136
AUUS46 KPDT 041325
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
525 AM PST THU DEC  4 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 3-7 MPH.          S 5-9 MPH.
TRANSPORT WINDS               S 4-8 MPH.          SW 7-14 MPH.
MIXING HEIGHT                 NEAR SURFACE.       NEAR SURFACE.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI DEC 5         GOOD.
OUTLOOK FOR SAT DEC 6         GOOD.

VENTILATION INDEX (CATEGORY)  32 (POOR).          58 (POOR).
OUTLOOK FOR FRI DEC 5         277 (POOR).
OUTLOOK FOR SAT DEC 6         754 (GOOD).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 1-3 MPH.          S 2-5 MPH.
TRANSPORT WINDS               S 2-6 MPH.          SW 2-5 MPH.
MIXING HEIGHT                 NEAR SURFACE.       NEAR SURFACE.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI DEC 5         GOOD.
OUTLOOK FOR SAT DEC 6         GOOD.

VENTILATION INDEX (CATEGORY)  27 (POOR).          30 (POOR).
OUTLOOK FOR FRI DEC 5         115 (POOR).
OUTLOOK FOR SAT DEC 6         619 (GOOD).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 5-6 MPH.          S 6-8 MPH.
TRANSPORT WINDS               S 7-10 MPH.         S 10-14 MPH.
MIXING HEIGHT                 4000 FT MSL.        4000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR FRI DEC 5         FAIR.
OUTLOOK FOR SAT DEC 6         GOOD.

VENTILATION INDEX (CATEGORY)  80 (POOR).          137 (POOR).
OUTLOOK FOR FRI DEC 5         166 (POOR).
OUTLOOK FOR SAT DEC 6         828 (GOOD).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 4-8 MPH.          S 6-13 MPH.
TRANSPORT WINDS               S 7-12 MPH.         SW 8-18 MPH.
MIXING HEIGHT                 NEAR SURFACE.       NEAR SURFACE.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR FRI DEC 5         GOOD.
OUTLOOK FOR SAT DEC 6         GOOD.

VENTILATION INDEX (CATEGORY)  58 (POOR).          105 (POOR).
OUTLOOK FOR FRI DEC 5         327 (FAIR).
OUTLOOK FOR SAT DEC 6         822 (GOOD).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      230 (POOR)
ELLENSBURG     65 (POOR)
GOLDENDALE    140 (POOR)
TRI-CITIES     57 (POOR)
WALLA WALLA    55 (POOR)
YAKIMA         25 (POOR)
BEND          120 (POOR)
PRINEVILLE     25 (POOR)
ENTERPRISE     81 (POOR)
HERMISTON      39 (POOR)
JOHN DAY      130 (POOR)
LA GRANDE     106 (POOR)
MADRAS        100 (POOR)
MEACHAM        70 (POOR)
PENDLETON      47 (POOR)
REDMOND        34 (POOR)
SENECA        127 (POOR)
THE DALLES     62 (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.
$$