Detailed Predictions for: Lake McClure
Launch Lat, Long, Altitude (f): 37.3803, -120.0769, 2000
LZ Altitude (f): 500
Sounding

Station:

KOAK

Date/Time:

16 SEP 2021

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Wind
Gust
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
12 Midnight Thu 74 74 N 8 8 2552 2482 482 Blue 23
1 AM Thu 72 72 N 3 4 2501 2444 444 Blue 21
2 AM Thu 70 70 N 4 4 2464 2387 387 Blue 19
3 AM Thu 69 69 NW 3 3 2445 2357 357 Blue 18
4 AM Thu 68 68 N 8 8 2417 2334 334 Blue 17
5 AM Thu 67 67 NNW 8 8 2388 2321 321 Blue 16
6 AM Thu 66 66 NNW 8 8 2358 2307 307 Blue 15
7 AM Thu 65 65 N 8 8 2334 2294 294 Blue 14
8 AM Thu 70 70 N 5 5 2464 2387 387 Blue 19
9 AM Thu 76 77 NW 4 5 2725 2549 549 Blue 26
10 AM Thu 78 81 W 5 8 3051 2780 780 Blue 30
11 AM Thu 79 83 W 6 10 3299 2920 920 Blue 32
12 Noon Thu 81 87 W 8 11 3994 3414 1414 Blue 35
1 PM Thu 83 89 W 8 12 4529 3703 1703 Blue 37
2 PM Thu 84 90 W 8 13 5407 3970 1970 Blue 38
3 PM Thu 85 89 W 8 13 4529 3703 1703 Blue 37
4 PM Thu 86 89 W 8 13 4529 3703 1703 Blue 37
5 PM Thu 86 87 W 8 12 3994 3414 1414 Blue 35
6 PM Thu 84 84 WNW 8 11 3423 3044 1044 Blue 32
7 PM Thu 80 80 NW 6 9 2927 2722 722 Blue 29
8 PM Thu 76 76 N 6 6 2667 2519 519 Blue 25
9 PM Thu 74 74 N 6 6 2552 2482 482 Blue 23
10 PM Thu 72 72 N 8 8 2501 2444 444 Blue 21
11 PM Thu 70 70 N 9 9 2464 2387 387 Blue 19
12 Midnight Fri 69 69 NE 8 8 2445 2357 357 Blue 18
1 AM Fri 67 67 NW 1 2 2388 2321 321 Blue 16
2 AM Fri 67 67 N 2 3 2388 2321 321 Blue 16
3 AM Fri 67 67 NNE 2 3 2388 2321 321 Blue 16
4 AM Fri 67 67 NNE 3 3 2388 2321 321 Blue 16
5 AM Fri 66 66 NNE 1 3 2358 2307 307 Blue 15
6 AM Fri 65 65 N 3 4 2334 2294 294 Blue 14
7 AM Fri 64 64 N 4 4 2321 2281 281 Blue 13
8 AM Fri 68 68 ESE 1 3 2417 2334 334 Blue 17
9 AM Fri 75 76 NE 0 5 2667 2519 519 Blue 25
10 AM Fri 78 81 SW 3 8 3051 2780 780 Blue 30
11 AM Fri 79 83 W 6 12 3299 2920 920 Blue 32
12 Noon Fri 82 88 W 6 12 4262 3538 1538 Blue 36
1 PM Fri 84 90 W 6 12 5407 3970 1970 Blue 38
2 PM Fri 85 91 W 8 12 5611 4236 2236 Blue 39
3 PM Fri 86 90 W 8 12 5407 3970 1970 Blue 38
4 PM Fri 87 90 W 8 12 5407 3970 1970 Blue 38
5 PM Fri 87 88 WNW 8 12 4262 3538 1538 Blue 36
6 PM Fri 85 85 WNW 8 12 3547 3167 1167 Blue 33
7 PM Fri 81 81 WNW 8 12 3051 2780 780 Blue 30
8 PM Fri 78 78 NNW 6 6 2783 2607 607 Blue 27
