548
FNUS76 KPDT 300706
FWSPDT

Spot Forecast for West Silvies RX...BLM
National Weather Service Pendleton OR
1206 AM PDT Tue Sep 30 2025

Forecast is based on ignition time of 0600 PDT on September 30.
***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...An offshore low-pressure system will continue to induce
breezy south to southwest winds, strongest in the late morning through
early evening hours, through Wednesday. Near-normal temperatures and
excellent overnight RH recovery are forecast. A chance (40 percent)
of showers is forecast late this afternoon, but the chance of lightning
is low (<10%).

.TODAY...

Sky/weather.........Partly cloudy (30-50 percent) then becoming
                    mostly cloudy (75-85 percent). Chance (40 percent)
                    of rain showers late in the afternoon.
CWR.................0 percent.
Chance of lightning.5 percent.
Max temperature.....61-64.
Min humidity........34-39 percent.
Wind (20 ft)........South winds 4-8 mph early morning, becoming south
                    to southwest 9-14 mph with gusts of 20-30 mph by
                    late morning.
Ridgetop wind.......South winds 4-8 mph early morning, becoming south
                    to southwest 12-17 mph with gusts of 20-30 mph by
                    late morning.
Mixing height.......Increasing to 6000-6500 ft AGL by afternoon.
Transport winds.....South 10-15 mph early morning, becoming south
                    to southwest 20-25 mph by late morning.
Ventilation Index...Poor to fair (150-220) increasing to excellent
                    (1050) in the afternoon.

TIME (PDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Chc of ltng (%).1   1   1   1   1   1   1   1   1   2   5   5
Temp............38  38  41  46  50  54  57  59  60  60  60  60
RH..............99  100 100 94  83  70  57  49  44  40  40  38
20 FT wind dir..S   S   S   S   S   S   S   S   SW  SW  SW  SW
20 FT wind spd..4   4   8   8   8   12  14  14  14  14  14  14
20 FT wind gust.7   7   14  14  14  22  25  25  25  28  28  28

.TONIGHT...

Sky/weather.........Partly to mostly cloudy (30-75 percent). Slight
                    chance (15 percent) of rain showers in the evening.
CWR.................0 percent.
Chance of lightning.2 percent.
Min temperature.....35-38.
Max humidity........95-100 percent.
Wind (20 ft)........South-southwest winds 8-12 mph with gusts of 15-25
                    mph in the evening, becoming south winds 4-8 mph
                    with gusts up to 15 mph overnight.
Ridgetop wind.......South-southwest winds 12-17 mph with gusts of 20-30
                    mph in the evening, becoming south winds 4-8 mph
                    with gusts up to 15 mph overnight.
Mixing height.......Decreasing to 400-700 ft AGL overnight.
Transport winds.....Southwest 20-25 mph in the evening, decreasing to
                    10-15 mph overnight.
Ventilation Index...Good (530-610) decreasing to poor (80-140)
                    overnight.

.WEDNESDAY...

Sky/weather.........Mostly cloudy (65-75 percent). Slight chance
                    (15 percent) of rain showers early in the morning.
CWR.................0 percent.
Chance of lightning.5 percent.
Max temperature.....59-62.
Min humidity........38-43 percent.
Wind (20 ft)........South to southwest winds 4-8 mph with gusts up to
                    15 mph in the morning, becoming 8-12 mph with gusts
                    of 20-25 mph by afternoon.
Ridgetop wind.......South to southwest winds 5-9 mph with gusts up to
                    20 mph in the morning, becoming 10-15 mph with gusts
                    of 20-30 mph by afternoon.
Mixing height.......Increasing to 5500-6000 ft AGL by afternoon.
Transport winds.....Southwest 15-20 mph.
Ventilation Index...Fair (210-300) increasing to excellent
                    (790-890) in the afternoon.

$$
Forecaster...Plunkett
Requested by...Joseph Sullivan
Type of request...PRESCRIBED
.TAG 2522527.2/PDT
.DELDT 09/30/25
.FormatterVersion 2.0.0
.EMAIL jrsullivan@blm.gov