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

Station:

 KOAK

Date/Time UTC:

 260912/1200

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 Sat 70 68 W 6 10 2589 3400 0 Blue 0
1 AM Sat 70 68 W 6 10 2589 3400 0 Blue 0
2 AM Sat 69 67 W 5 9 2526 3400 0 Blue 0
3 AM Sat 68 66 W 5 9 2526 3400 0 Blue 0
4 AM Sat 66 64 W 4 6 2526 3400 0 Blue 0
5 AM Sat 65 63 W 3 5 2526 3400 0 Blue 0
6 AM Sat 64 62 W 3 5 2526 3400 0 Blue 0
7 AM Sat 63 61 W 2 4 2526 3400 0 Blue 0
8 AM Sat 64 62 WSW 2 4 2526 3400 0 Blue 0
9 AM Sat 67 66 SW 2 4 2526 3400 0 Blue 0
10 AM Sat 72 72 SW 4 8 3151 3400 0 Blue 1
11 AM Sat 74 76 SW 5 11 3758 3400 0 Blue 5
12 Noon Sat 76 79 SW 9 18 4123 3755 355 Blue 8
1 PM Sat 77 81 WSW 11 24 4255 3975 575 Blue 10
2 PM Sat 77 80 WSW 13 27 4183 3839 439 Blue 9
3 PM Sat 78 80 WSW 16 29 4183 3839 439 Blue 9
4 PM Sat 75 75 WSW 17 32 3674 3400 0 Blue 4
5 PM Sat 73 72 WSW 18 35 3151 3400 0 Blue 1
6 PM Sat 69 67 W 19 36 2526 3400 0 Blue 0
7 PM Sat 62 60 W 19 35 2526 3400 0 Blue 0
8 PM Sat 59 57 W 17 32 2526 3400 0 Blue 0
9 PM Sat 57 55 W 19 34 2526 3400 0 Blue 0
10 PM Sat 57 55 W 18 33 2526 3400 0 Blue 0
11 PM Sat 56 54 W 16 31 2526 3400 0 Blue 0
12 Midnight Sun 55 53 W 14 27 2526 3400 0 Blue 0
1 AM Sun 55 53 W 12 24 2526 3400 0 Blue 0
2 AM Sun 54 52 W 9 17 2526 3400 0 Blue 0
3 AM Sun 53 51 W 8 12 2526 3400 0 Blue 0
4 AM Sun 52 50 WSW 4 10 2526 3400 0 Blue 0
5 AM Sun 51 49 W 2 6 2526 3400 0 Blue 0
6 AM Sun 50 48 W 2 6 2526 3400 0 Blue 0
7 AM Sun 50 48 W 2 6 2526 3400 0 Blue 0
8 AM Sun 52 50 N 3 5 2526 3400 0 Blue 0
9 AM Sun 56 55 N 3 5 2526 3400 0 Blue 0
10 AM Sun 61 62 N 3 5 2526 3400 0 Blue 0
11 AM Sun 62 64 E 4 11 2526 3400 0 Blue 0
12 Noon Sun 65 68 E 4 11 2589 3400 0 Blue 0
1 PM Sun 68 72 E 4 11 3151 3400 0 Blue 1
2 PM Sun 69 71 E 3 11 2990 3400 0 Blue 0
3 PM Sun 71 73 E 3 11 3334 3400 0 Blue 2
4 PM Sun 71 71 E 3 11 2990 3400 0 Blue 0
5 PM Sun 69 68 ENE 3 9 2589 3400 0 Blue 0
6 PM Sun 67 65 ENE 3 9 2526 3400 0 Blue 0
7 PM Sun 63 61 ENE 3 9 2526 3400 0 Blue 0
8 PM Sun 60 58 NW 2 5 2526 3400 0 Blue 0
9 PM Sun 59 57 NW 2 5 2526 3400 0 Blue 0