9 PM Fri 75 75 NNW 6 6 2610 2501 501 Blue 24
10 PM Fri 73 73 NNW 6 6 2520 2463 463 Blue 22
11 PM Fri 71 71 NNW 5 5 2483 2416 416 Blue 20
12 Midnight Sat 69 69 NNW 5 5 2445 2357 357 Blue 18
1 AM Sat 68 68 NNW 5 5 2417 2334 334 Blue 17
2 AM Sat 67 67 NNE 3 3 2388 2321 321 Blue 16
3 AM Sat 66 66 NNE 3 3 2358 2307 307 Blue 15
4 AM Sat 66 66 NNE 3 3 2358 2307 307 Blue 15
5 AM Sat 66 66 ENE 2 4 2358 2307 307 Blue 15
6 AM Sat 66 66 ENE 2 4 2358 2307 307 Blue 15
7 AM Sat 67 67 ENE 2 4 2388 2321 321 Blue 16
8 AM Sat 69 69 E 2 3 2445 2357 357 Blue 18
9 AM Sat 71 72 E 2 3 2501 2444 444 Blue 21
10 AM Sat 74 77 E 2 3 2725 2549 549 Blue 26
11 AM Sat 77 81 SW 5 11 3051 2780 780 Blue 30
12 Noon Sat 79 85 SW 5 11 3547 3167 1167 Blue 33
1 PM Sat 81 87 SW 5 11 3994 3414 1414 Blue 35
2 PM Sat 82 88 WSW 6 16 4262 3538 1538 Blue 36
3 PM Sat 83 88 WSW 6 16 4262 3538 1538 Blue 36
4 PM Sat 84 87 WSW 6 16 3994 3414 1414 Blue 35
5 PM Sat 83 84 W 6 14 3423 3044 1044 Blue 32
6 PM Sat 80 80 W 6 14 2927 2722 722 Blue 29
7 PM Sat 77 77 W 6 14 2725 2549 549 Blue 26
8 PM Sat 73 73 NW 4 8 2520 2463 463 Blue 22
9 PM Sat 71 71 NW 4 8 2483 2416 416 Blue 20
10 PM Sat 69 69 NW 4 8 2445 2357 357 Blue 18
11 PM Sat 67 67 NNW 4 5 2388 2321 321 Blue 16
12 Midnight Sun 65 65 NNW 4 5 2334 2294 294 Blue 14
1 AM Sun 64 64 NNW 4 5 2321 2281 281 Blue 13
2 AM Sun 63 63 N 4 5 2308 2268 268 Blue 12
3 AM Sun 62 62 N 4 5 2295 2254 254 Blue 11
4 AM Sun 62 62 N 4 5 2295 2254 254 Blue 11
5 AM Sun 62 62 N 4 6 2295 2254 254 Blue 11
6 AM Sun 62 62 N 4 6 2295 2254 254 Blue 11
7 AM Sun 63 63 N 4 6 2308 2268 268 Blue 12
8 AM Sun 64 64 NW 3 5 2321 2281 281 Blue 13
9 AM Sun 67 68 NW 3 5 2417 2334 334 Blue 17
10 AM Sun 70 73 NW 3 5 2520 2463 463 Blue 22
11 AM Sun 73 77 W 8 12 2725 2549 549 Blue 26
12 Noon Sun 75 80 W 8 12 2927 2722 722 Blue 29
1 PM Sun 76 82 W 8 12 3175 2838 838 Blue 31
2 PM Sun 77 82 W 10 16 3175 2838 838 Blue 31
3 PM Sun 77 81 W 10 16 3051 2780 780 Blue 30
4 PM Sun 77 80 W 10 16 2927 2722 722 Blue 29
5 PM Sun 76 77 WNW 12 19 2725 2549 549 Blue 26
6 PM Sun 74 74 WNW 12 19 2552 2482 482 Blue 23
7 PM Sun 72 72 WNW 12 19 2501 2444 444 Blue 21
8 PM Sun 70 70 NW 8 12 2464 2387 387 Blue 19
9 PM Sun 68 68 NW 8 12 2417 2334 334 Blue 17
10 PM Sun 66 66 NW 8 12 2358 2307 307 Blue 15
11 PM Sun 65 65 NW 6 10 2334 2294 294 Blue 14
