328  
FNUS76 KOTX 152234  
FWSOTX  
 
SPOT FORECAST FOR UPPER SMITH...USFS  
NATIONAL WEATHER SERVICE SPOKANE WA  
334 PM PDT TUE SEP 15 2026  
 
FORECAST IS BASED ON FORECAST START TIME OF 0000 PDT ON SEPTEMBER 16.    
DISCUSSION
 
 
A WEATHER DISTURBANCE WILL BRING LIGHT RAIN TO THE UPPER SMITH FIRE  
THROUGH THIS EVENING. DRIER AIR MOVING IN OVERNIGHT WILL RESULT IN  
CLEARING SKIES. A WARMING AND DRYING TREND WEDNESDAY INTO THURSDAY.  
TEMPERATURES WARM UP TO ABOVE NORMAL. THERE IS A 5 PERCENT CHANCE  
FOR SHOWERS TO MOVE INTO THE AREA FROM THE SOUTH THURSDAY EVENING.  
WINDS WILL GENERALLY BE LIGHT AND OUT OF THE NORTH TO NORTHEAST ON  
RIDGETOPS.  
 
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).  
***************************************************************  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLOUDY WITH A 70 PERCENT CHANCE FOR  
RAIN SHOWERS THROUGH 2200 HOURS THIS EVENING.  
CLEARING OVERNIGHT WITH PARTLY CLOUDY SKIES  
BY 0200 HOURS. TOTAL RAINFALL OF BETWEEN  
0.05 AND 0.12 INCHES EXPECTED.  
CWR.................10 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MIN TEMPERATURE.....MID SLOPES TO RIDGETOPS..........34-38.  
VALLEY BOTTOM TO LOWER SLOPES...38-42.  
MAX HUMIDITY........94-98 PERCENT.  
WIND (20 FT)........VALLEYS: DOWNSLOPE/DOWNVALLEY WINDS UP TO  
3 MPH.  
MID SLOPES TO RIDGETOPS: NORTHWEST WINDS 4 TO  
7 MPH IN THE EVENING BECOMING NORTHEAST  
AFTER 1900 HOURS.  
MIXING HEIGHT.......800 FT AGL.  
TRANSPORT WINDS.....NORTH AROUND 7 MPH.  
VENTILATION INDEX...LOW (35).  
   
WEDNESDAY
 
 
SKY/WEATHER.........SUNNY.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MAX TEMPERATURE.....MID SLOPES TO RIDGETOPS..........57-60.  
VALLEY BOTTOM AND LOWER SLOPES...67-71.  
MIN HUMIDITY........MID SLOPES TO RIDGETOPS.........38-42 PERCENT.  
VALLEY BOTTOM TO LOWER SLOPES...34-38 PERCENT.  
WIND (20 FT)........NORTHEAST WINDS 2 TO 5 MPH EXCEPT 5 TO 9 MPH  
ON RIDGETOPS.  
MIXING HEIGHT.......INVERSION LIFTING AROUND 1100 HOURS. MIXING  
HEIGHT INCREASING TO 3000 FT AGL BY 1500  
HOURS.  
TRANSPORT WINDS.....NORTHEAST AROUND 8 MPH.  
VENTILATION INDEX...LOW (166).  
   
WEDNESDAY NIGHT
 
 
SKY/WEATHER.........MOSTLY CLEAR.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MIN TEMPERATURE.....39-44.  
MAX HUMIDITY........MID SLOPES TO RIDGETOPS........68-72 PERCENT.  
VALLEY BOTTOM TO LOWER SLOPES..88-93 PERCENT.  
WIND (20 FT)........VALLEYS/MID SLOPES: DOWNSLOPE/DOWNVALLEY  
WINDS 1 TO 4 MPH.  
RIDGETOPS: NORTH-NORTHEAST WINDS 3 TO 7 MPH.  
MIXING HEIGHT.......1000 FT AGL.  
TRANSPORT WINDS.....NORTH-NORTHEAST 5 TO 7 MPH.  
VENTILATION INDEX...LOW (41).  
   
THURSDAY
 
 
SKY/WEATHER.........SUNNY.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MAX TEMPERATURE.....MID SLOPES TO RIDGETOPS..........65-68.  
VALLEY BOTTOM AND LOWER SLOPES...75-79.  
MIN HUMIDITY........MID SLOPES TO RIDGETOPS.........26-29 PERCENT.  
VALLEY BOTTOM TO LOWER SLOPES...22-25 PERCENT.  
WIND (20 FT)........VALLEYS/MID SLOPES: UPSLOPE/UPVALLEY WINDS  
2 TO 5 MPH.  
RIDGETOPS: NORTH-NORTHEAST WINDS 4 TO 7 MPH.  
MIXING HEIGHT.......INVERSION LIFTS AROUND 1200 HOURS. MIXING  
HEIGHT INCREASING TO 3000 FT AGL BY 1500 HOURS.  
TRANSPORT WINDS.....NORTH AROUND 6 MPH.  
VENTILATION INDEX...LOW (148).  
 

 
FORECASTER...SVH  
REQUESTED BY...INCIDENT COMMANDER  
TYPE OF REQUEST...WILDFIRE  
.TAG 2621955.0/OTX  
.DELDT 09/15/26  
.FORMATTERVERSION 2.0.0  
.EMAIL JESSE.COUNTRYMAN@USDA.GOV  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab WA Page
The Nexlab ID Page Main Text Page