Detailed Predictions for: Potato Hill
Launch Lat, Long, Altitude (f): 39.34098, -122.69, 3400
LZ Altitude (f): 1700
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 70 68 WSW 4 6 2706 3400 0 Blue 0
1 AM Thu 69 67 WSW 4 6 2647 3400 0 Blue 0
2 AM Thu 68 66 N 6 9 2588 3400 0 Blue 0
3 AM Thu 67 65 N 6 9 2533 3400 0 Blue 0
4 AM Thu 66 64 N 6 9 2533 3400 0 Blue 0
5 AM Thu 63 61 N 6 9 2533 3400 0 Blue 0
6 AM Thu 62 60 N 6 9 2533 3400 0 Blue 0
7 AM Thu 62 60 N 6 9 2533 3400 0 Blue 0
8 AM Thu 66 64 NNE 5 9 2533 3400 0 Blue 0
9 AM Thu 70 69 NNE 5 9 2765 3400 0 Blue 0
10 AM Thu 71 71 NNE 5 9 2893 3400 0 Blue 0
11 AM Thu 73 75 NE 8 11 3398 3400 0 Blue 4
12 Noon Thu 75 78 NE 8 11 3957 3400 0 Blue 7
1 PM Thu 77 81 NE 8 11 5397 3947 547 Blue 10
2 PM Thu 80 83 E 11 16 6875 4490 1090 Blue 12
3 PM Thu 82 84 E 11 16 8596 5379 1979 Blue 13
4 PM Thu 83 84 E 11 16 8596 5379 1979 Blue 13
5 PM Thu 81 80 ESE 5 9 4504 3673 273 Blue 9
6 PM Thu 78 76 ESE 5 9 3525 3400 0 Blue 5
7 PM Thu 72 70 ESE 5 9 2824 3400 0 Blue 0
8 PM Thu 71 69 W 5 8 2765 3400 0 Blue 0
9 PM Thu 70 68 W 5 8 2706 3400 0 Blue 0
10 PM Thu 68 66 W 5 8 2588 3400 0 Blue 0
11 PM Thu 67 65 S 3 5 2533 3400 0 Blue 0
12 Midnight Fri 66 64 S 3 5 2533 3400 0 Blue 0
1 AM Fri 66 64 S 3 5 2533 3400 0 Blue 0
2 AM Fri 65 63 N 3 4 2533 3400 0 Blue 0
3 AM Fri 65 63 N 3 4 2533 3400 0 Blue 0
4 AM Fri 64 62 N 3 4 2533 3400 0 Blue 0
5 AM Fri 63 61 NNW 3 4 2533 3400 0 Blue 0
6 AM Fri 63 61 NNW 3 4 2533 3400 0 Blue 0
7 AM Fri 64 62 NNW 3 4 2533 3400 0 Blue 0
8 AM Fri 70 68 NNE 3 3 2706 3400 0 Blue 0
9 AM Fri 75 74 NNE 3 3 3272 3400 0 Blue 3
10 AM Fri 76 76 NNE 3 3 3525 3400 0 Blue 5
11 AM Fri 80 82 E 5 8 5605 4219 819 Blue 11
12 Noon Fri 83 86 E 5 8 8742 5792 2392 Blue 15
1 PM Fri 85 89 E 5 8 9996 8724 5324 Blue 18
2 PM Fri 87 90 SE 12 17 10455 8815 5415 Blue 19
3 PM Fri 89 91 SE 12 17 10672 9272 5872 Blue 20
4 PM Fri 90 91 SE 12 17 10672 9272 5872 Blue 20
5 PM Fri 88 87 S 13 19 8840 8585 5185 Blue 16
6 PM Fri 84 82 S 13 19 5605 4219 819 Blue 11
7 PM Fri 77 75 S 13 19 3398 3400 0 Blue 4
8 PM Fri 72 70 WSW 8 13 2824 3400 0 Blue 0
9 PM Fri 68 66 WSW 8 13 2588 3400 0 Blue 0
