149
FNUS76 KPDT 080035
FWSPDT

Spot Forecast for Sunnyside Prescribed Burn...Mt Adams Resource Stewards
National Weather Service Pendleton OR
535 PM PDT Tue Oct 7 2025

Forecast is based on ignition time of 1000 PDT on October 08.
***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...West winds will prevail during the day Wednesday,
becoming southeast winds Thursday afternoon. Ridgetop winds will
shift to the north Wednesday night. Temperatures will be near to
just above freezing in the morning hours. A developing offshore
upper low will also bring rain chances to the burn area Wednesday
night through Thursday morning. Afternoon RHs will remain above
30% with excellent overnight recovery.

.WEDNESDAY...

Sky/weather.........Mostly sunny (25-35 percent).
CWR.................0 percent.
Chance of lightning.0 percent.
Max temperature.....65-68.
Min humidity........38-43 percent.
Wind (20 ft)........West winds 5 to 10 mph.
Ridgetop wind.......West winds 7 to 12 mph.
Mixing height.......4600 ft AGL.
Transport winds.....West 10 to 15 mph.
Ventilation Index...Good (510) in the afternoon.

TIME (PDT)      10 AM  NOON   2 PM   4 PM   6 PM   8 PM
Chc of ltng (%).0      0      0      0      0      0
Temp............51     59     63     64     59     49
RH..............79     54     45     42     51     69
20 ft wind......W 6    W 8    W 8    W 8    W 7    W 4
20 ft wind gust.10     12     13     13     13     10

.WEDNESDAY NIGHT...

Sky/weather.........Partly cloudy (40-50 percent) then becoming
                    mostly cloudy (60-70 percent). Slight chance of
                    rain showers early in the evening. Chance of
                    rain showers late in the evening.
CWR.................0 percent increasing to 43 percent late in the
                    evening, then decreasing to 33 percent early in
                    the morning.
Chance of lightning.3 percent.
Min temperature.....34-37.
Max humidity........95-100 percent.
Wind (20 ft)........West winds 5 to 8 mph early in the evening
                    becoming light drainage winds around 9PM.
Ridgetop wind.......Northwest winds 5 to 10 mph shifting to the north
4 to 7 mph after 11PM.
Mixing height.......1300 ft AGL.
Transport winds.....Northwest 6 to 13 mph shifting to the north
                    around 5 mph early in the morning.
Ventilation Index...Poor (200) decreasing to poor (70) overnight.

.THURSDAY...

Sky/weather.........Partly sunny (65-75 percent). Chance of rain
                    showers in the morning, then slight chance of
                    rain showers late in the morning. Rain showers
                    likely late in the afternoon.
CWR.................33 percent decreasing to 0 percent late in the
                    morning, then increasing to 23 percent late in
                    the afternoon.
Chance of lightning.8 percent.
Max temperature.....64-67.
Min humidity........42-47 percent.
Wind (20 ft)........Light drainage winds becoming southeast
4 to 7 mph around 11AM.
Ridgetop wind.......North winds 4 to 7 mph shifting to the southeast
5 to 8 mph around 11AM.
Mixing height.......3300 ft AGL.
Transport winds.....North around 5 mph early in the morning
                    becoming light, then becoming east 7 to 8 mph
                    late in the morning.
Ventilation Index...Poor (40) increasing to poor (190) in the
                    afternoon.

.FORECAST DAYS 3 THROUGH 7...
.FRIDAY...
Showers likely. Lows in the upper 30s. Highs in the mid 60s.
Light winds. Afternoon RHs in the mid 50s.
.SATURDAY...
Showers. Lows in the mid 30s. Highs in the mid 50s. West winds
around 6 mph. Afternoon RHs in the upper 60s.
.SUNDAY...
Showers. Lows in the lower 30s. Highs in the mid 50s. West winds
around 5 mph. Afternoon RHs in the upper 50s.
.COLUMBUS DAY...
Mostly cloudy. Showers likely. Lows in the lower 30s. Highs in
the mid 50s. Afternoon RHs in the lower 50s.
.TUESDAY...
Partly cloudy. Chance of showers. Lows in the lower 30s. Highs in
the upper 50s. Afternoon RHs in the lower 50s.

$$
Forecaster...Lawhorn
Requested by...Kylie England
Type of request...PRESCRIBED
.TAG 2523121.0/PDT
.DELDT 10/07/25
.FormatterVersion 2.0.0
.EMAIL kylie@mtadamsstewards.org,anthony.dobson@dnr.wa.gov