059  
FNUS76 KOTX 080005  
FWSOTX  
 
SPOT FORECAST FOR CHELAN FALLS...SEWAIMT TEAM 1  
NATIONAL WEATHER SERVICE SPOKANE WA  
505 PM PDT TUE JUL 7 2026  
 
FORECAST IS BASED ON FORECAST START TIME OF 1748 PDT ON JULY 07.    
..RED FLAG WARNING IN EFFECT UNTIL 10 PM PDT THIS EVENING
 
   
..RED FLAG WARNING IN EFFECT FROM 11 AM TO 10 PM PDT WEDNESDAY
 
 
   
DISCUSSION
 
 
THE PASSAGE OF A DRY COLD FRONT WEDNESDAY MORNING WILL LEAD TO  
ANOTHER DAY OF CRITICAL FIRE WEATHER CONDITONS. WHILE THE FRONT  
WILL BRING LOWER DAYTIME TEMPERATURES AND HIGHER MINIMUM RELATIVE  
HUMIDITIES COMPARED TO TUESDAY, VALUES WILL STILL BE CRITICAL AND  
WINDS WILL BE EVEN BREEZIER. WINDS WILL INITIALLY BE LIGHT AND  
OUT OF THE NORTHWEST TO BEGIN THE DAY, THEN STEADILY INCREASE  
THROUGHOUT THE MORNING. THE NOCTURNAL INVERSION WILL LIFT AROUND  
0800 HOURS AND ERODE THROUGH THE MORNING THEREAFTER. A SUBTLE WIND  
SHIFT FROM NORTHWESTERLY TO WEST-NORTHWESTERLY WILL OCCUR BETWEEN  
1200 HOURS AND 1400 HOURS, THEN SHIFT BACK TO NORTHWESTERLY WITH  
SPEEDS FURTHER INCREASING THROUGH THE AFTERNOON. WINDS WILL THEN  
DIMINISH BETWEEN 1900 HOURS AND 2100 HOURS WEDNESDAY BEFORE MAKING  
ANOTHER SUBTLE WESTERLY SHIFT AND BECOMING LIGHT WEDNESDAY NIGHT.  
HOT AND DRY WEATHER CONTINUES INTO THURSDAY WITH WESTERLY WINDS  
BECOMING BREEZY AGAIN THURSDAY 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).  
***************************************************************  
   
REST OF TODAY
 
 
SKY/WEATHER.........SUNNY.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MAX TEMPERATURE.....AROUND 89.  
MIN HUMIDITY........12 PERCENT.  
WIND (20 FT)........SOUTHWEST WINDS 9 TO 10 MPH.  
MIXING HEIGHT.......10500 FT AGL.  
TRANSPORT WINDS.....SOUTHWEST AROUND 15 MPH.  
VENTILATION INDEX...VERY HIGH (1371).  
   
TONIGHT
 
 
SKY/WEATHER.........PARTLY CLOUDY.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MIN TEMPERATURE.....AROUND 59.  
MAX HUMIDITY........53 PERCENT.  
WIND (20 FT)........WEST WINDS 7 TO 14 MPH.  
MIXING HEIGHT.......9500 FT AGL FALLING TO 500 FT AGL.  
TRANSPORT WINDS.....WEST 14 TO 16 MPH.  
VENTILATION INDEX...VERY HIGH (1340) DECREASING TO LOW (66)  
OVERNIGHT.  
   
WEDNESDAY
 
 
SKY/WEATHER.........SUNNY.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MAX TEMPERATURE.....85-92.  
MIN HUMIDITY........19 TO 24 PERCENT.  
WIND (20 FT)........NORTHWESTERLY WINDS 6 TO 11 MPH THROUGH 0900 HOURS  
INCREASING TO 12 TO 18MPH BY 1200 HOURS. WEST TO  
NORTHWEST WINDS 7 TO 15 MPH FROM 1200 TO 1400 HOURS,  
THEN NORTHWEST WINDS INCREASE TO 18 TO 25MPH THROUGH  
THE AFTERNOON. GUSTS UP TO 35 MPH IN THE AFTERNOON.  
WINDIEST CONDITIONS ACROSS THE RIDGETOPS.  
MIXING HEIGHT.......INVERSION BREAKING BETWEEN 0800 AND 0900 HOURS,  
WITH MIXING HEIGHT AROUND 5000 FT AGL BY 1100 HOURS.  
MIXING HEIGHTS INCREASING TO AROUND 6500 FT AGL IN  
THE AFTERNOON.  
TRANSPORT WINDS.....NORTHWEST 10 TO 15 MPH IN THE MORNING BECOMING  
WEST 12 TO 17 MPH IN THE AFTERNOON.  
VENTILATION INDEX...HIGH (547) INCREASING TO VERY HIGH (887) IN THE  
AFTERNOON.  
 
 

 
FORECASTER...PP  
REQUESTED BY...BILL BOX  
TYPE OF REQUEST...WILDFIRE  
.TAG 2616779.4/OTX  
.DELDT 07/07/26  
.FORMATTERVERSION 2.0.0  
.EMAIL BILL_BOX@FIRENET.GOV  
 
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