10 PM Fri 67 65 WSW 8 13 2533 3400 0 Blue 0
11 PM Fri 66 64 W 5 8 2533 3400 0 Blue 0
12 Midnight Sat 65 63 W 5 8 2533 3400 0 Blue 0
1 AM Sat 65 63 W 5 8 2533 3400 0 Blue 0
2 AM Sat 64 62 W 3 5 2533 3400 0 Blue 0
3 AM Sat 62 60 W 3 5 2533 3400 0 Blue 0
4 AM Sat 61 59 W 3 5 2533 3400 0 Blue 0
5 AM Sat 60 58 W 4 5 2533 3400 0 Blue 0
6 AM Sat 60 58 W 4 5 2533 3400 0 Blue 0
7 AM Sat 62 60 W 4 5 2533 3400 0 Blue 0
8 AM Sat 63 61 W 3 5 2533 3400 0 Blue 0
9 AM Sat 66 65 W 3 5 2533 3400 0 Blue 0
10 AM Sat 68 68 W 3 5 2706 3400 0 Blue 0
11 AM Sat 70 72 SSW 5 11 3019 3400 0 Blue 1
12 Noon Sat 72 75 SSW 5 11 3398 3400 0 Blue 4
1 PM Sat 73 76 SSW 5 11 3525 3400 0 Blue 5
2 PM Sat 74 77 SSW 9 16 3681 3400 0 Blue 6
3 PM Sat 75 77 SSW 9 16 3681 3400 0 Blue 6
4 PM Sat 75 76 SSW 9 16 3525 3400 0 Blue 5
5 PM Sat 74 73 WSW 11 17 3145 3400 0 Blue 2
6 PM Sat 71 69 WSW 11 17 2765 3400 0 Blue 0
7 PM Sat 67 65 WSW 11 17 2533 3400 0 Blue 0
8 PM Sat 64 62 W 10 14 2533 3400 0 Blue 0
9 PM Sat 62 60 W 10 14 2533 3400 0 Blue 0
10 PM Sat 62 60 W 10 14 2533 3400 0 Blue 0
11 PM Sat 62 60 W 10 14 2533 3400 0 Blue 0
12 Midnight Sun 61 59 W 10 14 2533 3400 0 Blue 0
1 AM Sun 61 59 W 10 14 2533 3400 0 Blue 0
2 AM Sun 60 58 W 8 14 2533 3400 0 Blue 0
3 AM Sun 59 57 W 8 14 2533 3400 0 Blue 0
4 AM Sun 59 57 W 8 14 2533 3400 0 Blue 0
5 AM Sun 59 57 WSW 11 17 2533 3400 0 Blue 0
6 AM Sun 60 58 WSW 11 17 2533 3400 0 Blue 0
7 AM Sun 61 59 WSW 11 17 2533 3400 0 Blue 0
8 AM Sun 61 59 WSW 9 13 2533 3400 0 Blue 0
9 AM Sun 61 59 WSW 9 13 2533 3400 0 Blue 0
10 AM Sun 61 59 WSW 9 13 2533 3400 0 Blue 0
11 AM Sun 61 60 W 9 16 2533 3400 0 Blue 0
12 Noon Sun 62 62 W 9 16 2533 3400 0 Blue 0
1 PM Sun 64 64 W 9 16 2533 3400 0 Blue 0
2 PM Sun 66 66 W 11 19 2588 3400 0 Blue 0
3 PM Sun 67 67 W 11 19 2647 3400 0 Blue 0
4 PM Sun 68 67 W 11 19 2647 3400 0 Blue 0
5 PM Sun 67 66 WNW 11 19 2588 3400 0 Blue 0
6 PM Sun 65 63 WNW 11 19 2533 3400 0 Blue 0
7 PM Sun 61 59 WNW 11 19 2533 3400 0 Blue 0
8 PM Sun 58 56 WNW 8 11 2533 3400 0 Blue 0
9 PM Sun 57 55 WNW 8 11 2533 3400 0 Blue 0
10 PM Sun 56 54 WNW 8 11 2533 3400 0 Blue 0
