Detailed Predictions for: Calabasas
Launch Altitude (f): 1640
LZ Altitude (f): 770
Sounding

Station:

 KVBG

Date/Time:

 3 SEP 2010

Temp/Wind data from:

NOAA Digital Forecast

Time
(Local)		 High
Temp
Puddle
Temp
Wind
 (mph)		 Thermal
Ceiling
(ft)		 Soaring
Ceiling
(ft)		 Above
Launch
(ft)		 Thermal
Type		 Thermal
Index
(F)
5 AM Fri 57 57 N 1 1435 1640 0 Blue 0
6 AM Fri 56 56 N 1 1390 1640 0 Blue 0
7 AM Fri 56 56 N 1 1390 1640 0 Blue 0
8 AM Fri 62 62 N 3 1629 1640 0 Blue 1
9 AM Fri 76 78 N 3 1895 1790 150 Blue 17
10 AM Fri 90 94 N 3 4094 3054 1414 Blue 33
11 AM Fri 94 100 SW 6 8998 6454 4814 Blue 39
12 Noon Fri 97 104 SW 6 11027 9427 7787 Blue 43
1 PM Fri 99 106 SW 6 11640 10624 8984 Blue 45
2 PM Fri 100 107 SW 12 11943 10933 9293 Blue 46
3 PM Fri 101 107 SW 12 11943 10933 9293 Blue 46
4 PM Fri 102 106 SW 12 11640 10624 8984 Blue 45
5 PM Fri 98 100 SW 12 8998 6454 4814 Blue 39
6 PM Fri 92 92 SW 12 3184 2982 1342 Blue 31
7 PM Fri 86 86 SW 12 2411 2131 491 Blue 25
8 PM Fri 79 79 NW 2 1933 1819 179 Blue 18
9 PM Fri 74 74 NW 2 1778 1741 101 Blue 13
10 PM Fri 71 71 NW 2 1741 1703 63 Blue 10
11 PM Fri 67 67 NW 5 1691 1654 14 Blue 6
12 Midnight Sat 64 64 NW 5 1654 1640 0 Blue 3
1 AM Sat 62 62 NW 5 1629 1640 0 Blue 1
2 AM Sat 60 60 NE 3 1571 1640 0 Blue 0
3 AM Sat 59 59 NE 3 1525 1640 0 Blue 0
4 AM Sat 58 58 NE 3 1480 1640 0 Blue 0
5 AM Sat 58 58 NE 3 1480 1640 0 Blue 0
6 AM Sat 56 56 NE 3 1390 1640 0 Blue 0
7 AM Sat 56 56 NE 3 1390 1640 0 Blue 0
8 AM Sat 62 62 NE 10 1629 1640 0 Blue 1
9 AM Sat 77 79 NE 10 1933 1819 179 Blue 18
10 AM Sat 91 95 NE 10 4731 3175 1535 Blue 34
11 AM Sat 95 101 SW 3 9570 7328 5688 Blue 40
12 Noon Sat 98 105 SW 3 11335 9975 8335 Blue 44
1 PM Sat 100 107 SW 3 11943 10933 9293 Blue 46
2 PM Sat 101 108 SW 12 12243 11238 9598 Blue 47
3 PM Sat 102 108 SW 12 12243 11238 9598 Blue 47
4 PM Sat 103 107 SW 12 11943 10933 9293 Blue 46
5 PM Sat 99 101 SW 12 9570 7328 5688 Blue 40
6 PM Sat 93 93 SW 12 3430 3018 1378 Blue 32
7 PM Sat 87 87 SW 12 2871 2222 582 Blue 26
8 PM Sat 80 80 SW 12 1971 1856 216 Blue 19
9 PM Sat 75 75 SW 12 1790 1753 113 Blue 14
10 PM Sat 71 71 SW 12 1741 1703 63 Blue 10
11 PM Sat 67 67 N 2 1691 1654 14 Blue 6
