327
AUUS46 KPDT 181112
DDOPDT

DAILY DISPERSION OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
412 AM PDT FRI APR 18 2025

*** AIR DISPERSION CATEGORIES:   GOOD, FAIR, POOR ***

FOR THE COLUMBIA BASIN FROM PENDLETON TO WALLA WALLA AND PASCO

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SE 4-8 MPH.         W 4-7 MPH.
TRANSPORT WINDS               SE 5-9 MPH.         W 5-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7000 FT MSL.
DISPERSION CATEGORY           POOR.               POOR.
OUTLOOK FOR SAT APR 19        GOOD.
OUTLOOK FOR SUN APR 20        GOOD.

VENTILATION INDEX (CATEGORY)  28 (POOR).          254 (POOR).
OUTLOOK FOR SAT APR 19        624 (GOOD).
OUTLOOK FOR SUN APR 20        730 (GOOD).

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

                              7:00 AM             AFTERNOON
SURFACE WINDS                 W 3-6 MPH.          SE 6-8 MPH.
TRANSPORT WINDS               NW 3-6 MPH.         SW 7-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       6500 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR SAT APR 19        FAIR.
OUTLOOK FOR SUN APR 20        GOOD.

VENTILATION INDEX (CATEGORY)  26 (POOR).          230 (POOR).
OUTLOOK FOR SAT APR 19        467 (FAIR).
OUTLOOK FOR SUN APR 20        646 (GOOD).

FOR THE GRANDE RONDE RIVER VALLEY

                              7:00 AM             AFTERNOON
SURFACE WINDS                 N 2-4 MPH.          NE 6-11 MPH.
TRANSPORT WINDS               N 2-4 MPH.          N 8-13 MPH.
MIXING HEIGHT                 NEAR SURFACE.       9000 FT MSL.
DISPERSION CATEGORY           POOR.               GOOD.
OUTLOOK FOR SAT APR 19        FAIR.
OUTLOOK FOR SUN APR 20        GOOD.

VENTILATION INDEX (CATEGORY)  44 (POOR).          476 (FAIR).
OUTLOOK FOR SAT APR 19        503 (FAIR).
OUTLOOK FOR SUN APR 20        706 (GOOD).

FOR THE BASE OF THE NORTHERN BLUE MOUNTAINS

                              7:00 AM             AFTERNOON
SURFACE WINDS                 SE 4-8 MPH.         NW 4-7 MPH.
TRANSPORT WINDS               SE 4-8 MPH.         NW 5-9 MPH.
MIXING HEIGHT                 NEAR SURFACE.       7000 FT MSL.
DISPERSION CATEGORY           POOR.               FAIR.
OUTLOOK FOR SAT APR 19        GOOD.
OUTLOOK FOR SUN APR 20        FAIR.

VENTILATION INDEX (CATEGORY)  43 (POOR).          310 (FAIR).
OUTLOOK FOR SAT APR 19        614 (GOOD).
OUTLOOK FOR SUN APR 20        769 (GOOD).

SELECT AFTERNOON FORECAST VENTILATION INDICES FOR SOME CITIES
CLE ELUM      320 (FAIR)
ELLENSBURG    193 (POOR)
GOLDENDALE    271 (POOR)
TRI-CITIES    219 (POOR)
WALLA WALLA   224 (POOR)
YAKIMA        213 (POOR)
BEND          337 (FAIR)
PRINEVILLE    394 (FAIR)
ENTERPRISE    411 (FAIR)
HERMISTON     158 (POOR)
JOHN DAY      621 (GOOD)
LA GRANDE     458 (FAIR)
MADRAS        290 (POOR)
MEACHAM       338 (FAIR)
PENDLETON     242 (POOR)
REDMOND       332 (FAIR)
SENECA        690 (GOOD)
THE DALLES     56 (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.
$$