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

Station:

KVBG

Date/Time:

21 JUL 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 Sat 72 72 NE 2 3220 5000 0 Blue 1
6 AM Sat 72 72 NE 2 3220 5000 0 Blue 1
7 AM Sat 74 74 NE 2 3545 5000 0 Blue 3
8 AM Sat 77 78 S 2 4852 5000 0 Blue 7
9 AM Sat 81 83 S 2 7429 5424 424 Blue 12
10 AM Sat 86 89 S 2 8937 8407 3407 Blue 18
11 AM Sat 90 95 W 9 10862 9401 4401 Blue 24
12 Noon Sat 93 99 W 9 13817 11466 6466 White 28
1 PM Sat 95 101 W 9 14231 12930 7930 White 30
2 PM Sat 97 103 SW 14 14637 14230 9230 White 32
3 PM Sat 97 102 SW 14 14435 13597 8597 White 31
4 PM Sat 97 101 SW 14 14231 12930 7930 White 30
5 PM Sat 95 97 W 16 12446 10061 5061 Blue 26
6 PM Sat 92 93 W 16 9704 9071 4071 Blue 22
7 PM Sat 89 89 W 16 8937 8407 3407 Blue 18
8 PM Sat 86 86 W 15 8436 7295 2295 Blue 15
9 PM Sat 84 84 W 15 8101 5661 661 Blue 13
10 PM Sat 82 82 W 15 6395 5186 186 Blue 11
11 PM Sat 80 80 W 12 5442 5000 0 Blue 9
12 Midnight Sun 79 79 W 12 5203 5000 0 Blue 8
1 AM Sun 77 77 W 12 4496 5000 0 Blue 6
2 AM Sun 76 76 S 7 4239 5000 0 Blue 5
3 AM Sun 73 73 S 7 3358 5000 0 Blue 2
4 AM Sun 72 72 S 7 3220 5000 0 Blue 1
5 AM Sun 71 71 S 5 3082 5000 0 Blue 0
6 AM Sun 72 72 S 5 3220 5000 0 Blue 1
7 AM Sun 74 74 S 5 3545 5000 0 Blue 3
8 AM Sun 77 78 NW 6 4852 5000 0 Blue 7
9 AM Sun 81 83 NW 6 7429 5424 424 Blue 12
10 AM Sun 84 88 NW 6 8770 8241 3241 Blue 17
11 AM Sun 87 92 W 9 9435 8905 3905 Blue 21
12 Noon Sun 90 96 W 9 11685 9605 4605 Blue 25
1 PM Sun 93 100 W 9 14024 12222 7222 White 29
2 PM Sun 95 101 SW 13 14231 12930 7930 White 30
3 PM Sun 96 101 SW 13 14231 12930 7930 White 30
4 PM Sun 96 100 SW 13 14024 12222 7222 White 29
5 PM Sun 95 97 SW 16 12446 10061 5061 Blue 26
6 PM Sun 92 93 SW 16 9704 9071 4071 Blue 22
7 PM Sun 89 89 SW 16 8937 8407 3407 Blue 18
8 PM Sun 85 85 SW 16 8269 6280 1280 Blue 14
9 PM Sun 82 82 SW 16 6395 5186 186 Blue 11
10 PM Sun 80 80 SW 16 5442 5000 0 Blue 9
11 PM Sun 79 79 NW 14 5203 5000 0 Blue 8
12 Midnight Mon 78 78 NW 14 4852 5000 0 Blue 7
1 AM Mon 77 77 NW 14 4496 5000 0 Blue 6
2 AM Mon 76 76 NW 14 4239 5000 0 Blue 5
3 AM Mon 74 74 NW 14 3545 5000 0 Blue 3
4 AM Mon 73 73 NW 14 3358 5000 0 Blue 2
5 AM Mon 72 72 NW 8 3220 5000 0 Blue 1
6 AM Mon 73 73 NW 8 3358 5000 0 Blue 2
7 AM Mon 75 75 NW 8 4029 5000 0 Blue 4
8 AM Mon 78 79 NW 8 5203 5000 0 Blue 8
9 AM Mon 82 85 NW 8 8269 6280 1280 Blue 14
10 AM Mon 86 91 NW 8 9269 8739 3739 Blue 20
11 AM Mon 91 97 SW 13 12446 10061 5061 Blue 26
12 Noon Mon 94 102 SW 13 14435 13597 8597 White 31
1 PM Mon 96 104 SW 13 14838 14838 9838 White 33
2 PM Mon 98 106 SW 13 15241 15241 10241 White 35
3 PM Mon 99 105 SW 13 15039 15039 10039 White 34
4 PM Mon 99 104 SW 13 14838 14838 9838 White 33
5 PM Mon 98 101 SW 14 14231 12930 7930 White 30
6 PM Mon 95 96 SW 14 11685 9605 4605 Blue 25
7 PM Mon 91 91 SW 14 9269 8739 3739 Blue 20
8 PM Mon 88 88 SW 14 8770 8241 3241 Blue 17
9 PM Mon 85 85 SW 14 8269 6280 1280 Blue 14
10 PM Mon 83 83 SW 14 7429 5424 424 Blue 12
11 PM Mon 82 82 W 10 6395 5186 186 Blue 11
12 Midnight Tue 80 80 W 10 5442 5000 0 Blue 9
1 AM Tue 79 79 W 10 5203 5000 0 Blue 8
2 AM Tue 77 77 W 10 4496 5000 0 Blue 6
3 AM Tue 76 76 W 10 4239 5000 0 Blue 5
4 AM Tue 74 74 W 10 3545 5000 0 Blue 3
