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

Station:

KOAK

Date/Time:

12 MAY 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 Wed 66 64 W 5 8 2566 3400 0 Blue 0
1 AM Wed 66 64 W 5 8 2566 3400 0 Blue 0
2 AM Wed 65 63 NW 2 4 2566 3400 0 Blue 0
3 AM Wed 65 63 NW 2 4 2566 3400 0 Blue 0
4 AM Wed 64 62 NW 2 4 2566 3400 0 Blue 0
5 AM Wed 63 61 W 3 3 2566 3400 0 Blue 0
6 AM Wed 63 61 W 3 3 2566 3400 0 Blue 0
7 AM Wed 66 64 W 3 3 2566 3400 0 Blue 0
8 AM Wed 73 72 NW 3 3 2794 3400 0 Blue 0
9 AM Wed 79 80 NW 3 3 7146 5526 2126 Blue 4
10 AM Wed 81 83 NW 3 3 9111 6981 3581 Blue 7
11 AM Wed 82 86 E 6 9 10134 9005 5605 Blue 10
12 Noon Wed 85 90 E 6 9 13265 10765 7365 Blue 14
1 PM Wed 88 94 E 6 9 15378 13688 10288 Blue 18
2 PM Wed 90 94 SE 11 16 15378 13688 10288 Blue 18
3 PM Wed 90 93 SE 11 16 15039 13027 9627 Blue 17
4 PM Wed 90 92 SE 11 16 14558 12326 8926 Blue 16
5 PM Wed 88 88 S 10 14 11807 9366 5966 Blue 12
6 PM Wed 82 81 S 10 14 8228 5805 2405 Blue 5
7 PM Wed 77 75 S 10 14 3804 3400 0 Blue 0
8 PM Wed 74 72 S 8 11 2794 3400 0 Blue 0
9 PM Wed 72 70 S 8 11 2566 3400 0 Blue 0
10 PM Wed 69 67 S 8 11 2566 3400 0 Blue 0
11 PM Wed 68 66 WSW 4 4 2566 3400 0 Blue 0
12 Midnight Thu 67 65 WSW 4 4 2566 3400 0 Blue 0
1 AM Thu 66 64 WSW 4 4 2566 3400 0 Blue 0
2 AM Thu 65 63 W 2 2 2566 3400 0 Blue 0
3 AM Thu 65 63 W 2 2 2566 3400 0 Blue 0
4 AM Thu 64 62 W 2 2 2566 3400 0 Blue 0
5 AM Thu 63 61 WNW 2 2 2566 3400 0 Blue 0
6 AM Thu 63 61 WNW 2 2 2566 3400 0 Blue 0
7 AM Thu 66 64 WNW 2 2 2566 3400 0 Blue 0
8 AM Thu 74 73 N 2 2 3134 3400 0 Blue 0
9 AM Thu 77 77 N 2 2 5551 3463 63 Blue 1
10 AM Thu 80 82 N 2 2 8583 6083 2683 Blue 6
11 AM Thu 81 85 E 6 9 9387 8492 5092 Blue 9
12 Noon Thu 84 89 E 6 9 12560 9960 6560 Blue 13
1 PM Thu 87 93 E 6 9 15039 13027 9627 Blue 17
2 PM Thu 89 95 ESE 12 17 15713 14316 10916 Blue 19
3 PM Thu 90 94 ESE 12 17 15378 13688 10288 Blue 18
4 PM Thu 90 93 ESE 12 17 15039 13027 9627 Blue 17
5 PM Thu 89 90 S 8 11 13265 10765 7365 Blue 14
6 PM Thu 85 84 S 8 11 9286 8077 4677 Blue 8
7 PM Thu 80 78 S 8 11 5833 3793 393 Blue 2
8 PM Thu 76 74 ESE 6 9 3470 3400 0 Blue 0
9 PM Thu 72 70 ESE 6 9 2566 3400 0 Blue 0
