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

Station:

 KOAK

Date/Time UTC:

 260911/1200

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 Fri 64 64 W 10 12 4337 6350 0 Blue 0
1 AM Fri 63 63 W 9 11 4337 6350 0 Blue 0
2 AM Fri 62 62 WNW 8 9 4337 6350 0 Blue 0
3 AM Fri 62 62 WNW 6 9 4337 6350 0 Blue 0
4 AM Fri 61 61 WNW 6 8 4337 6350 0 Blue 0
5 AM Fri 61 61 WNW 6 6 4337 6350 0 Blue 0
6 AM Fri 61 61 WNW 6 8 4337 6350 0 Blue 0
7 AM Fri 60 60 WNW 5 6 4337 6350 0 Blue 0
8 AM Fri 60 60 WNW 4 6 4337 6350 0 Blue 0
9 AM Fri 61 62 WNW 3 5 4337 6350 0 Blue 0
10 AM Fri 63 66 S 3 6 4337 6350 0 Blue 0
11 AM Fri 64 68 SW 3 8 4337 6350 0 Blue 0
12 Noon Fri 65 70 SSW 4 9 4337 6350 0 Blue 0
1 PM Fri 66 72 SW 5 11 4337 6350 0 Blue 0
2 PM Fri 67 73 WSW 5 12 4337 6350 0 Blue 0
3 PM Fri 69 74 WSW 6 12 4367 6350 0 Blue 0
4 PM Fri 66 69 W 6 12 4337 6350 0 Blue 0
5 PM Fri 66 68 W 5 11 4337 6350 0 Blue 0
6 PM Fri 65 65 W 4 9 4337 6350 0 Blue 0
7 PM Fri 62 62 W 4 8 4337 6350 0 Blue 0
8 PM Fri 58 58 W 8 11 4337 6350 0 Blue 0
9 PM Fri 58 58 W 10 12 4337 6350 0 Blue 0
10 PM Fri 58 58 W 9 12 4337 6350 0 Blue 0
11 PM Fri 59 59 W 9 12 4337 6350 0 Blue 0
12 Midnight Sat 58 58 W 10 12 4337 6350 0 Blue 0
1 AM Sat 57 57 W 9 11 4337 6350 0 Blue 0
2 AM Sat 57 57 W 9 11 4337 6350 0 Blue 0
3 AM Sat 57 57 W 9 10 4337 6350 0 Blue 0
4 AM Sat 56 56 W 9 10 4337 6350 0 Blue 0
5 AM Sat 56 56 W 8 10 4337 6350 0 Blue 0
6 AM Sat 55 55 W 8 10 4337 6350 0 Blue 0
7 AM Sat 55 55 W 8 10 4337 6350 0 Blue 0
8 AM Sat 55 55 W 6 10 4337 6350 0 Blue 0
9 AM Sat 55 56 W 6 10 4337 6350 0 Blue 0
10 AM Sat 56 58 W 6 10 4337 6350 0 Blue 0
11 AM Sat 56 60 SW 9 18 4337 6350 0 Blue 0
12 Noon Sat 57 62 SW 9 18 4337 6350 0 Blue 0
1 PM Sat 58 64 SW 9 18 4337 6350 0 Blue 0
2 PM Sat 57 62 WSW 14 23 4337 6350 0 Blue 0
3 PM Sat 59 63 WSW 14 23 4337 6350 0 Blue 0
4 PM Sat 54 57 WSW 14 23 4337 6350 0 Blue 0
5 PM Sat 52 54 W 18 27 4337 6350 0 Blue 0
6 PM Sat 51 51 W 18 27 4337 6350 0 Blue 0
7 PM Sat 47 47 W 18 27 4337 6350 0 Blue 0
8 PM Sat 44 44 W 17 24 4337 6350 0 Blue 0
