285
FNUS76 KSTO 201321
FWSSTO
SPOT FORECAST FOR CHALLENGE RX...USFS
NATIONAL WEATHER SERVICE SACRAMENTO CA
521 AM PST SAT DEC 20 2025
FORECAST IS BASED ON IGNITION TIME OF 0700 PST ON DECEMBER 20.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.
DISCUSSION
ACTIVE WEATHER IS EXPECTED OVER THE WEEKEND AND THROUGH THE
UPCOMING HOLIDAY PERIOD. A BRIEF LULL IN PRECIPITATION IS
ANTICIPATED EARLY THIS MORNING, WITH MODERATE TO HEAVY RAINFALL
BECOMING MORE WIDESPREAD BY THE AFTERNOON. WHILE ADDITIONAL MINOR
BREAKS BETWEEN SYSTEMS WILL BE POSSIBLE AT TIMES NEXT WEEK,
PERSISTENT PERIODS OF MODERATE TO HEAVY RAIN ARE GENERALLY
EXPECTED THROUGH AT LEAST THURSDAY AS STRONGER AND COLDER SYSTEMS
IMPACT THE REGION FROM TUESDAY ONWARD.
FORECAST PRECIPITATION TOTALS OF 3-5 INCHES ARE CURRENTLY
EXPECTED THROUGH SUNDAY EVENING WITH PROBABILITIES OF AN
ADDITIONAL 6 INCHES OF RAINFALL MONDAY-WEDNESDAY SITTING AROUND
60-80% AT THIS TIME. BREEZY SOUTH WINDS ARE EXPECTED OVER THE
FORECAST PERIOD WITH GUSTS 25 TO 30 MPH AT TIMES FROM THIS EVENING
INTO THE WEEK AHEAD. ADDITIONAL PERIODS OF GUSTY SOUTH WINDS ARE
ANTICIPATED THROUGH NEXT WEEK AS WELL, WITH A 20-40% PROBABILITY
OF GUSTS GREATER THAN 40 MPH TUESDAY INTO WEDNESDAY.
TODAY
SKY/WEATHER.........CLOUDY. CHANCE OF RAIN IN THE MORNING, THEN
RAIN LIKELY LATE IN THE MORNING. RAIN LATE IN
THE AFTERNOON.
MAX TEMPERATURE.....50-54.
MIN HUMIDITY........97-100 PERCENT.
WIND (20 FT)........
SLOPE/VALLEY.......SOUTH WINDS UP TO 5 MPH IN THE MORNING BECOMING
LIGHT.
RIDGETOP...........SOUTH 7 TO 12 MPH.
MIXING HEIGHT.......1100 FT AGL.
TRANSPORT WINDS.....SOUTH 7 TO 12 MPH.
CWR.................27 PERCENT INCREASING TO 98 PERCENT LATE IN THE
AFTERNOON.
CHANCE OF THUNDER...5 PERCENT.
TIME (PST) 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY COVER.......CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY
CWR.............30 30 30 20 20 20 20 20 20 100 100
CHC OF THDR (%).10 10 10 0 0 0 0 0 0 0 0
TEMP............48 49 50 50 51 51 51 52 52 52 51
RH..............98 100 99 99 100 100 99 97 98 98 100
SL/VL WIND DIR..S S S S S S S S S S S
SL/VL WIND SPD..5 5 5 5 5 3 3 3 3 2 2
SL/VL WIND GUST.13 14 14 13 13 13 13 12 12 10 9
RIDGE WIND DIR..S S S S S S S S S S S
RIDGE WIND SPD..10 10 10 12 12 12 9 9 9 7 7
MIX HGT (KFT)...0.9 0.9 0.9 1.1 1.1 1.1 1.0 1.0 1.0 0.6 0.6
TRANSP WIND DIR.S S S S S S S S S S S
TRANSP WIND SPD.10 10 10 12 12 12 9 9 9 7 7
TONIGHT
SKY/WEATHER.........CLOUDY. RAIN.
MIN TEMPERATURE.....47-51.
MAX HUMIDITY........98-100 PERCENT.
WIND (20 FT)........
SLOPE/VALLEY.......LIGHT WINDS BECOMING SOUTH UP TO 10 MPH WITH
GUSTS TO AROUND 25 MPH IN THE LATE EVENING AND
OVERNIGHT.
RIDGETOP...........SOUTH 7 TO 16 MPH INCREASING TO 17 TO 21 MPH
OVERNIGHT.
