Severe Thunderstorm Warning 24, NWS Spokane, WA

Area Forecast Discussion
National Weather Service Spokane WA
442 PM PDT Thu Jul 16 2026

.KEY MESSAGES...

- A mix of wet and dry thunderstorms through Friday will bring
  lightning, hail, and strong outflow winds.

- Breezy, dry conditions around the lee of the Cascades Friday
  and breezy and dry conditions across the region Saturday.

- Dry conditions this weekend, with temperatures remaining warm
  in the upper 80s and 90s.

&&

.SYNOPSIS...
Hot and unstable conditions, low humidity, lightning, and
gusty winds will maintain critical fire weather conditions
across portions of Central and Eastern Washington through at
least Thursday. Dry conditions resume this weekend.

&&

.DISCUSSION...
This afternoon through Friday: An evolving risk for isolated to
scattered showers and thunderstorms will be found this period,
as a low pressure trough tracks up the Washington coast and
eventually into British Columbia by late Friday night. This
afternoon that low sits off the WA coast and it is projected to
lift toward Vancouver Island by Friday morning. A deformation
axis wrapping from Idaho westward toward the Cascades will edge
north through that period too, then all these features will
start to lift into British Columbia. The moist and unstable
southerly flow ahead of and into that feature will be one of the
focal points for the precipitation threat. However the general
set-up will bring a risk for isolated showers/t-storms just
about anywhere in hit-and-miss fashion. Analysis shows around
500-2000 J/kg of CAPE are found around the region, with the
highest numbers around the central to southern Panhandle;
however, there is a 25-250 J/kg CIN that may be inhibiting some
of the convection from developing. The lift at this point it not
all that impressive to overcome that, but as we head into the
remainder of the afternoon into tonight activity is expected to
expand. For the afternoon and evening Friday the risk for
showers/t-storms linger near the Canadian border and around the
central Panhandle, with a slot of drier air wrapping into the
region reducing that threat of precipitation.

Right now the main activity around the 2 pm hour was showing up
from the Palouse to the Idaho Panhandle in isolated fashion.
However, the low edging closer and deformation axis lifting
north, I am expecting the showers to expand around the Cascades,
north and eastern WA and the ID Panhandle through this
afternoon and evening. Then heading into the overnight into
Friday morning the threat starts to lift the primarily the
northern mountain zones. Some of these thunderstorms will have
the potential for gusty outflow winds, small hail and lightning.
The SPC still has a marginal threat of severe t-storms over the
eastern third of WA and ID, so some of these produce strong
outflow winds (up to 60 mph) and hail (up to 1 inch). The
overall better threat of that is toward the ID/MT border
eastward, but this will still be monitored.

The threat of lighting and gusty outflow winds is reason for
the Red Flag Warnings that are currently in place. The cells
have been moving at a pretty good clip, around 30 to 40 mph and
lightning outside of the core of the storms and just given the
speed suggest this would be mostly dry lightning. So the risk
for fire starts remains. The other fire weather concerns will be
found heading into Friday afternoon due to breezy/windy and dry
conditions. Per the HREF, the combined probability of RH <20%
and winds >15 mph from the Okanogan Valley to Waterville Plateau
is starts to rise after midday and peaks in the late afternoon
to early evening. Thus fire weather watches remain in place for
some of that area, the Okanogan and Methow Valley for Friday
from noon to 9 pm. Relative humidity values bottom out around
the mid-teens with winds of 10-20 mph and gusts of 25-30 mph.

Saturday through Wednesday: Ensemble show the low pressure
continuing to track over British Columbia and east into Alberta,
but a secondary shortwave trough track around the backside of
the parent trough and into our region Saturday into Sunday,
before a dirty ridge takes over. The drier air over the region
means that the shortwave will not have much to work with in
terms of precipitation, meaning a dry weekend. However heading
toward Tuesday some monsoonal moisture edges toward again some
limited shower/t-storm chances will reemerge near the
southeastern CWA and eventually into most of the mountain zones
toward Wednesday (into next Thursday). We will see about the
lowland risk as we get closer.

