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

Station:

KVBG

Date/Time:

27 MAY 2018

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 49 49 SE 1 2884 5000 0 Blue 0
6 AM Sun 52 52 SE 1 2884 5000 0 Blue 0
7 AM Sun 55 55 SE 1 3164 5000 0 Blue 0
8 AM Sun 59 60 NW 7 4603 5000 0 Blue 4
9 AM Sun 65 68 NW 7 6506 6079 1079 Blue 12
10 AM Sun 70 75 NW 7 8142 7386 2386 Blue 19
11 AM Sun 74 80 W 13 9393 8600 3600 Blue 24
12 Noon Sun 77 85 W 13 10952 9830 4830 Blue 29
1 PM Sun 78 86 W 13 11135 10073 5073 Blue 30
2 PM Sun 79 86 W 18 11135 10073 5073 Blue 30
3 PM Sun 79 85 W 18 10952 9830 4830 Blue 29
4 PM Sun 78 82 W 18 9885 9095 4095 Blue 26
5 PM Sun 77 79 W 16 9145 8351 3351 Blue 23
6 PM Sun 73 74 W 16 7889 7176 2176 Blue 18
7 PM Sun 69 69 W 16 6663 6200 1200 Blue 13
8 PM Sun 65 65 W 6 6091 5000 0 Blue 9
9 PM Sun 61 61 W 6 4695 5000 0 Blue 5
10 PM Sun 58 58 W 6 4263 5000 0 Blue 2
11 PM Sun 57 57 SE 2 3845 5000 0 Blue 1
12 Midnight Mon 56 56 SE 2 3304 5000 0 Blue 0
1 AM Mon 55 55 SE 2 3164 5000 0 Blue 0
2 AM Mon 55 55 E 5 3164 5000 0 Blue 0
3 AM Mon 53 53 E 5 2884 5000 0 Blue 0
4 AM Mon 53 53 E 5 2884 5000 0 Blue 0
5 AM Mon 55 55 E 6 3164 5000 0 Blue 0
6 AM Mon 60 60 E 6 4603 5000 0 Blue 4
7 AM Mon 66 66 E 6 6213 5000 0 Blue 10
8 AM Mon 73 75 SE 0 8142 7386 2386 Blue 19
9 AM Mon 78 81 SE 0 9640 8848 3848 Blue 25
10 AM Mon 81 87 SE 0 11318 10722 5722 Blue 31
11 AM Mon 84 91 W 7 12157 11448 6448 Blue 35
12 Noon Mon 86 95 W 7 13394 12511 7511 White 39
1 PM Mon 87 96 W 7 13597 13019 8019 White 40
2 PM Mon 88 96 W 12 13597 13019 8019 White 40
3 PM Mon 89 96 W 12 13597 13019 8019 White 40
4 PM Mon 88 93 W 12 12986 11830 6830 White 37
5 PM Mon 86 88 W 12 11500 10904 5904 Blue 32
6 PM Mon 81 82 W 12 9885 9095 4095 Blue 26
7 PM Mon 75 75 W 12 8142 7386 2386 Blue 19
8 PM Mon 69 69 W 12 6663 6200 1200 Blue 13
9 PM Mon 65 65 W 12 6091 5000 0 Blue 9
10 PM Mon 63 63 W 12 4868 5000 0 Blue 7
11 PM Mon 61 61 SE 2 4695 5000 0 Blue 5
12 Midnight Tue 61 61 SE 2 4695 5000 0 Blue 5
1 AM Tue 60 60 SE 2 4603 5000 0 Blue 4
2 AM Tue 59 59 SE 2 4444 5000 0 Blue 3
3 AM Tue 57 57 SE 2 3845 5000 0 Blue 1
4 AM Tue 55 55 SE 2 3164 5000 0 Blue 0
5 AM Tue 56 56 E 6 3304 5000 0 Blue 0
6 AM Tue 62 62 E 6 4788 5000 0 Blue 6
7 AM Tue 70 70 E 6 6857 6331 1331 Blue 14
8 AM Tue 78 80 E 6 9393 8600 3600 Blue 24
9 AM Tue 83 86 E 6 11135 10073 5073 Blue 30
10 AM Tue 86 92 E 6 12781 11629 6629 White 36
11 AM Tue 89 96 S 10 13597 13019 8019 White 40
12 Noon Tue 91 99 S 10 14206 14206 9206 White 43
1 PM Tue 93 102 S 10 14808 14808 9808 White 46
2 PM Tue 94 102 S 10 14808 14808 9808 White 46
3 PM Tue 93 99 S 10 14206 14206 9206 White 43
4 PM Tue 91 95 S 10 13394 12511 7511 White 39
5 PM Tue 88 90 W 17 11905 11267 6267 Blue 34
6 PM Tue 83 84 W 17 10769 9586 4586 Blue 28
7 PM Tue 79 79 W 17 9145 8351 3351 Blue 23
8 PM Tue 74 74 W 17 7889 7176 2176 Blue 18
9 PM Tue 70 70 W 17 6857 6331 1331 Blue 14
10 PM Tue 67 67 W 17 6349 5619 619 Blue 11
11 PM Tue 64 64 W 12 5742 5000 0 Blue 8
12 Midnight Wed 62 62 W 12 4788 5000 0 Blue 6
1 AM Wed 60 60 W 12 4603 5000 0 Blue 4
2 AM Wed 59 59 W 12 4444 5000 0 Blue 3
