Detailed Predictions for: St John
Launch Lat, Long, Altitude (f): 39.424433, -122.689342, 6350
LZ Altitude (f): 1185
Sounding

Station:

KOAK

Date/Time:

21 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 Tue 64 64 NE 14 23 3963 6350 0 Blue 0
1 AM Tue 63 63 NE 14 23 3963 6350 0 Blue 0
2 AM Tue 61 61 NE 10 16 3963 6350 0 Blue 0
3 AM Tue 61 61 NE 10 16 3963 6350 0 Blue 0
4 AM Tue 60 60 NE 10 16 3963 6350 0 Blue 0
5 AM Tue 60 60 ESE 6 10 3963 6350 0 Blue 0
6 AM Tue 59 59 ESE 6 10 3963 6350 0 Blue 0
7 AM Tue 63 63 ESE 6 10 3963 6350 0 Blue 0
8 AM Tue 62 62 NNW 5 9 3963 6350 0 Blue 0
9 AM Tue 66 67 NNW 5 9 4040 6350 0 Blue 0
10 AM Tue 67 69 NNW 5 9 4591 6350 0 Blue 1
11 AM Tue 69 73 NNE 6 10 5029 6350 0 Blue 5
12 Noon Tue 72 77 NNE 6 10 6304 6350 0 Blue 9
1 PM Tue 74 79 NNE 6 10 7107 6350 0 Blue 11
2 PM Tue 75 80 SE 8 12 7315 6350 0 Blue 12
3 PM Tue 76 80 SE 8 12 7315 6350 0 Blue 12
4 PM Tue 76 79 SE 8 12 7107 6350 0 Blue 11
5 PM Tue 75 76 S 9 13 5745 6350 0 Blue 8
6 PM Tue 74 74 S 9 13 5091 6350 0 Blue 6
7 PM Tue 69 69 S 9 13 4591 6350 0 Blue 1
8 PM Tue 66 66 S 9 13 3963 6350 0 Blue 0
9 PM Tue 67 67 S 9 13 4040 6350 0 Blue 0
10 PM Tue 64 64 S 9 13 3963 6350 0 Blue 0
11 PM Tue 64 64 SW 9 13 3963 6350 0 Blue 0
12 Midnight Wed 64 64 SW 9 13 3963 6350 0 Blue 0
1 AM Wed 64 64 SW 9 13 3963 6350 0 Blue 0
2 AM Wed 63 63 SW 9 13 3963 6350 0 Blue 0
3 AM Wed 62 62 SW 9 13 3963 6350 0 Blue 0
4 AM Wed 62 62 SW 9 13 3963 6350 0 Blue 0
5 AM Wed 62 62 SW 9 13 3963 6350 0 Blue 0
6 AM Wed 63 63 SW 9 13 3963 6350 0 Blue 0
7 AM Wed 61 61 SW 9 13 3963 6350 0 Blue 0
8 AM Wed 61 61 SSW 8 12 3963 6350 0 Blue 0
9 AM Wed 65 66 SSW 8 12 3963 6350 0 Blue 0
10 AM Wed 66 68 SSW 8 12 4402 6350 0 Blue 0
11 AM Wed 68 71 SE 8 12 4815 6350 0 Blue 3
12 Noon Wed 70 74 SE 8 12 5091 6350 0 Blue 6
1 PM Wed 71 75 SE 8 12 5168 6350 0 Blue 7
2 PM Wed 72 77 SE 11 17 6304 6350 0 Blue 9
3 PM Wed 72 76 SE 11 17 5745 6350 0 Blue 8
4 PM Wed 71 73 SE 11 17 5029 6350 0 Blue 5
5 PM Wed 70 71 SE 6 10 4815 6350 0 Blue 3
6 PM Wed 68 68 SE 6 10 4402 6350 0 Blue 0
7 PM Wed 65 65 SE 6 10 3963 6350 0 Blue 0
8 PM Wed 63 63 E 6 10 3963 6350 0 Blue 0
