Detailed Predictions for: Potato Hill
Launch Lat, Long, Altitude (f): 39.34098, -122.69, 3400
LZ Altitude (f): 1700
Sounding

Station:

KOAK

Date/Time:

20 JUN 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 Sun 80 78 W 5 9 2431 3400 0 Blue 0
1 AM Sun 80 78 W 5 9 2431 3400 0 Blue 0
2 AM Sun 79 77 NW 4 6 2431 3400 0 Blue 0
3 AM Sun 78 76 NW 4 6 2431 3400 0 Blue 0
4 AM Sun 77 75 NW 4 6 2431 3400 0 Blue 0
5 AM Sun 75 73 WNW 2 3 2431 3400 0 Blue 0
6 AM Sun 75 73 WNW 2 3 2431 3400 0 Blue 0
7 AM Sun 78 76 WNW 2 3 2431 3400 0 Blue 0
8 AM Sun 84 83 ENE 5 9 2971 3400 0 Blue 0
9 AM Sun 88 89 ENE 5 9 4301 3582 182 Blue 5
10 AM Sun 91 94 ENE 5 9 6407 4758 1358 Blue 10
11 AM Sun 93 98 E 8 12 14804 7407 4007 Blue 14
12 Noon Sun 97 103 E 8 12 15593 15106 11706 Blue 19
1 PM Sun 99 106 E 8 12 16022 15533 12133 Blue 22
2 PM Sun 102 108 SE 12 19 16306 15817 12417 Blue 24
3 PM Sun 103 108 SE 12 19 16306 15817 12417 Blue 24
4 PM Sun 103 106 SE 12 19 16022 15533 12133 Blue 22
5 PM Sun 102 103 SSW 13 20 15593 15106 11706 Blue 19
6 PM Sun 98 98 SSW 13 20 14804 7407 4007 Blue 14
7 PM Sun 89 87 SSW 13 20 3826 3400 0 Blue 3
8 PM Sun 86 84 WSW 10 16 3108 3400 0 Blue 0
9 PM Sun 81 79 WSW 10 16 2446 3400 0 Blue 0
10 PM Sun 79 77 WSW 10 16 2431 3400 0 Blue 0
11 PM Sun 76 74 W 6 10 2431 3400 0 Blue 0
12 Midnight Mon 74 72 W 6 10 2431 3400 0 Blue 0
1 AM Mon 74 72 W 6 10 2431 3400 0 Blue 0
2 AM Mon 73 71 WNW 4 6 2431 3400 0 Blue 0
3 AM Mon 72 70 WNW 4 6 2431 3400 0 Blue 0
4 AM Mon 72 70 WNW 4 6 2431 3400 0 Blue 0
5 AM Mon 71 69 NNE 2 3 2431 3400 0 Blue 0
6 AM Mon 71 69 NNE 2 3 2431 3400 0 Blue 0
7 AM Mon 76 74 NNE 2 3 2431 3400 0 Blue 0
8 AM Mon 79 78 ENE 4 6 2431 3400 0 Blue 0
9 AM Mon 83 83 ENE 4 6 2971 3400 0 Blue 0
10 AM Mon 84 86 ENE 4 6 3588 3400 0 Blue 2
11 AM Mon 86 89 E 8 12 4301 3582 182 Blue 5
12 Noon Mon 89 94 E 8 12 6407 4758 1358 Blue 10
1 PM Mon 92 97 E 8 12 10051 6236 2836 Blue 13
2 PM Mon 94 100 SE 13 20 15165 9851 6451 Blue 16
3 PM Mon 96 100 SE 13 20 15165 9851 6451 Blue 16
4 PM Mon 96 99 SE 13 20 15022 7887 4487 Blue 15
5 PM Mon 94 95 SSW 13 20 7479 5245 1845 Blue 11
6 PM Mon 90 90 SSW 13 20 4537 3819 419 Blue 6
7 PM Mon 85 83 SSW 13 20 2971 3400 0 Blue 0
8 PM Mon 80 78 SW 10 16 2431 3400 0 Blue 0
