893
FNUS76 KPDT 261011
FWSPDT

Spot Forecast for South Ahtanum...Yakama Agency
National Weather Service Pendleton OR
311 AM PDT Sat Jul 26 2025

Forecast is based on forecast start time of 0800 PDT on July 26.
***Thunderstorms imply gusty and erratic winds***
***Winds are 20 foot 10-minute averages***
***CWR-Chance of wetting rain 0.10 or greater***
***Ventilation Index is derived from the
   transport wind multiplied by the mixing
   height in 100`s of feet. Index categories
   are a generalized indicator only.***

If you have questions or concerns with this forecast, please
contact our office at (541) 276-8134.

.DISCUSSION...

By the start of the forecast period, southerly winds
(southeast to south) will occur at the fire site this morning and
afternoon, with winds becoming northerly (northwest to north)
by late afternoon and tonight. These diurnally driven winds will
occur again tomorrow. RHs will remain in the mid to upper 20s
(24-27%) this afternoon, with moderate (60-65%) overnight
recovery. Sunday`s RHs will be slightly lower in the upper teens
to mid 20s (19-24%).


.REST OF TODAY...

Sky/weather.........Mostly sunny (20-30 percent).
CWR.................0 percent.
Chance of lightning.1 percent.
Max temperature.....84-88.
Min humidity........24-27 percent.
Wind (20 ft)........Southeast winds 5 to 8 mph shifting to the
    south by early afternoon, then shifting to
the northwest 5 to 10 mph late in the afternoon.
Mixing height.......9000 ft AGL.
Transport winds.....Light winds becoming northwest around 13 mph.
Ventilation Index...Poor (50) increasing to good (610) in the afternoon.

TIME (PDT)      8 AM   10 AM  NOON   2 PM   4 PM   6 PM
Chc of ltng (%).0      0      0      0      0      0
Temp............64     73     79     83     86     84
RH..............56     44     35     30     28     29
20 ft wind......SE 5   SE 5   S 7    S 8    S 8    NW 10
20 ft wind gust.6      6      10     13     13     14

.TONIGHT...

Sky/weather.........Partly cloudy (25-35 percent).
CWR.................0 percent.
Chance of lightning.1 percent.
Min temperature.....53-56.
Max humidity........60-65 percent.
Wind (20 ft)........Northwest winds 5 to 10 mph shifting to the
                    north early in the evening.
Mixing height.......600 ft AGL.
Transport winds.....Northwest 6 to 13 mph.
Ventilation Index...Fair (370) decreasing to poor (40) overnight.

.SUNDAY...

Sky/weather.........Sunny (5-15 percent).
CWR.................0 percent.
Chance of lightning.2 percent.
Max temperature.....89-92.
Min humidity........19-24 percent.
Wind (20 ft)........Northwest winds 5 to 7 mph early in the morning
                    becoming light, then becoming southerly 5 to 8
                    mph late in the morning.
Mixing height.......8600 ft AGL.
Transport winds.....Northwest around 6 mph early in the morning
                    becoming light, then becoming southwest 5 to 8
                    mph late in the morning.
Ventilation Index...Poor (30) increasing to fair (290) in the
                    afternoon.

$$
Forecaster...Melto
Requested by...Dolores Moore
Type of request...WILDFIRE
.TAG 2518623.0/PDT
.DELDT 07/26/25
.FormatterVersion 2.0.0
.EMAIL dolores_moore@yakama.com