389
FXUS66 KOTX 231156
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
456 AM PDT Sat Aug 23 2025

.KEY MESSAGES...

- Warm and dry through the weekend and into next week with much
  of Central WA and the L-C Valley in areas of Major HeatRisk
  with isolated areas of Extreme HeatRisk.

- Increased fire weather concerns over the Cascades Monday and
  Tuesday for hot/dry/unstable conditions.

- Ridge breakdown by end of next week.

&&

.SYNOPSIS...
Hot and dry conditions are expected to prevail through the weekend
into early next week. Near record temperatures are expected Monday
and Tuesday during the peak of the heatwave.

&&

.DISCUSSION...
The synoptic pattern early Saturday morning includes a weakening
surface high pressure over the northern Rockies. Although the
surface high is weakening, the upper level ridge is amplifying and
establishing its hold over the Pacific Northwest. This pattern
will remain relatively stable through Tuesday with Major to
Extreme HeatRisk, fire weather concerns, and smoke/haze invading
the region.

Friday`s northeast winds filtered wildfire smoke across the Camas
Prairie and over portions of north Idaho. Air quality has
decreased and hazy skies are becoming more evident over eastern WA
and north ID. It is difficult to predict exactly how widespread
the smoke will impact air quality but the assumption is that under
high pressure and continued active wildfires, we will need to
coordinate with our air quality partners for appropriate
messaging through next week.

Temperature forecasts have not changed significantly over the last
few runs. After doing a deeper dive in the run to run consistency
of the GEFS 850 mb temps, no changes were noticed until Thursday
of next week. That is remarkable consistency through the peak of
this heatwave.

Outside of heat and air quality, the final significant weather
hazard through early next week is the hot/dry/unstable conditions
expected to develop over the Cascades. The Incident Meteorologists
deployed to wildfires in the Cascades have been exceptionally
helpful determining when and where critical fire weather
conditions are expected. With their coordination, a Fire Weather
Watch has been issued for Monday and Tuesday. For more
information about fire weather concerns, see the Fire Weather
Forecast (FWF).

Lastly, the final big questions surround when the ridge will
relinquish its hold on the PacNW and will it lead to widespread
dangerous fire weather conditions? Thankfully, successive model
runs have lowered max temps on Thursday increasing confidence
that the heatwave will mercifully come to an end. At this time,
there is not a strong shortwave or cold front expected to come
through, but rather a weak and gradual transition to a slightly
cooler airmass. Max wind gusts in the ensemble spread are only
touching 20-30 mph across the Columbia Basin. Most long range
models include max temperatures decreasing into the 80s (still
5-8 deg above normal) with the potential for showers late next
week. Then sometime around Labor Day, a trough finally positions
itself over the Inland Northwest taking temperatures down closer
to normal with the chance of rain. Maybe I`m looking too hard and
wish-casting the end of summer but at least there are some signs
that cooler temperatures may stick around longer during the first
week of September...just in time. /AB

&&

.AVIATION...
12Z TAFS: High pressure will remain in control of the area
through the weekend. Northeast winds will increase again
Saturday morning but will not be as strong as Friday. Gusty
winds at times can be expected down N-S valleys including KSZT
and KOMK. Winds should remain less than 10 kts at the TAF
locations. Scattered high clouds will move over the region but
ceilings will remain well above 12k feet. Smoke from fires in
central Idaho will move into the Idaho Panhandle and southeast
Washington through the morning, so 6SM haze was included in the
TAFs for KPUW and KLWS.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Surface smoke
output from the HRRR and RRFS show smoke moving into KPUW and
KLWS this morning with high confidence of 6SM or higher visibilities
for most of the day. The RRFS does show intermittent periods of
5SM/MVFR visibilities in the afternoon, but the HRRR keeps
visibilities above 6SM. Given these differences, confidence is
too low to include MVFR visibilities in the TAFs.

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

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        94  61  95  61  97  63 /   0   0   0   0   0   0
Coeur d`Alene  94  62  95  61  96  62 /   0   0   0   0   0   0
Pullman        94  59  97  59  94  61 /   0   0   0   0   0   0
Lewiston      101  67 101  68 101  69 /   0   0   0   0   0   0
Colville       94  52  96  52  98  55 /   0   0   0   0   0   0
Sandpoint      90  56  94  55  96  56 /   0   0   0   0   0   0
Kellogg        91  64  95  64  96  66 /   0   0   0   0   0   0
Moses Lake     98  64  99  64 100  66 /   0   0   0   0   0   0
Wenatchee      97  74  99  74 101  75 /   0   0   0   0   0   0
Omak           97  64  99  66 100  66 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory from noon today to 9 PM PDT Wednesday for
     Northeast Blue Mountains-Northeast Mountains-Okanogan
     Highlands-Spokane Area-Washington Palouse.
     Extreme Heat Warning from noon today to 9 PM PDT Wednesday for
     Central Chelan County-Lower Garfield and Asotin Counties-
     Moses Lake Area-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area-Western Okanogan County.
     Fire Weather Watch from Monday afternoon through Tuesday
     evening 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).
ID...Heat Advisory from noon today to 9 PM PDT Wednesday for Coeur
     d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce
     Counties.
     Air Quality Alert until 9 AM PDT Monday for Central Panhandle
     Mountains-Idaho Palouse-Lewis and Southern Nez Perce
     Counties-Lewiston Area.
     Extreme Heat Warning from noon today to 9 PM PDT Wednesday for
     Lewiston Area.

&&

$$