9 PM Mon 76 74 SW 10 16 2431 3400 0 Blue 0
10 PM Mon 74 72 SW 10 16 2431 3400 0 Blue 0
11 PM Mon 72 70 WSW 8 12 2431 3400 0 Blue 0
12 Midnight Tue 71 69 WSW 8 12 2431 3400 0 Blue 0
1 AM Tue 71 69 WSW 8 12 2431 3400 0 Blue 0
2 AM Tue 69 67 W 4 6 2431 3400 0 Blue 0
3 AM Tue 67 65 W 4 6 2431 3400 0 Blue 0
4 AM Tue 65 63 W 4 6 2431 3400 0 Blue 0
5 AM Tue 65 63 ENE 4 6 2431 3400 0 Blue 0
6 AM Tue 67 65 ENE 4 6 2431 3400 0 Blue 0
7 AM Tue 70 68 ENE 4 6 2431 3400 0 Blue 0
8 AM Tue 74 73 E 5 9 2431 3400 0 Blue 0
9 AM Tue 76 77 E 5 9 2431 3400 0 Blue 0
10 AM Tue 78 81 E 5 9 2708 3400 0 Blue 0
11 AM Tue 80 85 ESE 9 13 3349 3400 0 Blue 1
12 Noon Tue 82 88 ESE 9 13 4064 3400 0 Blue 4
1 PM Tue 84 91 ESE 9 13 4784 4055 655 Blue 7
2 PM Tue 86 92 SE 10 16 5282 4290 890 Blue 8
3 PM Tue 88 93 SE 10 16 5759 4524 1124 Blue 9
4 PM Tue 88 91 SE 10 16 4784 4055 655 Blue 7
5 PM Tue 86 87 S 11 17 3826 3400 0 Blue 3
6 PM Tue 83 83 S 11 17 2971 3400 0 Blue 0
7 PM Tue 78 76 S 11 17 2431 3400 0 Blue 0
8 PM Tue 73 71 SSW 10 16 2431 3400 0 Blue 0
9 PM Tue 69 67 SSW 10 16 2431 3400 0 Blue 0
10 PM Tue 67 65 SSW 10 16 2431 3400 0 Blue 0
11 PM Tue 65 63 WSW 6 10 2431 3400 0 Blue 0
12 Midnight Wed 65 63 WSW 6 10 2431 3400 0 Blue 0
1 AM Wed 65 63 WSW 6 10 2431 3400 0 Blue 0
2 AM Wed 64 62 WSW 4 6 2431 3400 0 Blue 0
3 AM Wed 63 61 WSW 4 6 2431 3400 0 Blue 0
4 AM Wed 61 59 WSW 4 6 2431 3400 0 Blue 0
5 AM Wed 61 59 NNE 4 6 2431 3400 0 Blue 0
6 AM Wed 63 61 NNE 4 6 2431 3400 0 Blue 0
7 AM Wed 66 64 NNE 4 6 2431 3400 0 Blue 0
8 AM Wed 70 69 E 5 9 2431 3400 0 Blue 0
9 AM Wed 72 73 E 5 9 2431 3400 0 Blue 0
10 AM Wed 73 76 E 5 9 2431 3400 0 Blue 0
11 AM Wed 75 80 ESE 8 12 2577 3400 0 Blue 0
12 Noon Wed 78 84 ESE 8 12 3108 3400 0 Blue 0
1 PM Wed 81 88 ESE 8 12 4064 3400 0 Blue 4
2 PM Wed 84 90 SE 9 13 4537 3819 419 Blue 6
3 PM Wed 85 90 SE 9 13 4537 3819 419 Blue 6
4 PM Wed 86 89 SE 9 13 4301 3582 182 Blue 5
5 PM Wed 85 86 S 9 13 3588 3400 0 Blue 2
6 PM Wed 81 81 S 9 13 2708 3400 0 Blue 0
7 PM Wed 77 75 S 9 13 2431 3400 0 Blue 0
8 PM Wed 73 71 SW 9 13 2431 3400 0 Blue 0
9 PM Wed 70 68 SW 9 13 2431 3400 0 Blue 0
10 PM Wed 68 66 SW 9 13 2431 3400 0 Blue 0
11 PM Wed 68 66 W 5 9 2431 3400 0 Blue 0
