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

Station:

 KOAK

Date/Time:

 11 DEC 2023

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 Mon 42 40 W 3 7 3018 3400 0 Blue 0
1 AM Mon 42 40 W 3 7 3018 3400 0 Blue 0
2 AM Mon 42 40 W 3 7 3018 3400 0 Blue 0
3 AM Mon 42 40 W 3 7 3018 3400 0 Blue 0
4 AM Mon 42 40 W 3 7 3018 3400 0 Blue 0
5 AM Mon 42 40 W 3 6 3018 3400 0 Blue 0
6 AM Mon 36 34 N 2 6 3018 3400 0 Blue 0
7 AM Mon 42 40 W 3 6 3018 3400 0 Blue 0
8 AM Mon 43 41 W 2 6 3018 3400 0 Blue 0
9 AM Mon 46 44 W 3 6 3018 3400 0 Blue 0
10 AM Mon 51 50 WNW 1 2 3018 3400 0 Blue 0
11 AM Mon 54 53 E 2 2 3319 3400 0 Blue 2
12 Noon Mon 56 56 ENE 2 3 3805 3400 0 Blue 5
1 PM Mon 58 57 E 2 3 4092 3400 0 Blue 6
2 PM Mon 59 58 ESE 2 3 4215 3470 70 Blue 7
3 PM Mon 59 57 E 2 3 4092 3400 0 Blue 6
4 PM Mon 56 54 E 2 3 3395 3400 0 Blue 3
5 PM Mon 52 50 E 1 3 3018 3400 0 Blue 0
6 PM Mon 50 48 WNW 1 3 3018 3400 0 Blue 0
7 PM Mon 48 46 W 2 6 3018 3400 0 Blue 0
8 PM Mon 48 46 W 3 7 3018 3400 0 Blue 0
9 PM Mon 47 45 W 3 8 3018 3400 0 Blue 0
10 PM Mon 47 45 W 3 7 3018 3400 0 Blue 0
11 PM Mon 46 44 W 3 7 3018 3400 0 Blue 0
12 Midnight Tue 46 44 WNW 2 5 3018 3400 0 Blue 0
1 AM Tue 46 44 WNW 2 6 3018 3400 0 Blue 0
2 AM Tue 45 43 WNW 2 5 3018 3400 0 Blue 0
3 AM Tue 45 43 WNW 2 6 3018 3400 0 Blue 0
4 AM Tue 45 43 WNW 3 6 3018 3400 0 Blue 0
5 AM Tue 45 43 WNW 3 6 3018 3400 0 Blue 0
6 AM Tue 45 43 NW 2 6 3018 3400 0 Blue 0
7 AM Tue 44 42 NW 3 6 3018 3400 0 Blue 0
8 AM Tue 45 43 WNW 3 8 3018 3400 0 Blue 0
9 AM Tue 49 47 NW 4 8 3018 3400 0 Blue 0
10 AM Tue 54 53 NW 2 4 3319 3400 0 Blue 2
11 AM Tue 57 56 N 8 9 3805 3400 0 Blue 5
12 Noon Tue 59 59 NNE 9 10 4338 3792 392 Blue 8
1 PM Tue 60 60 NNE 9 11 4461 4087 687 Blue 9
2 PM Tue 61 60 NNE 9 11 4461 4087 687 Blue 9
3 PM Tue 61 59 NNE 9 11 4338 3792 392 Blue 8
4 PM Tue 58 56 NNE 7 9 3805 3400 0 Blue 5
5 PM Tue 53 51 N 6 11 3166 3400 0 Blue 0
6 PM Tue 50 48 NW 5 11 3018 3400 0 Blue 0
7 PM Tue 49 47 WNW 5 11 3018 3400 0 Blue 0
8 PM Tue 48 46 WNW 5 12 3018 3400 0 Blue 0
9 PM Tue 48 46 NW 5 12 3018 3400 0 Blue 0
10 PM Tue 48 46 NW 5 11 3018 3400 0 Blue 0
11 PM Tue 47 45 WNW 5 11 3018 3400 0 Blue 0
12 Midnight Wed 46 44 WNW 5 10 3018 3400 0 Blue 0
1 AM Wed 46 44 WNW 4 9 3018 3400 0 Blue 0
2 AM Wed 45 43 WNW 4 8 3018 3400 0 Blue 0
3 AM Wed 45 43 WNW 3 8 3018 3400 0 Blue 0
4 AM Wed 44 42 WNW 3 7 3018 3400 0 Blue 0
5 AM Wed 44 42 WNW 3 6 3018 3400 0 Blue 0
6 AM Wed 43 41 WNW 3 7 3018 3400 0 Blue 0
7 AM Wed 43 41 WNW 3 7 3018 3400 0 Blue 0
8 AM Wed 43 41 WNW 2 6 3018 3400 0 Blue 0
9 AM Wed 47 45 WNW 2 5 3018 3400 0 Blue 0
10 AM Wed 51 50 N 1 2 3018 3400 0 Blue 0
11 AM Wed 54 53 NE 2 3 3319 3400 0 Blue 2
12 Noon Wed 56 56 ENE 3 3 3805 3400 0 Blue 5
1 PM Wed 57 56 ENE 3 3 3805 3400 0 Blue 5
2 PM Wed 57 56 ENE 3 3 3805 3400 0 Blue 5
3 PM Wed 56 54 ENE 2 3 3395 3400 0 Blue 3
4 PM Wed 53 51 E 2 2 3166 3400 0 Blue 0
5 PM Wed 50 48 NNW 0 0 3018 3400 0 Blue 0
6 PM Wed 48 46 W 2 4 3018 3400 0 Blue 0
7 PM Wed 47 45 WNW 2 5 3018 3400 0 Blue 0
8 PM Wed 47 45 WNW 2 4 3018 3400 0 Blue 0
9 PM Wed 46 44 WNW 2 4 3018 3400 0 Blue 0
10 PM Wed 45 43 WNW 2 4 3018 3400 0 Blue 0
11 PM Wed 45 43 WNW 2 4 3018 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]