639
FNUS76 KPDT 160929
FWSPDT

Spot Forecast for McCully Fire...USFS
National Weather Service Pendleton OR
229 AM PDT Wed Sep 16 2026

Forecast is based on forecast start time of 0600 PDT on September 16.
***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 transport wind
   multiplied by the mixing height in 100`s of ft.
   Categories are a generalized indicator only:
   low (< 200), moderate (200-500), high (500-700),
   and very high (> 700).                           ***

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

.DISCUSSION...Clearing skies and dry conditions are forecast today.
A low-pressure system will facilitate increasing chances of showers
and thunderstorms later tonight through Thursday night. Significant
uncertainty in the maximum RH forecast for tonight and the minimum RH
forecast for Thursday, dependent on exactly when/where showers and
thunderstorms develop. Current forecast is leaning towards a low-end
scenario for humidity; if showers develop and persist tonight and
Thursday, humidity will be higher.

.TODAY...

Sky/weather.........Partly cloudy (25-50 percent) early morning,
                    becoming sunny (0-5 percent) by late morning.
CWR.................0 percent.
Chance of lightning.0 percent.
Max temperature.....64-67.
Min humidity........30-35 percent.
Wind (20 ft)........Drainage winds 1-4 mph early morning, becoming
                    northeast winds 3-7 mph by mid-morning.
Ridgetop wind.......Northeast to east winds 5-9 mph with gusts of
                    12-17 mph.
Mixing height.......Increasing to 4500-5000 ft AGL by afternoon.
Transport winds.....Northeast 8-12 mph.
Ventilation Index...Low (30-60) increasing to moderate (475) in the
                    afternoon.

TIME (PDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Chc of ltng (%).0   0   0   0   0   0   0   0   0   0   0   0
Temp............39  39  48  51  56  59  61  64  65  65  63  60
RH..............85  85  67  55  45  40  35  32  31  31  35  43
20 FT wind dir..VRB VRB NE  NE  NE  NE  NE  NE  NE  NE  NE  NE
20 FT wind spd..3   3   3   5   5   5   5   5   6   6   6   6
20 FT wind gust.                12  12  12  12  12  12  12  12

.TONIGHT...

Sky/weather.........Mostly clear (5-15 percent) then becoming
                    mostly cloudy (65-75 percent). Chance (30 percent)
                    of rain showers and very low (5 percent) chance
                    of thunderstorms early in the morning.
CWR.................1 percent increasing to 15 percent early in the
                    morning.
Chance of lightning.5 percent.
Min temperature.....47-50.
Max humidity........65-70 percent.
Wind (20 ft)........Becoming drainage winds 1-4 mph overnight.
Ridgetop wind.......Northeast to east winds 4-9 mph.
Mixing height.......Decreasing to 300-600 ft AGL overnight.
Transport winds.....Northeast to east 8-12 mph.
Ventilation Index...Decreasing to low (30-60) overnight.

.THURSDAY...

Sky/weather.........Mostly cloudy (70-85 percent). Rain showers
                    likely (60 percent chance) and very low (5-15
                    percent) chance of thunderstorms in the morning,
                    then rain showers (75 percent chance) and
                    chance (25 percent) of thunderstorms in the
                    afternoon.
CWR.................40 percent morning, increasing to 60 percent
                    afternoon.
Chance of lightning.25 percent.
Max temperature.....65-68.
Min humidity........30-35 percent.
Wind (20 ft)........Drainage winds 1-4 mph early morning, becoming
                    east winds 3-6 mph mid-morning, then southeast
                    winds 5-9 mph with gusts of 12-17 mph late morning.
                    Gusty and erratic winds expected near showers and
                    thunderstorms.
Ridgetop wind.......East winds 4-9 mph early morning, becoming
                    southeast 9-14 mph with gusts of 15-20 mph late
                    morning.
Mixing height.......Increasing to 6500-7000 ft AGL by afternoon.
Transport winds.....East 8-12 mph shifting to the southeast 8-12 mph
                    late morning.
Ventilation Index...Low (45) increasing to high (675) in the afternoon.

$$
Forecaster...Plunkett
Requested by...Lane McDonald
Type of request...WILDFIRE
.TAG 2621937.0/PDT
.DELDT 09/16/26
.FormatterVersion 2.0.0
.EMAIL lanemcd23@gmail.com,lane.mcdonald@usda.gov