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

Station:

KOAK

Date/Time:

20 JUN 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 Sun 75 75 S 4 6 3094 6350 0 Blue 0
1 AM Sun 74 74 S 4 6 3094 6350 0 Blue 0
2 AM Sun 71 71 WSW 4 6 3094 6350 0 Blue 0
3 AM Sun 70 70 WSW 4 6 3094 6350 0 Blue 0
4 AM Sun 69 69 WSW 4 6 3094 6350 0 Blue 0
5 AM Sun 68 68 NNE 4 6 3094 6350 0 Blue 0
6 AM Sun 72 72 NNE 4 6 3094 6350 0 Blue 0
7 AM Sun 68 68 NNE 4 6 3094 6350 0 Blue 0
8 AM Sun 73 74 E 4 6 3094 6350 0 Blue 0
9 AM Sun 75 78 E 4 6 3818 6350 0 Blue 0
10 AM Sun 78 83 E 4 6 5323 6350 0 Blue 1
11 AM Sun 79 86 ESE 6 10 7571 6350 0 Blue 4
12 Noon Sun 80 88 ESE 6 10 10215 6530 180 Blue 6
1 PM Sun 83 92 ESE 6 10 15376 14827 8477 Blue 10
2 PM Sun 84 92 SE 11 17 15376 14827 8477 Blue 10
3 PM Sun 85 92 SE 11 17 15376 14827 8477 Blue 10
4 PM Sun 85 90 SE 11 17 15085 8016 1666 Blue 8
5 PM Sun 84 87 S 12 19 8229 6350 0 Blue 5
6 PM Sun 84 86 S 12 19 7571 6350 0 Blue 4
7 PM Sun 81 81 S 12 19 4545 6350 0 Blue 0
8 PM Sun 77 77 WSW 6 10 3574 6350 0 Blue 0
9 PM Sun 74 74 WSW 6 10 3094 6350 0 Blue 0
10 PM Sun 73 73 WSW 6 10 3094 6350 0 Blue 0
11 PM Sun 71 71 WSW 6 10 3094 6350 0 Blue 0
12 Midnight Mon 71 71 WSW 6 10 3094 6350 0 Blue 0
1 AM Mon 69 69 WSW 6 10 3094 6350 0 Blue 0
2 AM Mon 68 68 SSE 6 10 3094 6350 0 Blue 0
3 AM Mon 66 66 SSE 6 10 3094 6350 0 Blue 0
4 AM Mon 66 66 SSE 6 10 3094 6350 0 Blue 0
5 AM Mon 65 65 ESE 5 9 3094 6350 0 Blue 0
6 AM Mon 66 66 ESE 5 9 3094 6350 0 Blue 0
7 AM Mon 66 66 ESE 5 9 3094 6350 0 Blue 0
8 AM Mon 68 69 E 5 9 3094 6350 0 Blue 0
9 AM Mon 69 71 E 5 9 3094 6350 0 Blue 0
10 AM Mon 71 74 E 5 9 3094 6350 0 Blue 0
11 AM Mon 72 78 ESE 8 12 3818 6350 0 Blue 0
12 Noon Mon 73 80 ESE 8 12 4304 6350 0 Blue 0
1 PM Mon 75 82 ESE 8 12 4815 6350 0 Blue 0
2 PM Mon 76 83 SE 12 19 5323 6350 0 Blue 1
3 PM Mon 77 83 SE 12 19 5323 6350 0 Blue 1
4 PM Mon 78 83 SE 12 19 5323 6350 0 Blue 1
5 PM Mon 77 80 S 13 20 4304 6350 0 Blue 0
6 PM Mon 75 77 S 13 20 3574 6350 0 Blue 0
7 PM Mon 73 73 S 13 20 3094 6350 0 Blue 0
8 PM Mon 70 70 SW 10 16 3094 6350 0 Blue 0
9 PM Mon 68 68 SW 10 16 3094 6350 0 Blue 0