11 PM Sun 56 54 NW 8 11 2533 3400 0 Blue 0
12 Midnight Mon 56 54 NW 8 11 2533 3400 0 Blue 0
1 AM Mon 56 54 NW 8 11 2533 3400 0 Blue 0
2 AM Mon 56 54 NNW 6 11 2533 3400 0 Blue 0
3 AM Mon 55 53 NNW 6 11 2533 3400 0 Blue 0
4 AM Mon 55 53 NNW 6 11 2533 3400 0 Blue 0
5 AM Mon 55 53 NNW 10 14 2533 3400 0 Blue 0
6 AM Mon 56 54 NNW 10 14 2533 3400 0 Blue 0
7 AM Mon 58 56 NNW 10 14 2533 3400 0 Blue 0
8 AM Mon 60 58 N 9 12 2533 3400 0 Blue 0
9 AM Mon 63 62 N 9 12 2533 3400 0 Blue 0
10 AM Mon 66 66 N 9 12 2588 3400 0 Blue 0
11 AM Mon 69 71 NNE 11 16 2893 3400 0 Blue 0
12 Noon Mon 72 75 NNE 11 16 3398 3400 0 Blue 4
1 PM Mon 75 79 NNE 11 16 4232 3521 121 Blue 8
2 PM Mon 78 81 N 13 19 5397 3947 547 Blue 10
3 PM Mon 80 82 N 13 19 5605 4219 819 Blue 11
4 PM Mon 81 82 N 13 19 5605 4219 819 Blue 11
5 PM Mon 80 79 N 12 17 4232 3521 121 Blue 8
6 PM Mon 77 75 N 12 17 3398 3400 0 Blue 4
7 PM Mon 72 70 N 12 17 2824 3400 0 Blue 0
8 PM Mon 68 66 N 10 14 2588 3400 0 Blue 0
9 PM Mon 66 64 N 10 14 2533 3400 0 Blue 0
10 PM Mon 66 64 N 10 14 2533 3400 0 Blue 0
11 PM Mon 66 64 N 9 12 2533 3400 0 Blue 0
12 Midnight Tue 66 64 N 9 12 2533 3400 0 Blue 0
1 AM Tue 66 64 N 9 12 2533 3400 0 Blue 0
2 AM Tue 65 63 NNW 11 16 2533 3400 0 Blue 0
3 AM Tue 64 62 NNW 11 16 2533 3400 0 Blue 0
4 AM Tue 63 61 NNW 11 16 2533 3400 0 Blue 0
5 AM Tue 62 60 NNW 10 14 2533 3400 0 Blue 0
6 AM Tue 63 61 NNW 10 14 2533 3400 0 Blue 0
7 AM Tue 65 63 NNW 10 14 2533 3400 0 Blue 0
8 AM Tue 67 65 N 9 12 2533 3400 0 Blue 0
9 AM Tue 71 70 N 9 12 2824 3400 0 Blue 0
10 AM Tue 74 74 N 9 12 3272 3400 0 Blue 3
11 AM Tue 77 79 NE 10 13 4232 3521 121 Blue 8
12 Noon Tue 80 83 NE 10 13 6875 4490 1090 Blue 12
1 PM Tue 82 86 NE 10 13 8742 5792 2392 Blue 15
2 PM Tue 85 88 E 9 12 9401 8647 5247 Blue 17
3 PM Tue 86 88 E 9 12 9401 8647 5247 Blue 17
4 PM Tue 87 88 E 9 12 9401 8647 5247 Blue 17
5 PM Tue 86 85 SE 9 12 8659 5586 2186 Blue 14
6 PM Tue 82 80 SE 9 12 4504 3673 273 Blue 9
7 PM Tue 76 74 SE 9 12 3272 3400 0 Blue 3
8 PM Tue 72 70 W 8 11 2824 3400 0 Blue 0
9 PM Tue 69 67 W 8 11 2647 3400 0 Blue 0
10 PM Tue 68 66 W 8 11 2588 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