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

Station:

KOAK

Date/Time:

19 JUN 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 Tue 60 60 N 5 2068 2000 0 Blue 9
6 AM Tue 62 62 N 5 2206 2031 31 Blue 11
7 AM Tue 66 66 N 5 2623 2272 272 Blue 15
8 AM Tue 70 71 S 5 2748 2681 681 Blue 20
9 AM Tue 74 77 S 5 2848 2797 797 Blue 26
10 AM Tue 78 83 S 5 5797 2967 967 Blue 32
11 AM Tue 82 89 W 5 8809 7232 5232 Blue 38
12 Noon Tue 85 93 W 5 9349 8936 6936 Blue 42
1 PM Tue 88 97 W 5 9728 9418 7418 Blue 46
2 PM Tue 91 99 W 8 10092 9607 7607 Blue 48
3 PM Tue 93 100 W 8 10449 9701 7701 Blue 49
4 PM Tue 94 99 W 8 10092 9607 7607 Blue 48
5 PM Tue 94 97 NW 10 9728 9418 7418 Blue 46
6 PM Tue 92 93 NW 10 9349 8936 6936 Blue 42
7 PM Tue 88 88 NW 10 8530 7002 5002 Blue 37
8 PM Tue 84 84 NW 8 6183 3289 1289 Blue 33
9 PM Tue 80 80 NW 8 2971 2847 847 Blue 29
10 PM Tue 76 76 NW 8 2831 2781 781 Blue 25
11 PM Tue 73 73 N 9 2781 2731 731 Blue 22
12 Midnight Wed 70 70 N 9 2731 2652 652 Blue 19
1 AM Wed 69 69 N 9 2711 2622 622 Blue 18
2 AM Wed 67 67 N 7 2653 2341 341 Blue 16
3 AM Wed 65 65 N 7 2508 2204 204 Blue 14
4 AM Wed 64 64 N 7 2344 2135 135 Blue 13
5 AM Wed 64 64 NE 5 2344 2135 135 Blue 13
6 AM Wed 66 66 NE 5 2623 2272 272 Blue 15
7 AM Wed 70 70 NE 5 2731 2652 652 Blue 19
8 AM Wed 75 76 NE 5 2831 2781 781 Blue 25
9 AM Wed 79 82 NE 5 5083 2900 900 Blue 31
10 AM Wed 84 89 NE 5 8809 7232 5232 Blue 38
11 AM Wed 87 94 W 6 9444 9104 7104 Blue 43
12 Noon Wed 91 99 W 6 10092 9607 7607 Blue 48
1 PM Wed 94 103 W 6 11354 10330 8330 Blue 52
2 PM Wed 96 104 W 6 11604 10716 8716 Blue 53
3 PM Wed 97 104 W 6 11604 10716 8716 Blue 53
4 PM Wed 98 103 W 6 11354 10330 8330 Blue 52
5 PM Wed 97 100 NW 9 10449 9701 7701 Blue 49
6 PM Wed 95 96 NW 9 9633 9323 7323 Blue 45
7 PM Wed 91 91 NW 9 9149 8414 6414 Blue 40
8 PM Wed 87 87 NW 9 7943 6122 4122 Blue 36
9 PM Wed 83 83 NW 9 5797 2967 967 Blue 32
10 PM Wed 79 79 NW 9 2903 2830 830 Blue 28
11 PM Wed 76 76 NW 7 2831 2781 781 Blue 25
12 Midnight Thu 75 75 NW 7 2815 2764 764 Blue 24
1 AM Thu 73 73 NW 7 2781 2731 731 Blue 22
2 AM Thu 72 72 NW 7 2765 2710 710 Blue 21
3 AM Thu 70 70 NW 7 2731 2652 652 Blue 19
4 AM Thu 68 68 NW 7 2682 2496 496 Blue 17
5 AM Thu 68 68 N 6 2682 2496 496 Blue 17
6 AM Thu 70 70 N 6 2731 2652 652 Blue 19
7 AM Thu 74 74 N 6 2798 2747 747 Blue 23
8 AM Thu 78 79 N 6 2903 2830 830 Blue 28
9 AM Thu 82 85 N 6 7063 5017 3017 Blue 34
10 AM Thu 86 91 N 6 9149 8414 6414 Blue 40
11 AM Thu 90 97 W 7 9728 9418 7418 Blue 46
12 Noon Thu 93 101 W 7 10838 9796 7796 Blue 50
1 PM Thu 96 105 W 7 12027 11021 9021 Blue 54
2 PM Thu 98 106 W 7 12508 11270 9270 Blue 55
3 PM Thu 100 107 W 7 12976 11518 9518 Blue 56
4 PM Thu 101 106 W 7 12508 11270 9270 Blue 55
5 PM Thu 100 103 NW 9 11354 10330 8330 Blue 52
6 PM Thu 98 99 NW 9 10092 9607 7607 Blue 48
7 PM Thu 93 93 NW 9 9349 8936 6936 Blue 42
8 PM Thu 88 88 NW 9 8530 7002 5002 Blue 37
9 PM Thu 83 83 NW 9 5797 2967 967 Blue 32
10 PM Thu 78 78 NW 9 2865 2814 814 Blue 27
11 PM Thu 75 75 N 6 2815 2764 764 Blue 24
12 Midnight Fri 72 72 N 6 2765 2710 710 Blue 21
1 AM Fri 71 71 N 6 2748 2681 681 Blue 20
2 AM Fri 69 69 N 6 2711 2622 622 Blue 18
3 AM Fri 68 68 N 6 2682 2496 496 Blue 17
4 AM Fri 66 66 N 6 2623 2272 272 Blue 15
