907
AUUS46 KPDT 301225
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
525 AM PDT WED SEP 30 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 3-10 MPH.         NW 3-7 MPH.
TRANSPORT WINDS               SW 5-13 MPH.        W 4-8 MPH.
MIXING HEIGHT                 NEAR SURFACE.       5000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR THU OCT 1         POOR.
OUTLOOK FOR FRI OCT 2         POOR.

VENTILATION INDEX (CATEGORY)  59 (POOR).          200 (POOR).
OUTLOOK FOR THU OCT 1         149 (POOR).
OUTLOOK FOR FRI OCT 2         108 (POOR).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 W 0-5 MPH.          E 2-6 MPH.
TRANSPORT WINDS               NW 3-7 MPH.         NW 3-6 MPH.
MIXING HEIGHT                 NEAR SURFACE.       5000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR THU OCT 1         POOR.
OUTLOOK FOR FRI OCT 2         POOR.

VENTILATION INDEX (CATEGORY)  30 (POOR).          114 (POOR).
OUTLOOK FOR THU OCT 1         133 (POOR).
OUTLOOK FOR FRI OCT 2         93 (POOR).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 1-3 MPH.          NW 5-9 MPH.
TRANSPORT WINDS               SW 3-6 MPH.         NW 8-11 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7000 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR THU OCT 1         FAIR.
OUTLOOK FOR FRI OCT 2         FAIR.

VENTILATION INDEX (CATEGORY)  37 (POOR).          292 (POOR).
OUTLOOK FOR THU OCT 1         203 (POOR).
OUTLOOK FOR FRI OCT 2         185 (POOR).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 5-11 MPH.         W 3-6 MPH.
TRANSPORT WINDS               SW 8-13 MPH.        W 7-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       4500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR THU OCT 1         FAIR.
OUTLOOK FOR FRI OCT 2         FAIR.

VENTILATION INDEX (CATEGORY)  86 (POOR).          257 (POOR).
OUTLOOK FOR THU OCT 1         184 (POOR).
OUTLOOK FOR FRI OCT 2         148 (POOR).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      238 (POOR)
ELLENSBURG    236 (POOR)
GOLDENDALE    267 (POOR)
TRI-CITIES    155 (POOR)
WALLA WALLA   219 (POOR)
YAKIMA        109 (POOR)
BEND          163 (POOR)
PRINEVILLE    144 (POOR)
ENTERPRISE    312 (FAIR)
HERMISTON     201 (POOR)
JOHN DAY      254 (POOR)
LA GRANDE     352 (FAIR)
MADRAS        132 (POOR)
MEACHAM       239 (POOR)
PENDLETON     307 (FAIR)
REDMOND       128 (POOR)
SENECA        331 (FAIR)
THE DALLES    338 (FAIR)

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.
$$