MIXING HEIGHT.......300 FT AGL.
TRANSPORT WINDS.....SOUTH 9 TO 21 MPH.
CWR.................100 PERCENT.
CHANCE OF THUNDER...7 PERCENT.
TIME (PST) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
SKY COVER.......CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY
CWR.............100 100 100 100 100 100 100 100 100 100 100 100
CHC OF THDR (%).0 0 0 0 10 10 10 10 10 10 10 10
TEMP............51 51 51 51 51 51 50 51 51 51 52 52
RH..............100 100 100 100 100 100 99 100 100 100 99 99
SL/VL WIND DIR..S SE S S S S S S S S S S
SL/VL WIND SPD..2 3 3 3 5 6 6 7 8 8 10 10
SL/VL WIND GUST.9 10 12 13 14 16 20 21 23 24 25 25
RIDGE WIND DIR..S S S S S S S S S S S S
RIDGE WIND SPD..7 9 9 9 16 16 16 17 17 17 21 21
MIX HGT (KFT)...0.6 0.3 0.3 0.3 0.5 0.5 0.5 1.0 1.0 1.0 1.1 1.1
TRANSP WIND DIR.S S S S S S S S S S S S
TRANSP WIND SPD.7 9 9 9 16 16 16 17 17 17 21 21
SUNDAY
SKY/WEATHER.........CLOUDY. RAIN.
MAX TEMPERATURE.....50-54.
MIN HUMIDITY........98-100 PERCENT.
WIND (20 FT)........
SLOPE/VALLEY.......SOUTH WINDS 5 TO 10 MPH WITH GUSTS TO AROUND 26
MPH.
RIDGETOP...........SOUTH 17 TO 26 MPH.
MIXING HEIGHT.......3100 FT AGL.
TRANSPORT WINDS.....SOUTH 17 TO 26 MPH.
CWR.................100 PERCENT.
CHANCE OF THUNDER...11 PERCENT.
TIME (PST) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY COVER.......CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY
CWR.............100 100 100 100 100 100 100 100 100 100 100 100
CHC OF THDR (%).10 10 10 10 10 10 10 10 10 10 10 10
TEMP............51 51 51 51 51 51 51 51 51 52 52 52
RH..............100 100 99 99 100 100 99 99 99 99 99 99
SL/VL WIND DIR..S S S S S S S S S S S S
SL/VL WIND SPD..10 10 10 10 9 9 9 8 8 8 7 7
SL/VL WIND GUST.25 26 26 26 25 25 25 25 25 25 24 24
RIDGE WIND DIR..S S S S S S S S S S S S
RIDGE WIND SPD..21 23 23 23 26 26 26 21 21 21 17 17
MIX HGT (KFT)...1.1 2.0 2.0 2.0 3.1 3.1 3.1 2.7 2.7 2.7 3.0 3.0
TRANSP WIND DIR.S S S S S S S S S S S S
TRANSP WIND SPD.21 23 23 23 26 26 26 21 21 21 17 17
FORECAST DAYS 3 THROUGH 5
MONDAY
RAIN. PERIODS OF MODERATE TO HEAVY RAINFALL. LOWS IN THE MID 40S. HIGHS AROUND 50. SOUTH WINDS AROUND
6 TO 10 MPH EARLY, BEFORE DECREASING TO AROUND 5 MPH.
TUESDAY
SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS. LOWS IN THE MID 40S. HIGHS IN THE LOWER 50S. SOUTH WINDS
INCREASING IN THE EVENING TO AROUND 10 MPH WITH GUSTS 20 TO 30 MPH.
WEDNESDAY
RAIN. PERIODS OF MODERATE TO HEAVY RAINFALL. 15% CHANCE OF THUNDERSTORMS. LOWS IN THE LOWER 40S. HIGHS IN THE UPPER 40S. SOUTH WINDS
AROUND 8 TO 13 MPH WITH GUSTS 20 TO 30 MPH. STRONGEST WINDS IN THE MORNING HOURS.
FORECASTER...KF
REQUESTED BY...JASON MILLER
TYPE OF REQUEST...PRESCRIBED
.TAG 2527619.5/STO
.DELDT 12/20/25
.FORMATTERVERSION 2.0.0
.EMAIL BOBBY.HONROTH@USDA.GOV,JASON.T.MILLER@USDA.GOV,MARK.CRESALIA@USDA.GOV,JAMES.LICO@USDA.GOV
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