10 PM Mon 67 67 SW 10 16 3094 6350 0 Blue 0
11 PM Mon 66 66 W 8 12 3094 6350 0 Blue 0
12 Midnight Tue 65 65 W 8 12 3094 6350 0 Blue 0
1 AM Tue 64 64 W 8 12 3094 6350 0 Blue 0
2 AM Tue 62 62 WNW 6 10 3094 6350 0 Blue 0
3 AM Tue 61 61 WNW 6 10 3094 6350 0 Blue 0
4 AM Tue 60 60 WNW 6 10 3094 6350 0 Blue 0
5 AM Tue 59 59 N 5 9 3094 6350 0 Blue 0
6 AM Tue 59 59 N 5 9 3094 6350 0 Blue 0
7 AM Tue 60 60 N 5 9 3094 6350 0 Blue 0
8 AM Tue 61 62 E 6 10 3094 6350 0 Blue 0
9 AM Tue 62 65 E 6 10 3094 6350 0 Blue 0
10 AM Tue 64 69 E 6 10 3094 6350 0 Blue 0
11 AM Tue 65 72 ESE 9 13 3094 6350 0 Blue 0
12 Noon Tue 67 75 ESE 9 13 3094 6350 0 Blue 0
1 PM Tue 69 78 ESE 9 13 3818 6350 0 Blue 0
2 PM Tue 70 78 SE 9 13 3818 6350 0 Blue 0
3 PM Tue 71 78 SE 9 13 3818 6350 0 Blue 0
4 PM Tue 71 76 SE 9 13 3330 6350 0 Blue 0
5 PM Tue 70 73 S 11 17 3094 6350 0 Blue 0
6 PM Tue 69 71 S 11 17 3094 6350 0 Blue 0
7 PM Tue 67 67 S 11 17 3094 6350 0 Blue 0
8 PM Tue 65 65 SW 10 16 3094 6350 0 Blue 0
9 PM Tue 63 63 SW 10 16 3094 6350 0 Blue 0
10 PM Tue 61 61 SW 10 16 3094 6350 0 Blue 0
11 PM Tue 60 60 W 6 10 3094 6350 0 Blue 0
12 Midnight Wed 59 59 W 6 10 3094 6350 0 Blue 0
1 AM Wed 59 59 W 6 10 3094 6350 0 Blue 0
2 AM Wed 58 58 W 6 10 3094 6350 0 Blue 0
3 AM Wed 56 56 W 6 10 3094 6350 0 Blue 0
4 AM Wed 55 55 W 6 10 3094 6350 0 Blue 0
5 AM Wed 54 54 N 6 10 3094 6350 0 Blue 0
6 AM Wed 55 55 N 6 10 3094 6350 0 Blue 0
7 AM Wed 56 56 N 6 10 3094 6350 0 Blue 0
8 AM Wed 58 59 E 6 10 3094 6350 0 Blue 0
9 AM Wed 59 62 E 6 10 3094 6350 0 Blue 0
10 AM Wed 61 66 E 6 10 3094 6350 0 Blue 0
11 AM Wed 62 69 ESE 8 12 3094 6350 0 Blue 0
12 Noon Wed 64 72 ESE 8 12 3094 6350 0 Blue 0
1 PM Wed 65 74 ESE 8 12 3094 6350 0 Blue 0
2 PM Wed 67 75 SE 6 10 3094 6350 0 Blue 0
3 PM Wed 68 75 SE 6 10 3094 6350 0 Blue 0
4 PM Wed 69 74 SE 6 10 3094 6350 0 Blue 0
5 PM Wed 69 72 S 8 12 3094 6350 0 Blue 0
6 PM Wed 68 70 S 8 12 3094 6350 0 Blue 0
7 PM Wed 67 67 S 8 12 3094 6350 0 Blue 0
8 PM Wed 65 65 SSW 9 13 3094 6350 0 Blue 0
9 PM Wed 63 63 SSW 9 13 3094 6350 0 Blue 0
10 PM Wed 62 62 SSW 9 13 3094 6350 0 Blue 0
