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

Station:

KVBG

Date/Time:

17 SEP 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 Tue 57 57 W 10 2539 5000 0 Blue 0
6 AM Tue 55 55 W 9 2539 5000 0 Blue 0
7 AM Tue 54 54 NW 8 2539 5000 0 Blue 0
8 AM Tue 56 56 NW 7 2539 5000 0 Blue 0
9 AM Tue 55 56 W 6 2539 5000 0 Blue 0
10 AM Tue 59 62 W 6 4349 5000 0 Blue 0
11 AM Tue 64 69 W 7 5558 5387 387 Blue 6
12 Noon Tue 69 75 W 9 7095 6348 1348 Blue 12
1 PM Tue 72 78 W 13 7571 7074 2074 Blue 15
2 PM Tue 73 79 W 15 7729 7232 2232 Blue 16
3 PM Tue 75 79 W 17 7729 7232 2232 Blue 16
4 PM Tue 73 76 W 18 7254 6758 1758 Blue 13
5 PM Tue 72 73 W 18 6777 5624 624 Blue 10
6 PM Tue 70 70 W 17 5633 5434 434 Blue 7
7 PM Tue 67 67 W 15 5439 5324 324 Blue 4
8 PM Tue 65 65 W 14 5358 5000 0 Blue 2
9 PM Tue 64 64 W 14 5326 5000 0 Blue 1
10 PM Tue 63 63 W 10 5117 5000 0 Blue 0
11 PM Tue 63 63 NW 10 5117 5000 0 Blue 0
12 Midnight Wed 62 62 NW 10 4349 5000 0 Blue 0
1 AM Wed 61 61 NW 9 3579 5000 0 Blue 0
2 AM Wed 60 60 NW 9 2754 5000 0 Blue 0
3 AM Wed 58 58 NW 9 2539 5000 0 Blue 0
4 AM Wed 57 57 NW 10 2539 5000 0 Blue 0
5 AM Wed 56 56 NW 10 2539 5000 0 Blue 0
6 AM Wed 55 55 W 9 2539 5000 0 Blue 0
7 AM Wed 55 55 W 9 2539 5000 0 Blue 0
8 AM Wed 58 58 W 9 2539 5000 0 Blue 0
9 AM Wed 57 58 W 9 2539 5000 0 Blue 0
10 AM Wed 62 65 W 10 5358 5000 0 Blue 2
11 AM Wed 67 72 W 13 6426 5553 553 Blue 9
12 Noon Wed 71 77 W 13 7412 6916 1916 Blue 14
1 PM Wed 74 80 W 13 7949 7390 2390 Blue 17
2 PM Wed 75 81 W 24 8213 7547 2547 Blue 18
3 PM Wed 75 80 W 24 7949 7390 2390 Blue 17
4 PM Wed 74 77 W 24 7412 6916 1916 Blue 14
5 PM Wed 72 73 W 24 6777 5624 624 Blue 10
6 PM Wed 70 70 W 24 5633 5434 434 Blue 7
7 PM Wed 68 68 W 24 5498 5356 356 Blue 5
8 PM Wed 66 66 W 16 5389 5060 60 Blue 3
9 PM Wed 65 65 W 16 5358 5000 0 Blue 2
10 PM Wed 64 64 W 16 5326 5000 0 Blue 1
11 PM Wed 64 64 W 13 5326 5000 0 Blue 1
12 Midnight Thu 63 63 W 13 5117 5000 0 Blue 0
1 AM Thu 63 63 W 13 5117 5000 0 Blue 0
2 AM Thu 62 62 W 12 4349 5000 0 Blue 0
3 AM Thu 60 60 W 12 2754 5000 0 Blue 0
4 AM Thu 59 59 W 12 2539 5000 0 Blue 0
5 AM Thu 57 57 W 12 2539 5000 0 Blue 0
6 AM Thu 56 56 W 12 2539 5000 0 Blue 0
7 AM Thu 55 55 W 12 2539 5000 0 Blue 0
8 AM Thu 56 56 W 12 2539 5000 0 Blue 0
9 AM Thu 58 59 W 12 2539 5000 0 Blue 0
10 AM Thu 60 63 W 12 5117 5000 0 Blue 0
11 AM Thu 63 68 W 16 5498 5356 356 Blue 5
12 Noon Thu 66 72 W 16 6426 5553 553 Blue 9
1 PM Thu 68 74 W 16 6936 5753 753 Blue 11
2 PM Thu 70 76 W 24 7254 6758 1758 Blue 13
3 PM Thu 70 75 W 24 7095 6348 1348 Blue 12
4 PM Thu 69 72 W 24 6426 5553 553 Blue 9
5 PM Thu 67 68 W 25 5498 5356 356 Blue 5
6 PM Thu 65 65 W 25 5358 5000 0 Blue 2
7 PM Thu 64 64 W 25 5326 5000 0 Blue 1
8 PM Thu 62 62 W 18 4349 5000 0 Blue 0
9 PM Thu 61 61 W 18 3579 5000 0 Blue 0
10 PM Thu 61 61 W 18 3579 5000 0 Blue 0
11 PM Thu 60 60 W 13 2754 5000 0 Blue 0
12 Midnight Fri 59 59 W 13 2539 5000 0 Blue 0
1 AM Fri 59 59 W 13 2539 5000 0 Blue 0
2 AM Fri 58 58 NW 9 2539 5000 0 Blue 0
3 AM Fri 56 56 NW 9 2539 5000 0 Blue 0