9 PM Wed 62 62 E 6 10 3963 6350 0 Blue 0
10 PM Wed 62 62 E 6 10 3963 6350 0 Blue 0
11 PM Wed 62 62 ENE 5 9 3963 6350 0 Blue 0
12 Midnight Thu 62 62 ENE 5 9 3963 6350 0 Blue 0
1 AM Thu 61 61 ENE 5 9 3963 6350 0 Blue 0
2 AM Thu 60 60 N 8 12 3963 6350 0 Blue 0
3 AM Thu 60 60 N 8 12 3963 6350 0 Blue 0
4 AM Thu 60 60 N 8 12 3963 6350 0 Blue 0
5 AM Thu 60 60 NNW 9 13 3963 6350 0 Blue 0
6 AM Thu 60 60 NNW 9 13 3963 6350 0 Blue 0
7 AM Thu 60 60 NNW 9 13 3963 6350 0 Blue 0
8 AM Thu 61 61 NNW 12 19 3963 6350 0 Blue 0
9 AM Thu 63 64 NNW 12 19 3963 6350 0 Blue 0
10 AM Thu 65 67 NNW 12 19 4040 6350 0 Blue 0
11 AM Thu 68 71 NNE 10 16 4815 6350 0 Blue 3
12 Noon Thu 70 74 NNE 10 16 5091 6350 0 Blue 6
1 PM Thu 72 77 NNE 10 16 6304 6350 0 Blue 9
2 PM Thu 74 78 NNE 11 17 6845 6350 0 Blue 10
3 PM Thu 74 77 NNE 11 17 6304 6350 0 Blue 9
4 PM Thu 74 76 NNE 11 17 5745 6350 0 Blue 8
5 PM Thu 73 74 NNE 6 10 5091 6350 0 Blue 6
6 PM Thu 71 71 NNE 6 10 4815 6350 0 Blue 3
7 PM Thu 70 70 NNE 6 10 4703 6350 0 Blue 2
8 PM Thu 68 68 NNE 11 17 4402 6350 0 Blue 0
9 PM Thu 68 68 NNE 11 17 4402 6350 0 Blue 0
10 PM Thu 67 67 NNE 11 17 4040 6350 0 Blue 0
11 PM Thu 67 67 NE 9 13 4040 6350 0 Blue 0
12 Midnight Fri 67 67 NE 9 13 4040 6350 0 Blue 0
1 AM Fri 67 67 NE 9 13 4040 6350 0 Blue 0
2 AM Fri 67 67 NE 8 12 4040 6350 0 Blue 0
3 AM Fri 66 66 NE 8 12 3963 6350 0 Blue 0
4 AM Fri 65 65 NE 8 12 3963 6350 0 Blue 0
5 AM Fri 65 65 NE 10 16 3963 6350 0 Blue 0
6 AM Fri 64 64 NE 10 16 3963 6350 0 Blue 0
7 AM Fri 64 64 NE 10 16 3963 6350 0 Blue 0
8 AM Fri 65 65 NNW 8 12 3963 6350 0 Blue 0
9 AM Fri 67 68 NNW 8 12 4402 6350 0 Blue 0
10 AM Fri 70 72 NNW 8 12 4927 6350 0 Blue 4
11 AM Fri 73 76 ESE 10 16 5745 6350 0 Blue 8
12 Noon Fri 75 80 ESE 10 16 7315 6350 0 Blue 12
1 PM Fri 76 81 ESE 10 16 7543 6805 455 Blue 13
2 PM Fri 77 82 S 10 16 7795 7089 739 Blue 14
3 PM Fri 77 81 S 10 16 7543 6805 455 Blue 13
4 PM Fri 77 80 S 10 16 7315 6350 0 Blue 12
5 PM Fri 76 77 S 8 12 6304 6350 0 Blue 9
6 PM Fri 73 73 S 8 12 5029 6350 0 Blue 5
7 PM Fri 70 70 S 8 12 4703 6350 0 Blue 2
8 PM Fri 68 68 W 10 16 4402 6350 0 Blue 0
9 PM Fri 66 66 W 10 16 3963 6350 0 Blue 0
