initially. This will result in the very
initial stages of the AR falling as snow generally at mid to
upper slopes in the Cascades. Except for the upper reaches of
the Methow Valley (Winthrop to Mazama) where heavy wet snow is
expected until about midnight to 2AM before warm air drives snow
levels up. Milder air with the advancing warm front will not
only result in snow transitioning to rain even for the ridges,
but also turn on a snowmelt contribution that will result in
sharp rises to rivers, small streams and creeks. The primary
concern will be across Chelan County. The first wave of rain
yesterday didn`t produce much in the way of impacts, but that
was just priming the pumps. Antecedent conditions are now even
more favorable for this second round of precipitation to produce
hydrology related impacts where significant flooding is
becoming more probable. This is in large part to an increase in
the expected rainfall accumulations. It`s looking more and more
likely that the Wenatchee River will hit major flood stage of
15 feet, which is the highest flows this river has seen in over
20 years!! With this update, the Entiat River is now expected to
flood, as well as the Stehekin River. Additional impacts
include the potential for mud/rock slides in steep terrain, as
well as the burn scars including the Labor Mountain, Sugarloaf,
and Pioneer burn scars. Rain will continue through Wednesday
night. Rain intensity looks to decrease a bit as the strength of
the AR decreases, but will keep river and stream flows rising.

The Idaho Panhandle will also see a significant amount of rain with
this AR. Rainfall totals are expected to range between an inch to up
to 4 inches in the Central Panhandle Mountains. The combination of
rain and mid elevation snowmelt will also contribute to rises on
rivers, small streams and creeks. The St. Joe River and Coeur
d`Alene River are both expected to see flooding impacts. Impact
levels are expected to be more of the minor variety and not as
severe as rivers in the Cascades. A flood watch remains in effect
for Chelan County and the Central Panhandle and has been extended in
time through Thursday night into Friday to account for a slower
recession in river flows and what was previously thought.

Another impact will be the winds as winds aloft increase with the
warm front pushing through tomorrow. Winds at 850 mb will
increase to between 50-60 mph, and the HREF model indicates that
these winds will mix down somewhat as the rain tapers off
across the Columbia Basin through the morning on Wednesday.
Winds look to increase into the afternoon peaking mid afternoon
into the evening hours. Wind gusts are expected to blow up to
45-55 mph, which will be similar to what was observed last
night. It looks to remain windy through Wednesday night,
although we should see winds come down a bit overnight Wednesday
as mixing potential decreases. A wind advisory is in effect for
6AM Wednesday through 7AM Thursday over much of the southeast
portion of the region. One caveat is for lower Garfield County
where there is a better potential for wind gusts up to 60 mph
tomorrow and a High Wind Warning is in effect for this same time
period. Winds will be capable of breaking tree limbs, toppling
trees, and causing hazardous travel due to strong cross-winds,
especially for high profile vehicles.

Temperatures remain mild and above normal for December.

Thursday night through Tuesday: Weather turns more benign at the end
of the week as a high pressure ridge builds over the eastern
Pacific. The ridge looks transitory though and model guidance does
indicate a frontal system pushing across over the weekend. However,
the ridge will give a reprieve to the wet weather on Friday at
least and allow levels on rivers and streams to decrease.
Precipitation over the weekend won`t be nearly of the scale as
over the next few days. Temperatures remain mild with any snow
remaining over the mountains. /SVH

&&

.AVIATION...
00Z TAFs: Rain is beginning to spread east of the Cascades as a
warm front with a strong plume of moisture lifts over the
region. Rain will become widespread into the evening bringing
deteriorating conditions and lowering ceilings. The moisture
plume will also be accompanied by a strong low level jet with
low level wind shear particularly at KPUW from 05Z into
Wednesday morning. Expect moderate rainfall intensity at times
overnight that will lower surface visibility with IFR conditions
developing, especially between 06-13Z. Westerly winds will also
be picking up by the early morning hours on Wednesday with
gusts increasing to between 30-40 kts on the Palouse to the
Spokane Area.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence is
high on MVFR and at least isolated/temporary IFR conditions as
rain increases tonight. Models have also been trending stronger
with winds on Wednesday and may see a trend toward higher gusts
at least between KPUW and KGEG with subsequent TAF updates.

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

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        40  55  48  53  41  50 / 100  50  60  60  30  20
Coeur d`Alene  39  53  48  51  41  48 / 100  80  90  80  50  40
Pullman        41  55  48  52  45  53 / 100  70  40  70  60  30
Lewiston       47  63  54  60  50  58 / 100  50  30  50  50  10
Colville       33  49  39  48  31  43 / 100  50  70  50  20  40
Sandpoint      35  50  45  49  37  44 / 100  90 100  80  50  70
Kellogg        37  50  47  49  42  48 / 100 100  90  90  70  70
Moses Lake     42  60  48  57  42  56 / 100  10  20  30  10   0
Wenatchee      41  58  46  54  43  54 / 100  40  60  50  30  10
Omak           38  52  39  47  34  43 / 100  30  60  30  20  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 6 AM Wednesday to 7 AM PST Thursday for
     Spokane Area-Upper Columbia Basin-Washington Palouse.
     High Wind Warning from 6 AM Wednesday to 7 AM PST Thursday for
     Lower Garfield and Asotin Counties.
     Flood Watch through Friday morning for Central Chelan County-
     Wenatchee Area-Western Chelan County.
ID...Flood Watch through Friday afternoon for Central Panhandle
     Mountains-Coeur d`Alene Area-Idaho Palouse-Northern
     Panhandle.
     Wind Advisory from 6 AM Wednesday to 7 AM PST Thursday for
     Coeur d`Alene Area-Idaho Palouse.

&&

$$