9 PM Sat 43 43 W 17 24 4337 6350 0 Blue 0
10 PM Sat 43 43 W 17 24 4337 6350 0 Blue 0
11 PM Sat 43 43 W 12 19 4337 6350 0 Blue 0
12 Midnight Sun 42 42 W 12 19 4337 6350 0 Blue 0
1 AM Sun 40 40 W 12 19 4337 6350 0 Blue 0
2 AM Sun 39 39 W 9 12 4337 6350 0 Blue 0
3 AM Sun 38 38 W 9 12 4337 6350 0 Blue 0
4 AM Sun 38 38 W 9 12 4337 6350 0 Blue 0
5 AM Sun 38 38 WNW 5 6 4337 6350 0 Blue 0
6 AM Sun 39 39 WNW 5 6 4337 6350 0 Blue 0
7 AM Sun 40 40 WNW 5 6 4337 6350 0 Blue 0
8 AM Sun 41 41 WNW 4 6 4337 6350 0 Blue 0
9 AM Sun 43 44 WNW 4 6 4337 6350 0 Blue 0
10 AM Sun 45 48 WNW 4 6 4337 6350 0 Blue 0
11 AM Sun 47 51 N 6 10 4337 6350 0 Blue 0
12 Noon Sun 49 54 N 6 10 4337 6350 0 Blue 0
1 PM Sun 51 57 N 6 10 4337 6350 0 Blue 0
2 PM Sun 53 59 SSE 3 8 4337 6350 0 Blue 0
3 PM Sun 54 59 SSE 3 8 4337 6350 0 Blue 0
4 PM Sun 54 57 SSE 3 8 4337 6350 0 Blue 0
5 PM Sun 53 55 S 2 5 4337 6350 0 Blue 0
6 PM Sun 51 51 S 2 5 4337 6350 0 Blue 0
7 PM Sun 49 49 S 2 5 4337 6350 0 Blue 0
8 PM Sun 47 47 W 3 5 4337 6350 0 Blue 0
9 PM Sun 48 48 W 3 5 4337 6350 0 Blue 0
10 PM Sun 49 49 W 3 5 4337 6350 0 Blue 0
11 PM Sun 50 50 W 6 9 4337 6350 0 Blue 0
12 Midnight Mon 50 50 W 6 9 4337 6350 0 Blue 0
1 AM Mon 50 50 W 6 9 4337 6350 0 Blue 0
2 AM Mon 49 49 W 9 13 4337 6350 0 Blue 0
3 AM Mon 49 49 W 9 13 4337 6350 0 Blue 0
4 AM Mon 48 48 W 9 13 4337 6350 0 Blue 0
5 AM Mon 48 48 W 6 9 4337 6350 0 Blue 0
6 AM Mon 48 48 W 6 9 4337 6350 0 Blue 0
7 AM Mon 48 48 W 6 9 4337 6350 0 Blue 0
8 AM Mon 49 49 W 4 5 4337 6350 0 Blue 0
9 AM Mon 51 52 W 4 5 4337 6350 0 Blue 0
10 AM Mon 54 57 W 4 5 4337 6350 0 Blue 0
11 AM Mon 56 60 S 4 8 4337 6350 0 Blue 0
12 Noon Mon 58 63 S 4 8 4337 6350 0 Blue 0
1 PM Mon 59 65 S 4 8 4337 6350 0 Blue 0
2 PM Mon 60 66 S 4 8 4337 6350 0 Blue 0
3 PM Mon 61 66 S 4 8 4337 6350 0 Blue 0
4 PM Mon 61 64 S 4 8 4337 6350 0 Blue 0
5 PM Mon 59 61 S 3 5 4337 6350 0 Blue 0
6 PM Mon 56 56 S 3 5 4337 6350 0 Blue 0
7 PM Mon 54 54 S 3 5 4337 6350 0 Blue 0
8 PM Mon 52 52 W 1 3 4337 6350 0 Blue 0
9 PM Mon 52 52 W 1 3 4337 6350 0 Blue 0
10 PM Mon 52 52 W 1 3 4337 6350 0 Blue 0
