984
AUUS46 KPDT 171225
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
525 AM PDT WED SEP 17 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 1-7 MPH.          NW 3-5 MPH.
TRANSPORT WINDS               S 3-7 MPH.          W 3-6 MPH.
MIXING HEIGHT                 NEAR SURFACE.       4000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR THU SEP 18        POOR.
OUTLOOK FOR FRI SEP 19        POOR.

VENTILATION INDEX (CATEGORY)  28 (POOR).          102 (POOR).
OUTLOOK FOR THU SEP 18        127 (POOR).
OUTLOOK FOR FRI SEP 19        166 (POOR).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 NW 2-5 MPH.         SE 2-5 MPH.
TRANSPORT WINDS               NW 4-7 MPH.         S 3-6 MPH.
MIXING HEIGHT                 NEAR SURFACE.       5500 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR THU SEP 18        POOR.
OUTLOOK FOR FRI SEP 19        POOR.

VENTILATION INDEX (CATEGORY)  36 (POOR).          121 (POOR).
OUTLOOK FOR THU SEP 18        119 (POOR).
OUTLOOK FOR FRI SEP 19        87 (POOR).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SE 4-8 MPH.         S 5-6 MPH.
TRANSPORT WINDS               SE 4-8 MPH.         S 9-11 MPH.
MIXING HEIGHT                 4000 FT MSL.        8500 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR THU SEP 18        GOOD.
OUTLOOK FOR FRI SEP 19        GOOD.

VENTILATION INDEX (CATEGORY)  75 (POOR).          518 (FAIR).
OUTLOOK FOR THU SEP 18        296 (POOR).
OUTLOOK FOR FRI SEP 19        192 (POOR).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SE 5-10 MPH.        N 4-5 MPH.
TRANSPORT WINDS               SE 6-12 MPH.        SW 5-6 MPH.
MIXING HEIGHT                 NEAR SURFACE.       5000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR THU SEP 18        POOR.
OUTLOOK FOR FRI SEP 19        FAIR.

VENTILATION INDEX (CATEGORY)  48 (POOR).          157 (POOR).
OUTLOOK FOR THU SEP 18        107 (POOR).
OUTLOOK FOR FRI SEP 19        170 (POOR).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      197 (POOR)
ELLENSBURG    272 (POOR)
GOLDENDALE    158 (POOR)
TRI-CITIES     71 (POOR)
WALLA WALLA   145 (POOR)
YAKIMA        150 (POOR)
BEND          180 (POOR)
PRINEVILLE    136 (POOR)
ENTERPRISE    119 (POOR)
HERMISTON      76 (POOR)
JOHN DAY      292 (POOR)
LA GRANDE     509 (FAIR)
MADRAS        105 (POOR)
MEACHAM       228 (POOR)
PENDLETON     123 (POOR)
REDMOND        78 (POOR)
SENECA        341 (FAIR)
THE DALLES    216 (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.
$$