550  
AUUS46 KPDT 241225  
DDOPDT  
 
DAILY DISPERSION OUTLOOK  
NATIONAL WEATHER SERVICE PENDLETON OR  
525 AM PDT FRI OCT 24 2025  
 
*** AIR DISPERSION CATEGORIES: GOOD, FAIR, POOR ***  
 
FOR THE COLUMBIA BASIN FROM PENDLETON TO WALLA WALLA AND PASCO  
 
7:00 AM AFTERNOON  
SURFACE WINDS S 4-10 MPH. NW 8-11 MPH.  
TRANSPORT WINDS S 5-10 MPH. W 8-11 MPH.  
MIXING HEIGHT NEAR SURFACE. 2000 FT MSL.  
DISPERSION CATEGORY POOR. POOR.  
OUTLOOK FOR SAT OCT 25 GOOD.  
OUTLOOK FOR SUN OCT 26 FAIR.  
 
VENTILATION INDEX (CATEGORY) 32 (POOR). 89 (POOR).  
OUTLOOK FOR SAT OCT 25 461 (FAIR).  
OUTLOOK FOR SUN OCT 26 470 (FAIR).  
 
FOR THE UPPER YAKIMA VALLEY INCLUDING YAKIMA...UNION GAP...  
SELAH...AND NACHES AREA  
 
7:00 AM AFTERNOON  
SURFACE WINDS SW 3-7 MPH. S 10-18 MPH.  
TRANSPORT WINDS S 4-8 MPH. SW 15-26 MPH.  
MIXING HEIGHT NEAR SURFACE. 3500 FT MSL.  
DISPERSION CATEGORY POOR. GOOD.  
OUTLOOK FOR SAT OCT 25 FAIR.  
OUTLOOK FOR SUN OCT 26 GOOD.  
 
VENTILATION INDEX (CATEGORY) 36 (POOR). 256 (POOR).  
OUTLOOK FOR SAT OCT 25 236 (POOR).  
OUTLOOK FOR SUN OCT 26 368 (FAIR).  
 
FOR THE GRANDE RONDE RIVER VALLEY  
 
7:00 AM AFTERNOON  
SURFACE WINDS S 12-21 MPH. S 23-28 MPH.  
TRANSPORT WINDS S 12-20 MPH. S 27-31 MPH.  
MIXING HEIGHT 4000 FT MSL. 6000 FT MSL.  
DISPERSION CATEGORY FAIR. GOOD.  
OUTLOOK FOR SAT OCT 25 GOOD.  
OUTLOOK FOR SUN OCT 26 GOOD.  
 
VENTILATION INDEX (CATEGORY) 183 (POOR). 721 (GOOD).  
OUTLOOK FOR SAT OCT 25 817 (GOOD).  
OUTLOOK FOR SUN OCT 26 715 (GOOD).  
 
FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS  
 
7:00 AM AFTERNOON  
SURFACE WINDS SE 8-15 MPH. W 9-19 MPH.  
TRANSPORT WINDS S 8-15 MPH. SW 11-19 MPH.  
MIXING HEIGHT NEAR SURFACE. 4000 FT MSL.  
DISPERSION CATEGORY POOR. FAIR.  
OUTLOOK FOR SAT OCT 25 GOOD.  
OUTLOOK FOR SUN OCT 26 FAIR.  
 
VENTILATION INDEX (CATEGORY) 62 (POOR). 201 (POOR).  
OUTLOOK FOR SAT OCT 25 764 (GOOD).  
OUTLOOK FOR SUN OCT 26 711 (GOOD).  
 
SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES  
CLE ELUM 174 (POOR)  
ELLENSBURG 307 (FAIR)  
GOLDENDALE 212 (POOR)  
TRI-CITIES 102 (POOR)  
WALLA WALLA 125 (POOR)  
YAKIMA 261 (POOR)  
BEND 1050 (GOOD)  
PRINEVILLE 811 (GOOD)  
ENTERPRISE 453 (FAIR)  
HERMISTON 62 (POOR)  
JOHN DAY 749 (GOOD)  
LA GRANDE 577 (FAIR)  
MADRAS 935 (GOOD)  
MEACHAM 383 (FAIR)  
PENDLETON 91 (POOR)  
REDMOND 1050 (GOOD)  
SENECA 666 (GOOD)  
THE DALLES 109 (POOR)  
 
METEOROLOGICAL INFORMATION PROVIDED IN THIS PRODUCT REPRESENTS ONLY  
SOME OF THE FACTORS USED IN BURN DECISIONS. BURN DECISIONS ARE  
OUTSIDE THE PURVIEW OF THE NATIONAL WEATHER SERVICE.  
 
THE VENTILATION INDEX IS A TOOL TO ASSIST SMOKE MANAGEMENT  
AGENCIES IN DETERMINING BURN OR NO BURN DECISIONS. A VENTILATION  
INDEX GRAPHIC IS ON THE PENDLETON WEBSITE AT THE FOLLOWING ADDRESS:  
HTTPS://WWW.WEATHER.GOV/PDT/DSSBRIEFING  
 
IF YOU WOULD LIKE TO KNOW MORE ABOUT THIS PRODUCT...CONTACT THE  
NATIONAL WEATHER SERVICE IN PENDLETON.  
 
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