145
FNUS76 KSTO 190428
FWSSTO

Spot Forecast for Butterfly Valley RX...CAL FIRE
National Weather Service Sacramento CA
928 PM PDT Fri Apr 18 2025

Forecast is based on ignition time of 0900 PDT on April 19.
If conditions become unrepresentative...contact the National Weather
Service.

.DISCUSSION...
Warmer and drier weather is expected through the weekend and into
early next week. There will be generally diurnally driven winds.
A Cooling trend returns mid to late week.

&&

.SATURDAY...

Sky/weather.........Sunny.
Max temperature.....72-76.
Min humidity........15-19 percent.
Wind (20 ft)........
 Slope/valley.......Light winds becoming west up to 6 mph late in
                    the afternoon.
 Ridgetop...........East around 6 mph shifting to the west 3 to 9
                    mph late in the morning.
Mixing height.......7100 ft AGL.
Transport winds.....East around 6 mph shifting to the west 3 to 9
                    mph late in the morning.
CWR.................1 percent.
Chance of thunder...1 percent.

TIME (PDT)      9 AM         1 PM         5 PM
Sky cover.......CLEAR        MCLEAR       MCLEAR
CWR.............0            0            0
Chc of thdr (%).0            0            0
Temp............44           70           72
RH..............39           18           21
SL/VL wind......N 0G1        W 2G6        W 6G12
Ridgetop wind...N 15         N 10         N 5
Mix hgt (ft)....2300         4700         4500
Transport wind..E 6          W 3          W 9

.SATURDAY NIGHT...

Sky/weather.........Mostly clear.
Min temperature.....38-42.
Max humidity........85-89 percent.
Wind (20 ft)........
 Slope/valley.......West winds 5 to 6 mph early in the evening
                    becoming light.
 Ridgetop...........Southwest 3 to 9 mph shifting to the east
                    around 5 mph overnight.
Mixing height.......1400 ft AGL.
Transport winds.....West around 9 mph shifting to the southwest 3
                    to 9 mph in the evening and overnight, then
                    shifting to the east around 5 mph overnight.
CWR.................0 percent.
Chance of thunder...0 percent.

TIME (PDT)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky cover.......MCR MCR CLR CLR CLR CLR CLR CLR CLR CLR CLR CLR
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of thdr (%).0   0   0   0   0   0   0   0   0   0   0   0
Temp............71  66  59  55  52  50  48  45  43  42  41  40
RH..............24  34  46  54  62  68  73  76  79  82  84  85
SL/VL wind dir..W   W   SW  SW  SW  S   S   S   N   N   N   N
SL/VL wind spd..6   6   2   2   2   1   1   1   0   0   0   0
SL/VL wind gust.12  12  7   7   7   2   2   2   1   1   1   1
Ridge wind dir..N   N   N   N   N   N   N   NW  W   W   W   W
Ridge wind spd..10  10  10  10  5   5   5   0   0   0   5   10
Mix hgt (kft)...4.5 4.5 1.7 1.7 1.7 1.4 1.4 1.4 1.4 1.4 1.4 1.4
Transp wind dir.W   W   SW  SW  SW  S   S   S   E   E   E   SE
Transp wind spd.9   9   6   6   6   3   3   3   5   5   5   5

.SUNDAY...

Sky/weather.........Sunny.
Max temperature.....73-77.
Min humidity........23-27 percent.
Wind (20 ft)........
 Slope/valley.......Light winds becoming southwest 5 to 7 mph late
                    in the afternoon.
 Ridgetop...........Southeast around 5 mph shifting to the west 5
                    to 10 mph late in the morning.
Mixing height.......8000 ft AGL.
Transport winds.....Southeast around 5 mph shifting to the west 10
                    to 17 mph late in the morning.
CWR.................1 percent.
Chance of thunder...2 percent.

TIME (PDT)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky cover.......CLR CLR CLR CLR CLR CLR CLR CLR MCR MCR MCR MCR
CWR.............0   0   0   0   0   0   0   0   0   0   0   0
Chc of thdr (%).0   0   0   0   0   0   0   0   0   0   0   0
Temp............40  41  44  50  57  63  68  72  74  75  75  73
RH..............85  83  77  66  54  42  34  28  25  22  22  25
SL/VL wind dir..N   N   N   N   N   SW  SW  SW  SW  SW  SW  SW
SL/VL wind spd..0   0   0   0   0   1   1   1   6   6   6   7
SL/VL wind gust.1   1               5   5   5   13  13  13  16
Ridge wind dir..W   W   W   W   W   W   W   W   W   W   W   W
Ridge wind spd..5   5   5   5   5   10  10  10  16  16  16  17
Mix hgt (kft)...1.4 1.4 2.0 2.0 2.0 4.9 4.9 4.9 8.0 8.0 8.0 7.2
Transp wind dir.SE  SE  S   S   S   W   W   W   W   W   W   W
Transp wind spd.5   5   5   5   5   10  10  10  16  16  16  17

.FORECAST DAYS 3 THROUGH 5...
.MONDAY...
Clear. Lows in the lower 40s. Highs in the upper 70s. Light
winds.
.TUESDAY...
Clear. Lows in the lower 40s. Highs in the mid 70s. Light winds.
.WEDNESDAY...
Mostly clear. Lows in the lower 40s. Highs in the lower 70s.
Light winds.

$$
Forecaster...CS
Requested by...Erik Hansen
Type of request...PRESCRIBED
.TAG 2511019.0/STO
.DELDT 04/19/25
.FormatterVersion 2.0.0
.EMAIL erik.hansen@fire.ca.gov,robbie.whitchurch@fire.ca.gov