Winds will be breezy/gusty on Saturday with the low still
tracking by, so speeds of 10-20 mph and gusts of 20-30 mph are
in the forecast. With minimum RH values in the teens and 20s, we
will have some elevated fire weather conditions with possible
pockets of critical fire weather conditions. High temperatures
will hover in the upper 80s to mid 90s through Sunday, warming
to mainly the 90s to low 100s next week but the model spread
starts to introduce some uncertainty into the forecast as to the
precise numbers. /Solveig

&&

.AVIATION...
00Z TAFS: Low pressure off the Northwest Pacific coast will
continue to promote a moist southerly flow across the region
through tonight across eastern WA and north ID. Elevated
instability in this airmass will promote occasional isolated to
scattered showers and thunderstorms. Radar and hi-res model
trends suggest a diminishing threat for thunderstorms near the
TAF sites through tonight so have removed -TSRA mention with
this update, but will continue to monitor as there will be a
nonzero threat through tonight. Greatest chances for -TSRA this
afternoon will be near KLWS/KPUW, and across northeast WA and
north ID (north of KGEG/KSFF/KCOE) thereafter tonight. Further
west towards the Cascades, drier weather will prevail with
occasionally gusty gap winds until early Friday morning.
Otherwise, VFR weather will prevail through the 00z TAF cycle.

Breezy south to southwest winds develop east of the Cascades
Friday, with gusty west-northwesterly gap winds closer to the
range. Some measure of -TSRA activity may roll over across the
northern mountains (mainly NE Washington/N Idaho) through 18z
Friday.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence in VFR prevailing region-wide. Low confidence in
timing and coverage of showers and thunderstorms through Friday
morning with several sporadic waves of convection possible.
Moderate confidence in the greatest chances for convection
tonight through Friday morning being across northeastern WA and
north ID.

-----------------------
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        62  92  59  91  59  92 /  30  10   0   0   0   0
Coeur d'Alene  64  91  61  90  59  90 /  40  10  10   0   0   0
Pullman        54  86  53  86  52  88 /  30  10  20   0   0   0
Lewiston       66  95  63  96  62  96 /  40  10  10   0   0   0
Colville       60  93  55  91  54  94 /  20  30   0   0   0   0
Sandpoint      60  91  58  89  56  91 /  50  20   0   0   0   0
Kellogg        60  89  59  87  56  87 /  50  10  10   0   0   0
Moses Lake     62  93  59  93  58  94 /  10  10   0   0   0   0
Wenatchee      66  93  64  91  64  94 /  10  10   0   0   0   0
Omak           68  95  62  94  62  96 /  30  10   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Red Flag Warning until 11 AM PDT Friday for Colville
     Reservation (Zone 702)-Okanogan Highlands and Kettle
     Mountains (Zone 699)-Okanogan Valley (Zone 703)-Selkirk
     Mountains of Northeast Washington (Zone 700).
     Heat Advisory until 9 PM PDT this evening for Lower Garfield
     and Asotin Counties-Moses Lake Area-Okanogan Valley-
     Spokane Area-Upper Columbia Basin-Washington Palouse-
     Waterville Plateau-Wenatchee Area.
     Red Flag Warning until 11 PM PDT this evening for Eastern
     Columbia Basin  -Palouse  -Spokane Area (Zone 708)-
     Foothills of Northeast Washington (Zone 701)-Lower
     Palouse  -Snake River (Zone 709).
     Fire Weather Watch from Friday afternoon through Friday
     evening for Methow Valley (Zone 704)-Okanogan Valley
     (Zone 703).
     Red Flag Warning until 5 AM PDT Friday for East Portion of
     North Cascades National Park/Lake Chelan National
     Recreation Area (Zone 697)-East Washington Central
     Cascades (Zone 696)-East Washington North Cascades (Zone
     698)-Foothills of Central Washington Cascades (Zone 705)-
     Methow Valley (Zone 704)-Waterville Plateau (Zone 706).
ID...Red Flag Warning until 11 AM PDT Friday for Northern and
     Central Idaho Panhandle (Zone 101).
     Heat Advisory until 9 PM PDT this evening for Coeur d'Alene
     Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-
     Lewiston Area.

&&

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