3 AM Wed 57 57 W 12 3845 5000 0 Blue 1
4 AM Wed 56 56 W 12 3304 5000 0 Blue 0
5 AM Wed 56 56 W 10 3304 5000 0 Blue 0
6 AM Wed 59 59 W 10 4444 5000 0 Blue 3
7 AM Wed 62 62 W 10 4788 5000 0 Blue 6
8 AM Wed 67 69 W 10 6663 6200 1200 Blue 13
9 AM Wed 72 75 W 10 8142 7386 2386 Blue 19
10 AM Wed 77 83 W 10 10191 9341 4341 Blue 27
11 AM Wed 81 88 W 22 11500 10904 5904 Blue 32
12 Noon Wed 83 91 W 22 12157 11448 6448 Blue 35
1 PM Wed 85 93 W 22 12986 11830 6830 White 37
2 PM Wed 85 92 W 22 12781 11629 6629 White 36
3 PM Wed 84 90 W 22 11905 11267 6267 Blue 34
4 PM Wed 82 86 W 22 11135 10073 5073 Blue 30
5 PM Wed 80 82 W 25 9885 9095 4095 Blue 26
6 PM Wed 77 78 W 25 8896 8100 3100 Blue 22
7 PM Wed 73 73 W 25 7634 6810 1810 Blue 17
8 PM Wed 69 69 W 25 6663 6200 1200 Blue 13
9 PM Wed 65 65 W 25 6091 5000 0 Blue 9
10 PM Wed 62 62 W 25 4788 5000 0 Blue 6
11 PM Wed 58 58 W 15 4263 5000 0 Blue 2
12 Midnight Thu 55 55 W 15 3164 5000 0 Blue 0
1 AM Thu 53 53 W 15 2884 5000 0 Blue 0
2 AM Thu 52 52 W 15 2884 5000 0 Blue 0
3 AM Thu 51 51 W 15 2884 5000 0 Blue 0
4 AM Thu 51 51 W 15 2884 5000 0 Blue 0
5 AM Thu 53 53 W 13 2884 5000 0 Blue 0
6 AM Thu 55 55 W 13 3164 5000 0 Blue 0
7 AM Thu 58 58 W 13 4263 5000 0 Blue 2
8 AM Thu 62 64 W 13 5742 5000 0 Blue 8
9 AM Thu 65 68 W 13 6506 6079 1079 Blue 12
10 AM Thu 69 75 W 13 8142 7386 2386 Blue 19
11 AM Thu 71 78 W 24 8896 8100 3100 Blue 22
12 Noon Thu 73 82 W 24 9885 9095 4095 Blue 26
1 PM Thu 74 83 W 24 10191 9341 4341 Blue 27
2 PM Thu 74 82 W 24 9885 9095 4095 Blue 26
3 PM Thu 73 80 W 24 9393 8600 3600 Blue 24
4 PM Thu 72 77 W 24 8646 7848 2848 Blue 21
5 PM Thu 71 73 W 25 7634 6810 1810 Blue 17
6 PM Thu 69 70 W 25 6857 6331 1331 Blue 14
7 PM Thu 67 67 W 25 6349 5619 619 Blue 11
8 PM Thu 64 64 W 25 5742 5000 0 Blue 8
9 PM Thu 62 62 W 25 4788 5000 0 Blue 6
10 PM Thu 59 59 W 25 4444 5000 0 Blue 3
11 PM Thu 56 56 W 17 3304 5000 0 Blue 0
12 Midnight Fri 54 54 W 17 3024 5000 0 Blue 0
1 AM Fri 52 52 W 17 2884 5000 0 Blue 0
2 AM Fri 50 50 W 17 2884 5000 0 Blue 0
3 AM Fri 49 49 W 17 2884 5000 0 Blue 0
4 AM Fri 49 49 W 17 2884 5000 0 Blue 0
5 AM Fri 50 50 W 16 2884 5000 0 Blue 0
6 AM Fri 52 52 W 16 2884 5000 0 Blue 0
7 AM Fri 55 55 W 16 3164 5000 0 Blue 0
8 AM Fri 59 61 W 16 4695 5000 0 Blue 5
9 AM Fri 63 66 W 16 6213 5000 0 Blue 10
10 AM Fri 67 73 W 16 7634 6810 1810 Blue 17
11 AM Fri 71 78 W 20 8896 8100 3100 Blue 22
12 Noon Fri 73 82 W 20 9885 9095 4095 Blue 26
1 PM Fri 75 84 W 20 10769 9586 4586 Blue 28
2 PM Fri 77 85 W 20 10952 9830 4830 Blue 29
3 PM Fri 77 84 W 20 10769 9586 4586 Blue 28
4 PM Fri 77 82 W 20 9885 9095 4095 Blue 26
5 PM Fri 75 77 W 20 8646 7848 2848 Blue 21
6 PM Fri 73 74 W 20 7889 7176 2176 Blue 18
7 PM Fri 70 70 W 20 6857 6331 1331 Blue 14
8 PM Fri 66 66 W 20 6213 5000 0 Blue 10
9 PM Fri 63 63 W 20 4868 5000 0 Blue 7
10 PM Fri 59 59 W 20 4444 5000 0 Blue 3
11 PM Fri 56 56 W 12 3304 5000 0 Blue 0
12 Midnight Sat 54 54 W 12 3024 5000 0 Blue 0
1 AM Sat 52 52 W 12 2884 5000 0 Blue 0
2 AM Sat 51 51 W 12 2884 5000 0 Blue 0
3 AM Sat 51 51 W 12 2884 5000 0 Blue 0
4 AM Sat 52 52 W 12 2884 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