361
FXUS66 KOTX 220003
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
503 PM PDT Fri Aug 21 2026

.KEY MESSAGES...

- A Heat Advisory has been issued through Friday evening due to
  very warm temperatures and widespread Major HeatRisk.

- Saturday system brings increased chances for showers,
  thunderstorms, and gusty winds. This will lead to critical
  fire weather conditions across the Inland Northwest.

- Patchy blowing dust is possible Saturday in the Western
  Columbia Basin.

&&

.SYNOPSIS...
Temperatures will be very warm Friday with widespread Major
HeatRisk. A pattern change Friday night into Saturday will
bring unsettled conditions with chances for showers,
thunderstorms, and gusty winds. Sunday will remain breezy and
dry, but cooler. Temperatures will warm again at the start of
next week with breezy conditions returning by the middle of next
week.

&&

.DISCUSSION...
Friday through Sunday: An incoming cold front will bring gusty winds
and isolated to scattered thunderstorms to the region Saturday into
Sunday. Today, ahead of the cold front passage on Saturday,
temperatures have warmed into the high 90s with triple digits
possible in the lower Basin. This has led to widespread Major
HeatRisk values, so anyone without adequate cooling and
hydration as well as health systems and industries could see
impacts. A Heat Advisory is valid through much of the Inland
Northwest through 10 PM this evening and low temperatures into
tomorrow will be in the 60s and 70s and provide little overnight
relief.

Tonight into Saturday, moisture advection ahead of the frontal
passage will raise PWATs to 125 to 150 percent of normal, around
0.75 to 1 inch. The arrival of the cold front on Saturday
accompanied by a 40-50kt 500mb jet and warm overnight and daytime
temperatures will create a favorable environment for isolated to
scattered thunderstorms across the Cascades and northern mountains.
While these showers will initially start out as isolated in nature,
as daytime warming increases, thunderstorms become more scattered in
nature, especially into Saturday afternoon and evening. With PWATs
near 1 inch and DCAPE values 500 J/kg and higher, main impacts look
to be isolated heavy rainfall rates, gusty outflow winds up to 50
mph, and lightning induced fire starts. Steep terrain and burn scars
will need to be monitored for any heavy rainfall rates. This threat
will move eastward across the forecast area through the day, and
Saturday night into Sunday morning the ID Panhandle sees isolated to
scattered thunderstorms. To reflect these critical fire weather
conditions, Red Flag Warnings have been issued. For the
Cascades and northern mountains, the Red Flag Warning is valid from
Saturday morning through Sunday morning. For the ID Panhandle,
the Red Flag Warning is valid from Saturday afternoon through
Sunday morning.

Another impact from this cold front will be gusty winds leading to
critical fire weather concerns across the Basin and Spokane area.
There is a 40 percent chance and higher for most locations in the
region to see wind gusts higher than 30 mph on Saturday night. Areas
that will see the highest gusts include the Lewiston, Moses Lake,
Wenatchee, and Waterville Plateau areas. A Red Flag Warning for
the basin, Palouse, and Spokane areas is valid from Saturday
afternoon through Saturday evening. Potential impacts from these
winds include rapid spreading of wildfires alongside blowing
objects and difficulties driving, especially for high profile
vehicles.

While models initially had the low moving out of the area quicker,
there is now better agreement that the low lingers over the state of
Washington through Sunday before moving out of the area Sunday night
into Monday. Impacts will continue to be seen into Sunday afternoon
with residual winds and isolated to scattered thunderstorms in the
northern Idaho Panhandle. One thing to keep a close eye on is the
extent of the thunderstorms post cold frontal passage on Sunday
morning. As high-res models pick up the end of the event Sunday
morning, they are showing enough lingering instability throughout
fire zone 708 (Eastern Columbia Basin/Palouse/Spokane area) that it
may need to be added into the Red Flag Warning. Wind gusts around 15-
20 mph will linger throughout the Cascade gaps, Okanogan Valley,
Waterville Plateau, Columbia Basin, Spokane/CdA, and Palouse areas
through late Sunday afternoon, bringing continued elevated fire
weather conditions.

