796
AUUS46 KPDT 221256
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
ISSUED BY NATIONAL WEATHER SERVICE SPOKANE WA
556 AM PDT TUE APR 22 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 4-8 MPH.         N 6-10 MPH.
TRANSPORT WINDS               SW 6-9 MPH.         N 5-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       8500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR WED APR 23        FAIR.
OUTLOOK FOR THU APR 24        FAIR.

VENTILATION INDEX (CATEGORY)  56 (POOR).          242 (POOR).
OUTLOOK FOR WED APR 23        435 (FAIR).
OUTLOOK FOR THU APR 24        309 (FAIR).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 NW 3-6 MPH.         NE 3-6 MPH.
TRANSPORT WINDS               NW 5-9 MPH.         NE 5-7 MPH.
MIXING HEIGHT                 NEAR SURFACE.       9500 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR WED APR 23        POOR.
OUTLOOK FOR THU APR 24        FAIR.

VENTILATION INDEX (CATEGORY)  66 (POOR).          344 (FAIR).
OUTLOOK FOR WED APR 23        338 (FAIR).
OUTLOOK FOR THU APR 24        557 (FAIR).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 N 1-3 MPH.          N 9-12 MPH.
TRANSPORT WINDS               NW 3-6 MPH.         N 9-12 MPH.
MIXING HEIGHT                 NEAR SURFACE.       10500 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR WED APR 23        GOOD.
OUTLOOK FOR THU APR 24        GOOD.

VENTILATION INDEX (CATEGORY)  61 (POOR).          385 (FAIR).
OUTLOOK FOR WED APR 23        629 (GOOD).
OUTLOOK FOR THU APR 24        457 (FAIR).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 3-8 MPH.          N 7-10 MPH.
TRANSPORT WINDS               SW 5-9 MPH.         N 7-10 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR WED APR 23        FAIR.
OUTLOOK FOR THU APR 24        FAIR.

VENTILATION INDEX (CATEGORY)  70 (POOR).          289 (POOR).
OUTLOOK FOR WED APR 23        515 (FAIR).
OUTLOOK FOR THU APR 24        400 (FAIR).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      250 (POOR)
ELLENSBURG    287 (POOR)
GOLDENDALE    346 (FAIR)
TRI-CITIES    328 (FAIR)
WALLA WALLA   252 (POOR)
YAKIMA        363 (FAIR)
BEND          233 (POOR)
PRINEVILLE    409 (FAIR)
ENTERPRISE    226 (POOR)
HERMISTON      91 (POOR)
JOHN DAY      424 (FAIR)
LA GRANDE     265 (POOR)
MADRAS        436 (FAIR)
MEACHAM       136 (POOR)
PENDLETON     333 (FAIR)
REDMOND       431 (FAIR)
SENECA        455 (FAIR)
THE DALLES    318 (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.
$$