12 Midnight Thu 67 65 W 5 9 2431 3400 0 Blue 0
1 AM Thu 67 65 W 5 9 2431 3400 0 Blue 0
2 AM Thu 67 65 NW 5 9 2431 3400 0 Blue 0
3 AM Thu 65 63 NW 5 9 2431 3400 0 Blue 0
4 AM Thu 64 62 NW 5 9 2431 3400 0 Blue 0
5 AM Thu 64 62 NNW 5 6 2431 3400 0 Blue 0
6 AM Thu 67 65 NNW 5 6 2431 3400 0 Blue 0
7 AM Thu 72 70 NNW 5 6 2431 3400 0 Blue 0
8 AM Thu 76 75 NNE 4 8 2431 3400 0 Blue 0
9 AM Thu 79 80 NNE 4 8 2577 3400 0 Blue 0
10 AM Thu 82 85 NNE 4 8 3349 3400 0 Blue 1
11 AM Thu 84 88 E 8 11 4064 3400 0 Blue 4
12 Noon Thu 87 93 E 8 11 5759 4524 1124 Blue 9
1 PM Thu 90 96 E 8 11 7965 5716 2316 Blue 12
2 PM Thu 92 98 ESE 9 13 14804 7407 4007 Blue 14
3 PM Thu 93 98 ESE 9 13 14804 7407 4007 Blue 14
4 PM Thu 94 97 ESE 9 13 10051 6236 2836 Blue 13
5 PM Thu 93 94 SSW 9 14 6407 4758 1358 Blue 10
6 PM Thu 90 90 SSW 9 14 4537 3819 419 Blue 6
7 PM Thu 86 84 SSW 9 14 3108 3400 0 Blue 0
8 PM Thu 82 80 W 9 13 2577 3400 0 Blue 0
9 PM Thu 79 77 W 9 13 2431 3400 0 Blue 0
10 PM Thu 76 74 W 9 13 2431 3400 0 Blue 0
11 PM Thu 75 73 WNW 6 11 2431 3400 0 Blue 0
12 Midnight Fri 74 72 WNW 6 11 2431 3400 0 Blue 0
1 AM Fri 74 72 WNW 6 11 2431 3400 0 Blue 0
2 AM Fri 74 72 NNW 6 9 2431 3400 0 Blue 0
3 AM Fri 73 71 NNW 6 9 2431 3400 0 Blue 0
4 AM Fri 72 70 NNW 6 9 2431 3400 0 Blue 0
5 AM Fri 73 71 N 6 9 2431 3400 0 Blue 0
6 AM Fri 76 74 N 6 9 2431 3400 0 Blue 0
7 AM Fri 80 78 N 6 9 2431 3400 0 Blue 0
8 AM Fri 85 84 NNE 6 10 3108 3400 0 Blue 0
9 AM Fri 88 89 NNE 6 10 4301 3582 182 Blue 5
10 AM Fri 90 93 NNE 6 10 5759 4524 1124 Blue 9
11 AM Fri 93 98 ENE 9 14 14804 7407 4007 Blue 14
12 Noon Fri 95 101 ENE 9 14 15307 14671 11271 Blue 17
1 PM Fri 97 104 ENE 9 14 15736 15248 11848 Blue 20
2 PM Fri 99 105 E 10 18 15879 15390 11990 Blue 21
3 PM Fri 101 106 E 10 18 16022 15533 12133 Blue 22
4 PM Fri 101 104 E 10 18 15736 15248 11848 Blue 20
5 PM Fri 99 100 S 10 17 15165 9851 6451 Blue 16
6 PM Fri 95 94 S 10 17 6407 4758 1358 Blue 10
7 PM Fri 90 88 S 10 17 4064 3400 0 Blue 4
8 PM Fri 86 84 WSW 10 16 3108 3400 0 Blue 0
9 PM Fri 82 80 WSW 10 16 2577 3400 0 Blue 0
10 PM Fri 80 78 WSW 10 16 2431 3400 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 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 [email protected]