10 PM Thu 70 68 ESE 6 9 2566 3400 0 Blue 0
11 PM Thu 68 66 ESE 5 8 2566 3400 0 Blue 0
12 Midnight Fri 67 65 ESE 5 8 2566 3400 0 Blue 0
1 AM Fri 66 64 ESE 5 8 2566 3400 0 Blue 0
2 AM Fri 65 63 E 4 4 2566 3400 0 Blue 0
3 AM Fri 63 61 E 4 4 2566 3400 0 Blue 0
4 AM Fri 62 60 E 4 4 2566 3400 0 Blue 0
5 AM Fri 62 60 N 3 3 2566 3400 0 Blue 0
6 AM Fri 64 62 N 3 3 2566 3400 0 Blue 0
7 AM Fri 67 65 N 3 3 2566 3400 0 Blue 0
8 AM Fri 70 69 E 2 2 2566 3400 0 Blue 0
9 AM Fri 73 73 E 2 2 3134 3400 0 Blue 0
10 AM Fri 76 77 E 2 2 5551 3463 63 Blue 1
11 AM Fri 78 81 E 6 9 8228 5805 2405 Blue 5
12 Noon Fri 81 85 E 6 9 9387 8492 5092 Blue 9
1 PM Fri 83 88 E 6 9 11807 9366 5966 Blue 12
2 PM Fri 85 89 E 8 11 12560 9960 6560 Blue 13
3 PM Fri 86 89 E 8 11 12560 9960 6560 Blue 13
4 PM Fri 85 87 E 8 11 10992 9265 5865 Blue 11
5 PM Fri 83 83 E 8 11 9111 6981 3581 Blue 7
6 PM Fri 79 78 E 8 11 5833 3793 393 Blue 2
7 PM Fri 75 73 E 8 11 3134 3400 0 Blue 0
8 PM Fri 70 68 NW 8 11 2566 3400 0 Blue 0
9 PM Fri 67 65 NW 8 11 2566 3400 0 Blue 0
10 PM Fri 64 62 NW 8 11 2566 3400 0 Blue 0
11 PM Fri 63 61 N 6 9 2566 3400 0 Blue 0
12 Midnight Sat 62 60 N 6 9 2566 3400 0 Blue 0
1 AM Sat 61 59 N 6 9 2566 3400 0 Blue 0
2 AM Sat 60 58 N 5 8 2566 3400 0 Blue 0
3 AM Sat 59 57 N 5 8 2566 3400 0 Blue 0
4 AM Sat 58 56 N 5 8 2566 3400 0 Blue 0
5 AM Sat 58 56 N 4 4 2566 3400 0 Blue 0
6 AM Sat 60 58 N 4 4 2566 3400 0 Blue 0
7 AM Sat 63 61 N 4 4 2566 3400 0 Blue 0
8 AM Sat 66 65 NNE 6 9 2566 3400 0 Blue 0
9 AM Sat 69 70 NNE 6 9 2566 3400 0 Blue 0
10 AM Sat 72 74 NNE 6 9 3470 3400 0 Blue 0
11 AM Sat 75 79 NE 10 14 6113 4792 1392 Blue 3
12 Noon Sat 78 83 NE 10 14 9111 6981 3581 Blue 7
1 PM Sat 81 87 NE 10 14 10992 9265 5865 Blue 11
2 PM Sat 83 88 NE 10 14 11807 9366 5966 Blue 12
3 PM Sat 84 87 NE 10 14 10992 9265 5865 Blue 11
4 PM Sat 84 86 NE 10 14 10134 9005 5605 Blue 10
5 PM Sat 82 82 NE 9 12 8583 6083 2683 Blue 6
6 PM Sat 79 78 NE 9 12 5833 3793 393 Blue 2
7 PM Sat 75 73 NE 9 12 3134 3400 0 Blue 0
8 PM Sat 72 70 NNW 5 8 2566 3400 0 Blue 0
9 PM Sat 69 67 NNW 5 8 2566 3400 0 Blue 0
10 PM Sat 67 65 NNW 5 8 2566 3400 0 Blue 0
