932
FXUS66 KOTX 290122
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
622 PM PDT Thu Aug 28 2025

.KEY MESSAGES...

- Scattered showers with isolated thunderstorms through Friday.
  Thunderstorms will be capable of heavy rainfall.

- Warming up into the 90s next week, locally near 100, with
  elevated HeatRisk. Record warm temperatures for September
  possible.

&&

.SYNOPSIS...
An area of low pressure will bring scattered showers and
isolated thunderstorms to the Inland Northwest through Friday.
Thunderstorms will bring the potential for heavy rainfall
particularly in the Cascades and in the Idaho Panhandle.
Isolated showers and thunderstorms expected in the Cascades over
the weekend. Hot temperatures return next week with highs
climbing back into the 90s to near 100 degrees.

&&

.DISCUSSION...

Tonight and Friday: An upper level low pressure area will
continue its slow march northward across the Inland Northwest.
Lower heights with the trough extend west to east across the
region where mid to high level clouds are currently and very
light precipitation is falling in spots. A more well defined low
pressure circulation is spinning over western Washington. This
compact low is push across a vorticity maximum into the Cascades
this afternoon where ample moisture and surface based
instability will result in showers and thunderstorms into this
evening. Otherwise, there is a lot of moisture with P-wats
180-200% of normal; however, a lack of good synoptic lift is
holding back convection from forming away from the Cascades.
There is potential over the mountains where differential heating
may result in isolated storm cells. The atmosphere will be
similarly conditionally unstable across the northern mountains
into the Idaho Panhandle for Friday. A lack of good synoptic
lift will once again limit convection to being isolated in
coverage.

Friday night through Sunday night: A deep upper level low
pressure system will approach the Northwest off of the eastern
Pacific. This will have the effect of pumping up a ridge of high
pressure over the region. Some moisture and limited amount of
forcing on the backside of the ridge will result in isolated
showers and thunderstorms over the Cascades. The building ridge
will win out and keep the low offshore from advancing much more
eastward through the weekend. Temperatures will warm back up
with highs climbing into the mid 90s by Sunday.

Monday through Thursday: Temperatures will continue to warm into
next week and become hot. Highs will warm up into the upper 90s
to near 100 by Monday into Tuesday. It will be record heat if
the forecast temperatures verify. It`s possible that some places
will see their warmest temperatures on record for the month of
September. Spokane hasn`t seen a 100 degree day in the month of
September and that mark may be reached on Tuesday with a 20%
chance of occurring. Major HeatRisk will be expanding across the
region during this period as well. Model guidance suggests
gradual cooling around mid week, but there is uncertainty with
how the ridge eventually breaks down. /SVH

&&

.AVIATION...
00Z TAFS: Low pressure will be over the Inland Northwest with a
conditionally unstable air mass through Friday. Diurnal heat
will result in pop up showers with isolated to scattered
afternoon thunderstorms near the Cascades this evening then
shifting into the northern mountains for Friday afternoon.
Thunderstorms will be capable of torrential rainfall and will
be slow moving. The heavy rain may result in ponding of water on
runways and air strips under where they develop.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in continued VFR conditions at most TAF sites. Low confidence
for thunderstorms impacting airport terminals. Wenatchee
Airport (KEAT) will see a 30% chance for thunderstorms today,
while KGEG,KSFF,KCOE,KPUW,KLWS,KMWH will see a less than 20%
chance for thunderstorms. /SB

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

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:/weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        58  89  60  92  62  95 /  10  10   0   0   0  10
Coeur d`Alene  61  88  60  92  62  96 /  10  20   0   0   0   0
Pullman        53  87  54  90  59  93 /   0   0   0   0  10   0
Lewiston       64  94  65  97  66  99 /   0   0   0   0   0   0
Colville       51  88  49  92  51  93 /  20  30  10   0  10  10
Sandpoint      55  83  53  90  55  93 /  20  20  10   0   0  10
Kellogg        60  83  62  89  64  93 /  30  30  10   0   0   0
Moses Lake     60  93  59  95  65  95 /   0   0   0   0  10  10
Wenatchee      67  93  68  94  71  93 /  10   0   0   0  20  10
Omak           63  93  63  96  66  96 /  20  10   0   0  10  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Flood Watch until 9 PM PDT this evening for Central Chelan
     County-Okanogan Highlands-Okanogan Valley-Wenatchee Area-
     Western Chelan County-Western Okanogan County.
ID...Air Quality Alert until 10 AM PDT Tuesday for Lewis and
     Southern Nez Perce Counties-Lewiston Area.

&&

$$