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

Station:

KVBG

Date/Time:

26 MAY 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 49 49 W 10 5043 5000 0 White 3
6 AM Sun 49 49 W 13 5043 5000 0 White 3
7 AM Sun 50 50 W 14 5261 5054 54 White 4
8 AM Sun 51 51 W 18 5479 5172 172 White 5
9 AM Sun 52 52 W 18 5696 5289 289 White 6
10 AM Sun 53 54 W 18 6128 6128 1128 White 8
11 AM Sun 54 56 W 21 6558 6311 1311 White 10
12 Noon Sun 55 59 W 22 7162 6641 1641 Blue 13
1 PM Sun 55 58 W 23 6985 6496 1496 Blue 12
2 PM Sun 56 58 W 25 6985 6496 1496 Blue 12
3 PM Sun 56 56 W 25 6558 6311 1311 White 10
4 PM Sun 54 54 W 25 6128 6128 1128 White 8
5 PM Sun 53 53 W 25 5911 5469 469 White 7
6 PM Sun 53 53 W 23 5911 5469 469 White 7
7 PM Sun 51 51 W 22 5479 5172 172 White 5
8 PM Sun 49 49 W 20 5043 5000 0 White 3
9 PM Sun 48 48 W 21 4825 5000 0 White 2
10 PM Sun 47 47 W 20 4608 5000 0 White 0
11 PM Sun 47 47 W 18 4608 5000 0 White 0
12 Midnight Mon 46 46 W 20 4385 5000 0 White 0
1 AM Mon 46 46 W 18 4385 5000 0 White 0
2 AM Mon 45 45 W 18 4164 5000 0 White 0
3 AM Mon 44 44 W 18 3940 5000 0 White 0
4 AM Mon 43 43 W 17 3614 5000 0 Blue 0
5 AM Mon 42 42 W 16 3223 5000 0 Blue 0
6 AM Mon 42 42 W 15 3223 5000 0 Blue 0
7 AM Mon 45 45 W 16 4164 5000 0 White 0
8 AM Mon 48 49 W 17 5043 5000 0 White 3
9 AM Mon 51 54 W 17 6128 6128 1128 White 8
10 AM Mon 54 59 W 18 7162 6641 1641 Blue 13
11 AM Mon 56 63 W 18 7730 7303 2303 Blue 17
12 Noon Mon 58 66 W 20 8219 7704 2704 Blue 20
1 PM Mon 60 67 W 22 8382 7866 2866 Blue 21
2 PM Mon 62 69 W 23 8717 8191 3191 Blue 23
3 PM Mon 62 67 W 23 8382 7866 2866 Blue 21
4 PM Mon 60 63 W 23 7730 7303 2303 Blue 17
5 PM Mon 59 61 W 22 7455 6961 1961 Blue 15
6 PM Mon 58 58 W 21 6985 6496 1496 Blue 12
7 PM Mon 56 56 W 20 6558 6311 1311 White 10
8 PM Mon 55 55 W 18 6343 6252 1252 White 9
9 PM Mon 54 54 W 17 6128 6128 1128 White 8
10 PM Mon 53 53 W 15 5911 5469 469 White 7
11 PM Mon 52 52 W 14 5696 5289 289 White 6
12 Midnight Tue 51 51 W 13 5479 5172 172 White 5
1 AM Tue 51 51 NW 12 5479 5172 172 White 5
2 AM Tue 50 50 NW 10 5261 5054 54 White 4
3 AM Tue 49 49 NW 9 5043 5000 0 White 3
4 AM Tue 48 48 NW 8 4825 5000 0 White 2
5 AM Tue 47 47 NW 8 4608 5000 0 White 0
6 AM Tue 47 47 NW 8 4608 5000 0 White 0
7 AM Tue 50 50 NW 9 5261 5054 54 White 4
8 AM Tue 55 56 NW 10 6558 6311 1311 White 10
9 AM Tue 58 60 NW 10 7322 6786 1786 Blue 14
10 AM Tue 62 66 W 10 8219 7704 2704 Blue 20
11 AM Tue 65 70 W 12 8955 8353 3353 Blue 24
12 Noon Tue 67 73 W 14 10207 8856 3856 White 27
1 PM Tue 70 76 W 15 10831 10303 5303 White 30
2 PM Tue 72 78 W 17 11245 11245 6245 White 32
3 PM Tue 72 77 W 18 11038 11038 6038 White 31
4 PM Tue 70 73 W 18 10207 8856 3856 White 27
5 PM Tue 68 70 W 18 8955 8353 3353 Blue 24
6 PM Tue 68 69 W 17 8717 8191 3191 Blue 23
7 PM Tue 65 65 W 16 8056 7568 2568 Blue 19
8 PM Tue 63 63 W 14 7730 7303 2303 Blue 17
9 PM Tue 62 62 W 13 7588 7137 2137 Blue 16
10 PM Tue 60 60 NW 12 7322 6786 1786 Blue 14
11 PM Tue 60 60 NW 10 7322 6786 1786 Blue 14
12 Midnight Wed 58 58 NW 9 6985 6496 1496 Blue 12
1 AM Wed 58 58 NW 9 6985 6496 1496 Blue 12
2 AM Wed 57 57 NW 8 6775 6370 1370 White 11
3 AM Wed 56 56 NW 7 6558 6311 1311 White 10
4 AM Wed 54 54 N 7 6128 6128 1128 White 8
5 AM Wed 53 53 N 7 5911 5469 469 White 7