A significant cooldown due to the cold front will be observed
Saturday into Sunday, with high temperatures dropping around ten or
more degrees. Temperatures will end up being a couple degrees below
normal on Sunday. Apart from the northern mountains and Cascades,
precipitation chances drop down to near zero.

Monday through Wednesday: With high confidence (80 percent of
clusters) indicating a strengthening ridge building over the area
early next week, the temperature drop will be short lived. By
Tuesday, temperatures will again warm into the high 80s to low 90s.
Clusters show a 50 percent chance of another trough approaching the
PNW coast, though timing and track are uncertain. This could lead to
a return of gusty winds and thunderstorm chances. Overall chances
for precipitation remain low, with PoPs 15 percent and lower
expected Monday through Wednesday. /AS

&&

.AVIATION...
00Z TAFs: VFR conditions are expected to continue through the
TAF period except KEAT. There will be elevated showers that move
through the region late this evening and overnight. There is a
small chance (10-15% chance) of sprinkles) from 06-15Z for most
TAF sites as a vort max moves through. Chance of TS out of these
is very low (5%) but cannot be ruled out. Bands of convection
will form in the Cascades in the very late morning to early
afternoon and eventually SE WA and southern ID Panhandle around
23-00z. Confidence is too low for TS in the TAF but there is a
10-20% chance around 00z for KLWS-KPUW-KEAT. Vsbys at KEAT will
degrade this evening around 07-08z as northwest winds bring in
smoke from the Little Giant Fire. South to southwest winds will
increase in the Columbia Basin, Palouse, and Spokane area in the
late morning to early afternoon.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence
for TS impacts before 0Z for KEAT-KLWS-KPUW.

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

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        68  94  59  82  54  87 /  10  10  20   0   0   0
Coeur d`Alene  68  95  60  81  53  86 /  10  10  40   0   0   0
Pullman        62  91  51  78  46  86 /  10  10  30   0   0   0
Lewiston       72  98  62  87  59  92 /  10  10  40   0   0   0
Colville       60  95  52  81  45  87 /  10  10  40  10   0   0
Sandpoint      62  93  56  77  47  83 /  10  20  40  10   0   0
Kellogg        63  92  55  77  52  84 /  10  10  40   0   0   0
Moses Lake     69  95  56  85  54  89 /  10  10   0   0   0   0
Wenatchee      76  94  63  83  62  88 /  20  20   0   0   0   0
Omak           71  96  56  85  56  88 /  10  20  20  10   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory until 10 PM PDT this evening for Central Chelan
     County-Lower Garfield and Asotin Counties-Moses Lake Area-
     Northeast Blue Mountains-Northeast Mountains-Okanogan
     Highlands-Okanogan Valley-Spokane Area-Upper Columbia
     Basin-Washington Palouse-Waterville Plateau-Wenatchee
     Area-Western Okanogan County.
     Red Flag Warning from 4 PM Saturday to 11 AM PDT Sunday for
     Selkirk Mountains of Northeast Washington (Zone 700).
     Red Flag Warning from noon to 10 PM PDT Saturday for Colville
     Reservation (Zone 702)-Eastern Columbia Basin  -Palouse  -
     Spokane Area (Zone 708)-Foothills of Central Washington
     Cascades (Zone 705)-Foothills of Northeast Washington
     (Zone 701)-Lower Palouse  -Snake River (Zone 709)-
     Waterville Plateau (Zone 706)-Western Columbia Basin
     (Zone 707).
     Air Quality Alert until 2 PM PDT Monday for Central Chelan
     County-Okanogan Highlands-Okanogan Valley-Upper Columbia
     Basin-Waterville Plateau-Wenatchee Area-Western Chelan
     County-Western Okanogan County.
     Red Flag Warning from 11 AM Saturday to 8 AM PDT Sunday 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)-Methow Valley (Zone 704)-Okanogan
     Highlands and Kettle Mountains (Zone 699)-Okanogan Valley
     (Zone 703).
ID...Heat Advisory until 10 PM PDT this evening for Central
     Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
     Lewis and Southern Nez Perce Counties-Lewiston Area-
     Northern Panhandle.
     Red Flag Warning from 4 PM Saturday to 11 AM PDT Sunday for
     Northern and Central Idaho Panhandle (Zone 101).

&&

$$