173
FXUS66 KOTX 011157
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
457 AM PDT Tue Sep 1 2026

.KEY MESSAGES...

- Warm, dry conditions continue for Tuesday.

- Active weather returns mid week. Wetter conditions with widely
  scattered rain showers and isolated thunderstorms. There is a
  50-70% chance of at least a quarter of an inch of rain
  Wednesday through Wednesday night in the mountains.

- Gusty southerly winds Wednesday afternoon across the Columbia
  Basin and Okanogan Valley may result in visibility reductions
  from blowing dust.

&&

.SYNOPSIS...
Warming, dry pattern through Tuesday will push highs back into
the 80s. Active weather returns Tuesday night through the rest
of the workweek with widely scattered showers and isolated
thunderstorms, breezy winds and temperatures cooling back below
normal.

&&

.DISCUSSION...
Today and tonight: One more warm to hot day, before a pattern
change. A broad trough sits off the Pacific Coast and a mild
southerly flow is found in advance of it. In that flow some
shortwave energy begins to eject northward. A more notable wave
comes around the east third of WA and ID this afternoon and
evening, with deepening moisture (PWATS 130-150% of normal). It
also encounters modestly steep lapse rates. The previous forecast
and the NBM have not shown much precipitation potential during the
day, but most of the CAM models are indicating some showers
developing with it and the NBM has been under-doing this kind of
thing much of the summer. So I increased PoPs for this afternoon
and evening over the east third of WA and ID. I do not think it
will be very significant amounts, but some showers are definitely
possible. I do not have enough confidence for t-storms but that is
not out of the question; the main potential is found over SE
WA/lower ID this afternoon and some may slip northward tonight.
Some breezy conditions develop this afternoon as well, with gusts
of 15-20 mph. Temperature push into the 80s this afternoon.

Wednesday and Thursday: The offshore low spirals inland. This
will bring periods of rain to the Inland NW as shortwave pivot
around it. The first round is forecast to increase through the
day Wednesday and a second Wednesday night into Thursday AM. The
highest precipitation potential and amounts are forecast around
the southeast WA and mountains zones, with around 0.25 to 0.50
inches through Thursday night, locally higher. Some embedded
t-storms are also forecast, but they are not expected to be very
strong at this time. We will have to keep an eye on any burn
scars that may see rain for possible flooding/debris flows, but
confidence is low.

Winds will be breezy through the period, with the strongest winds
on Wednesday out of the south to southwest gusting between 20 to
40 mph. The strongest winds are forecast over central WA. Central
WA will have less rain than other areas, so we will have to watch
for some patchy blowing dust. Gusty winds are forecast for
Thursday as well, with gusts around 15-30 mph. Temperatures will
be notably cooler, with highs in the mid-60s to upper 70s
Wednesday and 60s to low 70s Saturday. Overnight lows will start
to drop in the 30s and 40s in spots. We will have to keep an eye
toward possible frost in some areas over eastern WA and ID, in the
sheltered valley and outlying areas, Thursday night into Friday
AM.

Friday to Monday: The Inland NW remains dominated by low pressure, as
models trend to the low being cut off from the jet over the
weekend. Ensembles continue to retrograde it off the Oregon coast
into the weekend. This will allow for the showery pattern to
continue, with occasional embedded t-storm chances. Models are not
entirely consistent on that detail but at this time Sunday has
some higher potential. Expect some moderating temperatures into
the weekend, though patchy frost may still be possible in
sheltered valleys and outlying areas Saturday morning. /Solveig

&&

.AVIATION...
12Z TAFs: VFR conditions expected to prevail with build middle
and high clouds. A wave passing by the area Tuesday afternoon
may bring some brief light showers between 18-01Z over eastern
WA/ID, including KGEG,KSFF,KCOE,KPUW,KLWS, but confidence is
low to include in the TAF. Smoke and haze will be present in
the Cascades valleys primarily down the Entiat River drainage
and Lake Chelan, and north of the Wenatchee Airport (KEAT).

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence for VFR conditions to continue at TAF sites. A
low probability alternate scenario is for some smoke and haze to
filter down drainage into KEAT, but little to no chance for
visibility to drop below 5SM. Low confidence in showers between
18Z Tuesday to 01Z Wednesday.

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

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        85  51  70  48  65  41 /  30  20  60  80  50  30
Coeur d`Alene  87  51  68  47  64  42 /  20  20  80  90  80  30
Pullman        81  43  67  39  63  35 /  20  20  80  90  70  50
Lewiston       86  57  72  54  69  48 /  20  20  80  90  70  50
Colville       86  44  71  39  65  33 /  20  20  30  70  70  40
Sandpoint      86  46  66  40  61  36 /  20  20  80  90  90  50
Kellogg        87  49  64  45  60  40 /  40  30  90  90  90  40
Moses Lake     84  53  76  47  69  41 /   0   0   0  40  20  10
Wenatchee      86  61  76  57  68  51 /   0  10  10  50  40  30
Omak           87  54  77  52  69  45 /   0  10  10  50  60  20

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Air Quality Alert until 10 AM PDT Wednesday for Central Chelan
     County-Okanogan Valley-Upper Columbia Basin-Waterville
     Plateau-Wenatchee Area-Western Chelan County.
ID...None.

&&

$$