FNUS76 KOTX 191553
FWSOTX

Spot Forecast for Roundhouse Rx...USFS
National Weather Service Spokane WA
853 AM PDT Tue May 19 2026

Forecast is based on ignition time of 0900 PDT on May 19. 
.DISCUSSION...

Area will be impacted by weak systems moving along the backside 
of a ridge along the MT/ID border. Isolated showers/thunderstorms 
will be possible but amounts expected to be only a few hundredths 
of an inch. A stronger wave increases thunder and rain potential 
for Wednesday. Winds will be westerly with increased gusts in the 
afternoon. 

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.........Partly cloudy then becoming mostly cloudy. 
CWR.................5 percent. 
Chance of lightning.15 percent. 
Max temperature.....Around 58. 
Min humidity........45-50 percent. 
Wind (20 ft)........West winds 6 to 10 mph with gusts to 15 mph. 
Mixing height.......4000 ft AGL increasing to 6000 ft AGL in the 
                    afternoon. 
Transport winds.....West 13 to 15 mph. 
Ventilation Index...High (663) increasing to high (705) in the 
                    afternoon. 

.TONIGHT...

Sky/weather.........Mostly cloudy then becoming mostly cloudy. 
CWR.................0 percent. 
Chance of lightning.5 percent. 
Min temperature.....Around 42. 
Max humidity........71-76 percent. 
Wind (20 ft)........Light winds. 
Mixing height.......4500 ft AGL falling to 500 ft AGL. 
Transport winds.....Southwest 7 to 10 mph. 
Ventilation Index...High (549) decreasing to low (30) overnight. 

.WEDNESDAY...

Sky/weather.........Mostly cloudy. Chance of rain showers through 
                    the day. Slight chance of thunderstorms in the 
                    afternoon. 
CWR.................5 percent. 
Chance of lightning.20 percent. 
Max temperature.....Around 59. 
Min humidity........48-53 percent. 
Wind (20 ft)........West winds 8 to 12 mph with gusts to 18 mph. 
                    Gusty and erratic winds expected near 
                    thunderstorms in the afternoon. 
Mixing height.......4000 ft AGL increasing to 6000 ft AGL in the 
                    afternoon. 
Transport winds.....West 12 to 18 mph. 
Ventilation Index...High (573) increasing to very high (880) in the 
                    afternoon. 

$$
Forecaster...JCLEV
Requested by...Marshall Myhre
Type of request...PRESCRIBED
.TAG 2614028.0/OTX
.DELDT 05/19/26
.FormatterVersion 2.0.0
.EMAIL marshall.myhre@usda.gov