11 PM Wed 61 61 W 6 10 3094 6350 0 Blue 0
12 Midnight Thu 61 61 W 6 10 3094 6350 0 Blue 0
1 AM Thu 60 60 W 6 10 3094 6350 0 Blue 0
2 AM Thu 60 60 WNW 5 9 3094 6350 0 Blue 0
3 AM Thu 59 59 WNW 5 9 3094 6350 0 Blue 0
4 AM Thu 58 58 WNW 5 9 3094 6350 0 Blue 0
5 AM Thu 58 58 NW 6 10 3094 6350 0 Blue 0
6 AM Thu 59 59 NW 6 10 3094 6350 0 Blue 0
7 AM Thu 61 61 NW 6 10 3094 6350 0 Blue 0
8 AM Thu 63 64 N 5 9 3094 6350 0 Blue 0
9 AM Thu 65 68 N 5 9 3094 6350 0 Blue 0
10 AM Thu 68 73 N 5 9 3094 6350 0 Blue 0
11 AM Thu 70 76 E 6 10 3330 6350 0 Blue 0
12 Noon Thu 72 80 E 6 10 4304 6350 0 Blue 0
1 PM Thu 73 81 E 6 10 4545 6350 0 Blue 0
2 PM Thu 75 83 SE 8 12 5323 6350 0 Blue 1
3 PM Thu 76 83 SE 8 12 5323 6350 0 Blue 1
4 PM Thu 76 81 SE 8 12 4545 6350 0 Blue 0
5 PM Thu 76 79 SSW 9 12 4061 6350 0 Blue 0
6 PM Thu 75 77 SSW 9 12 3574 6350 0 Blue 0
7 PM Thu 73 73 SSW 9 12 3094 6350 0 Blue 0
8 PM Thu 72 72 WSW 10 14 3094 6350 0 Blue 0
9 PM Thu 70 70 WSW 10 14 3094 6350 0 Blue 0
10 PM Thu 69 69 WSW 10 14 3094 6350 0 Blue 0
11 PM Thu 68 68 W 9 13 3094 6350 0 Blue 0
12 Midnight Fri 67 67 W 9 13 3094 6350 0 Blue 0
1 AM Fri 67 67 W 9 13 3094 6350 0 Blue 0
2 AM Fri 66 66 NW 8 12 3094 6350 0 Blue 0
3 AM Fri 65 65 NW 8 12 3094 6350 0 Blue 0
4 AM Fri 65 65 NW 8 12 3094 6350 0 Blue 0
5 AM Fri 65 65 NNW 9 12 3094 6350 0 Blue 0
6 AM Fri 67 67 NNW 9 12 3094 6350 0 Blue 0
7 AM Fri 69 69 NNW 9 12 3094 6350 0 Blue 0
8 AM Fri 71 72 N 9 12 3094 6350 0 Blue 0
9 AM Fri 73 76 N 9 12 3330 6350 0 Blue 0
10 AM Fri 75 80 N 9 12 4304 6350 0 Blue 0
11 AM Fri 77 84 NE 9 13 5812 6350 0 Blue 2
12 Noon Fri 79 87 NE 9 13 8229 6350 0 Blue 5
1 PM Fri 81 90 NE 9 13 15085 8016 1666 Blue 8
2 PM Fri 82 90 E 10 16 15085 8016 1666 Blue 8
3 PM Fri 83 90 E 10 16 15085 8016 1666 Blue 8
4 PM Fri 83 88 E 10 16 10215 6530 180 Blue 6
5 PM Fri 82 85 SSW 11 17 6635 6350 0 Blue 3
6 PM Fri 80 81 SSW 11 17 4545 6350 0 Blue 0
7 PM Fri 78 78 SSW 11 17 3818 6350 0 Blue 0
8 PM Fri 76 76 WNW 12 18 3330 6350 0 Blue 0
9 PM Fri 74 74 WNW 12 18 3094 6350 0 Blue 0
10 PM Fri 73 73 WNW 12 18 3094 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]