Detailed Predictions for: Lake Isabella Ground Launch Center
Launch Altitude (f): 5000
LZ Altitude (f): 2591
Sounding

Station:

KVBG

Date/Time:

25 AUG 2019

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
5 AM Sun 72 72 W 7 2592 5000 0 Blue 0
6 AM Sun 70 70 NW 7 2592 5000 0 Blue 0
7 AM Sun 71 71 NW 8 2592 5000 0 Blue 0
8 AM Sun 75 75 W 8 2932 5000 0 Blue 0
9 AM Sun 74 76 W 7 3138 5000 0 Blue 0
10 AM Sun 80 84 W 8 4774 5000 0 Blue 0
11 AM Sun 85 91 W 12 7806 6658 1658 Blue 6
12 Noon Sun 89 96 W 15 11420 11126 6126 Blue 11
1 PM Sun 91 99 W 20 11557 11407 6407 Blue 14
2 PM Sun 92 99 W 21 11557 11407 6407 Blue 14
3 PM Sun 93 99 W 22 11557 11407 6407 Blue 14
4 PM Sun 92 96 W 21 11420 11126 6126 Blue 11
5 PM Sun 91 93 W 21 11281 7193 2193 Blue 8
6 PM Sun 89 89 W 18 6778 5159 159 Blue 4
7 PM Sun 85 85 W 18 4981 5000 0 Blue 0
8 PM Sun 83 83 W 15 4571 5000 0 Blue 0
9 PM Sun 82 82 W 16 4368 5000 0 Blue 0
10 PM Sun 81 81 W 14 4164 5000 0 Blue 0
11 PM Sun 82 82 SW 14 4368 5000 0 Blue 0
12 Midnight Mon 81 81 NW 12 4164 5000 0 Blue 0
1 AM Mon 80 80 NW 10 3960 5000 0 Blue 0
2 AM Mon 78 78 NW 10 3550 5000 0 Blue 0
3 AM Mon 77 77 NW 9 3344 5000 0 Blue 0
4 AM Mon 75 75 NW 8 2932 5000 0 Blue 0
5 AM Mon 74 74 NW 7 2725 5000 0 Blue 0
6 AM Mon 72 72 NW 6 2592 5000 0 Blue 0
7 AM Mon 72 72 NW 7 2592 5000 0 Blue 0
8 AM Mon 75 75 W 6 2932 5000 0 Blue 0
9 AM Mon 75 76 W 6 3138 5000 0 Blue 0
10 AM Mon 80 81 W 6 4164 5000 0 Blue 0
11 AM Mon 85 86 W 6 5171 5000 0 Blue 1
12 Noon Mon 89 91 W 6 7806 6658 1658 Blue 6
1 PM Mon 92 94 W 6 11327 7727 2727 Blue 9
2 PM Mon 94 99 SE 16 11557 11407 6407 Blue 14
3 PM Mon 95 99 SE 16 11557 11407 6407 Blue 14
4 PM Mon 94 97 SE 16 11466 11314 6314 Blue 12
5 PM Mon 93 94 W 16 11327 7727 2727 Blue 9
6 PM Mon 91 91 W 16 7806 6658 1658 Blue 6
7 PM Mon 88 88 W 16 6670 5000 0 Blue 3
8 PM Mon 85 85 W 14 4981 5000 0 Blue 0
9 PM Mon 84 84 W 14 4774 5000 0 Blue 0
10 PM Mon 83 83 W 14 4571 5000 0 Blue 0
11 PM Mon 82 82 W 12 4368 5000 0 Blue 0
12 Midnight Tue 81 81 W 12 4164 5000 0 Blue 0
1 AM Tue 80 80 W 12 3960 5000 0 Blue 0
2 AM Tue 79 79 NW 8 3755 5000 0 Blue 0
3 AM Tue 77 77 NW 8 3344 5000 0 Blue 0
4 AM Tue 76 76 NW 8 3138 5000 0 Blue 0
5 AM Tue 75 75 NW 6 2932 5000 0 Blue 0
6 AM Tue 75 75 NW 6 2932 5000 0 Blue 0
7 AM Tue 75 75 NW 6 2932 5000 0 Blue 0
8 AM Tue 77 77 NE 6 3344 5000 0 Blue 0
9 AM Tue 80 82 NE 6 4368 5000 0 Blue 0
10 AM Tue 84 88 NE 6 6670 5000 0 Blue 3
11 AM Tue 88 93 SE 8 11281 7193 2193 Blue 8
12 Noon Tue 91 98 SE 8 11512 11361 6361 Blue 13
1 PM Tue 93 100 SE 8 11625 11454 6454 Blue 15
2 PM Tue 95 102 SE 17 12852 11545 6545 Blue 17
3 PM Tue 96 102 SE 17 12852 11545 6545 Blue 17
4 PM Tue 96 100 SE 17 11625 11454 6454 Blue 15
5 PM Tue 95 97 SW 16 11466 11314 6314 Blue 12
6 PM Tue 92 92 SW 16 10302 6765 1765 Blue 7
7 PM Tue 89 89 SW 16 6778 5159 159 Blue 4
8 PM Tue 86 86 W 14 5171 5000 0 Blue 1
9 PM Tue 85 85 W 14 4981 5000 0 Blue 0
10 PM Tue 84 84 W 14 4774 5000 0 Blue 0
11 PM Tue 84 84 W 12 4774 5000 0 Blue 0
12 Midnight Wed 83 83 W 12 4571 5000 0 Blue 0
1 AM Wed 82 82 W 12 4368 5000 0 Blue 0
2 AM Wed 80 80 NW 8 3960 5000 0 Blue 0