12 Midnight Sun 65 65 N 2 1666 1640 0 Blue 4
1 AM Sun 62 62 N 2 1629 1640 0 Blue 1
2 AM Sun 61 61 N 2 1616 1640 0 Blue 0
3 AM Sun 60 60 N 2 1571 1640 0 Blue 0
4 AM Sun 59 59 N 2 1525 1640 0 Blue 0
5 AM Sun 58 58 NE 2 1480 1640 0 Blue 0
6 AM Sun 57 57 NE 2 1435 1640 0 Blue 0
7 AM Sun 57 57 NE 2 1435 1640 0 Blue 0
8 AM Sun 61 61 NE 2 1616 1640 0 Blue 0
9 AM Sun 72 74 NE 2 1778 1741 101 Blue 13
10 AM Sun 83 87 NE 2 2871 2222 582 Blue 26
11 AM Sun 86 92 SW 12 3184 2982 1342 Blue 31
12 Noon Sun 88 95 SW 12 4731 3175 1535 Blue 34
1 PM Sun 90 97 SW 12 6599 4043 2403 Blue 36
2 PM Sun 91 98 SW 12 7485 4670 3030 Blue 37
3 PM Sun 91 97 SW 12 6599 4043 2403 Blue 36
4 PM Sun 92 96 SW 12 5618 3390 1750 Blue 35
5 PM Sun 89 91 SW 12 3057 2947 1307 Blue 30
6 PM Sun 84 84 SW 12 2225 2008 368 Blue 23
7 PM Sun 79 79 SW 12 1933 1819 179 Blue 18
8 PM Sun 74 74 SW 12 1778 1741 101 Blue 13
9 PM Sun 70 70 SW 12 1728 1691 51 Blue 9
10 PM Sun 67 67 SW 12 1691 1654 14 Blue 6
11 PM Sun 64 64 E 6 1654 1640 0 Blue 3
12 Midnight Mon 62 62 E 6 1629 1640 0 Blue 1
1 AM Mon 60 60 E 6 1571 1640 0 Blue 0
2 AM Mon 59 59 E 6 1525 1640 0 Blue 0
3 AM Mon 58 58 E 6 1480 1640 0 Blue 0
4 AM Mon 57 57 E 6 1435 1640 0 Blue 0
5 AM Mon 56 56 E 5 1390 1640 0 Blue 0
6 AM Mon 56 56 E 5 1390 1640 0 Blue 0
7 AM Mon 56 56 E 5 1390 1640 0 Blue 0
8 AM Mon 59 59 E 5 1525 1640 0 Blue 0
9 AM Mon 69 70 E 5 1728 1691 51 Blue 9
10 AM Mon 77 80 E 5 1971 1856 216 Blue 19
11 AM Mon 81 87 S 7 2871 2222 582 Blue 26
12 Noon Mon 82 89 S 7 2984 2406 766 Blue 28
1 PM Mon 83 90 S 7 3019 2863 1223 Blue 29
2 PM Mon 84 91 S 7 3057 2947 1307 Blue 30
3 PM Mon 85 91 S 7 3057 2947 1307 Blue 30
4 PM Mon 85 89 S 7 2984 2406 766 Blue 28
5 PM Mon 83 85 S 7 2316 2050 410 Blue 24
6 PM Mon 79 79 S 7 1933 1819 179 Blue 18
7 PM Mon 74 74 S 7 1778 1741 101 Blue 13
8 PM Mon 69 69 S 7 1716 1679 39 Blue 8
9 PM Mon 66 66 S 7 1679 1642 2 Blue 5
10 PM Mon 64 64 S 7 1654 1640 0 Blue 3
11 PM Mon 61 61 E 3 1616 1640 0 Blue 0
12 Midnight Tue 59 59 E 3 1525 1640 0 Blue 0
1 AM Tue 57 57 E 3 1435 1640 0 Blue 0
2 AM Tue 56 56 E 3 1390 1640 0 Blue 0
3 AM Tue 56 56 E 3 1390 1640 0 Blue 0
4 AM Tue 55 55 E 3 1358 1640 0 Blue 0
