982
FNUS76 KOTX 172041
FWSOTX

Spot Forecast for Upper Smith...USFS
National Weather Service Spokane WA
141 PM PDT Mon Aug 17 2026

Forecast is based on forecast start time of 1300 PDT on August 18.
.DISCUSSION...

209:
Another period of relatively warm and moist air remained in place
over the fire on Monday. Good to Excellent overnight humidity
recovery has set up Monday to see a slow drying as we move toward
minimum humidities in the mid 30 percent range during the day
Monday. Afternoon temperatures climbed to the mid 70s to mid 80s.
Daytime heating along with a weak weather disturbance to the north
resulted in afternoon cumulus cloud development. Isolated areas of
showers and thunderstorms were observed. Winds were light with
speeds less than 10 mph away from thunderstorm outflows that
reached close to 25 mph.

The air mass will remain mild with a subtle drying trend Monday through
Wednesday. The threat for afternoon showers and thunderstorms
will lower through the week closer to 10-15%. Winds will be light
and mainly terrain driven with increasing southerly breezes near
the US 95 corridor on Wednesday.

Discussion:
Expect a subtle warming and drying trend the next several days.
There remains a 5-10% chance for afternoon showers and
thunderstorms Tuesday (1300-2000). Any thunderstorms that do
develop in the afternoon will be capable of producing brief heavy
downpours and gusty, erratic winds. Winds will generally be light
and terrain driven away from outflow winds from nearby
thunderstorms. On Tuesday, midlevel winds increase slightly from
the southwest and again could be stronger and erratic with any
thunderstorm development. This is reflected in the transport winds
and would only impact the highest ridges.


If conditions become unrepresentative, contact the National Weather
Service.
***************************************************************
Forecasts for 20 foot wind speeds (valleys and ridge tops) are
10 minute averages reflecting RAWS wind.
***Ventilation Index is derived from transport wind
   multiplied by the mixing height divided by 100.
   Categories: low (< 200), moderate (200-500),
   high (500-800), and very high (> 800).
***************************************************************

.TUESDAY...

Sky/weather.........Sunny. Patchy smoke.
CWR.................0 percent.
Chance of lightning.5 percent.
Max temperature.....Around 71.
Min humidity........35 percent.
Wind (20 ft)........Southwest winds around 5 mph, gusts 10 to 12 mph.
Mixing height.......8500 ft AGL.
Transport winds.....Southwest around 12 mph.
Ventilation Index...Very high (906).

.TUESDAY NIGHT...

Sky/weather.........Partly cloudy.
CWR.................0 percent.
Chance of lightning.0 percent.
Min temperature.....Around 56.
Max humidity........52 percent.
Wind (20 ft)........West winds around 5 mph in the evening becoming
                    light.
Mixing height.......6000 ft AGL falling to 500 ft AGL.
Transport winds.....Southwest 6 to 8 mph.
Ventilation Index...High (717) decreasing to low (30) overnight.

.WEDNESDAY...

Sky/weather.........Sunny.
CWR.................0 percent.
Chance of lightning.0 percent.
Max temperature.....Around 70.
Min humidity........33 percent.
Wind (20 ft)........Light winds becoming south around 5 mph in the
                    afternoon.
Mixing height.......4000 ft AGL increasing to 7500 ft AGL in the
                    afternoon.
Transport winds.....Southwest 5 to 9 mph.
Ventilation Index...Moderate (240) increasing to high (623) in the
                    afternoon.

$$
Forecaster...CD
Requested by...David Pearson
Type of request...WILDFIRE
.TAG 2619090.12/OTX
.DELDT 08/17/26
.FormatterVersion 2.0.0
.EMAIL IDCDC@firenet.gov,david_pearson@firenet.gov,2026.uppersmith.plans@firenet.gov