Detailed Predictions for: Lake McClure
Launch Altitude (f): 2000
LZ Altitude (f): 500
Sounding

Station:

KOAK

Date/Time:

24 AUG 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 Sat 72 72 E 2 1805 2000 0 Blue 13
6 AM Sat 71 71 E 2 1788 2000 0 Blue 12
7 AM Sat 72 72 E 2 1805 2000 0 Blue 13
8 AM Sat 77 77 S 2 1915 2000 0 Blue 18
9 AM Sat 82 84 S 2 2833 2289 289 Blue 25
10 AM Sat 86 90 SW 5 4463 3150 1150 Blue 31
11 AM Sat 88 93 SW 5 5659 4411 2411 Blue 34
12 Noon Sat 90 97 W 6 7282 5853 3853 Blue 38
1 PM Sat 92 99 W 6 7555 7120 5120 Blue 40
2 PM Sat 94 101 W 6 7845 7392 5392 Blue 42
3 PM Sat 95 101 W 6 7845 7392 5392 Blue 42
4 PM Sat 96 99 W 6 7555 7120 5120 Blue 40
5 PM Sat 96 98 W 6 7419 6155 4155 Blue 39
6 PM Sat 95 96 W 6 7146 5627 3627 Blue 37
7 PM Sat 92 92 W 6 5431 3544 1544 Blue 33
8 PM Sat 88 88 NW 6 3416 2935 935 Blue 29
9 PM Sat 84 84 NW 3 2833 2289 289 Blue 25
10 PM Sat 82 82 NW 2 2488 2080 80 Blue 23
11 PM Sat 80 80 N 2 2188 2000 0 Blue 21
12 Midnight Sun 79 79 N 2 2083 2000 0 Blue 20
1 AM Sun 77 77 N 2 1915 2000 0 Blue 18
2 AM Sun 75 75 N 2 1863 2000 0 Blue 16
3 AM Sun 75 75 N 2 1863 2000 0 Blue 16
4 AM Sun 74 74 N 2 1838 2000 0 Blue 15
5 AM Sun 73 73 NE 2 1822 2000 0 Blue 14
6 AM Sun 72 72 E 3 1805 2000 0 Blue 13
7 AM Sun 73 73 E 3 1822 2000 0 Blue 14
8 AM Sun 79 79 SE 2 2083 2000 0 Blue 20
9 AM Sun 85 87 S 3 3156 2827 827 Blue 28
10 AM Sun 87 90 SW 5 4463 3150 1150 Blue 31
11 AM Sun 90 94 SW 6 5887 4813 2813 Blue 35
12 Noon Sun 93 98 SW 6 7419 6155 4155 Blue 39
1 PM Sun 95 101 SW 6 7845 7392 5392 Blue 42
2 PM Sun 96 102 W 7 8213 7528 5528 Blue 43
3 PM Sun 97 102 W 7 8213 7528 5528 Blue 43
4 PM Sun 98 101 W 7 7845 7392 5392 Blue 42
5 PM Sun 97 99 W 8 7555 7120 5120 Blue 40
6 PM Sun 95 96 W 8 7146 5627 3627 Blue 37
7 PM Sun 91 91 W 8 4858 3407 1407 Blue 32
8 PM Sun 88 88 NW 6 3416 2935 935 Blue 29
9 PM Sun 85 85 NW 6 2941 2481 481 Blue 26
10 PM Sun 83 83 NW 6 2725 2185 185 Blue 24
11 PM Sun 81 81 NW 3 2293 2000 0 Blue 22
12 Midnight Mon 79 79 NW 3 2083 2000 0 Blue 20
1 AM Mon 77 77 NW 3 1915 2000 0 Blue 18
2 AM Mon 76 76 N 3 1889 2000 0 Blue 17
3 AM Mon 75 75 N 3 1863 2000 0 Blue 16
4 AM Mon 74 74 N 3 1838 2000 0 Blue 15
5 AM Mon 74 74 N 3 1838 2000 0 Blue 15
6 AM Mon 75 75 N 3 1863 2000 0 Blue 16
7 AM Mon 77 77 N 3 1915 2000 0 Blue 18
8 AM Mon 80 80 NE 2 2188 2000 0 Blue 21
9 AM Mon 84 86 NE 2 3049 2720 720 Blue 27
10 AM Mon 87 91 NE 2 4858 3407 1407 Blue 32
11 AM Mon 91 96 W 6 7146 5627 3627 Blue 37
12 Noon Mon 94 101 W 6 7845 7392 5392 Blue 42
1 PM Mon 96 103 W 6 8481 7663 5663 Blue 44
2 PM Mon 97 104 W 7 8589 7799 5799 Blue 45
3 PM Mon 98 104 W 7 8589 7799 5799 Blue 45
4 PM Mon 99 103 W 7 8481 7663 5663 Blue 44
5 PM Mon 98 100 W 8 7692 7256 5256 Blue 41
6 PM Mon 96 96 W 8 7146 5627 3627 Blue 37
7 PM Mon 92 92 W 8 5431 3544 1544 Blue 33
8 PM Mon 89 89 NW 6 3554 3042 1042 Blue 30
9 PM Mon 86 86 NW 6 3049 2720 720 Blue 27
10 PM Mon 84 84 NW 6 2833 2289 289 Blue 25
11 PM Mon 82 82 NW 2 2488 2080 80 Blue 23
12 Midnight Tue 80 80 NW 2 2188 2000 0 Blue 21
1 AM Tue 78 78 NW 2 1978 2000 0 Blue 19
2 AM Tue 77 77 N 3 1915 2000 0 Blue 18
