Detailed Predictions for: Calabasas
Launch Lat, Long, Altitude (f): 34.134575, -118.687689, 1640
LZ Altitude (f): 770
Sounding

Station:

KVBG

Date/Time:

17 APR 2021

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Wind
Gust
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
12 Midnight Sat 62 62 ESE 3 3 2055 1789 149 Blue 3
1 AM Sat 62 62 ESE 2 3 2055 1789 149 Blue 3
2 AM Sat 61 61 ESE 2 2 1967 1767 127 Blue 2
3 AM Sat 61 61 E 2 2 1967 1767 127 Blue 2
4 AM Sat 60 60 ENE 1 2 1878 1745 105 Blue 1
5 AM Sat 59 59 NE 1 1 1790 1723 83 Blue 0
6 AM Sat 60 60 NE 1 1 1878 1745 105 Blue 1
7 AM Sat 62 62 NNE 1 1 2055 1789 149 Blue 3
8 AM Sat 63 64 NNE 0 1 2232 1965 325 Blue 5
9 AM Sat 67 69 NNE 0 0 5331 3082 1442 Blue 10
10 AM Sat 72 76 NE 0 0 8685 7676 6036 Blue 17
11 AM Sat 75 81 NE 0 0 10147 9224 7584 Blue 22
12 Noon Sat 76 83 ESE 0 0 10811 9825 8185 Blue 24
1 PM Sat 76 84 S 1 1 11085 10099 8459 Blue 25
2 PM Sat 76 83 SW 1 1 10811 9825 8185 Blue 24
3 PM Sat 75 80 WSW 4 5 9908 8920 7280 Blue 21
4 PM Sat 74 77 WSW 7 8 8995 7991 6351 Blue 18
5 PM Sat 73 75 W 10 11 8373 7357 5717 Blue 16
6 PM Sat 72 72 W 8 10 7419 5109 3469 Blue 13
7 PM Sat 72 72 WNW 6 9 7419 5109 3469 Blue 13
8 PM Sat 71 71 NW 5 7 7095 4422 2782 Blue 12
9 PM Sat 70 70 SSW 5 8 6748 3768 2128 Blue 11
10 PM Sat 70 70 ESE 5 8 6748 3768 2128 Blue 11
11 PM Sat 69 69 NNE 4 8 5331 3082 1442 Blue 10
12 Midnight Sun 69 69 NNE 4 8 5331 3082 1442 Blue 10
1 AM Sun 69 69 NNE 5 8 5331 3082 1442 Blue 10
2 AM Sun 69 69 NNE 5 7 5331 3082 1442 Blue 10
3 AM Sun 67 67 NNE 6 10 3816 2230 590 Blue 8
4 AM Sun 66 66 NNE 6 13 3117 2142 502 Blue 7
5 AM Sun 65 65 N 7 15 2355 2054 414 Blue 6
6 AM Sun 66 66 NNE 8 15 3117 2142 502 Blue 7
7 AM Sun 68 68 NNE 8 15 4481 2350 710 Blue 9
8 AM Sun 69 70 NNE 8 14 6748 3768 2128 Blue 11
9 AM Sun 71 73 NNE 13 19 7740 6564 4924 Blue 14
10 AM Sun 74 78 NNE 17 23 9302 8303 6663 Blue 19
11 AM Sun 77 83 NE 21 27 10811 9825 8185 Blue 24
12 Noon Sun 78 85 NE 21 26 12283 10267 8627 White 26
1 PM Sun 80 88 NE 20 25 12875 11691 10051 White 29
2 PM Sun 82 89 NE 19 24 13071 13071 11431 White 30
3 PM Sun 82 88 SE 16 19 12875 11691 10051 White 29
4 PM Sun 82 86 SW 12 15 12480 10615 8975 White 27
5 PM Sun 82 84 NW 9 10 11085 10099 8459 Blue 25
6 PM Sun 81 81 WNW 8 11 10147 9224 7584 Blue 22
7 PM Sun 79 79 WNW 8 12 9606 8613 6973 Blue 20
8 PM Sun 78 78 WNW 8 13 9302 8303 6663 Blue 19
9 PM Sun 76 76 NW 7 12 8685 7676 6036 Blue 17
10 PM Sun 74 74 NW 6 11 8058 7036 5396 Blue 15
11 PM Sun 72 72 NNW 5 10 7419 5109 3469 Blue 13
12 Midnight Mon 71 71 NNW 5 10 7095 4422 2782 Blue 12
1 AM Mon 71 71 N 6 11 7095 4422 2782 Blue 12
2 AM Mon 70 70 N 6 11 6748 3768 2128 Blue 11
3 AM Mon 69 69 WSW 6 12 5331 3082 1442 Blue 10
4 AM Mon 68 68 SE 6 13 4481 2350 710 Blue 9
5 AM Mon 67 67 N 6 14 3816 2230 590 Blue 8
6 AM Mon 69 69 N 6 11 5331 3082 1442 Blue 10
7 AM Mon 71 71 NNE 5 9 7095 4422 2782 Blue 12
8 AM Mon 73 74 NNE 4 7 8058 7036 5396 Blue 15
9 AM Mon 77 79 E 4 5 9606 8613 6973 Blue 20
10 AM Mon 81 85 SSE 3 4 12283 10267 8627 White 26
11 AM Mon 85 91 SW 2 2 13465 13465 11825 White 32
12 Noon Mon 84 91 SW 5 6 13465 13465 11825 White 32
1 PM Mon 83 90 SW 7 9 13268 13268 11628 White 31
2 PM Mon 81 87 WSW 10 13 12678 11009 9369 White 28
3 PM Mon 81 85 WSW 10 13 12283 10267 8627 White 26
4 PM Mon 81 84 WSW 11 13 11085 10099 8459 Blue 25
5 PM Mon 81 82 W 11 13 10316 9526 7886 Blue 23
6 PM Mon 79 79 W 8 11 9606 8613 6973 Blue 20
7 PM Mon 77 77 W 6 9 8995 7991 6351 Blue 18
8 PM Mon 75 75 WNW 4 8 8373 7357 5717 Blue 16
9 PM Mon 75 75 SSW 3 6 8373 7357 5717 Blue 16
10 PM Mon 75 75 SE 2 4 8373 7357 5717 Blue 16
11 PM Mon 75 75 ENE 1 2 8373 7357 5717 Blue 16

