891  
AUUS46 KPDT 181329  
DDOPDT  
 
DAILY DISPERSION OUTLOOK  
NATIONAL WEATHER SERVICE PENDLETON OR  
629 AM PDT FRI JUL 18 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 8-15 MPH. SW 16-22 MPH.  
TRANSPORT WINDS SW 9-15 MPH. W 20-25 MPH.  
MIXING HEIGHT NEAR SURFACE. 8000 FT MSL.  
DISPERSION CATEGORY FAIR. GOOD.  
OUTLOOK FOR SAT JUL 19 GOOD.  
OUTLOOK FOR SUN JUL 20 FAIR.  
 
VENTILATION INDEX (CATEGORY) 180 (POOR). 1004 (GOOD).  
OUTLOOK FOR SAT JUL 19 882 (GOOD).  
OUTLOOK FOR SUN JUL 20 704 (GOOD).  
 
FOR THE UPPER YAKIMA VALLEY INCLUDING YAKIMA...UNION GAP...  
SELAH...AND NACHES AREA  
 
7:00 AM AFTERNOON  
SURFACE WINDS W 3-7 MPH. W 11-16 MPH.  
TRANSPORT WINDS W 5-9 MPH. W 16-20 MPH.  
MIXING HEIGHT NEAR SURFACE. 9500 FT MSL.  
DISPERSION CATEGORY POOR. GOOD.  
OUTLOOK FOR SAT JUL 19 FAIR.  
OUTLOOK FOR SUN JUL 20 FAIR.  
 
VENTILATION INDEX (CATEGORY) 81 (POOR). 878 (GOOD).  
OUTLOOK FOR SAT JUL 19 420 (FAIR).  
OUTLOOK FOR SUN JUL 20 282 (POOR).  
 
FOR THE GRANDE RONDE RIVER VALLEY  
 
7:00 AM AFTERNOON  
SURFACE WINDS SE 2-5 MPH. W 9-11 MPH.  
TRANSPORT WINDS W 3-6 MPH. W 16-18 MPH.  
MIXING HEIGHT 4000 FT MSL. 12000 FT MSL.  
DISPERSION CATEGORY POOR. GOOD.  
OUTLOOK FOR SAT JUL 19 GOOD.  
OUTLOOK FOR SUN JUL 20 GOOD.  
 
VENTILATION INDEX (CATEGORY) 85 (POOR). 1001 (GOOD).  
OUTLOOK FOR SAT JUL 19 1049 (GOOD).  
OUTLOOK FOR SUN JUL 20 772 (GOOD).  
 
FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS  
 
7:00 AM AFTERNOON  
SURFACE WINDS S 6-15 MPH. W 14-18 MPH.  
TRANSPORT WINDS SW 9-15 MPH. W 21-23 MPH.  
MIXING HEIGHT NEAR SURFACE. 8500 FT MSL.  
DISPERSION CATEGORY FAIR. GOOD.  
OUTLOOK FOR SAT JUL 19 GOOD.  
OUTLOOK FOR SUN JUL 20 GOOD.  
 
VENTILATION INDEX (CATEGORY) 194 (POOR). 1020 (GOOD).  
OUTLOOK FOR SAT JUL 19 1024 (GOOD).  
OUTLOOK FOR SUN JUL 20 849 (GOOD).  
 
SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES  
CLE ELUM 934 (GOOD)  
ELLENSBURG 1021 (GOOD)  
GOLDENDALE 884 (GOOD)  
TRI-CITIES 840 (GOOD)  
WALLA WALLA 1050 (GOOD)  
YAKIMA 918 (GOOD)  
BEND 865 (GOOD)  
PRINEVILLE 884 (GOOD)  
ENTERPRISE 981 (GOOD)  
HERMISTON 1050 (GOOD)  
JOHN DAY 1050 (GOOD)  
LA GRANDE 1050 (GOOD)  
MADRAS 688 (GOOD)  
MEACHAM 817 (GOOD)  
PENDLETON 1050 (GOOD)  
REDMOND 956 (GOOD)  
SENECA 1050 (GOOD)  
THE DALLES 1050 (GOOD)  
 
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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