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

Station:

KVBG

Date/Time:

12Z 23 SEP 2017

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 44 44 NE 6 2421 5000 0 Blue 0
6 AM Sat 44 44 NE 6 2421 5000 0 Blue 0
7 AM Sat 45 45 NE 6 2421 5000 0 Blue 0
8 AM Sat 48 48 NE 6 2421 5000 0 Blue 0
9 AM Sat 53 54 NE 6 2609 5000 0 Blue 0
10 AM Sat 58 61 NE 6 7874 5870 870 Blue 6
11 AM Sat 63 67 NW 5 9046 8424 3424 Blue 12
12 Noon Sat 66 71 NW 5 10205 9211 4211 Blue 16
1 PM Sat 68 73 NW 5 10617 9814 4814 Blue 18
2 PM Sat 69 74 NW 5 10822 10155 5155 Blue 19
3 PM Sat 69 73 NW 5 10617 9814 4814 Blue 18
4 PM Sat 69 71 NW 5 10205 9211 4211 Blue 16
5 PM Sat 67 68 W 7 9254 8618 3618 Blue 13
6 PM Sat 65 65 W 7 8654 8035 3035 Blue 10
7 PM Sat 62 62 W 7 8068 6784 1784 Blue 7
8 PM Sat 59 59 W 7 6899 5000 0 Blue 4
9 PM Sat 56 56 W 7 4084 5000 0 Blue 1
10 PM Sat 54 54 W 7 2609 5000 0 Blue 0
11 PM Sat 53 53 SW 5 2421 5000 0 Blue 0
12 Midnight Sun 52 52 SW 5 2421 5000 0 Blue 0
1 AM Sun 51 51 SW 5 2421 5000 0 Blue 0
2 AM Sun 50 50 SW 5 2421 5000 0 Blue 0
3 AM Sun 49 49 SW 5 2421 5000 0 Blue 0
4 AM Sun 47 47 SW 5 2421 5000 0 Blue 0
5 AM Sun 46 46 NE 6 2421 5000 0 Blue 0
6 AM Sun 47 47 NE 6 2421 5000 0 Blue 0
7 AM Sun 49 49 NE 6 2421 5000 0 Blue 0
8 AM Sun 52 52 NE 6 2421 5000 0 Blue 0
9 AM Sun 57 58 NE 6 5948 5000 0 Blue 3
10 AM Sun 63 66 NE 6 8849 8230 3230 Blue 11
11 AM Sun 67 72 SE 5 10412 9417 4417 Blue 17
12 Noon Sun 70 76 SE 5 11185 10565 5565 Blue 21
1 PM Sun 71 77 SE 5 11370 10769 5769 Blue 22
2 PM Sun 72 77 S 5 11370 10769 5769 Blue 22
3 PM Sun 73 77 S 5 11370 10769 5769 Blue 22
4 PM Sun 73 75 S 5 11000 10360 5360 Blue 20
5 PM Sun 72 73 W 3 10617 9814 4814 Blue 18
6 PM Sun 69 69 W 3 9462 8811 3811 Blue 14
7 PM Sun 65 65 W 3 8654 8035 3035 Blue 10
8 PM Sun 61 61 W 3 7874 5870 870 Blue 6
9 PM Sun 58 58 W 3 5948 5000 0 Blue 3
10 PM Sun 56 56 W 3 4084 5000 0 Blue 1
11 PM Sun 55 55 N 6 3357 5000 0 Blue 0
12 Midnight Mon 54 54 N 6 2609 5000 0 Blue 0
1 AM Mon 52 52 N 6 2421 5000 0 Blue 0
2 AM Mon 51 51 N 6 2421 5000 0 Blue 0
3 AM Mon 49 49 N 6 2421 5000 0 Blue 0
4 AM Mon 48 48 N 6 2421 5000 0 Blue 0
5 AM Mon 48 48 NE 7 2421 5000 0 Blue 0
6 AM Mon 48 48 NE 7 2421 5000 0 Blue 0
7 AM Mon 50 50 NE 7 2421 5000 0 Blue 0
8 AM Mon 53 53 NE 7 2421 5000 0 Blue 0
9 AM Mon 58 59 NE 7 6899 5000 0 Blue 4
10 AM Mon 64 67 NE 7 9046 8424 3424 Blue 12
11 AM Mon 69 73 E 6 10617 9814 4814 Blue 18
12 Noon Mon 73 78 E 6 11555 10956 5956 Blue 23
1 PM Mon 75 81 E 6 12099 11501 6501 Blue 26
2 PM Mon 76 81 E 6 12099 11501 6501 Blue 26
3 PM Mon 77 81 E 6 12099 11501 6501 Blue 26
4 PM Mon 77 79 E 6 11739 11134 6134 Blue 24
5 PM Mon 76 77 SW 5 11370 10769 5769 Blue 22
6 PM Mon 72 72 SW 5 10412 9417 4417 Blue 17
7 PM Mon 68 68 SW 5 9254 8618 3618 Blue 13
8 PM Mon 64 64 SW 5 8459 7843 2843 Blue 9
9 PM Mon 61 61 SW 5 7874 5870 870 Blue 6
10 PM Mon 60 60 SW 5 7647 5029 29 Blue 5
11 PM Mon 59 59 NE 7 6899 5000 0 Blue 4
12 Midnight Tue 58 58 NE 7 5948 5000 0 Blue 3
1 AM Tue 56 56 NE 7 4084 5000 0 Blue 1
2 AM Tue 55 55 NE 7 3357 5000 0 Blue 0
3 AM Tue 53 53 NE 7 2421 5000 0 Blue 0
4 AM Tue 52 52 NE 7 2421 5000 0 Blue 0
