916
AUUS46 KPDT 201325
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
525 AM PST THU NOV 20 2025

*** AIR DISPERSION CATEGORIES:   GOOD, FAIR, POOR ***

FOR THE COLUMBIA BASIN FROM PENDLETON TO WALLA WALLA AND PASCO

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SW 2-6 MPH.         SW 3-6 MPH.
TRANSPORT WINDS               SW 4-7 MPH.         SW 5-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       3000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI NOV 21        POOR.
OUTLOOK FOR SAT NOV 22        POOR.

VENTILATION INDEX (CATEGORY)  30 (POOR).          110 (POOR).
OUTLOOK FOR FRI NOV 21        66 (POOR).
OUTLOOK FOR SAT NOV 22        54 (POOR).

FOR THE UPPER YAKIMA VALLEY INCLUDING YAKIMA...UNION GAP...
SELAH...AND NACHES AREA

                              7:00 AM             AFTERNOON
SURFACE WINDS                 W 1-4 MPH.          S 2-5 MPH.
TRANSPORT WINDS               W 2-6 MPH.          SW 2-5 MPH.
MIXING HEIGHT                 NEAR SURFACE.       3500 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI NOV 21        POOR.
OUTLOOK FOR SAT NOV 22        POOR.

VENTILATION INDEX (CATEGORY)  27 (POOR).          62 (POOR).
OUTLOOK FOR FRI NOV 21        37 (POOR).
OUTLOOK FOR SAT NOV 22        36 (POOR).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 NE 1-3 MPH.         NW 2-5 MPH.
TRANSPORT WINDS               S 3-6 MPH.          NW 6-11 MPH.
MIXING HEIGHT                 4000 FT MSL.        5000 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR FRI NOV 21        POOR.
OUTLOOK FOR SAT NOV 22        FAIR.

VENTILATION INDEX (CATEGORY)  38 (POOR).          168 (POOR).
OUTLOOK FOR FRI NOV 21        74 (POOR).
OUTLOOK FOR SAT NOV 22        260 (POOR).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SW 1-5 MPH.         SW 3-6 MPH.
TRANSPORT WINDS               SW 5-9 MPH.         SW 5-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       2500 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI NOV 21        POOR.
OUTLOOK FOR SAT NOV 22        POOR.

VENTILATION INDEX (CATEGORY)  38 (POOR).          93 (POOR).
OUTLOOK FOR FRI NOV 21        80 (POOR).
OUTLOOK FOR SAT NOV 22        82 (POOR).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      235 (POOR)
ELLENSBURG    164 (POOR)
GOLDENDALE    247 (POOR)
TRI-CITIES    116 (POOR)
WALLA WALLA    75 (POOR)
YAKIMA         48 (POOR)
BEND           95 (POOR)
PRINEVILLE    124 (POOR)
ENTERPRISE     91 (POOR)
HERMISTON     124 (POOR)
JOHN DAY      203 (POOR)
LA GRANDE     211 (POOR)
MADRAS         97 (POOR)
MEACHAM        90 (POOR)
PENDLETON     116 (POOR)
REDMOND       102 (POOR)
SENECA        191 (POOR)
THE DALLES    142 (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.
$$