6 AM Wed 53 53 N 7 5911 5469 469 White 7
7 AM Wed 56 56 N 7 6558 6311 1311 White 10
8 AM Wed 61 62 N 8 7588 7137 2137 Blue 16
9 AM Wed 64 66 NW 8 8219 7704 2704 Blue 20
10 AM Wed 68 71 SW 9 9468 8515 3515 Blue 25
11 AM Wed 71 76 S 10 10831 10303 5303 White 30
12 Noon Wed 73 78 S 13 11245 11245 6245 White 32
1 PM Wed 76 80 SW 16 11656 11656 6656 White 34
2 PM Wed 78 82 SW 18 12062 12062 7062 White 36
3 PM Wed 78 81 W 20 11859 11859 6859 White 35
4 PM Wed 75 77 W 21 11038 11038 6038 White 31
5 PM Wed 73 74 W 16 10416 9358 4358 White 28
6 PM Wed 73 73 W 16 10207 8856 3856 White 27
7 PM Wed 70 70 W 16 8955 8353 3353 Blue 24
8 PM Wed 67 67 W 16 8382 7866 2866 Blue 21
9 PM Wed 66 66 W 16 8219 7704 2704 Blue 20
10 PM Wed 64 64 W 16 7893 7435 2435 Blue 18
11 PM Wed 64 64 W 10 7893 7435 2435 Blue 18
12 Midnight Thu 62 62 W 10 7588 7137 2137 Blue 16
1 AM Thu 62 62 W 10 7588 7137 2137 Blue 16
2 AM Thu 60 60 W 10 7322 6786 1786 Blue 14
3 AM Thu 60 60 W 10 7322 6786 1786 Blue 14
4 AM Thu 58 58 W 10 6985 6496 1496 Blue 12
5 AM Thu 56 56 NW 8 6558 6311 1311 White 10
6 AM Thu 56 56 NW 8 6558 6311 1311 White 10
7 AM Thu 59 59 NW 8 7162 6641 1641 Blue 13
8 AM Thu 63 64 NW 8 7893 7435 2435 Blue 18
9 AM Thu 66 69 NW 8 8717 8191 3191 Blue 23
10 AM Thu 70 75 NW 8 10624 9869 4869 White 29
11 AM Thu 72 77 SW 16 11038 11038 6038 White 31
12 Noon Thu 75 81 SW 16 11859 11859 6859 White 35
1 PM Thu 77 83 SW 16 12265 12265 7265 White 37
2 PM Thu 79 84 SW 16 12467 12467 7467 White 38
3 PM Thu 79 83 SW 16 12265 12265 7265 White 37
4 PM Thu 76 79 SW 16 11450 11450 6450 White 33
5 PM Thu 74 76 W 17 10831 10303 5303 White 30
6 PM Thu 74 75 W 17 10624 9869 4869 White 29
7 PM Thu 70 70 W 17 8955 8353 3353 Blue 24
8 PM Thu 68 68 W 17 8545 8029 3029 Blue 22
9 PM Thu 66 66 W 17 8219 7704 2704 Blue 20
10 PM Thu 64 64 W 17 7893 7435 2435 Blue 18
11 PM Thu 64 64 W 10 7893 7435 2435 Blue 18
12 Midnight Fri 62 62 W 10 7588 7137 2137 Blue 16
1 AM Fri 62 62 W 10 7588 7137 2137 Blue 16
2 AM Fri 60 60 W 10 7322 6786 1786 Blue 14
3 AM Fri 60 60 W 10 7322 6786 1786 Blue 14
4 AM Fri 58 58 W 10 6985 6496 1496 Blue 12
5 AM Fri 56 56 W 8 6558 6311 1311 White 10
6 AM Fri 56 56 W 8 6558 6311 1311 White 10
7 AM Fri 59 59 W 8 7162 6641 1641 Blue 13
8 AM Fri 63 64 W 8 7893 7435 2435 Blue 18
9 AM Fri 66 68 W 8 8545 8029 3029 Blue 22
10 AM Fri 71 74 W 8 10416 9358 4358 White 28
11 AM Fri 73 77 W 15 11038 11038 6038 White 31
12 Noon Fri 76 80 W 15 11656 11656 6656 White 34
1 PM Fri 78 82 W 15 12062 12062 7062 White 36
2 PM Fri 80 84 W 15 12467 12467 7467 White 38
3 PM Fri 80 83 W 15 12265 12265 7265 White 37
4 PM Fri 77 79 W 15 11450 11450 6450 White 33
5 PM Fri 75 76 W 17 10831 10303 5303 White 30
6 PM Fri 75 75 W 17 10624 9869 4869 White 29
7 PM Fri 71 71 W 17 9468 8515 3515 Blue 25
8 PM Fri 69 69 W 17 8717 8191 3191 Blue 23
9 PM Fri 67 67 W 17 8382 7866 2866 Blue 21
10 PM Fri 65 65 W 17 8056 7568 2568 Blue 19
11 PM Fri 65 65 W 12 8056 7568 2568 Blue 19
12 Midnight Sat 63 63 W 12 7730 7303 2303 Blue 17
1 AM Sat 63 63 W 12 7730 7303 2303 Blue 17
2 AM Sat 61 61 W 12 7455 6961 1961 Blue 15
3 AM Sat 61 61 W 12 7455 6961 1961 Blue 15
4 AM Sat 59 59 W 12 7162 6641 1641 Blue 13

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