4 AM Fri 55 55 NW 9 2539 5000 0 Blue 0
5 AM Fri 54 54 NW 8 2539 5000 0 Blue 0
6 AM Fri 54 54 NW 8 2539 5000 0 Blue 0
7 AM Fri 54 54 NW 8 2539 5000 0 Blue 0
8 AM Fri 56 56 N 6 2539 5000 0 Blue 0
9 AM Fri 58 59 N 6 2539 5000 0 Blue 0
10 AM Fri 62 65 N 6 5358 5000 0 Blue 2
11 AM Fri 65 70 N 9 5633 5434 434 Blue 7
12 Noon Fri 69 75 N 9 7095 6348 1348 Blue 12
1 PM Fri 72 78 N 9 7571 7074 2074 Blue 15
2 PM Fri 75 81 W 15 8213 7547 2547 Blue 18
3 PM Fri 76 81 W 15 8213 7547 2547 Blue 18
4 PM Fri 75 78 W 15 7571 7074 2074 Blue 15
5 PM Fri 74 75 SW 15 7095 6348 1348 Blue 12
6 PM Fri 72 72 SW 15 6426 5553 553 Blue 9
7 PM Fri 69 69 SW 15 5558 5387 387 Blue 6
8 PM Fri 67 67 W 12 5439 5324 324 Blue 4
9 PM Fri 66 66 W 12 5389 5060 60 Blue 3
10 PM Fri 66 66 W 12 5389 5060 60 Blue 3
11 PM Fri 65 65 NW 9 5358 5000 0 Blue 2
12 Midnight Sat 64 64 NW 9 5326 5000 0 Blue 1
1 AM Sat 62 62 NW 9 4349 5000 0 Blue 0
2 AM Sat 61 61 NW 7 3579 5000 0 Blue 0
3 AM Sat 60 60 NW 7 2754 5000 0 Blue 0
4 AM Sat 58 58 NW 7 2539 5000 0 Blue 0
5 AM Sat 58 58 N 7 2539 5000 0 Blue 0
6 AM Sat 58 58 N 7 2539 5000 0 Blue 0
7 AM Sat 59 59 N 7 2539 5000 0 Blue 0
8 AM Sat 61 61 N 6 3579 5000 0 Blue 0
9 AM Sat 64 65 N 6 5358 5000 0 Blue 2
10 AM Sat 67 70 N 6 5633 5434 434 Blue 7
11 AM Sat 71 76 E 8 7254 6758 1758 Blue 13
12 Noon Sat 75 81 E 8 8213 7547 2547 Blue 18
1 PM Sat 78 84 E 8 9363 8168 3168 Blue 21
2 PM Sat 80 86 S 14 10374 8778 3778 Blue 23
3 PM Sat 81 85 S 14 9841 8429 3429 Blue 22
4 PM Sat 80 83 S 14 8872 7907 2907 Blue 20
5 PM Sat 79 80 SW 14 7949 7390 2390 Blue 17
6 PM Sat 77 77 SW 14 7412 6916 1916 Blue 14
7 PM Sat 74 74 SW 14 6936 5753 753 Blue 11
8 PM Sat 71 71 W 10 5768 5494 494 Blue 8
9 PM Sat 70 70 W 10 5633 5434 434 Blue 7
10 PM Sat 69 69 W 10 5558 5387 387 Blue 6
11 PM Sat 68 68 W 9 5498 5356 356 Blue 5
12 Midnight Sun 67 67 W 9 5439 5324 324 Blue 4
1 AM Sun 65 65 W 9 5358 5000 0 Blue 2
2 AM Sun 64 64 N 7 5326 5000 0 Blue 1
3 AM Sun 63 63 N 7 5117 5000 0 Blue 0
4 AM Sun 61 61 N 7 3579 5000 0 Blue 0
5 AM Sun 61 61 NE 7 3579 5000 0 Blue 0
6 AM Sun 61 61 NE 7 3579 5000 0 Blue 0
7 AM Sun 62 62 NE 7 4349 5000 0 Blue 0
8 AM Sun 64 64 NE 6 5326 5000 0 Blue 1
9 AM Sun 67 68 NE 6 5498 5356 356 Blue 5
10 AM Sun 70 72 NE 6 6426 5553 553 Blue 9
11 AM Sun 74 78 S 8 7571 7074 2074 Blue 15
12 Noon Sun 77 82 S 8 8475 7705 2705 Blue 19
1 PM Sun 80 85 S 8 9841 8429 3429 Blue 22
2 PM Sun 82 87 S 16 11056 9263 4263 Blue 24
3 PM Sun 82 86 S 16 10374 8778 3778 Blue 23
4 PM Sun 82 84 S 16 9363 8168 3168 Blue 21
5 PM Sun 80 81 W 17 8213 7547 2547 Blue 18
6 PM Sun 78 78 W 17 7571 7074 2074 Blue 15
7 PM Sun 75 75 W 17 7095 6348 1348 Blue 12
8 PM Sun 72 72 W 14 6426 5553 553 Blue 9
9 PM Sun 70 70 W 14 5633 5434 434 Blue 7
10 PM Sun 69 69 W 14 5558 5387 387 Blue 6
11 PM Sun 68 68 W 12 5498 5356 356 Blue 5
12 Midnight Mon 67 67 W 12 5439 5324 324 Blue 4
1 AM Mon 67 67 W 12 5439 5324 324 Blue 4
2 AM Mon 66 66 W 10 5389 5060 60 Blue 3
3 AM Mon 64 64 W 10 5326 5000 0 Blue 1
4 AM Mon 63 63 W 10 5117 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