587
AUUS46 KPDT 201053
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
353 AM PDT SUN APR 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 9-17 MPH.        SW 12-20 MPH.
TRANSPORT WINDS               SW 10-17 MPH.       W 14-22 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7000 FT MSL.
DISPERSION CATEGORY           FAIR.               GOOD.
OUTLOOK FOR MON APR 21        GOOD.
OUTLOOK FOR TUE APR 22        POOR.

VENTILATION INDEX (CATEGORY)  142 (POOR).         660 (GOOD).
OUTLOOK FOR MON APR 21        824 (GOOD).
OUTLOOK FOR TUE APR 22        260 (POOR).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 W 4-9 MPH.          W 11-15 MPH.
TRANSPORT WINDS               NW 4-9 MPH.         W 12-17 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR MON APR 21        FAIR.
OUTLOOK FOR TUE APR 22        POOR.

VENTILATION INDEX (CATEGORY)  58 (POOR).          471 (FAIR).
OUTLOOK FOR MON APR 21        503 (FAIR).
OUTLOOK FOR TUE APR 22        158 (POOR).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 W 3-6 MPH.          NW 12-16 MPH.
TRANSPORT WINDS               W 3-6 MPH.          W 13-19 MPH.
MIXING HEIGHT                 NEAR SURFACE.       9000 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR MON APR 21        GOOD.
OUTLOOK FOR TUE APR 22        GOOD.

VENTILATION INDEX (CATEGORY)  61 (POOR).          546 (FAIR).
OUTLOOK FOR MON APR 21        708 (GOOD).
OUTLOOK FOR TUE APR 22        319 (FAIR).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SW 8-18 MPH.        W 14-18 MPH.
TRANSPORT WINDS               SW 10-18 MPH.       W 16-20 MPH.
MIXING HEIGHT                 NEAR SURFACE.       6500 FT MSL.
DISPERSION CATEGORY           FAIR.               FAIR.
OUTLOOK FOR MON APR 21        GOOD.
OUTLOOK FOR TUE APR 22        POOR.

VENTILATION INDEX (CATEGORY)  163 (POOR).         713 (GOOD).
OUTLOOK FOR MON APR 21        866 (GOOD).
OUTLOOK FOR TUE APR 22        287 (POOR).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      710 (GOOD)
ELLENSBURG    877 (GOOD)
GOLDENDALE    762 (GOOD)
TRI-CITIES    488 (FAIR)
WALLA WALLA   652 (GOOD)
YAKIMA        541 (FAIR)
BEND          426 (FAIR)
PRINEVILLE    487 (FAIR)
ENTERPRISE    409 (FAIR)
HERMISTON     691 (GOOD)
JOHN DAY      640 (GOOD)
LA GRANDE     656 (GOOD)
MADRAS        511 (FAIR)
MEACHAM       631 (GOOD)
PENDLETON     818 (GOOD)
REDMOND       559 (FAIR)
SENECA        672 (GOOD)
THE DALLES   1011 (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.
$$