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

Station:

 KOAK

Date/Time:

 17 APR 2024

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 56 54 NW 5 6 2661 3400 0 Blue 0
1 AM Wed 55 53 NW 4 5 2661 3400 0 Blue 0
2 AM Wed 55 53 WNW 3 4 2661 3400 0 Blue 0
3 AM Wed 53 51 W 2 4 2661 3400 0 Blue 0
4 AM Wed 52 50 WNW 3 4 2661 3400 0 Blue 0
5 AM Wed 51 49 WNW 2 4 2661 3400 0 Blue 0
6 AM Wed 51 49 WNW 2 3 2661 3400 0 Blue 0
7 AM Wed 51 49 W 2 3 2661 3400 0 Blue 0
8 AM Wed 52 50 NNW 2 3 2661 3400 0 Blue 0
9 AM Wed 54 53 NE 2 2 2661 3400 0 Blue 0
10 AM Wed 58 58 NE 3 4 2661 3400 0 Blue 0
11 AM Wed 60 61 NE 4 4 2661 3400 0 Blue 0
12 Noon Wed 62 64 NE 5 6 2739 3400 0 Blue 0
1 PM Wed 63 65 ENE 5 8 2986 3400 0 Blue 0
2 PM Wed 63 64 ENE 5 9 2739 3400 0 Blue 0
3 PM Wed 65 65 ENE 5 8 2986 3400 0 Blue 0
4 PM Wed 64 63 ENE 5 8 2661 3400 0 Blue 0
5 PM Wed 64 63 NE 5 8 2661 3400 0 Blue 0
6 PM Wed 63 61 NE 4 5 2661 3400 0 Blue 0
7 PM Wed 60 58 N 4 5 2661 3400 0 Blue 0
8 PM Wed 57 55 W 3 5 2661 3400 0 Blue 0
9 PM Wed 55 53 W 4 6 2661 3400 0 Blue 0
10 PM Wed 55 53 W 5 8 2661 3400 0 Blue 0
11 PM Wed 55 53 WNW 5 8 2661 3400 0 Blue 0
12 Midnight Thu 54 52 WNW 5 8 2661 3400 0 Blue 0
1 AM Thu 54 52 WNW 5 8 2661 3400 0 Blue 0
2 AM Thu 54 52 WNW 5 8 2661 3400 0 Blue 0
3 AM Thu 53 51 WNW 4 5 2661 3400 0 Blue 0
4 AM Thu 53 51 W 4 6 2661 3400 0 Blue 0
5 AM Thu 53 51 WNW 3 5 2661 3400 0 Blue 0
6 AM Thu 51 49 WNW 3 5 2661 3400 0 Blue 0
7 AM Thu 53 51 WNW 3 5 2661 3400 0 Blue 0
8 AM Thu 53 51 ESE 3 5 2661 3400 0 Blue 0
9 AM Thu 57 57 ESE 3 5 2661 3400 0 Blue 0
10 AM Thu 60 61 ESE 3 5 2661 3400 0 Blue 0
11 AM Thu 63 65 ENE 4 5 2986 3400 0 Blue 0
12 Noon Thu 65 68 ENE 4 5 3970 3400 0 Blue 3
1 PM Thu 67 71 ENE 4 5 4582 3959 559 Blue 6
2 PM Thu 68 71 E 5 9 4582 3959 559 Blue 6
3 PM Thu 69 71 E 5 9 4582 3959 559 Blue 6
4 PM Thu 69 70 E 5 9 4378 3688 288 Blue 5
5 PM Thu 68 67 ESE 5 9 3697 3400 0 Blue 2
6 PM Thu 66 64 ESE 5 9 2739 3400 0 Blue 0
7 PM Thu 63 61 ESE 5 9 2661 3400 0 Blue 0
8 PM Thu 60 58 WSW 5 9 2661 3400 0 Blue 0
9 PM Thu 59 57 WSW 5 9 2661 3400 0 Blue 0
10 PM Thu 58 56 WSW 5 9 2661 3400 0 Blue 0