10 PM Fri 66 66 W 10 16 3963 6350 0 Blue 0
11 PM Fri 66 66 WSW 10 16 3963 6350 0 Blue 0
12 Midnight Sat 66 66 WSW 10 16 3963 6350 0 Blue 0
1 AM Sat 65 65 WSW 10 16 3963 6350 0 Blue 0
2 AM Sat 65 65 WNW 9 13 3963 6350 0 Blue 0
3 AM Sat 64 64 WNW 9 13 3963 6350 0 Blue 0
4 AM Sat 63 63 WNW 9 13 3963 6350 0 Blue 0
5 AM Sat 63 63 NW 5 9 3963 6350 0 Blue 0
6 AM Sat 62 62 NW 5 9 3963 6350 0 Blue 0
7 AM Sat 62 62 NW 5 9 3963 6350 0 Blue 0
8 AM Sat 63 63 WNW 5 9 3963 6350 0 Blue 0
9 AM Sat 65 66 WNW 5 9 3963 6350 0 Blue 0
10 AM Sat 67 69 WNW 5 9 4591 6350 0 Blue 1
11 AM Sat 70 73 SW 6 10 5029 6350 0 Blue 5
12 Noon Sat 72 76 SW 6 10 5745 6350 0 Blue 8
1 PM Sat 73 78 SW 6 10 6845 6350 0 Blue 10
2 PM Sat 74 79 SW 6 10 7107 6350 0 Blue 11
3 PM Sat 74 78 SW 6 10 6845 6350 0 Blue 10
4 PM Sat 73 76 SW 6 10 5745 6350 0 Blue 8
5 PM Sat 72 73 SW 6 10 5029 6350 0 Blue 5
6 PM Sat 69 69 SW 6 10 4591 6350 0 Blue 1
7 PM Sat 66 66 SW 6 10 3963 6350 0 Blue 0
8 PM Sat 64 64 W 8 12 3963 6350 0 Blue 0
9 PM Sat 63 63 W 8 12 3963 6350 0 Blue 0
10 PM Sat 63 63 W 8 12 3963 6350 0 Blue 0
11 PM Sat 63 63 WSW 6 10 3963 6350 0 Blue 0
12 Midnight Sun 63 63 WSW 6 10 3963 6350 0 Blue 0
1 AM Sun 62 62 WSW 6 10 3963 6350 0 Blue 0
2 AM Sun 61 61 WNW 5 9 3963 6350 0 Blue 0
3 AM Sun 61 61 WNW 5 9 3963 6350 0 Blue 0
4 AM Sun 61 61 WNW 5 9 3963 6350 0 Blue 0
5 AM Sun 61 61 N 4 6 3963 6350 0 Blue 0
6 AM Sun 61 61 N 4 6 3963 6350 0 Blue 0
7 AM Sun 60 60 N 4 6 3963 6350 0 Blue 0
8 AM Sun 60 60 WNW 4 6 3963 6350 0 Blue 0
9 AM Sun 62 63 WNW 4 6 3963 6350 0 Blue 0
10 AM Sun 64 66 WNW 4 6 3963 6350 0 Blue 0
11 AM Sun 66 69 S 6 10 4591 6350 0 Blue 1
12 Noon Sun 69 73 S 6 10 5029 6350 0 Blue 5
1 PM Sun 70 74 S 6 10 5091 6350 0 Blue 6
2 PM Sun 72 76 SSW 6 10 5745 6350 0 Blue 8
3 PM Sun 72 75 SSW 6 10 5168 6350 0 Blue 7
4 PM Sun 72 74 SSW 6 10 5091 6350 0 Blue 6
5 PM Sun 70 71 SW 5 9 4815 6350 0 Blue 3
6 PM Sun 68 68 SW 5 9 4402 6350 0 Blue 0
7 PM Sun 65 65 SW 5 9 3963 6350 0 Blue 0
8 PM Sun 63 63 W 8 12 3963 6350 0 Blue 0
9 PM Sun 62 62 W 8 12 3963 6350 0 Blue 0
10 PM Sun 62 62 W 8 12 3963 6350 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]