DISCLAIMER: These estimates are intended to assist in daily site selection only.  No warranty is made concerning the accuracy of these estimates.  These estimates cannot be used to determine if conditions are safe for flying.  Conditions should be evaluated at the launch site by experienced pilots before launching.

Sounding: This is the site at which the weather balloon was released.  If the flying site predicted is far from the sounding site, the estimate is not valid.  Also, the sounding is done at 12Z (4AM PST).  If a front comes through, the sounding is no longer valid. The sounding becomes less valid later in the day.

Thermal Ceiling: the lower of the height at which the thermal stops rising and the cloud level.  We can't fly into the clouds, so it doesn't matter how much higher the thermal goes.  Remember that we can't get to the top of the thermal because of our sink rate.  Our upper limit will be lower than the reported ceiling.

Soaring Ceiling: We will stop going up when the thermal is rising just fast enough to offset our sink.  It is estimated that this happens when the temperature difference between the thermal and the surrounding air is about 2 degrees F. This number is an estimate of the maximum altitude we might reach if we start at launch height, and should be more reflective of our chances of soaring than the thermal top. Please let me know how this compares with actually flying, and I will adjust it as necessary.

Above Launch: The difference between how high we might get and how high we start. This estimate does not account for ridge lift.

High Temp: This estimate is taken from the National Weather Service or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com estimate of cloudiness, and the angle of the sun.  When the sun is directly overhead on a sunny day, the puddle temp is esimated to be 25 degrees warmer than the high ambient temperature. This estimate now includes a rigorous calculation of the Sun Angle, and accounts for the seasonal differences in zenith and daylight hours.

Wind: This estimate is taken from the National Weather Service or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com website.

Thermal Type: Blue (no cloud formation) or White (Cloud formation)

Thermal Index: This is the maximum difference in temperature between the rising packet of air (the thermal) and the surrounding air.  The difference in temperature is responsible for the buoyancy of the thermal, and larger temperature differences mean faster rising thermals.  A value of about 10 F or greater often means that the conditions are soarable.  Values above 20 could indicate rowdy thermals.

Validity of estimate: Many factors (including strong wind, fronts, cloud shadows, incorrectly predicted temperatures, etc) can affect the validity of the estimates. 

Author: Tad Hurst

Supported By: Alan Crouse ac_soaring@yahoo.com