11 PM Thu 58 56 WNW 5 5 2661 3400 0 Blue 0
12 Midnight Fri 57 55 WNW 5 5 2661 3400 0 Blue 0
1 AM Fri 57 55 WNW 5 5 2661 3400 0 Blue 0
2 AM Fri 56 54 NW 3 4 2661 3400 0 Blue 0
3 AM Fri 55 53 NW 3 4 2661 3400 0 Blue 0
4 AM Fri 54 52 NW 3 4 2661 3400 0 Blue 0
5 AM Fri 53 51 NNW 3 4 2661 3400 0 Blue 0
6 AM Fri 53 51 NNW 3 4 2661 3400 0 Blue 0
7 AM Fri 54 52 NNW 3 4 2661 3400 0 Blue 0
8 AM Fri 56 54 N 2 3 2661 3400 0 Blue 0
9 AM Fri 59 59 N 2 3 2661 3400 0 Blue 0
10 AM Fri 62 63 N 2 3 2661 3400 0 Blue 0
11 AM Fri 65 68 E 5 8 3970 3400 0 Blue 3
12 Noon Fri 67 71 E 5 8 4582 3959 559 Blue 6
1 PM Fri 69 74 E 5 8 5964 4565 1165 Blue 9
2 PM Fri 69 73 SSE 8 11 5251 4371 971 Blue 8
3 PM Fri 70 73 SSE 8 11 5251 4371 971 Blue 8
4 PM Fri 70 72 SSE 8 11 4872 4229 829 Blue 7
5 PM Fri 69 69 SW 10 14 4239 3400 0 Blue 4
6 PM Fri 67 65 SW 10 14 2986 3400 0 Blue 0
7 PM Fri 63 61 SW 10 14 2661 3400 0 Blue 0
8 PM Fri 60 58 W 8 12 2661 3400 0 Blue 0
9 PM Fri 58 56 W 8 12 2661 3400 0 Blue 0
10 PM Fri 58 56 W 8 12 2661 3400 0 Blue 0
11 PM Fri 57 55 WNW 6 11 2661 3400 0 Blue 0
12 Midnight Sat 56 54 WNW 6 11 2661 3400 0 Blue 0
1 AM Sat 56 54 WNW 6 11 2661 3400 0 Blue 0
2 AM Sat 55 53 WNW 5 10 2661 3400 0 Blue 0
3 AM Sat 54 52 WNW 5 10 2661 3400 0 Blue 0
4 AM Sat 53 51 WNW 5 10 2661 3400 0 Blue 0
5 AM Sat 52 50 WNW 5 9 2661 3400 0 Blue 0
6 AM Sat 52 50 WNW 5 9 2661 3400 0 Blue 0
7 AM Sat 53 51 WNW 5 9 2661 3400 0 Blue 0
8 AM Sat 55 53 NW 8 11 2661 3400 0 Blue 0
9 AM Sat 58 58 NW 8 11 2661 3400 0 Blue 0
10 AM Sat 62 64 NW 8 11 2739 3400 0 Blue 0
11 AM Sat 65 68 NNE 8 11 3970 3400 0 Blue 3
12 Noon Sat 67 72 NNE 8 11 4872 4229 829 Blue 7
1 PM Sat 68 73 NNE 8 11 5251 4371 971 Blue 8
2 PM Sat 68 73 WSW 10 14 5251 4371 971 Blue 8
3 PM Sat 69 72 WSW 10 14 4872 4229 829 Blue 7
4 PM Sat 69 71 WSW 10 14 4582 3959 559 Blue 6
5 PM Sat 68 68 W 10 16 3970 3400 0 Blue 3
6 PM Sat 65 63 W 10 16 2661 3400 0 Blue 0
7 PM Sat 61 59 W 10 16 2661 3400 0 Blue 0
8 PM Sat 58 56 WNW 10 16 2661 3400 0 Blue 0
9 PM Sat 56 54 WNW 10 16 2661 3400 0 Blue 0
10 PM Sat 55 53 WNW 10 16 2661 3400 0 Blue 0
