Daily Dispersion Outlook
Issued by NWS Pendleton, OR

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394
AUUS46 KPDT 231225
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
525 AM PDT WED JUL 23 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.          W 6-8 MPH.
TRANSPORT WINDS               SW 5-9 MPH.         W 7-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       10000 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR THU JUL 24        GOOD.
OUTLOOK FOR FRI JUL 25        GOOD.

VENTILATION INDEX (CATEGORY)  79 (POOR).          512 (FAIR).
OUTLOOK FOR THU JUL 24        981 (GOOD).
OUTLOOK FOR FRI JUL 25        912 (GOOD).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 NW 2-5 MPH.         SW 4-7 MPH.
TRANSPORT WINDS               NW 4-7 MPH.         W 6-8 MPH.
MIXING HEIGHT                 NEAR SURFACE.       10500 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR THU JUL 24        GOOD.
OUTLOOK FOR FRI JUL 25        FAIR.

VENTILATION INDEX (CATEGORY)  56 (POOR).          431 (FAIR).
OUTLOOK FOR THU JUL 24        507 (FAIR).
OUTLOOK FOR FRI JUL 25        547 (FAIR).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SE 1-3 MPH.         N 3-4 MPH.
TRANSPORT WINDS               N 2-4 MPH.          W 6-8 MPH.
MIXING HEIGHT                 4000 FT MSL.        12000 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR THU JUL 24        GOOD.
OUTLOOK FOR FRI JUL 25        GOOD.

VENTILATION INDEX (CATEGORY)  41 (POOR).          419 (FAIR).
OUTLOOK FOR THU JUL 24        745 (GOOD).
OUTLOOK FOR FRI JUL 25        614 (GOOD).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 S 4-8 MPH.          W 6-8 MPH.
TRANSPORT WINDS               S 7-10 MPH.         W 7-8 MPH.
MIXING HEIGHT                 NEAR SURFACE.       9500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR THU JUL 24        GOOD.
OUTLOOK FOR FRI JUL 25        GOOD.

VENTILATION INDEX (CATEGORY)  95 (POOR).          537 (FAIR).
OUTLOOK FOR THU JUL 24        959 (GOOD).
OUTLOOK FOR FRI JUL 25        904 (GOOD).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      768 (GOOD)
ELLENSBURG    637 (GOOD)
GOLDENDALE    607 (GOOD)
TRI-CITIES    496 (FAIR)
WALLA WALLA   539 (FAIR)
YAKIMA        454 (FAIR)
BEND          364 (FAIR)
PRINEVILLE    485 (FAIR)
ENTERPRISE    455 (FAIR)
HERMISTON     493 (FAIR)
JOHN DAY      726 (GOOD)
LA GRANDE     474 (FAIR)
MADRAS        431 (FAIR)
MEACHAM       462 (FAIR)
PENDLETON     514 (FAIR)
REDMOND       398 (FAIR)
SENECA        691 (GOOD)
THE DALLES    577 (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.
$$