279
FNUS76 KPDT 070138
FWSPDT

Spot Forecast for BIG LAKE...DNR
National Weather Service Pendleton OR
638 PM PDT Sat Sep 6 2025

Forecast is based on forecast start time of 0600 PDT on September 07.
***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.

...RED FLAG WARNING IN EFFECT UNTIL 3 AM PDT SUNDAY...

.DISCUSSION...Shower and thunderstorm chances will continue through
the weekend. Thunderstorms will be capable of producing small hail,
locally heavy rainfall, and gusty outflow winds up to 50 mph. Outside
of thunderstorm outflow, lighter winds are forecast. Temperatures
will cool into next week with higher relative humidity also expected.

.SUNDAY...

Sky/weather.........Mostly sunny (45-55 percent). Haze through the
                    day. Areas of smoke late in the morning. Slight
                    chance of thunderstorms in the morning. Chance
                    of rain showers through the day. Chance of
                    thunderstorms in the afternoon.
CWR.................1 percent increasing to 18 percent late in the
                    morning, then decreasing to 0 percent late in
                    the afternoon.
Chance of lightning.26 percent.
Max temperature.....Around 80.
Min humidity........45-50 percent.
Wind (20 ft)........West to southwest winds 5 to 10 mph. Gusts up
                    to 21 mph after 4 PM. Gusty and erratic winds
                    expected near thunderstorms beginning around
                    11 PM through 5 PM.
Ridgetop wind.......West winds 8 to 13 mph. Gusts up to 26 mph
                    after 4 PM. Gusty and erratic winds
                    expected near thunderstorms beginning around
                    11 PM through 5 PM.
Mixing height.......3500 ft AGL.
Transport winds.....West 10 to 15 mph.
Ventilation Index...Poor (150) increasing to fair (330) in the
                    afternoon.

TIME (PDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Chc of ltng (%).0   0   10  10  10  20  20  20  30  30  30  10
Temp............57  55  57  62  67  69  73  75  77  76  75  74
RH..............98  100 97  86  75  69  58  53  50  51  54  54
20 FT wind dir..W   W   W   W   W   W   W   W   W   W   W   W
20 FT wind spd..5   5   7   7   7   10  10  10  10  10  10  10
20 FT wind gust.10  10  14  14  14  14  14  14  16  16  16  17

.SUNDAY NIGHT...

Sky/weather.........Partly cloudy (30-40 percent). Haze and areas
                    of smoke in the evening. Slight chance of rain
                    showers in the evening.
CWR.................0 percent.
Chance of lightning.10 percent.
Min temperature.....49-52.
Max humidity........95-100 percent.
Wind (20 ft)........West to southwest winds 5 to 10 mph with gusts to
                    around 20 mph becoming downslope/down-valley
                    after 8PM.
Ridgetop wind.......West winds 8 to 13 mph with gusts to around 25
                    mph becoming 5 to 7 mph.
Mixing height.......1000 ft AGL.
Transport winds.....West 10 to 16 mph.
Ventilation Index...Fair (250) decreasing to poor (130) overnight.

.MONDAY...

Sky/weather.........Partly sunny (50-60 percent). Slight chance of
                    rain showers late in the morning. Chance of
                    rain showers and slight chance of thunderstorms
                    late in the afternoon.
CWR.................0 percent increasing to 10 percent late in the
                    afternoon.
Chance of lightning.15 percent.
Max temperature.....Around 80.
Min humidity........34-39 percent.
Wind (20 ft)........Upslope/up-valley winds. Gusty and erratic winds
                    expected near thunderstorms around 5 PM.
Ridgetop wind.......West to southwest 5 to 8 mph around 5 PM and gusty
                    and erratic winds expected near thunderstorms.
Mixing height.......5900 ft AGL.
Transport winds.....West 6 to 10 mph.
Ventilation Index...Poor (120) increasing to fair (240) in the
                    afternoon.

$$
Forecaster...Bennese
Requested by...CWICC
Type of request...WILDFIRE
.TAG 2521484.0/PDT
.DELDT 09/06/25
.FormatterVersion 2.0.0
.EMAIL andrew.clark@dnr.wa.gov,Wacwc@firenet.gov