661
FNUS76 KOTX 181249
FWSOTX

Spot Forecast for Upper Smith...USFS
National Weather Service Spokane WA
549 AM PDT Fri Sep 18 2026

Forecast is based on forecast start time of 0600 PDT on September 18.
.DISCUSSION...

Conditions will be dry with mild temperatures through the period.
RH recovery tonight will be fair. Friday trends a few degrees
cooler with slightly higher relative humidity. Winds will be light.

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

.TODAY...

Sky/weather.........Sunny.
CWR.................0 percent.
Chance of lightning.0 percent.
Max temperature.....Mid Slopes to Ridgetops..........60-67.
                    Valley Bottom and Lower Slopes...70-77.
Min humidity........Mid Slopes to Ridgetops.........35-40 percent.
                    Valley Bottom to Lower Slopes...30-35 percent.
Wind (20 ft)........Valleys/Mid Slopes: Upslope/Upvalley winds 2 to
                    5 mph. Becoming east 3 to 6 mph after 1300.
                    Ridgetops: South-Southeast winds 4 to 7 mph.
Mixing height.......Inversion lifts around 0900 hours. 2500 ft AGL
                    increasing to 4500 ft AGL in the afternoon.
Transport winds.....Light winds becoming southwest around 8 mph
                    after 1400.
Ventilation Index...Moderate (280).

.TONIGHT...

Sky/weather.........Mostly clear.
CWR.................0 percent.
Chance of lightning.0 percent.
Min temperature.....Mid Slopes to Ridgetops.........42-47.
                    Valley Bottom and Lower Slopes...48-53.
Max humidity........Mid Slopes to Ridgetops.........65-70 percent.
                    Valley Bottom to Lower Slopes...60-65 percent.
Wind (20 ft)........Valleys/Mid Slopes: Upslope/Upvalley winds, east
                    3 to 6 mph. Shifting downslope/down valley,
                    southwest 4 to 8 mph after 1900.
                    Ridgetops: South-Southeast winds 4 to 7 mph.
                    Becoming southwest 6 to 10 mph after 1900.
Mixing height.......1500 ft AGL falling to near surface after 2000.
Transport winds.....West around 10 mph shifting to the northwest
                    overnight around 5 mph.
Ventilation Index...Low (53).

.SATURDAY...

Sky/weather.........Mostly sunny.
CWR.................0 percent.
Chance of lightning.0 percent.
Max temperature.....Mid Slopes to Ridgetops.........58-64.
                    Valley Bottom and Lower Slopes....65-72.
Min humidity........Mid Slopes to Ridgetops.........42-49 percent.
                    Valley Bottom to Lower Slopes...36-42 percent.
Wind (20 ft)........Valleys/Mid Slopes: Upslope/Upvalley winds 2 to
                    5 mph.
                    Ridgetops: South-Southeast winds 4 to 7 mph.
Mixing height.......Inversion lifts around 0900 hours. 3000 ft AGL
                    increasing to 5500 ft AGL in the afternoon.
Transport winds.....Light winds becoming southwest around 5 mph in
                    the after 1300.
Ventilation Index...Low (108) increasing to moderate (315) in the
                    afternoon.

$$
Forecaster...JCLEV
Requested by...Incident Commander
Type of request...WILDFIRE
.TAG 2621955.2/OTX
.DELDT 09/18/26
.FormatterVersion 2.0.0
.EMAIL jesse.countryman@usda.gov