479
FXUS66 KOTX 250853
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
153 AM PDT Fri Sep 25 2026

.KEY MESSAGES...

- A system brings stronger winds and an increasing risk for
  rain, thunderstorms, and high mountain snow today and tonight.

- Possible frost late Saturday night and Sunday morning over
  eastern Washington and Idaho Panhandle mountain valleys, as
  well the outlying areas around the Spokane area and Palouse.

&&

.SYNOPSIS...
A strong system today will bring gusty winds, rain and along
with chance of thunderstorms, and high mountain snow.
Temperatures will trend cooler. A dry, fall like pattern
expected for start of next week. Some patchy frost is possible
this weekend.

&&

.DISCUSSION...

...WINDY CONDITIONS TODAY...

Today and tonight: A low pressure system and cold front coming
ashore over western Washington and Oregon this morning will
sweep through the Pacific Northwest and bring rains, high
mountain snow, a small chance of thunderstorms and windy
conditions. This low loses definition inland later this
morning, but a secondary surface low deepens over southwest
Alberta. That and high pressure nosing into southwest Washington
will increase pressure gradients across the Inland Northwest.
Overall, expect strong southwest winds around 20-30 mph with
gusts around 40-50 mph late this morning through this evening.
Winds will start to relax around sunset and surface based
instability will erode as surface inversions form. Chances for
high mountain snow are limited to the Cascades above 5000 feet
late this afternoon through tonight.

The cold front passage this morning and early afternoon will
bring light rain to much of the region. By sunrise, the band of
precipitation will be sweeping through the Columbia Basin. This
band of precipitation along and ahead of the cold front will
have moved through most of the region by 4 PM, leaving a
conditionally unstable air mass behind it. The 500 mb cold pool
will overspread the area in the late morning and early
afternoon, with temperatures around -19 to -21C. Surface-based
CAPE will quickly increase to around 200-500 J/kg into the
afternoon. Showers will form across much of the region, bringing
the chance (10-30%) for thunderstorms, particularly near the
Canadian border. Associated threats would be brief heavy rain
(minor burn scar threat in the Cascades), gusty winds up to
50 mph (although background winds will already be strong),
small hail, and isolated to scattered lightning. Strong winds
from thunderstorm outflows and the broader-scale strong winds
will bring a risk for blowing dust across the Columbia Basin
this afternoon. The HREF 10th to 90th total precipitation for
Moses Lake through early this afternoon is only 0.04-0.12
inches, likely not enough to completely stop blowing dust.

There is a 40-60% chance of 1 inch of snow in the Enchantments
of southwest Chelan County and Washington Pass through Saturday
morning. Temperatures tonight will be much cooler in the low 30s
to mid 40s as the post frontal airmass looks dry (PWATs
50-80%).

Saturday through Thursday: Conditions look precipitation-free
through Monday as the dry airmass over the Inland Northwest
stays put. High temperatures will be near normal to slightly
below normal in the 60s. Many locations in the northern valleys
and even parts of the Spokane area to Palouse will see their
first frost or freeze with this pattern, so wrap up those
gardens. We will keep a close eye on Saturday night into Sunday
morning for frost and we may have to consider highlights. Clouds
increase Monday evening with the next system. That system will
bring beneficial rains and high mountain snow primarily to the
Cascades and north Idaho thanks to strong zonal flow. There is a
40-60% chance of 0.5 inches of rain near the Cascade crest and
a 5-10% chance for the Idaho Panhandle from Tuesday morning to
Wednesday morning. Conditions look cool, but dry after this
system with minor shortwave ridging mid to late week.
/DB/Solveig


.AVIATION...
12Z TAFS: Shower chances spread east through this morning. Winds
will increasing with frontal passage, shifting to southwest
with gust 25-40 kt between late morning and early evening. There
is a small chance of blowing dust in the Columbia Basin and
Spokane area in the afternoon but confidence is low. There is a
chance of MVFR cigs (20-40%) for KGEG-KSFF- KPUW-KCOE from
17-21z with the rain coming through. Thunderstorm chances will
be found over the northern counties, from Okanogan County to
north ID with chances in places like Omak, Colville, Sandpoint
and Bonners Ferry. Some chances may also be found over the
Columbia Basin, with risk possibly skimming across KGEG to KCOE
from 21-03Z, but the risk is too small to include in the TAFs.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in VFR conditions. Moderate to high confidence in -ra over
EAT/MWH this morning, expanding to eastern TAF sites after
16-18Z through about 20-22Z. Low to moderate confidence in MVFR
conditions at KGEG-KSFF-KCOE-KPUW. Low confidence in -tsra at
TAF sites. /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        63  42  62  38  66  40 /  80  20   0   0   0   0
Coeur d`Alene  62  42  60  38  64  40 /  90  30   0   0   0   0
Pullman        63  39  59  35  64  38 /  80  10   0   0   0   0
Lewiston       70  45  65  43  69  45 /  60  10   0   0   0   0
Colville       64  34  64  31  68  32 /  80  50   0   0   0   0
Sandpoint      62  38  57  34  64  36 /  90  70  10   0   0   0
Kellogg        62  41  56  36  62  39 /  90  40   0   0   0   0
Moses Lake     66  40  65  38  68  39 /  80   0   0   0   0   0
Wenatchee      66  47  64  46  66  47 /  80  10   0   0   0   0
Omak           64  41  64  40  66  41 /  80  40   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 11 AM this morning to 9 PM PDT this evening
     for Lower Garfield and Asotin Counties-Moses Lake Area-
     Northeast Blue Mountains-Spokane Area-Upper Columbia
     Basin-Washington Palouse-Waterville Plateau.
ID...Wind Advisory from 11 AM this morning to 9 PM PDT this evening
     for Coeur d`Alene Area-Idaho Palouse.

&&

$$