558
FXUS66 KOTX 172246
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
246 PM PST Mon Nov 17 2025

.KEY MESSAGES...

- Light snow over Washington Pass and Stevens Pass Monday night.

- Temperatures trending cooler this week.

&&

.SYNOPSIS...
Next round of precipitation arrives Monday night into Tuesday
morning. Mild temperatures will keep snow levels high with
primarily light rain expected. Temperatures cooling closer to
normal for the latter half of next week. Forecast has trended
drier for the end of the week into the beginning of the weekend,
but there still exists a 5-10% chance for moderate snow over
Stevens and Washington Pass on Saturday.

&&

.DISCUSSION...
Monday night and Tuesday: An upper-level low, currently
centered over southern Vancouver Island/northwest Washington,
will track across northeastern Washington this evening. This
system will be the primary driver for the next round of
precipitation. The highest probabilities (greater than 80%) for
precipitation are focused across the north Cascades, northeast
WA, and the ID Panhandle this evening and overnight, with
chances diminishing further south. Lingering precipitation
chances (30-50%) will persist over northeast WA and the ID
Panhandle through Tuesday afternoon.

The primary forecast challenge is exact precipitation amounts,
which will be dependent on the lows exact track. Ensemble
guidance highlights this uncertainty: members tracking the lows
center near the US/Canadian border produce lower precipitation
amounts, whereas a more southern track through eastern
Washington yields higher totals.

Snow levels over the Cascades, currently near 6000 feet, will
fall to approximately 3000 feet overnight. This will transition
pass- level precipitation from rain to snow. Accumulations are
track- dependent, with the NBM indicating the greatest potential
over Washington Pass (40% chance of 4 inches, 25% chance of 6
inches). Probabilities for Stevens Pass are lower (20% chance of
4 inches, 10% chance of 6 inches). Travelers over the passes
tonight should be prepared for winter driving conditions, though
accumulations are expected to remain below advisory criteria.

Cool air behind the low will result in Tuesdays highs being
5-10 degrees cooler than Monday, with most locations in the 40s.
A building upper ridge and drier air mass Tuesday night will
promote efficient radiational cooling, leading to high
confidence in widespread freezing temperatures Wednesday
morning. Fog development in sheltered valleys may mitigate the
lowest temperatures in those specific areas.

Wednesday through Sunday: Model consensus is high for a
transient upper-level ridge to build over the region, providing
dry conditions on Wednesday. Uncertainty increases significantly
for the Thursday- Sunday period as models show another upper-
level low digging in the eastern Pacific and closing off as it
moves toward California.

Recent ensemble guidance has trended drier for the Inland
Northwest, suggesting a split flow pattern over the western US
and subtle ridging over the region. This is a significant change
from guidance 24 hours ago, which had indicated potential for a
moderate snow event in the Cascades. Given the poor run- to-run
model consistency, precipitation chances will be maintained in
the forecast from Thursday onward until a clearer solution
emerges. /vmt

&&

.AVIATION...
18Z TAFs: An abundance of boundary layer moisture and light
winds will promote widespread stratus with IFR/MVFR conditions
across the region through tonight. There are a few exceptions
one being over SE Washington and Lewiston area where southeast
boundary layer winds this afternoon may allow conditions to
become VFR. Second exception is around KEAT/KMWH after 06z Tue
as a passing system brings an increase in westerly downslope
winds off the Cascades which is expected to help break up the
stratus. This system will also bring increasing chances for
light rain and winds 8-13 knots this evening and overnight to
all TAF sites except KLWS where probabilities were too low to
include in the TAF.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence of IFR/MVFR conditions for most of the region
today. Moderate confidence that downslope boundary layer winds
brings improvement this afternoon to KPUW/KLWS and to KEAT/KMWH
after 06z Tue.

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

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        36  44  31  45  30  46 /  70  40  10   0  10  10
Coeur d`Alene  39  45  32  45  32  46 /  80  60  30  10  10  20
Pullman        36  44  29  46  32  47 /  50  40  20  10  10  20
Lewiston       44  50  34  49  35  50 /  40  30  20   0  10  10
Colville       33  47  28  46  26  46 /  90  70  30  10  10  20
Sandpoint      38  45  32  44  30  44 /  90  90  50  20  10  30
Kellogg        40  45  32  46  34  49 /  80  80  50  20  10  30
Moses Lake     34  48  29  47  31  48 /  40  10   0   0  10  10
Wenatchee      37  48  33  46  35  48 /  60  20   0   0  20  10
Omak           39  47  32  45  33  46 /  80  40  10   0  10  10

&&

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

&&

$$