5 AM Tue 54 54 E 3 1358 1640 0 Blue 0
6 AM Tue 54 54 E 3 1358 1640 0 Blue 0
7 AM Tue 54 54 E 3 1358 1640 0 Blue 0
8 AM Tue 57 57 E 3 1435 1640 0 Blue 0
9 AM Tue 66 66 E 3 1679 1642 2 Blue 5
10 AM Tue 74 74 E 3 1778 1741 101 Blue 13
11 AM Tue 77 83 S 12 2133 1970 330 Blue 22
12 Noon Tue 79 86 S 12 2411 2131 491 Blue 25
1 PM Tue 80 87 S 12 2871 2222 582 Blue 26
2 PM Tue 81 88 S 12 2949 2314 674 Blue 27
3 PM Tue 81 87 S 12 2871 2222 582 Blue 26
4 PM Tue 82 86 S 12 2411 2131 491 Blue 25
5 PM Tue 80 82 S 12 2051 1932 292 Blue 21
6 PM Tue 76 76 S 12 1819 1765 125 Blue 15
7 PM Tue 72 72 S 12 1753 1716 76 Blue 11
8 PM Tue 67 67 S 12 1691 1654 14 Blue 6
9 PM Tue 64 64 S 12 1654 1640 0 Blue 3
10 PM Tue 62 62 S 12 1629 1640 0 Blue 1
11 PM Tue 59 59 SE 3 1525 1640 0 Blue 0
12 Midnight Wed 58 58 SE 3 1480 1640 0 Blue 0
1 AM Wed 56 56 SE 3 1390 1640 0 Blue 0
2 AM Wed 55 55 SE 3 1358 1640 0 Blue 0
3 AM Wed 54 54 SE 3 1358 1640 0 Blue 0
4 AM Wed 54 54 SE 3 1358 1640 0 Blue 0
5 AM Wed 53 53 E 3 1358 1640 0 Blue 0
6 AM Wed 53 53 E 3 1358 1640 0 Blue 0
7 AM Wed 53 53 E 3 1358 1640 0 Blue 0
8 AM Wed 56 56 E 3 1390 1640 0 Blue 0
9 AM Wed 64 64 E 3 1654 1640 0 Blue 3
10 AM Wed 71 71 E 3 1741 1703 63 Blue 10
11 AM Wed 74 80 SW 8 1971 1856 216 Blue 19
12 Noon Wed 76 83 SW 8 2133 1970 330 Blue 22
1 PM Wed 77 84 SW 8 2225 2008 368 Blue 23
2 PM Wed 77 84 SW 8 2225 2008 368 Blue 23
3 PM Wed 78 84 SW 8 2225 2008 368 Blue 23
4 PM Wed 78 82 SW 8 2051 1932 292 Blue 21
5 PM Wed 76 78 SW 8 1895 1790 150 Blue 17
6 PM Wed 73 73 SW 8 1765 1728 88 Blue 12
7 PM Wed 69 69 SW 8 1716 1679 39 Blue 8
8 PM Wed 65 65 SW 8 1666 1640 0 Blue 4
9 PM Wed 63 63 SW 8 1642 1640 0 Blue 2
10 PM Wed 61 61 SW 8 1616 1640 0 Blue 0
11 PM Wed 59 59 E 3 1525 1640 0 Blue 0
12 Midnight Thu 57 57 E 3 1435 1640 0 Blue 0
1 AM Thu 56 56 E 3 1390 1640 0 Blue 0
2 AM Thu 55 55 E 3 1358 1640 0 Blue 0
3 AM Thu 54 54 E 3 1358 1640 0 Blue 0
4 AM Thu 54 54 E 3 1358 1640 0 Blue 0

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 website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service 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 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