FNUS76 KOTX 181144
FWSOTX

Spot Forecast for St Joe Divide...USFS
National Weather Service Spokane WA
444 AM PDT Mon May 18 2026

Forecast is based on ignition time of 0600 PDT on May 18. 

.DISCUSSION...
An unstable atmosphere will be over the project today, resulting 
in a 30 percent chance of showers with a 25 percent chance of 
thunderstorms this afternoon into the early evening. Any 
thunderstorms will be capable of producing brief downpours, sudden
wind gusts up to 30 mph, and small hail. Total rain amounts for 
today are forecasted to be less than 0.10 inches. The risk for 
showers and thunderstorms decreases for Tuesday afternoon, but 
increases again for Wednesday afternoon. 

Temperatures will trend warmer through the week with drier 
conditions and lighter winds expected for Thursday and Friday. 

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 sunny becoming partly sunny. 30% chance of 
                    rain showers and a 25% chance of thunderstorms 
                    in the late morning and afternoon. 
                    Rain amounts up to 0.07 inches.
CWR.................0 percent. 
Chance of lightning.25 percent. 
Max temperature.....52-57. 
Min humidity........50-55 percent. 
Wind (20 ft)........Light and variable winds in the morning becoming 
                    west to northwest 3 to 7 mph after 0900 hours. 
                    Gusty and erratic winds up to 30 mph expected 
                    near thunderstorms. 
Mixing height.......5500 ft AGL in the afternoon. 
Transport winds.....Northwest 5 to 8 mph. 
Ventilation Index...Moderate (300) increasing to moderate (371) in 
                    the afternoon. 

.TONIGHT...

Sky/weather.........Partly cloudy. 20% chance of rain showers 
                    in the evening.
CWR.................0 percent. 
Chance of lightning.10 percent. 
Min temperature.....33-37. 
Max humidity........80-85 percent. 
Wind (20 ft)........Becoming south 1 to 5 mph around 2200 hours.
Mixing height.......3000 ft AGL falling to 500 ft AGL after 1900 hours.
Transport winds.....Southwest 5 to 8 mph. 
Ventilation Index...Moderate (226). 

.TUESDAY...

Sky/weather.........Mostly sunny. 15% chance of rain showers and a
                    5% chance of thunderstorms in the afternoon. 
CWR.................0 percent. 
Chance of lightning.5 percent. 
Max temperature.....55-60. 
Min humidity........45-50 percent. 
Wind (20 ft)........South to southwest winds 4 to 8 mph in the 
                    morning becoming west to southwest 4 to 8 mph 
                    in the afternoon. 
Mixing height.......6500 ft AGL in the afternoon. 
Transport winds.....Southwest 10 to 15 mph. 
Ventilation Index...Very high (889) in the afternoon. 

.FORECAST DAYS 3 THROUGH 5...
.WEDNESDAY...
Partly cloudy. 25% chance of rain showers and a 15% chance of thunderstorms
in the afternoon and evening. Precipitation amounts up to 0.12 inches.
Lows in the upper 30s. Highs in the upper 50s. West to northwest winds
4 to 7 mph. Wind gusts up to 30 mph with any nearby thunderstorms.
.THURSDAY...
Partly cloudy. Lows in the upper 30s. Highs around 60. Terrain driven winds.
.FRIDAY...
Partly cloudy. Lows in the lower 40s. Highs in the lower 60s.
Terrain driven winds.

$$
Forecaster...VT
Requested by...Megan Primmer
Type of request...PRESCRIBED
.TAG 2613597.2/OTX
.DELDT 05/18/26
.FormatterVersion 2.0.0
.EMAIL megan.primmer@usda.gov,marshall.myhre@usda.gov