629
FNUS76 KPDT 092141
FWSPDT
SPOT FORECAST FOR BLACK ROCK FIRE...COIMT3
NATIONAL WEATHER SERVICE PENDLETON OR
241 PM PDT TUE SEP 9 2025
FORECAST IS BASED ON FORECAST START TIME OF 0600 PDT ON SEPTEMBER 10.
***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
SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE FOR
THE REGION AS A LOW PRESSURE SYSTEM CONTINUES TO MOVE INTO THE
PACIFIC NORTHWEST. RAIN CHANCES WILL BE AT THEIR GREATEST DURING
THE OVERNIGHT PERIOD WEDNESDAY NIGHT INTO THURSDAY, BEFORE SHOWERS
GENERALLY SHIFT EASTWARD. ISOLATED STORMS ARE POSSIBLE, BUT ARE
EXPECTED TO BE WETTING IN NATURE. WINDS WILL START OUT TERRAIN-
DRIVEN, BEFORE SHIFTING MORE WESTERLY AS THIS WEATHER SYSTEM MOVES
THROUGH.
WEDNESDAY
SKY/WEATHER.........PARTLY CLOUDY (45-55 PERCENT). CHANCE OF RAIN
SHOWERS AND THUNDERSTORMS. (30-40 PERCENT)
CWR.................8 PERCENT.
CHANCE OF LIGHTNING.29 PERCENT.
MAX TEMPERATURE.....82-85.
MIN HUMIDITY........36-41 PERCENT.
WIND (20 FT)........UPVALLEY WINDS 5 TO 8 MPH. GUSTY AND
ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS.
RIDGETOP WIND.......NORTH WINDS 7 TO 14 MPH.
MIXING HEIGHT.......6300 FT AGL.
TRANSPORT WINDS.....NORTH AROUND 9 MPH.
VENTILATION INDEX...POOR (60) INCREASING TO FAIR (280) IN THE
AFTERNOON.
TIME (PDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM
CHC OF LTNG (%).0 0 0 10 20 20
TEMP............58 62 70 76 79 81
RH..............81 73 58 51 45 41
20 FT WIND......SW 6 SW 6 SW 6 N 6 N 7 N 7
20 FT WIND GUST. 8 11 11
WEDNESDAY NIGHT
SKY/WEATHER.........MOSTLY CLOUDY (65-75 PERCENT). SHOWERS LIKELY
(50-60 PERCENT) WITH A CHANCE OF THUNDERSTORMS
(20-30 PERCENT).
CWR.................11 PERCENT INCREASING TO 22 PERCENT EARLY IN
THE MORNING.
CHANCE OF LIGHTNING.29 PERCENT.
MIN TEMPERATURE.....59-62.
MAX HUMIDITY........71-76 PERCENT.
WIND (20 FT)........DRAINAGE WINDS AROUND 5 MPH. GUSTY AND ERRATIC
WINDS EXPECTED NEAR THUNDERSTORMS.
RIDGETOP WIND.......WEST-NORTHWEST WINDS 5 TO 10 MPH.
MIXING HEIGHT.......1900 FT AGL.
TRANSPORT WINDS.....WEST AROUND 8 MPH.
VENTILATION INDEX...FAIR (240) DECREASING TO POOR (130) OVERNIGHT.
THURSDAY
SKY/WEATHER.........MOSTLY CLOUDY (55-65 PERCENT). CHANCE OF SHOWERS
AND THUNDERSTORMS EARLY (40-50 PERCENT),
DECREASING THROUGHOUT THE DAY.
CWR.................22 PERCENT DECREASING TO 4 PERCENT LATE IN THE
MORNING.
CHANCE OF LIGHTNING.20 PERCENT.
MAX TEMPERATURE.....79-82.
MIN HUMIDITY........41-46 PERCENT.
WIND (20 FT)........WEST WINDS 5 TO 10 MPH. GUSTY AND
ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS.
RIDGETOP WIND.......NORTHWEST WINDS 7 TO 14 MPH.
MIXING HEIGHT.......6100 FT AGL.
TRANSPORT WINDS.....WEST-NORTHWEST AROUND 9 MPH.
VENTILATION INDEX...POOR (100) INCREASING TO FAIR (250) IN THE
AFTERNOON.
FORECASTER...EVANS
REQUESTED BY...KATHY REED
TYPE OF REQUEST...WILDFIRE
.TAG 2521423.5/PDT
.DELDT 09/09/25
.FORMATTERVERSION 2.0.0
.EMAIL KATHERINE.REED@USDA.GOV
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