519
FXUS66 KOTX 200712
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1212 AM PDT Sun Sep 20 2026

.KEY MESSAGES...

- Warm temperatures through Tuesday with afternoon highs in the
  mid 70s to mid 80s.

- Temperatures begin cooling midweek, with an increasing risk
  for showers and high elevation snow Friday into Saturday.

- Breezy Tuesday into Wednesday. Potential for stronger winds
  Friday.

&&

.SYNOPSIS...
Warm and dry weather is expected through the middle of next
week, with high temperatures through Tuesday in the mid 70s to
low 80s. Wednesday through the weekend, temperatures cool closer
to normal with increasing winds. A stronger cold front arrives
Friday with gusty winds and chances for showers and high
elevation snow.

&&

.DISCUSSION...
Sunday-Tuesday: Mild and dry conditions start off the new week.
A ridge will be over the region Sunday with mostly clear skies
then begin to flatten Monday and Tuesday as a broad upper-level
trough expands toward the WA Coast and sends impulses across
southern British Columbia. Skies will largely remain mostly
sunny but Monday and Tuesday will feature bands of high clouds
associated with the decaying upper-level fronts. Temperatures
will warm another 1-2 degrees Sunday and further Monday before a
gently cooling trend on Tuesday. Despite the flattening ridge
on Monday, the air mass actually warms in response to the upper-
low that has been spinning south of Lewiston departing which
has been blocking the warmth from the south from expanding
northward. Overall, weather impacts will be low with minor
heatrisk the main concern in the afternoon as temperatures climb
into the 80s, roughly 10 degrees above normal. Nights will
continue to offer relief with overnight lows dipping into the
40s to lower 50s. Winds will remain light Sunday with speeds
generally under 10 mph. The exception will be localized
southerly winds near 10 mph and gusts 15-20 mph in the upper
Okanogan Valley. By Monday, the evening sun-downer winds will
increase from the west and northwest through the Cascade river
valleys as the pressure gradient begins to tighten. Winds for
Tuesday will become a bit more breezy region-wide as cooler air
begins to bleed into the region. West to southwest winds will
increase closer to 10-15 mph with gusts up to 20 mph and locally
25 mph through the Cascade gaps. Definitely not anomalous by
any means but noticeably more wind vs Sunday and Monday. Models
are in good agreement through this period.

Wednesday-weekend: The broad trough will have carved into the
region by Wednesday with temperatures cooling further and
residual breeziness. A reinforcing shot of cooler air and
shortwave dropping into the offshore trough on Thursday will dig
into the base of the trough allowing flow to buckle slightly
over the Inland NW. 70% of the ensemble solutions indicate a
slight warming trend Thursday before the cooler fall-like trough
swings inland Friday into the weekend. Models look to be coming
into good agreement for this pattern evolution with the main
differences coming with the precise arrival of the main cold
front (Friday morning or Friday evening) but generally on
Friday. The main trough will pass through Saturday and leave a
broad trough and cool air mass in place for Sunday.

As for impacts: Winds on Friday, Cooler temperatures,
particularly in the mountains with high elevations near
freezing, and increased chances for precipitation Friday-
Saturday with high elevation snow.

Friday looks to be a windy day across the region with potential
for sustained west to southwest winds around 15 mph and gusts
20-30 mph. There is a 50-70% chance for wind gusts greater than
20 mph and 20-40% for gusts to exceed 30 mph. This is to be
expected with the air mass cooling as 850mb temperatures drop
from near 14C Thursday to 6C Friday in the post frontal air
mass. This will knock lowland high temperatures back into the
60s by the weekend. As for precipitation, ensembles are
indicating a 50% chance for at least 0.10" along the Cascade
Crest and mountains of NE WA and N ID. The potential outcomes
for these areas is as high as 0.60 inches which could equate to
several inches of snow for those venturing into the high
country. Confidence is much lower for rainfall amounts outside
of these areas and will depend how progressive the Friday-
Saturday wave is. A slower solution could result in rainfall
amounts in excess of 0.10" across much of Idaho and far eastern
reaches of WA...a faster solution would deliver less than a
tenth to most areas outside the Cascade Crest and Selkirks. Stay
tuned. /sb

&&

.AVIATION...
12Z TAFS: VFR conditions forecast with high pressure. Winds
generally 10kts or less. Exception one near KPUW between 15-18Z
with possible winds 10-15kts. Exception two near Omak and
Oroville where southerly gusts of 15-20 mph 21-0Z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in VFR conditions. /Solveig


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

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        81  50  83  52  78  51 /   0   0   0   0   0   0
Coeur d`Alene  79  51  81  52  77  51 /   0   0   0   0   0   0
Pullman        80  49  82  50  76  47 /   0   0   0   0   0   0
Lewiston       84  54  86  57  82  54 /   0   0   0   0   0   0
Colville       81  45  82  46  79  44 /   0   0   0   0   0   0
Sandpoint      76  48  78  49  76  48 /   0   0   0   0   0   0
Kellogg        77  50  80  52  76  48 /   0   0   0   0   0   0
Moses Lake     83  50  84  51  79  48 /   0   0   0   0   0   0
Wenatchee      81  58  82  58  78  51 /   0   0   0   0   0   0
Omak           82  53  82  53  79  50 /   0   0   0   0   0   0

&&

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

&&

$$