649
FNUS76 KOTX 132009
FWSOTX

Spot Forecast for Upper Smith...USFS
National Weather Service Spokane WA
109 PM PDT Thu Aug 13 2026

Forecast is based on forecast start time of 1300 PDT on August 14.
.DISCUSSION...

209:
Showers and thunderstorms moved through the Upper Smith Fire
early Thursday morning producing erratic wind gusts to 25 mph.
A nearby RAWS reported 0.47 inches of rain.  Conditions remained
cool and cloudy through the afternoon with spotty showers but
little in the way of additional rainfall.  Temperatures warmed
into the 50s-60s with humidity levels around 70%.

Friday will be warmer with breaks in the clouds allowing temperatures
to rebound into the 60s to lower 70s.  Scattered cumulus buildups in the
afternoon have a 10-20% chance of maturing into showers or weak
thunderstorms. High pressure building over the area will continue
to promote warming and drying through the weekend though residual
moisture will lead to good recoveries at night and afternoon humidity
levels above 30%.

Discussion:
The air mass will slowly warm over the next few days. Residual moisture
will remain in place keeping humidity levels elevated.  Breaks in the
clouds on Friday will allow for cumulus build-ups with a small threat
(20%) for afternoon showers and 5-10% chance for lightning mainly
between 1300-1700.  Additional weak impulses rotating through Friday
night and Saturday will continue to bring on and off cloud cover with
a 10-30% chance for showers.  Winds will be light through the period.


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).
***************************************************************

.FRIDAY...

Sky/weather.........Partly sunny. Slight chance of showers and
                    thunderstorms.
CWR.................0 percent.
Chance of lightning.10 percent.
Max temperature.....61 ridgetop to 73 valley bottom.
Min humidity........50-58 percent.
Wind (20 ft)........Upslope to northeast winds 3 to 6 mph.
                    Gusty and erratic winds to 20 mph expected
                    near thunderstorms.
Mixing height.......4000 ft AGL.
Transport winds.....Northeast around 5 mph.
Ventilation Index...Moderate (245).

.FRIDAY NIGHT...

Sky/weather.........Partly cloudy then becoming mostly cloudy.
                    Slight chance for showers.
CWR.................5 percent.
Chance of lightning.5 percent.
Min temperature.....51.
Max humidity........80-85 percent.
Wind (20 ft)........Variable to down drainage winds 0 to 3 mph.
Mixing height.......500 ft AGL.
Transport winds.....Northeast around 5 mph shifting to the north
                    around 6 mph overnight.
Ventilation Index...Low (85).

.SATURDAY...

Sky/weather.........Partly cloudy.
CWR.................5 percent.
Chance of lightning.5 percent.
Max temperature.....67 ridgetop to 79 valley bottom.
Min humidity........45-53 percent.
Wind (20 ft)........Upslope/upvalley 3 to 6 mph.
Mixing height.......6500 ft AGL in the afternoon.
Transport winds.....Light winds becoming southwest around 7 mph in
                    the afternoon.
Ventilation Index...Low (140) increasing to moderate (442) in the
                    afternoon.

$$
Forecaster...SB
Requested by...David Pearson
Type of request...WILDFIRE
.TAG 2619090.8/OTX
.DELDT 08/13/26
.FormatterVersion 2.0.0
.EMAIL 2026.uppersmith.plans@firenet.gov,IDCDC@firenet.gov,david_pearson@firenet.gov