11 PM Sat 66 64 NNW 6 9 2566 3400 0 Blue 0
12 Midnight Sun 65 63 NNW 6 9 2566 3400 0 Blue 0
1 AM Sun 64 62 NNW 6 9 2566 3400 0 Blue 0
2 AM Sun 63 61 NNW 6 9 2566 3400 0 Blue 0
3 AM Sun 61 59 NNW 6 9 2566 3400 0 Blue 0
4 AM Sun 59 57 NNW 6 9 2566 3400 0 Blue 0
5 AM Sun 59 57 NNE 5 9 2566 3400 0 Blue 0
6 AM Sun 62 60 NNE 5 9 2566 3400 0 Blue 0
7 AM Sun 66 64 NNE 5 9 2566 3400 0 Blue 0
8 AM Sun 70 69 NE 5 9 2566 3400 0 Blue 0
9 AM Sun 74 74 NE 5 9 3470 3400 0 Blue 0
10 AM Sun 77 79 NE 5 9 6113 4792 1392 Blue 3
11 AM Sun 79 83 E 5 9 9111 6981 3581 Blue 7
12 Noon Sun 82 87 E 5 9 10992 9265 5865 Blue 11
1 PM Sun 85 91 E 5 9 13928 11576 8176 Blue 15
2 PM Sun 87 92 SE 8 12 14558 12326 8926 Blue 16
3 PM Sun 88 92 SE 8 12 14558 12326 8926 Blue 16
4 PM Sun 87 89 SE 8 12 12560 9960 6560 Blue 13
5 PM Sun 85 86 WSW 8 12 10134 9005 5605 Blue 10
6 PM Sun 82 81 WSW 8 12 8228 5805 2405 Blue 5
7 PM Sun 77 75 WSW 8 12 3804 3400 0 Blue 0
8 PM Sun 73 71 W 5 9 2566 3400 0 Blue 0
9 PM Sun 70 68 W 5 9 2566 3400 0 Blue 0
10 PM Sun 67 65 W 5 9 2566 3400 0 Blue 0
11 PM Sun 65 63 WSW 5 9 2566 3400 0 Blue 0
12 Midnight Mon 64 62 WSW 5 9 2566 3400 0 Blue 0
1 AM Mon 62 60 WSW 5 9 2566 3400 0 Blue 0
2 AM Mon 61 59 NW 5 9 2566 3400 0 Blue 0
3 AM Mon 58 56 NW 5 9 2566 3400 0 Blue 0
4 AM Mon 57 55 NW 5 9 2566 3400 0 Blue 0
5 AM Mon 56 54 NNW 3 5 2566 3400 0 Blue 0
6 AM Mon 58 56 NNW 3 5 2566 3400 0 Blue 0
7 AM Mon 61 59 NNW 3 5 2566 3400 0 Blue 0
8 AM Mon 65 64 NE 4 6 2566 3400 0 Blue 0
9 AM Mon 68 69 NE 4 6 2566 3400 0 Blue 0
10 AM Mon 71 73 NE 4 6 3134 3400 0 Blue 0
11 AM Mon 74 78 S 5 9 5833 3793 393 Blue 2
12 Noon Mon 78 84 S 5 9 9286 8077 4677 Blue 8
1 PM Mon 81 87 S 5 9 10992 9265 5865 Blue 11
2 PM Mon 83 88 SSW 8 12 11807 9366 5966 Blue 12
3 PM Mon 84 88 SSW 8 12 11807 9366 5966 Blue 12
4 PM Mon 84 86 SSW 8 12 10134 9005 5605 Blue 10
5 PM Mon 82 82 WSW 8 12 8583 6083 2683 Blue 6
6 PM Mon 78 77 WSW 8 12 5551 3463 63 Blue 1
7 PM Mon 73 71 WSW 8 12 2566 3400 0 Blue 0
8 PM Mon 69 67 W 8 12 2566 3400 0 Blue 0
9 PM Mon 65 63 W 8 12 2566 3400 0 Blue 0
10 PM Mon 62 60 W 8 12 2566 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 ac_soaring@yahoo.com