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

Station:

KVBG

Date/Time:

21 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 Wed 68 68 NW 8 2992 5000 0 Blue 0
6 AM Wed 66 66 NW 7 2992 5000 0 Blue 0
7 AM Wed 66 66 NW 5 2992 5000 0 Blue 0
8 AM Wed 70 70 W 5 2992 5000 0 Blue 0
9 AM Wed 70 72 W 7 2992 5000 0 Blue 0
10 AM Wed 76 80 W 7 4306 5000 0 Blue 0
11 AM Wed 82 88 W 8 5230 5000 0 Blue 8
12 Noon Wed 86 93 W 13 7518 5711 711 Blue 13
1 PM Wed 90 98 W 15 10638 8723 3723 Blue 18
2 PM Wed 90 97 W 16 10047 8088 3088 Blue 17
3 PM Wed 90 96 W 18 9454 7422 2422 Blue 16
4 PM Wed 90 94 W 20 8193 5978 978 Blue 14
5 PM Wed 88 90 W 18 5729 5000 0 Blue 10
6 PM Wed 86 87 W 18 4966 5000 0 Blue 7
7 PM Wed 82 82 W 17 4486 5000 0 Blue 2
8 PM Wed 80 80 W 15 4306 5000 0 Blue 0
9 PM Wed 78 78 W 15 2992 5000 0 Blue 0
10 PM Wed 77 77 W 13 2992 5000 0 Blue 0
11 PM Wed 77 77 W 9 2992 5000 0 Blue 0
12 Midnight Thu 76 76 SW 10 2992 5000 0 Blue 0
1 AM Thu 74 74 W 8 2992 5000 0 Blue 0
2 AM Thu 72 72 W 7 2992 5000 0 Blue 0
3 AM Thu 71 71 NW 5 2992 5000 0 Blue 0
4 AM Thu 69 69 NW 3 2992 5000 0 Blue 0
5 AM Thu 68 68 NW 5 2992 5000 0 Blue 0
6 AM Thu 66 66 NW 8 2992 5000 0 Blue 0
7 AM Thu 67 67 NW 8 2992 5000 0 Blue 0
8 AM Thu 70 71 NW 3 2992 5000 0 Blue 0
9 AM Thu 71 73 W 7 2992 5000 0 Blue 0
10 AM Thu 76 80 W 8 4306 5000 0 Blue 0
11 AM Thu 81 87 W 8 4966 5000 0 Blue 7
12 Noon Thu 85 92 W 8 6806 5498 498 Blue 12
1 PM Thu 88 96 W 8 9454 7422 2422 Blue 16
2 PM Thu 90 96 W 17 9454 7422 2422 Blue 16
3 PM Thu 91 96 W 17 9454 7422 2422 Blue 16
4 PM Thu 90 94 W 17 8193 5978 978 Blue 14
5 PM Thu 88 90 W 18 5729 5000 0 Blue 10
6 PM Thu 85 86 W 18 4848 5000 0 Blue 6
7 PM Thu 83 83 W 18 4577 5000 0 Blue 3
8 PM Thu 80 80 W 14 4306 5000 0 Blue 0
9 PM Thu 79 79 W 14 3337 5000 0 Blue 0
10 PM Thu 78 78 W 14 2992 5000 0 Blue 0
11 PM Thu 78 78 NW 10 2992 5000 0 Blue 0
12 Midnight Fri 77 77 NW 10 2992 5000 0 Blue 0
1 AM Fri 76 76 NW 10 2992 5000 0 Blue 0
2 AM Fri 75 75 NW 8 2992 5000 0 Blue 0
3 AM Fri 73 73 NW 8 2992 5000 0 Blue 0
4 AM Fri 72 72 NW 8 2992 5000 0 Blue 0
5 AM Fri 71 71 NW 6 2992 5000 0 Blue 0
6 AM Fri 71 71 NW 6 2992 5000 0 Blue 0
7 AM Fri 71 71 NW 6 2992 5000 0 Blue 0
8 AM Fri 73 73 N 5 2992 5000 0 Blue 0
9 AM Fri 76 78 N 5 2992 5000 0 Blue 0
10 AM Fri 80 84 N 5 4667 5000 0 Blue 4
11 AM Fri 84 89 SE 8 5515 5000 0 Blue 9
12 Noon Fri 87 93 SE 8 7518 5711 711 Blue 13
1 PM Fri 90 97 SE 8 10047 8088 3088 Blue 17
2 PM Fri 92 99 S 17 11233 9332 4332 Blue 19
3 PM Fri 93 99 S 17 11233 9332 4332 Blue 19
4 PM Fri 92 96 S 17 9454 7422 2422 Blue 16
5 PM Fri 91 93 SW 16 7518 5711 711 Blue 13
6 PM Fri 89 90 SW 16 5729 5000 0 Blue 10
7 PM Fri 86 86 SW 16 4848 5000 0 Blue 6
8 PM Fri 83 83 W 13 4577 5000 0 Blue 3
9 PM Fri 82 82 W 13 4486 5000 0 Blue 2
10 PM Fri 81 81 W 13 4396 5000 0 Blue 1
11 PM Fri 80 80 W 10 4306 5000 0 Blue 0
12 Midnight Sat 79 79 W 10 3337 5000 0 Blue 0
1 AM Sat 77 77 W 10 2992 5000 0 Blue 0
2 AM Sat 76 76 W 7 2992 5000 0 Blue 0
3 AM Sat 74 74 W 7 2992 5000 0 Blue 0
