851
FNUS76 KPDT 121846
FWSPDT
SPOT FORECAST FOR BLACK ROCK FIRE...COIMT3
NATIONAL WEATHER SERVICE PENDLETON OR
1146 AM PDT FRI SEP 12 2025
FORECAST IS BASED ON FORECAST START TIME OF 0600 PDT ON SEPTEMBER 13.
***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
DRY CONDITIONS WITH LIGHT WINDS SATURDAY AS HIGH
PRESSURE MOVES OVER THE AREA. A COLD FRONT AND UPPER LOW WILL MOVE
ACROSS THE AREA STARTING EARLY SUNDAY, WITH CURRENT TIMING OF INCREASED
WINDS EXPECTED AFTER 11AM ON SUNDAY. WINDS WILL BE STRONGEST ALONG
EXPOSED RIDGES. BEST CHANCE OF WETTING RAINS WILL BE ASSOCIATED WITH
THE COLD FRONT PASSAGE, WITH CHANCES SHARPLY DECREASING IN THE EVENING.
AN ISOLATED THUNDERSTORM OR TWO MAY IMPACT THE FIRE SITE WITH THE
FRONTAL PASSAGE. AFTERNOON RH WILL BE IN THE MID 20S TOMORROW,
INCREASING INTO THE 50S SUNDAY, WITH GOOD OVERNIGHT RECOVERY.
SATURDAY
SKY/WEATHER.........SUNNY (5-15 PERCENT).
CWR.................0 PERCENT.
CHANCE OF LIGHTNING.1 PERCENT.
MAX TEMPERATURE.....83-86.
MIN HUMIDITY........26-31 PERCENT.
WIND (20 FT)........SOUTH WINDS 5 TO 8 MPH SHIFTING TO THE
NORTHWEST AFTER 2PM.
RIDGETOP WIND.......SOUTH WINDS 5 TO 8 MPH SHIFTING TO THE
NORTHWEST AFTER 2PM.
MIXING HEIGHT.......6000 FT AGL.
TRANSPORT WINDS.....SOUTH AROUND 6 MPH SHIFTING TO THE WEST AROUND
7 MPH LATE IN THE AFTERNOON.
VENTILATION INDEX...POOR (50) INCREASING TO FAIR (200) IN THE
AFTERNOON.
TIME (PDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM
CHC OF LTNG (%).0 0 0 0 0 0
TEMP............57 60 67 75 80 83
RH..............71 67 59 45 34 30
20 FT WIND......S 7 S 7 S 7 SW 7 W 7 NW 7
20 FT WIND GUST. 10 10
SATURDAY NIGHT
SKY/WEATHER.........PARTLY CLOUDY (25-35 PERCENT) THEN BECOMING
MOSTLY CLOUDY (60-70 PERCENT). SLIGHT CHANCE OF
SHOWERS LATE IN THE EVENING. CHANCE OF SHOWERS
EARLY IN THE MORNING.
CWR.................2 PERCENT INCREASING TO 45 PERCENT EARLY IN THE
MORNING.
CHANCE OF LIGHTNING.12 PERCENT.
MIN TEMPERATURE.....59-62.
MAX HUMIDITY........68-73 PERCENT.
WIND (20 FT)........NORTHWEST WINDS 5 TO 8 MPH SHIFTING TO THE WEST
AFTER 1AM.
RIDGETOP WIND.......NORTHWEST WINDS 5 TO 10 MPH.
MIXING HEIGHT.......800 FT AGL.
TRANSPORT WINDS.....WEST AROUND 7 MPH SHIFTING TO THE NORTH AROUND
10 MPH EARLY IN THE EVENING, THEN SHIFTING TO
THE NORTHWEST AROUND 7 MPH LATE IN THE EVENING.
VENTILATION INDEX...FAIR (210) DECREASING TO POOR (50) OVERNIGHT.
SUNDAY
SKY/WEATHER.........PARTLY SUNNY (55-65 PERCENT). CHANCE OF
SHOWERS. SLIGHT CHANCE OF THUNDERSTORMS LATE IN
THE MORNING.
CWR.................45 PERCENT DECREASING TO 0 PERCENT.
CHANCE OF LIGHTNING.21 PERCENT.
MAX TEMPERATURE.....AROUND 70.
MIN HUMIDITY........53-58 PERCENT.
WIND (20 FT)........WEST WINDS 5 TO 10 MPH INCREASING TO 8 TO 14 MPH
AFTER 12PM. GUSTY AND ERRATIC WINDS EXPECTED NEAR
THUNDERSTORMS IN THE MORNING AND AFTERNOON.
RIDGETOP WIND.......NORTHWEST WINDS 5 TO 10 MPH SHIFTING TO THE WEST
10 TO 15 MPH WITH GUSTS TO 25 MPH AFTER 12PM.
MIXING HEIGHT.......4600 FT AGL.
TRANSPORT WINDS.....WEST 7 TO 16 MPH.
VENTILATION INDEX...POOR (110) INCREASING TO FAIR (460) IN THE
AFTERNOON.
FORECASTER...LAWHORN
REQUESTED BY...KATHY REED
TYPE OF REQUEST...WILDFIRE
.TAG 2521872.0/PDT
.DELDT 09/12/25
.FORMATTERVERSION 2.0.0
.EMAIL KATHERINE.REED@USDA.GOV
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