917
AUUS46 KPDT 201225
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
525 AM PDT THU AUG 20 2026

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

FOR THE COLUMBIA BASIN FROM PENDLETON TO WALLA WALLA AND PASCO

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 1-7 MPH.          NW 3-6 MPH.
TRANSPORT WINDS               S 5-9 MPH.          W 4-6 MPH.
MIXING HEIGHT                 NEAR SURFACE.       5500 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI AUG 21        FAIR.
OUTLOOK FOR SAT AUG 22        GOOD.

VENTILATION INDEX (CATEGORY)  40 (POOR).          167 (POOR).
OUTLOOK FOR FRI AUG 21        189 (POOR).
OUTLOOK FOR SAT AUG 22        528 (FAIR).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 NW 1-5 MPH.         SE 2-6 MPH.
TRANSPORT WINDS               NW 4-8 MPH.         SW 5-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7000 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR FRI AUG 21        POOR.
OUTLOOK FOR SAT AUG 22        GOOD.

VENTILATION INDEX (CATEGORY)  33 (POOR).          209 (POOR).
OUTLOOK FOR FRI AUG 21        112 (POOR).
OUTLOOK FOR SAT AUG 22        644 (GOOD).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 NE 0-0 MPH.         NW 3-5 MPH.
TRANSPORT WINDS               N 2-4 MPH.          W 7-8 MPH.
MIXING HEIGHT                 NEAR SURFACE.       9000 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR FRI AUG 21        FAIR.
OUTLOOK FOR SAT AUG 22        GOOD.

VENTILATION INDEX (CATEGORY)  26 (POOR).          237 (POOR).
OUTLOOK FOR FRI AUG 21        150 (POOR).
OUTLOOK FOR SAT AUG 22        532 (FAIR).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SE 2-6 MPH.         NW 5-7 MPH.
TRANSPORT WINDS               S 4-8 MPH.          NW 6-8 MPH.
MIXING HEIGHT                 NEAR SURFACE.       5500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR FRI AUG 21        FAIR.
OUTLOOK FOR SAT AUG 22        FAIR.

VENTILATION INDEX (CATEGORY)  33 (POOR).          204 (POOR).
OUTLOOK FOR FRI AUG 21        217 (POOR).
OUTLOOK FOR SAT AUG 22        433 (FAIR).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      331 (FAIR)
ELLENSBURG    262 (POOR)
GOLDENDALE    303 (FAIR)
TRI-CITIES    106 (POOR)
WALLA WALLA   195 (POOR)
YAKIMA        219 (POOR)
BEND          553 (FAIR)
PRINEVILLE    406 (FAIR)
ENTERPRISE    396 (FAIR)
HERMISTON     133 (POOR)
JOHN DAY      536 (FAIR)
LA GRANDE     241 (POOR)
MADRAS        214 (POOR)
MEACHAM       204 (POOR)
PENDLETON     202 (POOR)
REDMOND       456 (FAIR)
SENECA        766 (GOOD)
THE DALLES    284 (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.
$$