800
FXUS66 KOTX 041114
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
414 AM PDT Fri Sep 4 2026

.KEY MESSAGES...

- Cool and showery weather expected through Labor Day Weekend with
isolated thunderstorms.

- A warming and drying trend returns around the middle of next week.


&&

.SYNOPSIS...
Active weather sticks around through Labor Day Weekend with
scattered showers, isolated thunderstorms, and cooler than normal
temperatures. A warming and drying trend commences around the middle
of next week as higher pressure returns to the region.

&&

.DISCUSSION...

Friday through Monday: An upper level low pressure system will spin
over the Inland Northwest keeping temperatures seasonably cool and
the weather active. The center of the low is situated over northwest
Oregon. A deformation band forming on the eastern flank will swing
across the Idaho Panhandle through early Friday morning.
Periods of light to moderate rain will soak the ground from the
Lewiston- Clarkston Valley up across the Palouse region, and
across the southern to central Idaho Panhandle. Total
precipitation under this band will be up to between 0.50-1.0
inches across much of this area. Much needed rainfall after a
warmer and drier than average June- August. Steady rain will
transition to showers for Friday afternoon. Showers will favor
the higher terrain, but even the Columbia Basin will see at
least isolated showers. Weak surface based instability over the
Cascades and the mountains of north-central Washington will
bring an isolated threat for thunderstorms. Any storms that
develop this afternoon will be capable of brief heavy rain, and
infrequent lightning strikes.

The center of the upper level low wobbles around over the Northwest
Region through at least Sunday. This will keep the region
conditionally unstable. Best chances for showers will come in the
afternoon with diurnally forced showers. Perturbations that
spin around the upper low will also help to force precipitation.
The next one looks to be around Saturday afternoon with more
organized development of showers across extreme eastern
Washington into the Idaho Panhandle. Then another round with
another shortwave spinning in across these same areas for Sunday
night into Monday. It`s really tough to pin point how much
precipitation will fall as there will be some convective
elements in place with modestly steep lapse rates at mid levels
of the atmosphere. There will be the potential for heavier
showers that brings wetting rains (greater than a tenth of an
inch), and this will all largely be beneficial for the ongoing
drought across the region. Where rain may be of a nuisance is if
it gets heavy over a recent burn scar, and that would bring a
small chance for minor flooding impacts.

The upper level low gets picked up by the Polar Jet stream around
late Sunday into Monday. A 30-60% chance of precipitation will
continue across the eastern half of the region while the Cascades
begins to dry out. Temperatures will be below normal with highs
generally in the upper 60s to mid 70s through Labor Day Weekend.
Breaks in the cloud cover overnight may yield patchy fog as rain
will moisten up the boundary layer. The next few days is a reminder
that the fall season is right around the corner.

Monday night through Friday: The Inland Northwest remains under a
baggy longwave trough of low pressure into next week. A longwave
high pressure area will be situated over the central portion of the
U.S. The trough axis will be situated more offshore and it looks to
dig around the Tuesday into Wednesday timeframe. The equatorial
Pacific is also quite active with tropical systems, and there`s some
indication that one of these systems could get entrained into the
mid latitudes off of the coast of Baja California by Wednesday. This
tends to muck up the models with reduced confidence in the extended
forecast. The general consensus, however, is that the ridging in the
central U.S. will build in toward the Inland Northwest with a
warming and drying trend around mid week. We will need to keep an
eye on that tropical moisture for later in the week though as
there is a possibility for some of that to get entrained and
advect northward into the region. Early indications is that if
this happens, it will be a small fraction and won`t be more than
a minor impact. /SVH

&&

.AVIATION...
12Z TAFS: Light to moderate rain will fall across extreme
eastern Washington into the Idaho Panhandle this morning under
a deformation band for the next 4-6 hours. Ceilings will
approach but most likely stay above MVFR for KGEG and KSFF as
this band has been under performing in southeast Washington.
Ceilings will lift to VFR for KCOE around 18z as showers depart
to the north. Isolated afternoon thunderstorms expected over
the Cascades and mountains of north-central Washington late
this morning into the afternoon.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
for VFR conditions after the band of rain in central Washington
departs northward after 18z.

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

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        67  44  70  46  72  48 /  40  10  20  20  10  40
Coeur d`Alene  67  44  71  46  73  48 /  50   0  30  20  30  50
Pullman        65  41  68  41  70  42 /  50   0  20  10  20  50
Lewiston       70  51  73  52  74  54 /  30  10  30  10  20  60
Colville       67  39  71  39  74  42 /  30   0  30  30  10  30
Sandpoint      65  42  68  43  71  45 /  40   0  30  20  30  40
Kellogg        63  42  68  45  70  47 /  50  10  40  20  40  60
Moses Lake     71  45  72  46  76  48 /  10   0  20  20  10  30
Wenatchee      70  52  71  54  76  58 /  20  10  40  20  10  30
Omak           70  46  72  47  74  49 /  10  10  30  40  10  20

&&

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

&&

$$