FNUS76 KOTX 231100
FWSOTX

Spot Forecast for Ptarmigan...USFS
National Weather Service Spokane WA
400 AM PDT Sun Aug 23 2026

Forecast is based on forecast start time of 0600 PDT on August 23. 

.DISCUSSION...

Sunday will be much cooler under mostly cloudy skies with high
relative humidity through the day. A warming and drying trend 
commences Monday and Tuesday with lighter, terrain driven winds.  

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.........Mostly cloudy and cooler. A 20 percent chance of
                    rain showers through the day.
CWR.................5 percent. 
Chance of lightning.5 percent. 
Max temperature.....50-60. 
Min humidity........60-70 percent. 
Wind (20 ft)........West winds 5 to 10 mph.  
Mixing height.......Near surface through 0800 increasing to 2500
                    feet AGL in the afternoon. 
Transport winds.....West around 12 mph. 
Ventilation Index...Moderate (272). 

.TONIGHT...

Sky/weather.........Mostly cloudy then becoming mostly clear. 
CWR.................0 percent. 
Chance of lightning.0 percent. 
Min temperature.....38-44. 
Max humidity........89-97 percent. 
Wind (20 ft)........Northwest 3 to 8 mph through 2000 PDT then
                    downslope/downvalley 1 to 4 mph. 
Mixing height.......2000 ft AGL decreasing to near surface at 2000
                    PDT. 
Transport winds.....Northwest around 8 mph through 2000 then
                    downslope/downvalley less than 5 mph. 
Ventilation Index...Low (163). 

.MONDAY...

Sky/weather.........Mostly sunny and much warmer. 
CWR.................0 percent. 
Chance of lightning.0 percent. 
Max temperature.....65-74. 
Min humidity........28-35 percent. 
Wind (20 ft)........Downslope/downvalley 1 to 4 mph through 
                    0900-1000 then upslope/upvalley 3 to 7 mph. 
Mixing height.......Near surface through 0900 increasing to 6500 ft 
                    AGL in the afternoon. 
Transport winds.....Southeast 4 to 8 mph. 
Ventilation Index...Moderate (244) increasing to moderate (412) in 
                    the afternoon. 

$$
Forecaster...JW
Requested by...Brian Campbell
Type of request...WILDFIRE
.TAG 2620029.3/OTX
.DELDT 08/23/26
.FormatterVersion 2.0.0
.EMAIL William.Burks4@usda.gov,michael.barajas@usda.gov,brian.d.campbell@usda.gov