3 AM Tue 76 76 N 3 1889 2000 0 Blue 17
4 AM Tue 75 75 N 3 1863 2000 0 Blue 16
5 AM Tue 75 75 NE 3 1863 2000 0 Blue 16
6 AM Tue 76 76 NE 3 1889 2000 0 Blue 17
7 AM Tue 78 78 NE 3 1978 2000 0 Blue 19
8 AM Tue 81 81 N 2 2293 2000 0 Blue 22
9 AM Tue 85 87 N 2 3156 2827 827 Blue 28
10 AM Tue 89 93 N 2 5659 4411 2411 Blue 34
11 AM Tue 93 98 SW 5 7419 6155 4155 Blue 39
12 Noon Tue 95 101 SW 5 7845 7392 5392 Blue 42
1 PM Tue 96 103 SW 5 8481 7663 5663 Blue 44
2 PM Tue 97 104 W 6 8589 7799 5799 Blue 45
3 PM Tue 98 104 W 6 8589 7799 5799 Blue 45
4 PM Tue 99 103 W 6 8481 7663 5663 Blue 44
5 PM Tue 99 101 W 8 7845 7392 5392 Blue 42
6 PM Tue 97 98 W 8 7419 6155 4155 Blue 39
7 PM Tue 94 94 W 8 5887 4813 2813 Blue 35
8 PM Tue 90 90 NW 6 4463 3150 1150 Blue 31
9 PM Tue 87 87 NW 6 3156 2827 827 Blue 28
10 PM Tue 84 84 NW 6 2833 2289 289 Blue 25
11 PM Tue 82 82 N 3 2488 2080 80 Blue 23
12 Midnight Wed 80 80 N 3 2188 2000 0 Blue 21
1 AM Wed 79 79 N 3 2083 2000 0 Blue 20
2 AM Wed 78 78 NW 3 1978 2000 0 Blue 19
3 AM Wed 76 76 NW 3 1889 2000 0 Blue 17
4 AM Wed 75 75 NW 3 1863 2000 0 Blue 16
5 AM Wed 75 75 NE 3 1863 2000 0 Blue 16
6 AM Wed 76 76 NE 3 1889 2000 0 Blue 17
7 AM Wed 78 78 NE 3 1978 2000 0 Blue 19
8 AM Wed 81 81 N 2 2293 2000 0 Blue 22
9 AM Wed 84 86 N 2 3049 2720 720 Blue 27
10 AM Wed 88 91 N 2 4858 3407 1407 Blue 32
11 AM Wed 91 96 W 5 7146 5627 3627 Blue 37
12 Noon Wed 93 99 W 5 7555 7120 5120 Blue 40
1 PM Wed 95 102 W 5 8213 7528 5528 Blue 43
2 PM Wed 96 103 W 6 8481 7663 5663 Blue 44
3 PM Wed 98 104 W 6 8589 7799 5799 Blue 45
4 PM Wed 98 102 W 6 8213 7528 5528 Blue 43
5 PM Wed 98 100 W 7 7692 7256 5256 Blue 41
6 PM Wed 96 97 W 7 7282 5853 3853 Blue 38
7 PM Wed 92 92 W 7 5431 3544 1544 Blue 33
8 PM Wed 88 88 NW 6 3416 2935 935 Blue 29
9 PM Wed 85 85 NW 6 2941 2481 481 Blue 26
10 PM Wed 82 82 NW 6 2488 2080 80 Blue 23
11 PM Wed 80 80 NW 3 2188 2000 0 Blue 21
12 Midnight Thu 78 78 NW 3 1978 2000 0 Blue 19
1 AM Thu 77 77 NW 3 1915 2000 0 Blue 18
2 AM Thu 76 76 N 3 1889 2000 0 Blue 17
3 AM Thu 74 74 N 3 1838 2000 0 Blue 15
4 AM Thu 73 73 N 3 1822 2000 0 Blue 14
5 AM Thu 73 73 N 3 1822 2000 0 Blue 14
6 AM Thu 74 74 N 3 1838 2000 0 Blue 15
7 AM Thu 76 76 N 3 1889 2000 0 Blue 17
8 AM Thu 78 78 W 2 1978 2000 0 Blue 19
9 AM Thu 81 83 W 2 2725 2185 185 Blue 24
10 AM Thu 85 88 W 2 3416 2935 935 Blue 29
11 AM Thu 88 93 W 6 5659 4411 2411 Blue 34
12 Noon Thu 90 96 W 6 7146 5627 3627 Blue 37
1 PM Thu 92 99 W 6 7555 7120 5120 Blue 40
2 PM Thu 93 100 W 6 7692 7256 5256 Blue 41
3 PM Thu 94 100 W 6 7692 7256 5256 Blue 41
4 PM Thu 95 99 W 6 7555 7120 5120 Blue 40
5 PM Thu 95 97 W 7 7282 5853 3853 Blue 38
6 PM Thu 93 94 W 7 5887 4813 2813 Blue 35
7 PM Thu 90 90 W 7 4463 3150 1150 Blue 31
8 PM Thu 87 87 NW 6 3156 2827 827 Blue 28
9 PM Thu 84 84 NW 6 2833 2289 289 Blue 25
10 PM Thu 81 81 NW 6 2293 2000 0 Blue 22
11 PM Thu 79 79 NW 3 2083 2000 0 Blue 20
12 Midnight Fri 77 77 NW 3 1915 2000 0 Blue 18
1 AM Fri 76 76 NW 3 1889 2000 0 Blue 17
2 AM Fri 75 75 N 3 1863 2000 0 Blue 16
3 AM Fri 73 73 N 3 1822 2000 0 Blue 14
4 AM Fri 72 72 N 3 1805 2000 0 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