5 AM Fri 66 66 S 5 2623 2272 272 Blue 15
6 AM Fri 68 68 S 5 2682 2496 496 Blue 17
7 AM Fri 71 71 S 5 2748 2681 681 Blue 20
8 AM Fri 75 76 S 5 2831 2781 781 Blue 25
9 AM Fri 80 83 S 5 5797 2967 967 Blue 32
10 AM Fri 85 90 S 5 8979 7620 5620 Blue 39
11 AM Fri 90 97 W 6 9728 9418 7418 Blue 46
12 Noon Fri 94 102 W 6 11103 9993 7993 Blue 51
1 PM Fri 97 106 W 6 12508 11270 9270 Blue 55
2 PM Fri 99 107 W 6 12976 11518 9518 Blue 56
3 PM Fri 101 108 W 6 13432 11853 9853 Blue 57
4 PM Fri 101 106 W 6 12508 11270 9270 Blue 55
5 PM Fri 100 103 NW 10 11354 10330 8330 Blue 52
6 PM Fri 98 99 NW 10 10092 9607 7607 Blue 48
7 PM Fri 95 95 NW 10 9538 9229 7229 Blue 44
8 PM Fri 91 91 NW 10 9149 8414 6414 Blue 40
9 PM Fri 87 87 NW 10 7943 6122 4122 Blue 36
10 PM Fri 82 82 NW 10 5083 2900 900 Blue 31
11 PM Fri 78 78 N 7 2865 2814 814 Blue 27
12 Midnight Sat 74 74 N 7 2798 2747 747 Blue 23
1 AM Sat 71 71 N 7 2748 2681 681 Blue 20
2 AM Sat 69 69 N 7 2711 2622 622 Blue 18
3 AM Sat 68 68 N 7 2682 2496 496 Blue 17
4 AM Sat 68 68 N 7 2682 2496 496 Blue 17
5 AM Sat 69 69 N 6 2711 2622 622 Blue 18
6 AM Sat 72 72 N 6 2765 2710 710 Blue 21
7 AM Sat 75 75 N 6 2815 2764 764 Blue 24
8 AM Sat 79 80 N 6 2971 2847 847 Blue 29
9 AM Sat 84 87 N 6 7943 6122 4122 Blue 36
10 AM Sat 89 94 N 6 9444 9104 7104 Blue 43
11 AM Sat 93 100 W 6 10449 9701 7701 Blue 49
12 Noon Sat 97 105 W 6 12027 11021 9021 Blue 54
1 PM Sat 100 109 W 6 14005 12329 10329 Blue 58
2 PM Sat 102 110 W 6 14357 12794 10794 Blue 59
3 PM Sat 103 110 W 6 14357 12794 10794 Blue 59
4 PM Sat 103 108 W 6 13432 11853 9853 Blue 57
5 PM Sat 102 105 NW 10 12027 11021 9021 Blue 54
6 PM Sat 100 101 NW 10 10838 9796 7796 Blue 50
7 PM Sat 97 97 NW 10 9728 9418 7418 Blue 46
8 PM Sat 93 93 NW 10 9349 8936 6936 Blue 42
9 PM Sat 89 89 NW 10 8809 7232 5232 Blue 38
10 PM Sat 85 85 NW 10 7063 5017 3017 Blue 34
11 PM Sat 82 82 N 6 5083 2900 900 Blue 31
12 Midnight Sun 78 78 N 6 2865 2814 814 Blue 27
1 AM Sun 76 76 N 6 2831 2781 781 Blue 25
2 AM Sun 74 74 N 6 2798 2747 747 Blue 23
3 AM Sun 73 73 N 6 2781 2731 731 Blue 22
4 AM Sun 73 73 N 6 2781 2731 731 Blue 22
5 AM Sun 74 74 NE 5 2798 2747 747 Blue 23
6 AM Sun 76 76 NE 5 2831 2781 781 Blue 25
7 AM Sun 79 79 NE 5 2903 2830 830 Blue 28
8 AM Sun 83 84 NE 5 6183 3289 1289 Blue 33
9 AM Sun 87 90 NE 5 8979 7620 5620 Blue 39
10 AM Sun 91 96 NE 5 9633 9323 7323 Blue 45
11 AM Sun 94 101 W 5 10838 9796 7796 Blue 50
12 Noon Sun 98 106 W 5 12508 11270 9270 Blue 55
1 PM Sun 100 108 W 5 13432 11853 9853 Blue 57
2 PM Sun 102 110 W 5 14357 12794 10794 Blue 59
3 PM Sun 103 110 W 5 14357 12794 10794 Blue 59
4 PM Sun 103 108 W 5 13432 11853 9853 Blue 57
5 PM Sun 102 105 W 7 12027 11021 9021 Blue 54
6 PM Sun 99 100 W 7 10449 9701 7701 Blue 49
7 PM Sun 95 95 W 7 9538 9229 7229 Blue 44
8 PM Sun 91 91 W 7 9149 8414 6414 Blue 40
9 PM Sun 86 86 W 7 7273 5710 3710 Blue 35
10 PM Sun 81 81 W 7 3323 2864 864 Blue 30
11 PM Sun 77 77 NW 7 2848 2797 797 Blue 26
12 Midnight Mon 74 74 NW 7 2798 2747 747 Blue 23
1 AM Mon 71 71 NW 7 2748 2681 681 Blue 20
2 AM Mon 69 69 NW 7 2711 2622 622 Blue 18
3 AM Mon 68 68 NW 7 2682 2496 496 Blue 17
4 AM Mon 68 68 NW 7 2682 2496 496 Blue 17

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