280  
FNUS76 KPDT 040715  
FWSPDT  
 
SPOT FORECAST FOR TUMBLE FIRE...USFS  
NATIONAL WEATHER SERVICE PENDLETON OR  
1215 AM PDT THU JUN 4 2026  
 
FORECAST IS BASED ON FORECAST START TIME OF 0400 PDT ON JUNE 04.  
***THUNDERSTORMS IMPLY GUSTY AND ERRATIC WINDS ***  
***WINDS ARE 20 FOOT 10-MINUTE AVERAGES ***  
***CWR: CHANCE OF WETTING RAIN 0.10 OR GREATER ***  
***VENTILATION INDEX IS DERIVED FROM TRANSPORT WIND  
MULTIPLIED BY THE MIXING HEIGHT IN 100'S OF FT.  
CATEGORIES ARE A GENERALIZED INDICATOR ONLY:  
LOW (< 200), MODERATE (200-500), HIGH (500-700),  
AND VERY HIGH (> 700). ***  
 
IF YOU HAVE QUESTIONS OR CONCERNS WITH THIS FORECAST, PLEASE  
CONTACT OUR OFFICE AT (541) 276-8134.  
   
DISCUSSION  
 
RELATIVE HUMIDITY THIS MORNING NEAR 80 PERCENT WILL DECREASE TO  
AROUND 27 PERCENT BY THE MID TO LATE AFTERNOON ON LIGHT WINDS  
(UNDER 10 MPH) OUT OF THE NORTH NORTHWEST. THE EXPECTED DRY CONDITIONS  
FOR TODAY WILL GIVE WAY TO GREATER CHANCES FOR SHOWERS, (30 TO 50% BY  
FRIDAY EVENING AND OVERNIGHT).  
   
REST OF TONIGHT  
 
SKY/WEATHER.........MOSTLY CLEAR (15-25 PERCENT).  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.2 PERCENT.  
MIN TEMPERATURE.....41-44.  
MAX HUMIDITY........77-82 PERCENT.  
WIND (20 FT)........NORTHWEST WINDS 5 TO 7 MPH.  
RIDGETOP WIND.......NORTHWEST WINDS 5 TO 7 MPH.  
MIXING HEIGHT.......500 FT AGL.  
TRANSPORT WINDS.....WEST 12 TO 13 MPH.  
VENTILATION INDEX...  
 
TIME (PDT) 4AM 5AM 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM  
CHC OF LTNG (%).0 0 0 0 0 0 0 0 0 0 0 0  
TEMP............41 41 41 43 45 48 52 55 58 61 62 62  
RH..............83 82 79 71 63 55 48 44 39 35 34 32  
20 FT WIND DIR..NW NW S SW SW NW N N N N NW NW  
20 FT WIND SPD..5 5 4 4 3 3 4 4 4 5 5 6  
20 FT WIND GUST.10 10 8 7 6 6 7 8 10 10 11 11  
   
THURSDAY  
 
SKY/WEATHER.........SUNNY (10-20 PERCENT).  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MAX TEMPERATURE.....63-66.  
MIN HUMIDITY........25-30 PERCENT.  
WIND (20 FT)........LIGHT WINDS BECOMING NORTHWEST 5 TO 7 MPH IN  
THE AFTERNOON.  
RIDGETOP WIND.......LIGHT WINDS BECOMING NORTHWEST 7 TO 10 MPH IN  
THE AFTERNOON.  
MIXING HEIGHT.......3600 FT AGL.  
TRANSPORT WINDS.....WEST 9 TO 14 MPH.  
VENTILATION INDEX...LOW (120) INCREASING TO MODERATE (320) IN THE  
AFTERNOON.  
   
THURSDAY NIGHT  
 
SKY/WEATHER.........MOSTLY CLEAR (10-20 PERCENT).  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MIN TEMPERATURE.....AROUND 40.  
MAX HUMIDITY........72-77 PERCENT.  
WIND (20 FT)........NORTHWEST WINDS 5 TO 8 MPH SHIFTING TO THE  
SOUTHWEST 5 TO 8 MPH LATE IN THE EVENING, THEN  
SHIFTING TO THE SOUTHWEST 6 TO 12 MPH EARLY BY  
IN THE MORNING.  
RIDGETOP WIND.......NORTHWEST WINDS 5 TO 8 MPH SHIFTING TO THE  
SOUTHWEST 5 TO 8 MPH LATE IN THE EVENING, THEN  
SHIFTING TO THE SOUTHWEST 8 TO 16 MPH EARLY BY  
IN THE MORNING.  
MIXING HEIGHT.......500 FT AGL.  
TRANSPORT WINDS.....WEST 12 TO 14 MPH.  
VENTILATION INDEX...LOW (180) DECREASING TO LOW (50) OVERNIGHT.  
   
FRIDAY  
 
SKY/WEATHER.........MOSTLY SUNNY (35-45 PERCENT). CHANCE OF RAIN  
SHOWERS LATE IN THE AFTERNOON.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.5 PERCENT.  
MAX TEMPERATURE.....55-58.  
MIN HUMIDITY........43-48 PERCENT.  
WIND (20 FT)........WEST WINDS 5 TO 10 MPH. GUSTS UP TO 23 MPH LATE  
IN THE MORNING.  
RIDGETOP WIND.......WEST WINDS 8 TO 13 MPH. GUSTS UP TO 26 MPH LATE  
IN THE MORNING.  
MIXING HEIGHT.......4400 FT AGL.  
TRANSPORT WINDS.....WEST 12 TO 21 MPH INCREASING TO AROUND 22 MPH  
LATE IN THE AFTERNOON.  
VENTILATION INDEX...LOW (180) INCREASING TO VERY HIGH (710) IN THE  
AFTERNOON.  
 
 
FORECASTER...RUSSELL  
REQUESTED BY...WACCC  
TYPE OF REQUEST...WILDFIRE  
.TAG 2614938.0/PDT  
.DELDT 06/04/26  
.FORMATTERVERSION 2.0.0  
.EMAIL MICHAEL.WHITAKER@USDA.GOV,MILES.OBRIEN@USDA.GOV,WACCC@FIRENET.GOV  
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