3 AM Wed 78 78 NW 8 3550 5000 0 Blue 0
4 AM Wed 76 76 NW 8 3138 5000 0 Blue 0
5 AM Wed 75 75 NW 6 2932 5000 0 Blue 0
6 AM Wed 75 75 NW 6 2932 5000 0 Blue 0
7 AM Wed 76 76 NW 6 3138 5000 0 Blue 0
8 AM Wed 78 78 SW 6 3550 5000 0 Blue 0
9 AM Wed 81 83 SW 6 4571 5000 0 Blue 0
10 AM Wed 84 88 SW 6 6670 5000 0 Blue 3
11 AM Wed 87 93 S 9 11281 7193 2193 Blue 8
12 Noon Wed 90 97 S 9 11466 11314 6314 Blue 12
1 PM Wed 92 100 S 9 11625 11454 6454 Blue 15
2 PM Wed 94 101 SW 18 12326 11499 6499 Blue 16
3 PM Wed 94 100 SW 18 11625 11454 6454 Blue 15
4 PM Wed 94 98 SW 18 11512 11361 6361 Blue 13
5 PM Wed 92 94 SW 20 11327 7727 2727 Blue 9
6 PM Wed 89 89 SW 20 6778 5159 159 Blue 4
7 PM Wed 87 87 SW 20 6562 5000 0 Blue 2
8 PM Wed 84 84 W 15 4774 5000 0 Blue 0
9 PM Wed 83 83 W 15 4571 5000 0 Blue 0
10 PM Wed 82 82 W 15 4368 5000 0 Blue 0
11 PM Wed 82 82 W 13 4368 5000 0 Blue 0
12 Midnight Thu 81 81 W 13 4164 5000 0 Blue 0
1 AM Thu 80 80 W 13 3960 5000 0 Blue 0
2 AM Thu 78 78 NW 9 3550 5000 0 Blue 0
3 AM Thu 76 76 NW 9 3138 5000 0 Blue 0
4 AM Thu 74 74 NW 9 2725 5000 0 Blue 0
5 AM Thu 73 73 W 7 2592 5000 0 Blue 0
6 AM Thu 72 72 W 7 2592 5000 0 Blue 0
7 AM Thu 73 73 W 7 2592 5000 0 Blue 0
8 AM Thu 74 74 W 6 2725 5000 0 Blue 0
9 AM Thu 77 79 W 6 3755 5000 0 Blue 0
10 AM Thu 80 84 W 6 4774 5000 0 Blue 0
11 AM Thu 84 89 SW 9 6778 5159 159 Blue 4
12 Noon Thu 87 93 SW 9 11281 7193 2193 Blue 8
1 PM Thu 90 97 SW 9 11466 11314 6314 Blue 12
2 PM Thu 91 97 SW 20 11466 11314 6314 Blue 12
3 PM Thu 91 96 SW 20 11420 11126 6126 Blue 11
4 PM Thu 91 95 SW 20 11373 10197 5197 Blue 10
5 PM Thu 89 91 W 21 7806 6658 1658 Blue 6
6 PM Thu 86 86 W 21 5171 5000 0 Blue 1
7 PM Thu 84 84 W 21 4774 5000 0 Blue 0
8 PM Thu 81 81 W 16 4164 5000 0 Blue 0
9 PM Thu 80 80 W 16 3960 5000 0 Blue 0
10 PM Thu 79 79 W 16 3755 5000 0 Blue 0
11 PM Thu 79 79 W 14 3755 5000 0 Blue 0
12 Midnight Fri 78 78 W 14 3550 5000 0 Blue 0
1 AM Fri 77 77 W 14 3344 5000 0 Blue 0
2 AM Fri 76 76 W 10 3138 5000 0 Blue 0
3 AM Fri 74 74 W 10 2725 5000 0 Blue 0
4 AM Fri 72 72 W 10 2592 5000 0 Blue 0
5 AM Fri 71 71 W 8 2592 5000 0 Blue 0
6 AM Fri 71 71 W 8 2592 5000 0 Blue 0
7 AM Fri 71 71 W 8 2592 5000 0 Blue 0
8 AM Fri 73 73 W 7 2592 5000 0 Blue 0
9 AM Fri 76 78 W 7 3550 5000 0 Blue 0
10 AM Fri 79 83 W 7 4571 5000 0 Blue 0
11 AM Fri 83 88 W 10 6670 5000 0 Blue 3
12 Noon Fri 86 93 W 10 11281 7193 2193 Blue 8
1 PM Fri 89 96 W 10 11420 11126 6126 Blue 11
2 PM Fri 91 98 W 20 11512 11361 6361 Blue 13
3 PM Fri 91 97 W 20 11466 11314 6314 Blue 12
4 PM Fri 91 95 W 20 11373 10197 5197 Blue 10
5 PM Fri 89 91 W 22 7806 6658 1658 Blue 6
6 PM Fri 87 87 W 22 6562 5000 0 Blue 2
7 PM Fri 84 84 W 22 4774 5000 0 Blue 0
8 PM Fri 81 81 W 16 4164 5000 0 Blue 0
9 PM Fri 80 80 W 16 3960 5000 0 Blue 0
10 PM Fri 79 79 W 16 3755 5000 0 Blue 0
11 PM Fri 78 78 W 13 3550 5000 0 Blue 0
12 Midnight Sat 77 77 W 13 3344 5000 0 Blue 0
1 AM Sat 76 76 W 13 3138 5000 0 Blue 0
2 AM Sat 75 75 W 10 2932 5000 0 Blue 0
3 AM Sat 73 73 W 10 2592 5000 0 Blue 0
4 AM Sat 72 72 W 10 2592 5000 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