12 Midnight Mon 64 64 NW 6 10 2321 2281 281 Blue 13
1 AM Mon 63 63 NW 6 10 2308 2268 268 Blue 12
2 AM Mon 62 62 NNW 6 10 2295 2254 254 Blue 11
3 AM Mon 61 61 NNW 6 10 2281 2241 241 Blue 10
4 AM Mon 61 61 NNW 6 10 2281 2241 241 Blue 10
5 AM Mon 61 61 NNW 5 9 2281 2241 241 Blue 10
6 AM Mon 61 61 NNW 5 9 2281 2241 241 Blue 10
7 AM Mon 61 61 NNW 5 9 2281 2241 241 Blue 10
8 AM Mon 62 62 NW 3 6 2295 2254 254 Blue 11
9 AM Mon 65 66 NW 3 6 2358 2307 307 Blue 15
10 AM Mon 68 71 NW 3 6 2483 2416 416 Blue 20
11 AM Mon 71 75 W 6 13 2610 2501 501 Blue 24
12 Noon Mon 73 79 W 6 13 2841 2665 665 Blue 28
1 PM Mon 75 81 W 6 13 3051 2780 780 Blue 30
2 PM Mon 77 83 W 6 14 3299 2920 920 Blue 32
3 PM Mon 79 84 W 6 14 3423 3044 1044 Blue 32
4 PM Mon 80 83 W 6 14 3299 2920 920 Blue 32
5 PM Mon 80 81 WNW 8 13 3051 2780 780 Blue 30
6 PM Mon 78 78 WNW 8 13 2783 2607 607 Blue 27
7 PM Mon 75 75 WNW 8 13 2610 2501 501 Blue 24
8 PM Mon 72 72 NNW 3 6 2501 2444 444 Blue 21
9 PM Mon 70 70 NNW 3 6 2464 2387 387 Blue 19
10 PM Mon 68 68 NNW 3 6 2417 2334 334 Blue 17
11 PM Mon 67 67 NNE 2 3 2388 2321 321 Blue 16
12 Midnight Tue 66 66 NNE 2 3 2358 2307 307 Blue 15
1 AM Tue 65 65 NNE 2 3 2334 2294 294 Blue 14
2 AM Tue 65 65 NE 2 3 2334 2294 294 Blue 14
3 AM Tue 65 65 NE 2 3 2334 2294 294 Blue 14
4 AM Tue 65 65 NE 2 3 2334 2294 294 Blue 14
5 AM Tue 65 65 NE 3 3 2334 2294 294 Blue 14
6 AM Tue 65 65 NE 3 3 2334 2294 294 Blue 14
7 AM Tue 66 66 NE 3 3 2358 2307 307 Blue 15
8 AM Tue 68 68 ENE 2 3 2417 2334 334 Blue 17
9 AM Tue 72 73 ENE 2 3 2520 2463 463 Blue 22
10 AM Tue 76 78 ENE 2 3 2783 2607 607 Blue 27
11 AM Tue 80 84 SSW 4 9 3423 3044 1044 Blue 32
12 Noon Tue 82 87 SSW 4 9 3994 3414 1414 Blue 35
1 PM Tue 84 90 SSW 4 9 5407 3970 1970 Blue 38
2 PM Tue 85 90 SW 5 12 5407 3970 1970 Blue 38
3 PM Tue 87 91 SW 5 12 5611 4236 2236 Blue 39
4 PM Tue 87 90 SW 5 12 5407 3970 1970 Blue 38
5 PM Tue 87 88 W 5 12 4262 3538 1538 Blue 36
6 PM Tue 85 85 W 5 12 3547 3167 1167 Blue 33
7 PM Tue 81 81 W 5 12 3051 2780 780 Blue 30
8 PM Tue 78 78 N 3 3 2783 2607 607 Blue 27
9 PM Tue 75 75 N 3 3 2610 2501 501 Blue 24
10 PM Tue 73 73 N 3 3 2520 2463 463 Blue 22

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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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