11 PM Mon 53 53 W 2 5 4337 6350 0 Blue 0
12 Midnight Tue 53 53 W 2 5 4337 6350 0 Blue 0
1 AM Tue 52 52 W 2 5 4337 6350 0 Blue 0
2 AM Tue 52 52 W 2 5 4337 6350 0 Blue 0
3 AM Tue 52 52 W 2 5 4337 6350 0 Blue 0
4 AM Tue 52 52 W 2 5 4337 6350 0 Blue 0
5 AM Tue 52 52 NW 2 4 4337 6350 0 Blue 0
6 AM Tue 51 51 NW 2 4 4337 6350 0 Blue 0
7 AM Tue 51 51 NW 2 4 4337 6350 0 Blue 0
8 AM Tue 51 51 NNW 2 4 4337 6350 0 Blue 0
9 AM Tue 53 54 NNW 2 4 4337 6350 0 Blue 0
10 AM Tue 55 57 NNW 2 4 4337 6350 0 Blue 0
11 AM Tue 57 61 ESE 5 8 4337 6350 0 Blue 0
12 Noon Tue 59 64 ESE 5 8 4337 6350 0 Blue 0
1 PM Tue 60 66 ESE 5 8 4337 6350 0 Blue 0
2 PM Tue 61 66 SE 4 6 4337 6350 0 Blue 0
3 PM Tue 61 65 SE 4 6 4337 6350 0 Blue 0
4 PM Tue 60 63 SE 4 6 4337 6350 0 Blue 0
5 PM Tue 59 60 SSE 4 8 4337 6350 0 Blue 0
6 PM Tue 57 57 SSE 4 8 4337 6350 0 Blue 0
7 PM Tue 54 54 SSE 4 8 4337 6350 0 Blue 0
8 PM Tue 52 52 S 0 2 4337 6350 0 Blue 0
9 PM Tue 52 52 S 0 2 4337 6350 0 Blue 0
10 PM Tue 53 53 S 0 2 4337 6350 0 Blue 0
11 PM Tue 54 54 W 1 4 4337 6350 0 Blue 0
12 Midnight Wed 53 53 W 1 4 4337 6350 0 Blue 0
1 AM Wed 53 53 W 1 4 4337 6350 0 Blue 0
2 AM Wed 52 52 WNW 2 4 4337 6350 0 Blue 0
3 AM Wed 52 52 WNW 2 4 4337 6350 0 Blue 0
4 AM Wed 53 53 WNW 2 4 4337 6350 0 Blue 0
5 AM Wed 53 53 NNW 3 5 4337 6350 0 Blue 0
6 AM Wed 53 53 NNW 3 5 4337 6350 0 Blue 0
7 AM Wed 52 52 NNW 3 5 4337 6350 0 Blue 0
8 AM Wed 52 52 N 3 5 4337 6350 0 Blue 0
9 AM Wed 53 54 N 3 5 4337 6350 0 Blue 0
10 AM Wed 54 56 N 3 5 4337 6350 0 Blue 0
11 AM Wed 55 59 E 6 9 4337 6350 0 Blue 0
12 Noon Wed 56 61 E 6 9 4337 6350 0 Blue 0
1 PM Wed 57 63 E 6 9 4337 6350 0 Blue 0
2 PM Wed 58 64 ESE 5 8 4337 6350 0 Blue 0
3 PM Wed 58 63 ESE 5 8 4337 6350 0 Blue 0
4 PM Wed 58 61 ESE 5 8 4337 6350 0 Blue 0
5 PM Wed 57 59 SE 3 6 4337 6350 0 Blue 0
6 PM Wed 55 55 SE 3 6 4337 6350 0 Blue 0
7 PM Wed 53 53 SE 3 6 4337 6350 0 Blue 0
8 PM Wed 52 52 WSW 1 3 4337 6350 0 Blue 0
9 PM Wed 52 52 WSW 1 3 4337 6350 0 Blue 0
10 PM Wed 53 53 WSW 1 3 4337 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]