511  
FNUS76 KPDT 231521  
FWSPDT  
 
SPOT FORECAST FOR TRIPLE BUTTE UNIT 4...CONFEDERATED TRIBES OF WARM SPRINGS  
NATIONAL WEATHER SERVICE PENDLETON OR  
821 AM PDT FRI OCT 23 2026  
 
FORECAST IS BASED ON IGNITION TIME OF 1000 PDT ON OCTOBER 23.  
***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
 
BREEZY WEST TO NORTHWEST WINDS ALONG RIDGETOPS THIS  
MORNING WILL SLACKEN THROUGH THE DAY. IN SHELTERED AREAS OF THE BURN  
SITE, EXPECTING LIGHTER WEST WINDS WITH PERIODIC GUSTS. FOR SHELTERED  
AREAS, TERRAIN-DRIVEN WINDS ARE FORECAST TO RETURN LATE THIS EVENING,  
WHILE WEST WINDS WILL BECOME SOUTHEAST ALONG RIDGETOPS. EXCELLENT RH  
RECOVERY IS ANTICIPATED LATE EVENING INTO THE EARLY OVERNIGHT, ALBEIT  
WITH RH DECREASING TO GOOD OVERNIGHT INTO EARLY MORNING.  
   
REST OF TODAY
 
 
SKY/WEATHER.........MOSTLY CLOUDY (55-85 PERCENT) EARLY MORNING,  
BECOMING MOSTLY SUNNY (5-25 PERCENT) BY LATE  
MORNING.  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MAX TEMPERATURE.....46-49.  
MIN HUMIDITY........55-60 PERCENT.  
WIND (20 FT)........WEST-NORTHWEST WINDS 4-8 MPH WITH GUSTS UP TO 15 MPH.  
RIDGETOP WIND.......WEST TO NORTHWEST 15-25 MPH WITH GUSTS UP TO 30 MPH  
IN THE MORNING, DECREASING TO 8-12 MPH WITH GUSTS  
OF 12-17 MPH BY AFTERNOON.  
MIXING HEIGHT.......INCREASING TO 1800-2200 FT AGL BY EARLY AFTERNOON.  
TRANSPORT WINDS.....WEST TO WEST-NORTHWEST 10-15 MPH, STRONGEST IN THE  
MORNING.  
VENTILATION INDEX...INCREASING TO MODERATE (210) IN THE AFTERNOON.  
 
TIME (PDT) 10 AM NOON 2 PM 4 PM 6 PM 8 PM  
CHC OF LTNG (%).0 0 0 0 0 0  
TEMP............36 40 43 44 39 33  
RH..............75 65 60 61 78 85  
20 FT WIND......WNW 8 WNW 6 WNW 6 WNW 5 W 4 W 4  
20 FT WIND GUST.14 12 10 8  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLEAR TO PARTLY CLOUDY (15-35 PERCENT).  
CWR.................0 PERCENT.  
CHANCE OF LIGHTNING.0 PERCENT.  
MIN TEMPERATURE.....29-32.  
MAX HUMIDITY........85-90 PERCENT.  
WIND (20 FT)........BECOMING TERRAIN-DRIVEN WINDS 1-4 MPH BY LATE  
EVENING.  
RIDGETOP WIND.......WEST 4-8 MPH IN THE EVENING, BECOMING SOUTHEAST  
3-7 MPH AROUND MIDNIGHT.  
MIXING HEIGHT.......DECREASING TO 200-500 FT AGL OVERNIGHT.  
TRANSPORT WINDS.....WEST 8-12 MPH IN THE EVENING, BECOMING SOUTH  
TO SOUTHEAST 3-7 MPH AROUND MIDNIGHT.  
VENTILATION INDEX...DECREASING TO LOW (30) OVERNIGHT.  
 

 
FORECASTER...PLUNKETT  
REQUESTED BY...JEFFREY CASEY  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2624421.0/PDT  
.DELDT 10/23/26  
.FORMATTERVERSION 2.0.0  
.EMAIL JEFF.CASEY@CTWSBNR.ORG  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab OR Page
The Nexlab WA Page Main Text Page