4 AM Sat 73 73 W 7 2992 5000 0 Blue 0
5 AM Sat 72 72 NW 6 2992 5000 0 Blue 0
6 AM Sat 72 72 NW 6 2992 5000 0 Blue 0
7 AM Sat 72 72 NW 6 2992 5000 0 Blue 0
8 AM Sat 74 74 E 5 2992 5000 0 Blue 0
9 AM Sat 77 79 E 5 3337 5000 0 Blue 0
10 AM Sat 81 85 E 5 4757 5000 0 Blue 5
11 AM Sat 85 90 SE 8 5729 5000 0 Blue 10
12 Noon Sat 88 95 SE 8 8837 6721 1721 Blue 15
1 PM Sat 91 98 SE 8 10638 8723 3723 Blue 18
2 PM Sat 93 100 SW 17 11805 9919 4919 Blue 20
3 PM Sat 94 100 SW 17 11805 9919 4919 Blue 20
4 PM Sat 94 98 SW 17 10638 8723 3723 Blue 18
5 PM Sat 93 95 SW 17 8837 6721 1721 Blue 15
6 PM Sat 90 91 SW 17 6051 5209 209 Blue 11
7 PM Sat 87 87 SW 17 4966 5000 0 Blue 7
8 PM Sat 84 84 W 14 4667 5000 0 Blue 4
9 PM Sat 83 83 W 14 4577 5000 0 Blue 3
10 PM Sat 82 82 W 14 4486 5000 0 Blue 2
11 PM Sat 81 81 W 12 4396 5000 0 Blue 1
12 Midnight Sun 80 80 W 12 4306 5000 0 Blue 0
1 AM Sun 78 78 W 12 2992 5000 0 Blue 0
2 AM Sun 77 77 NW 9 2992 5000 0 Blue 0
3 AM Sun 75 75 NW 9 2992 5000 0 Blue 0
4 AM Sun 73 73 NW 9 2992 5000 0 Blue 0
5 AM Sun 72 72 W 7 2992 5000 0 Blue 0
6 AM Sun 72 72 W 7 2992 5000 0 Blue 0
7 AM Sun 73 73 W 7 2992 5000 0 Blue 0
8 AM Sun 75 75 W 6 2992 5000 0 Blue 0
9 AM Sun 78 80 W 6 4306 5000 0 Blue 0
10 AM Sun 82 86 W 6 4848 5000 0 Blue 6
11 AM Sun 86 91 W 8 6051 5209 209 Blue 11
12 Noon Sun 89 96 W 8 9454 7422 2422 Blue 16
1 PM Sun 92 99 W 8 11233 9332 4332 Blue 19
2 PM Sun 94 101 W 17 12357 10492 5492 Blue 21
3 PM Sun 94 100 W 17 11805 9919 4919 Blue 20
4 PM Sun 94 98 W 17 10638 8723 3723 Blue 18
5 PM Sun 92 93 W 18 7518 5711 711 Blue 13
6 PM Sun 89 89 W 18 5515 5000 0 Blue 9
7 PM Sun 87 87 W 18 4966 5000 0 Blue 7
8 PM Sun 84 84 W 14 4667 5000 0 Blue 4
9 PM Sun 83 83 W 14 4577 5000 0 Blue 3
10 PM Sun 82 82 W 14 4486 5000 0 Blue 2
11 PM Sun 82 82 W 12 4486 5000 0 Blue 2
12 Midnight Mon 81 81 W 12 4396 5000 0 Blue 1
1 AM Mon 79 79 W 12 3337 5000 0 Blue 0
2 AM Mon 78 78 W 10 2992 5000 0 Blue 0
3 AM Mon 76 76 W 10 2992 5000 0 Blue 0
4 AM Mon 75 75 W 10 2992 5000 0 Blue 0
5 AM Mon 74 74 W 7 2992 5000 0 Blue 0
6 AM Mon 74 74 W 7 2992 5000 0 Blue 0
7 AM Mon 74 74 W 7 2992 5000 0 Blue 0
8 AM Mon 76 76 W 6 2992 5000 0 Blue 0
9 AM Mon 79 80 W 6 4306 5000 0 Blue 0
10 AM Mon 82 83 W 6 4577 5000 0 Blue 3
11 AM Mon 86 88 W 7 5230 5000 0 Blue 8
12 Noon Mon 89 91 W 7 6051 5209 209 Blue 11
1 PM Mon 92 94 W 7 8193 5978 978 Blue 14
2 PM Mon 94 96 SW 16 9454 7422 2422 Blue 16
3 PM Mon 95 97 SW 16 10047 8088 3088 Blue 17
4 PM Mon 94 95 SW 16 8837 6721 1721 Blue 15
5 PM Mon 93 94 W 16 8193 5978 978 Blue 14
6 PM Mon 91 91 W 16 6051 5209 209 Blue 11
7 PM Mon 88 88 W 16 5230 5000 0 Blue 8
8 PM Mon 85 85 W 14 4757 5000 0 Blue 5
9 PM Mon 84 84 W 14 4667 5000 0 Blue 4
10 PM Mon 83 83 W 14 4577 5000 0 Blue 3
11 PM Mon 83 83 W 10 4577 5000 0 Blue 3
12 Midnight Tue 82 82 W 10 4486 5000 0 Blue 2
1 AM Tue 80 80 W 10 4306 5000 0 Blue 0
2 AM Tue 79 79 W 8 3337 5000 0 Blue 0
3 AM Tue 77 77 W 8 2992 5000 0 Blue 0
4 AM Tue 76 76 W 8 2992 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