11 PM Sat 55 53 NW 9 13 2661 3400 0 Blue 0
12 Midnight Sun 55 53 NW 9 13 2661 3400 0 Blue 0
1 AM Sun 54 52 NW 9 13 2661 3400 0 Blue 0
2 AM Sun 54 52 NW 8 12 2661 3400 0 Blue 0
3 AM Sun 53 51 NW 8 12 2661 3400 0 Blue 0
4 AM Sun 52 50 NW 8 12 2661 3400 0 Blue 0
5 AM Sun 52 50 NW 6 9 2661 3400 0 Blue 0
6 AM Sun 52 50 NW 6 9 2661 3400 0 Blue 0
7 AM Sun 53 51 NW 6 9 2661 3400 0 Blue 0
8 AM Sun 55 53 N 6 10 2661 3400 0 Blue 0
9 AM Sun 58 57 N 6 10 2661 3400 0 Blue 0
10 AM Sun 62 63 N 6 10 2661 3400 0 Blue 0
11 AM Sun 65 67 E 9 12 3697 3400 0 Blue 2
12 Noon Sun 67 70 E 9 12 4378 3688 288 Blue 5
1 PM Sun 69 73 E 9 12 5251 4371 971 Blue 8
2 PM Sun 69 72 SE 9 13 4872 4229 829 Blue 7
3 PM Sun 70 72 SE 9 13 4872 4229 829 Blue 7
4 PM Sun 70 71 SE 9 13 4582 3959 559 Blue 6
5 PM Sun 69 69 S 9 13 4239 3400 0 Blue 4
6 PM Sun 67 65 S 9 13 2986 3400 0 Blue 0
7 PM Sun 63 61 S 9 13 2661 3400 0 Blue 0
8 PM Sun 60 58 W 8 12 2661 3400 0 Blue 0
9 PM Sun 58 56 W 8 12 2661 3400 0 Blue 0
10 PM Sun 57 55 W 8 12 2661 3400 0 Blue 0
11 PM Sun 56 54 WNW 6 10 2661 3400 0 Blue 0
12 Midnight Mon 55 53 WNW 6 10 2661 3400 0 Blue 0
1 AM Mon 55 53 WNW 6 10 2661 3400 0 Blue 0
2 AM Mon 54 52 NW 6 10 2661 3400 0 Blue 0
3 AM Mon 54 52 NW 6 10 2661 3400 0 Blue 0
4 AM Mon 53 51 NW 6 10 2661 3400 0 Blue 0
5 AM Mon 53 51 NNW 5 9 2661 3400 0 Blue 0
6 AM Mon 52 50 NNW 5 9 2661 3400 0 Blue 0
7 AM Mon 53 51 NNW 5 9 2661 3400 0 Blue 0
8 AM Mon 54 52 N 6 10 2661 3400 0 Blue 0
9 AM Mon 57 56 N 6 10 2661 3400 0 Blue 0
10 AM Mon 61 61 N 6 10 2661 3400 0 Blue 0
11 AM Mon 64 66 ESE 9 13 3405 3400 0 Blue 1
12 Noon Mon 66 69 ESE 9 13 4239 3400 0 Blue 4
1 PM Mon 67 71 ESE 9 13 4582 3959 559 Blue 6
2 PM Mon 67 70 SSE 10 17 4378 3688 288 Blue 5
3 PM Mon 68 70 SSE 10 17 4378 3688 288 Blue 5
4 PM Mon 68 69 SSE 10 17 4239 3400 0 Blue 4
5 PM Mon 66 65 SSW 11 17 2986 3400 0 Blue 0
6 PM Mon 64 62 SSW 11 17 2661 3400 0 Blue 0
7 PM Mon 60 58 SSW 11 17 2661 3400 0 Blue 0
8 PM Mon 57 55 W 11 16 2661 3400 0 Blue 0
9 PM Mon 55 53 W 11 16 2661 3400 0 Blue 0
10 PM Mon 54 52 W 11 16 2661 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]