074
FXUS66 KOTX 271803
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1103 AM PDT Sun Sep 27 2026

.KEY MESSAGES...

- Areas of frost Monday morning over eastern Washington and
  Idaho Panhandle mountain valleys and Upper Columbia Basin, as
  well the outlying areas around the Spokane area.

- Mild and dry pattern this week, except for rain near the Cascade crest
  and chance of rain North Idaho Panhandle on Tuesday

&&

.SYNOPSIS...
Chilly fall like overnight temperatures will result in areas of
frost for Monday morning again over Northeast Washington and the
Idaho Panhandle as well as the Upper Columbia Basin. Moisture
off the Pacific will bring rain to the Cascade crest on Tuesday,
but remaining mostly dry east of the Cascades. Temperatures
will moderate back to near normal next week. Seasonal
temperatures then continue through the rest of the work week.

&&

.DISCUSSION...
Today through Monday: A dry air mass will remain over the Inland
NW through Sunday night with precipitable water values ranging
from near 40-70 percent of normal. This combined with light
winds will promote strong radiational cooling with areas of
frost. Another Frost Advisory has been issued from 12 AM to 9 AM
PDT Monday for areas still within their climatological growing
season where areas of frost are forecast. This includes the
Upper Columbia Basin, Moses Lake area, and outlying areas around
the Spokane and Coeur d`Alene area. For high temperatures
gradual warming is expected for Monday as southwest flow
develops ahead of the next system. High temperatures on Monday
will be right near normal values with readings in the mid 60s to
low 70s.

Monday Night and Tuesday: A weak atmospheric river takes aim at
the region with an increase in moisture as precipitable water
increases to 150-200 percent of normal. Yet with the strong
westerly flow and dry air mass to start, precipitation will have a
hard time reaching the ground other than potential sprinkles, and
a chance for light rain over the northern mountains. Upslope flow
into the Cascade crest will lead to wet conditions with around
0.50-1.00 inch of rain, with light rain spilling over the crest
into the upper reaches of the Methow Valley, Lake Chelan, and Lake
Wenatchee.

Wednesday through Saturday: Following Tuesday`s influx of clouds
and areas of light rain or sprinkles, the weather looks very
quiet for the rest of the week. A mild west-southwest flow
pattern occurs for the rest of the week with weak ridging bringing
near to slightly above normal temperatures. About 25 percent of
the model clusters show the stronger ridge building in sooner, by
Friday, which would result in a more rapid warming trend by
Saturday if realized. JW

&&

.AVIATION...
18Z TAFS: Broken to overcast cirrus will be present through
much of the day. Ceilings with lower between 12-15k ft AGL at
times, especially around Lewiston and Pullman as a shortwave
passes south of the region.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
for VFR conditions at all TAF sites. There is a small risk for
sprinkles around KLWS from the thicker midlevel clouds. This
comes with low confidence and was left out of the forecast at
this time. JW

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

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  39  68  45  68  47 /   0   0   0   0   0   0
Coeur d`Alene  63  35  66  43  65  47 /   0   0   0   0  10  10
Pullman        63  38  66  42  68  45 /   0   0   0   0   0   0
Lewiston       66  46  71  46  75  53 /   0   0   0   0   0   0
Colville       66  28  69  41  67  36 /   0   0   0   0  10   0
Sandpoint      62  31  64  41  61  41 /   0   0   0   0  10  20
Kellogg        63  36  64  42  63  47 /   0   0   0   0  10  30
Moses Lake     68  35  71  46  72  45 /   0   0   0   0   0   0
Wenatchee      67  46  71  50  69  51 /   0   0   0   0  10  10
Omak           68  36  70  48  68  42 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Frost Advisory from midnight tonight to 9 AM PDT Monday for
     Moses Lake Area-Spokane Area-Upper Columbia Basin.
ID...Frost Advisory from midnight tonight to 9 AM PDT Monday for
     Coeur d`Alene Area.

&&

$$