5 AM Tue 51 51 N 8 2421 5000 0 Blue 0
6 AM Tue 51 51 N 8 2421 5000 0 Blue 0
7 AM Tue 53 53 N 8 2421 5000 0 Blue 0
8 AM Tue 56 56 N 8 4084 5000 0 Blue 1
9 AM Tue 62 63 N 8 8264 7528 2528 Blue 8
10 AM Tue 68 71 N 8 10205 9211 4211 Blue 16
11 AM Tue 74 78 E 6 11555 10956 5956 Blue 23
12 Noon Tue 78 84 E 6 13252 12046 7046 White 29
1 PM Tue 81 87 E 6 13848 12992 7992 White 32
2 PM Tue 82 87 E 6 13848 12992 7992 White 32
3 PM Tue 82 86 E 6 13650 12422 7422 White 31
4 PM Tue 81 83 E 6 12612 11867 6867 Blue 28
5 PM Tue 79 80 NE 7 11923 11318 6318 Blue 25
6 PM Tue 76 76 NE 7 11185 10565 5565 Blue 21
7 PM Tue 71 71 NE 7 10205 9211 4211 Blue 16
8 PM Tue 67 67 NE 7 9046 8424 3424 Blue 12
9 PM Tue 64 64 NE 7 8459 7843 2843 Blue 9
10 PM Tue 62 62 NE 7 8068 6784 1784 Blue 7
11 PM Tue 61 61 E 5 7874 5870 870 Blue 6
12 Midnight Wed 60 60 E 5 7647 5029 29 Blue 5
1 AM Wed 59 59 E 5 6899 5000 0 Blue 4
2 AM Wed 58 58 E 5 5948 5000 0 Blue 3
3 AM Wed 57 57 E 5 5088 5000 0 Blue 2
4 AM Wed 56 56 E 5 4084 5000 0 Blue 1
5 AM Wed 54 54 NE 6 2609 5000 0 Blue 0
6 AM Wed 54 54 NE 6 2609 5000 0 Blue 0
7 AM Wed 55 55 NE 6 3357 5000 0 Blue 0
8 AM Wed 58 58 NE 6 5948 5000 0 Blue 3
9 AM Wed 64 65 NE 6 8654 8035 3035 Blue 10
10 AM Wed 71 74 NE 6 10822 10155 5155 Blue 19
11 AM Wed 77 81 E 6 12099 11501 6501 Blue 26
12 Noon Wed 81 87 E 6 13848 12992 7992 White 32
1 PM Wed 83 89 E 6 14250 14058 9058 White 34
2 PM Wed 83 88 E 6 14048 13531 8531 White 33
3 PM Wed 84 88 E 6 14048 13531 8531 White 33
4 PM Wed 84 86 E 6 13650 12422 7422 White 31
5 PM Wed 82 83 NE 7 12612 11867 6867 Blue 28
6 PM Wed 78 78 NE 7 11555 10956 5956 Blue 23
7 PM Wed 74 74 NE 7 10822 10155 5155 Blue 19
8 PM Wed 69 69 NE 7 9462 8811 3811 Blue 14
9 PM Wed 66 66 NE 7 8849 8230 3230 Blue 11
10 PM Wed 64 64 NE 7 8459 7843 2843 Blue 9
11 PM Wed 63 63 N 5 8264 7528 2528 Blue 8
12 Midnight Thu 61 61 N 5 7874 5870 870 Blue 6
1 AM Thu 60 60 N 5 7647 5029 29 Blue 5
2 AM Thu 59 59 N 5 6899 5000 0 Blue 4
3 AM Thu 58 58 N 5 5948 5000 0 Blue 3
4 AM Thu 57 57 N 5 5088 5000 0 Blue 2
5 AM Thu 56 56 NE 6 4084 5000 0 Blue 1
6 AM Thu 56 56 NE 6 4084 5000 0 Blue 1
7 AM Thu 57 57 NE 6 5088 5000 0 Blue 2
8 AM Thu 60 60 NE 6 7647 5029 29 Blue 5
9 AM Thu 66 67 NE 6 9046 8424 3424 Blue 12
10 AM Thu 72 75 NE 6 11000 10360 5360 Blue 20
11 AM Thu 78 82 E 6 12269 11684 6684 Blue 27
12 Noon Thu 81 86 E 6 13650 12422 7422 White 31
1 PM Thu 83 89 E 6 14250 14058 9058 White 34
2 PM Thu 84 89 E 6 14250 14058 9058 White 34
3 PM Thu 85 89 E 6 14250 14058 9058 White 34
4 PM Thu 85 87 E 6 13848 12992 7992 White 32
5 PM Thu 83 84 NE 7 13252 12046 7046 White 29
6 PM Thu 79 79 NE 7 11739 11134 6134 Blue 24
7 PM Thu 75 75 NE 7 11000 10360 5360 Blue 20
8 PM Thu 71 71 NE 7 10205 9211 4211 Blue 16
9 PM Thu 68 68 NE 7 9254 8618 3618 Blue 13
10 PM Thu 66 66 NE 7 8849 8230 3230 Blue 11
11 PM Thu 65 65 S 5 8654 8035 3035 Blue 10
12 Midnight Fri 64 64 S 5 8459 7843 2843 Blue 9
1 AM Fri 62 62 S 5 8068 6784 1784 Blue 7
2 AM Fri 61 61 S 5 7874 5870 870 Blue 6
3 AM Fri 59 59 S 5 6899 5000 0 Blue 4
4 AM Fri 58 58 S 5 5948 5000 0 Blue 3

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