10 PM Sun 60 58 NW 2 5 2526 3400 0 Blue 0
11 PM Sun 61 59 NW 4 8 2526 3400 0 Blue 0
12 Midnight Mon 61 59 NW 4 8 2526 3400 0 Blue 0
1 AM Mon 60 58 NW 4 8 2526 3400 0 Blue 0
2 AM Mon 59 57 NW 6 14 2526 3400 0 Blue 0
3 AM Mon 58 56 NW 6 14 2526 3400 0 Blue 0
4 AM Mon 58 56 NW 6 14 2526 3400 0 Blue 0
5 AM Mon 57 55 NW 4 10 2526 3400 0 Blue 0
6 AM Mon 57 55 NW 4 10 2526 3400 0 Blue 0
7 AM Mon 57 55 NW 4 10 2526 3400 0 Blue 0
8 AM Mon 58 56 NW 4 9 2526 3400 0 Blue 0
9 AM Mon 62 61 NW 4 9 2526 3400 0 Blue 0
10 AM Mon 67 68 NW 4 9 2589 3400 0 Blue 0
11 AM Mon 71 73 NE 4 9 3334 3400 0 Blue 2
12 Noon Mon 74 77 NE 4 9 3841 3513 113 Blue 6
1 PM Mon 77 81 NE 4 9 4255 3975 575 Blue 10
2 PM Mon 78 82 ESE 3 10 4333 4120 720 Blue 11
3 PM Mon 79 82 ESE 3 10 4333 4120 720 Blue 11
4 PM Mon 79 80 ESE 3 10 4183 3839 439 Blue 9
5 PM Mon 78 78 SSE 2 6 3982 3672 272 Blue 7
6 PM Mon 74 72 SSE 2 6 3151 3400 0 Blue 1
7 PM Mon 69 67 SSE 2 6 2526 3400 0 Blue 0
8 PM Mon 66 64 W 2 4 2526 3400 0 Blue 0
9 PM Mon 65 63 W 2 4 2526 3400 0 Blue 0
10 PM Mon 65 63 W 2 4 2526 3400 0 Blue 0
11 PM Mon 65 63 WNW 2 5 2526 3400 0 Blue 0
12 Midnight Tue 65 63 WNW 2 5 2526 3400 0 Blue 0
1 AM Tue 64 62 WNW 2 5 2526 3400 0 Blue 0
2 AM Tue 63 61 WNW 2 4 2526 3400 0 Blue 0
3 AM Tue 62 60 WNW 2 4 2526 3400 0 Blue 0
4 AM Tue 61 59 WNW 2 4 2526 3400 0 Blue 0
5 AM Tue 60 58 NNW 1 3 2526 3400 0 Blue 0
6 AM Tue 59 57 NNW 1 3 2526 3400 0 Blue 0
7 AM Tue 59 57 NNW 1 3 2526 3400 0 Blue 0
8 AM Tue 60 58 N 1 3 2526 3400 0 Blue 0
9 AM Tue 64 63 N 1 3 2526 3400 0 Blue 0
10 AM Tue 68 68 N 1 3 2589 3400 0 Blue 0
11 AM Tue 73 75 E 4 8 3674 3400 0 Blue 4
12 Noon Tue 75 78 E 4 8 3982 3672 272 Blue 7
1 PM Tue 77 81 E 4 8 4255 3975 575 Blue 10
2 PM Tue 78 82 SE 4 11 4333 4120 720 Blue 11
3 PM Tue 79 82 SE 4 11 4333 4120 720 Blue 11
4 PM Tue 80 81 SE 4 11 4255 3975 575 Blue 10
5 PM Tue 79 78 S 5 10 3982 3672 272 Blue 7
6 PM Tue 74 72 S 5 10 3151 3400 0 Blue 1
7 PM Tue 70 68 S 5 10 2589 3400 0 Blue 0
8 PM Tue 67 65 WSW 1 4 2526 3400 0 Blue 0
9 PM Tue 66 64 WSW 1 4 2526 3400 0 Blue 0
10 PM Tue 66 64 WSW 1 4 2526 3400 0 Blue 0