5 AM Tue 73 73 NW 8 3358 5000 0 Blue 2
6 AM Tue 73 73 NW 8 3358 5000 0 Blue 2
7 AM Tue 75 75 NW 8 4029 5000 0 Blue 4
8 AM Tue 79 80 NW 8 5442 5000 0 Blue 9
9 AM Tue 84 87 NW 8 8603 8074 3074 Blue 16
10 AM Tue 90 95 NW 8 10862 9401 4401 Blue 24
11 AM Tue 95 102 S 10 14435 13597 8597 White 31
12 Noon Tue 99 107 S 10 15441 15441 10441 White 36
1 PM Tue 101 109 S 10 15838 15838 10838 White 38
2 PM Tue 103 111 S 10 16234 16234 11234 White 40
3 PM Tue 104 111 S 10 16234 16234 11234 White 40
4 PM Tue 104 109 S 10 15838 15838 10838 White 38
5 PM Tue 103 106 W 16 15241 15241 10241 White 35
6 PM Tue 99 100 W 16 14024 12222 7222 White 29
7 PM Tue 95 95 W 16 10862 9401 4401 Blue 24
8 PM Tue 90 90 W 16 9103 8573 3573 Blue 19
9 PM Tue 87 87 W 16 8603 8074 3074 Blue 16
10 PM Tue 85 85 W 16 8269 6280 1280 Blue 14
11 PM Tue 83 83 NW 10 7429 5424 424 Blue 12
12 Midnight Wed 81 81 NW 10 5681 5000 0 Blue 10
1 AM Wed 79 79 NW 10 5203 5000 0 Blue 8
2 AM Wed 77 77 NW 10 4496 5000 0 Blue 6
3 AM Wed 75 75 NW 10 4029 5000 0 Blue 4
4 AM Wed 73 73 NW 10 3358 5000 0 Blue 2
5 AM Wed 72 72 NW 7 3220 5000 0 Blue 1
6 AM Wed 72 72 NW 7 3220 5000 0 Blue 1
7 AM Wed 74 74 NW 7 3545 5000 0 Blue 3
8 AM Wed 78 79 NW 7 5203 5000 0 Blue 8
9 AM Wed 84 87 NW 7 8603 8074 3074 Blue 16
10 AM Wed 90 95 NW 7 10862 9401 4401 Blue 24
11 AM Wed 96 103 S 13 14637 14230 9230 White 32
12 Noon Wed 99 107 S 13 15441 15441 10441 White 36
1 PM Wed 102 110 S 13 16037 16037 11037 White 39
2 PM Wed 103 111 S 13 16234 16234 11234 White 40
3 PM Wed 105 112 S 13 16431 16431 11431 White 41
4 PM Wed 105 110 S 13 16037 16037 11037 White 39
5 PM Wed 103 106 W 5 15241 15241 10241 White 35
6 PM Wed 100 101 W 5 14231 12930 7930 White 30
7 PM Wed 95 95 W 5 10862 9401 4401 Blue 24
8 PM Wed 90 90 W 5 9103 8573 3573 Blue 19
9 PM Wed 87 87 W 5 8603 8074 3074 Blue 16
10 PM Wed 84 84 W 5 8101 5661 661 Blue 13
11 PM Wed 82 82 NW 7 6395 5186 186 Blue 11
12 Midnight Thu 81 81 NW 7 5681 5000 0 Blue 10
1 AM Thu 79 79 NW 7 5203 5000 0 Blue 8
2 AM Thu 76 76 NW 7 4239 5000 0 Blue 5
3 AM Thu 74 74 NW 7 3545 5000 0 Blue 3
4 AM Thu 73 73 NW 7 3358 5000 0 Blue 2
5 AM Thu 72 72 NW 8 3220 5000 0 Blue 1
6 AM Thu 73 73 NW 8 3358 5000 0 Blue 2
7 AM Thu 75 75 NW 8 4029 5000 0 Blue 4
8 AM Thu 80 81 NW 8 5681 5000 0 Blue 10
9 AM Thu 85 88 NW 8 8770 8241 3241 Blue 17
10 AM Thu 91 96 NW 8 11685 9605 4605 Blue 25
11 AM Thu 96 103 W 8 14637 14230 9230 White 32
12 Noon Thu 100 108 W 8 15640 15640 10640 White 37
1 PM Thu 102 110 W 8 16037 16037 11037 White 39
2 PM Thu 104 112 W 8 16431 16431 11431 White 41
3 PM Thu 105 112 W 8 16431 16431 11431 White 41
4 PM Thu 105 110 W 8 16037 16037 11037 White 39
5 PM Thu 104 107 W 13 15441 15441 10441 White 36
6 PM Thu 100 101 W 13 14231 12930 7930 White 30
7 PM Thu 96 96 W 13 11685 9605 4605 Blue 25
8 PM Thu 92 92 W 13 9435 8905 3905 Blue 21
9 PM Thu 88 88 W 13 8770 8241 3241 Blue 17
10 PM Thu 85 85 W 13 8269 6280 1280 Blue 14
11 PM Thu 83 83 W 13 7429 5424 424 Blue 12
12 Midnight Fri 80 80 W 13 5442 5000 0 Blue 9
1 AM Fri 78 78 W 13 4852 5000 0 Blue 7
2 AM Fri 77 77 W 13 4496 5000 0 Blue 6
3 AM Fri 75 75 W 13 4029 5000 0 Blue 4
4 AM Fri 73 73 W 13 3358 5000 0 Blue 2

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