11 PM Tue 66 64 W 2 5 2526 3400 0 Blue 0
12 Midnight Wed 65 63 W 2 5 2526 3400 0 Blue 0
1 AM Wed 65 63 W 2 5 2526 3400 0 Blue 0
2 AM Wed 64 62 NW 1 4 2526 3400 0 Blue 0
3 AM Wed 63 61 NW 1 4 2526 3400 0 Blue 0
4 AM Wed 63 61 NW 1 4 2526 3400 0 Blue 0
5 AM Wed 62 60 NNW 1 4 2526 3400 0 Blue 0
6 AM Wed 61 59 NNW 1 4 2526 3400 0 Blue 0
7 AM Wed 60 58 NNW 1 4 2526 3400 0 Blue 0
8 AM Wed 61 59 N 2 4 2526 3400 0 Blue 0
9 AM Wed 64 63 N 2 4 2526 3400 0 Blue 0
10 AM Wed 68 68 N 2 4 2589 3400 0 Blue 0
11 AM Wed 72 74 E 5 9 3517 3400 0 Blue 3
12 Noon Wed 75 78 E 5 9 3982 3672 272 Blue 7
1 PM Wed 77 81 E 5 9 4255 3975 575 Blue 10
2 PM Wed 78 82 ESE 4 9 4333 4120 720 Blue 11
3 PM Wed 79 82 ESE 4 9 4333 4120 720 Blue 11
4 PM Wed 79 80 ESE 4 9 4183 3839 439 Blue 9
5 PM Wed 78 78 SE 3 6 3982 3672 272 Blue 7
6 PM Wed 74 72 SE 3 6 3151 3400 0 Blue 1
7 PM Wed 70 68 SE 3 6 2589 3400 0 Blue 0
8 PM Wed 66 64 W 1 3 2526 3400 0 Blue 0
9 PM Wed 65 63 W 1 3 2526 3400 0 Blue 0
10 PM Wed 66 64 W 1 3 2526 3400 0 Blue 0
11 PM Wed 66 64 WNW 1 4 2526 3400 0 Blue 0
12 Midnight Thu 65 63 WNW 1 4 2526 3400 0 Blue 0
1 AM Thu 65 63 WNW 1 4 2526 3400 0 Blue 0
2 AM Thu 64 62 NW 1 4 2526 3400 0 Blue 0
3 AM Thu 63 61 NW 1 4 2526 3400 0 Blue 0
4 AM Thu 63 61 NW 1 4 2526 3400 0 Blue 0
5 AM Thu 62 60 N 0 3 2526 3400 0 Blue 0
6 AM Thu 61 59 N 0 3 2526 3400 0 Blue 0
7 AM Thu 61 59 N 0 3 2526 3400 0 Blue 0
8 AM Thu 62 60 N 1 3 2526 3400 0 Blue 0
9 AM Thu 65 64 N 1 3 2526 3400 0 Blue 0
10 AM Thu 69 69 N 1 3 2723 3400 0 Blue 0
11 AM Thu 73 75 E 5 9 3674 3400 0 Blue 4
12 Noon Thu 76 79 E 5 9 4123 3755 355 Blue 8
1 PM Thu 79 83 E 5 9 4455 4180 780 Blue 12
2 PM Thu 80 83 SE 5 11 4455 4180 780 Blue 12
3 PM Thu 81 83 SE 5 11 4455 4180 780 Blue 12
4 PM Thu 80 81 SE 5 11 4255 3975 575 Blue 10
5 PM Thu 78 77 SSE 4 9 3841 3513 113 Blue 6
6 PM Thu 75 73 SSE 4 9 3334 3400 0 Blue 2
7 PM Thu 70 68 SSE 4 9 2589 3400 0 Blue 0
8 PM Thu 67 65 WSW 2 5 2526 3400 0 Blue 0
9 PM Thu 66 64 WSW 2 5 2526 3400 0 Blue 0
10 PM Thu 66 64 WSW 2 5 2526 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]