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

Station:

KOAK

Date/Time:

12 MAY 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 Wed 58 58 WNW 5 6 4229 6350 0 Blue 0
1 AM Wed 58 58 WNW 5 6 4229 6350 0 Blue 0
2 AM Wed 57 57 NNW 4 4 4229 6350 0 Blue 0
3 AM Wed 57 57 NNW 4 4 4229 6350 0 Blue 0
4 AM Wed 56 56 NNW 4 4 4229 6350 0 Blue 0
5 AM Wed 56 56 S 4 4 4229 6350 0 Blue 0
6 AM Wed 62 62 S 4 4 4229 6350 0 Blue 0
7 AM Wed 56 56 S 4 4 4229 6350 0 Blue 0
8 AM Wed 61 62 SSW 4 4 4229 6350 0 Blue 0
9 AM Wed 64 66 SSW 4 4 4229 6350 0 Blue 0
10 AM Wed 67 71 SSW 4 4 7298 6350 0 Blue 4
11 AM Wed 68 74 SE 5 9 9208 7188 838 Blue 7
12 Noon Wed 70 77 SE 5 9 10380 9147 2797 Blue 10
1 PM Wed 72 79 SE 5 9 12105 9451 3101 Blue 12
2 PM Wed 74 80 SE 10 16 12864 10216 3866 Blue 13
3 PM Wed 75 80 SE 10 16 12864 10216 3866 Blue 13
4 PM Wed 75 79 SE 10 16 12105 9451 3101 Blue 12
5 PM Wed 74 76 S 9 13 9583 8613 2263 Blue 9
6 PM Wed 73 74 S 9 13 9208 7188 838 Blue 7
7 PM Wed 69 69 S 9 13 5849 6350 0 Blue 2
8 PM Wed 66 66 SSE 9 13 4229 6350 0 Blue 0
9 PM Wed 64 64 SSE 9 13 4229 6350 0 Blue 0
10 PM Wed 63 63 SSE 9 13 4229 6350 0 Blue 0
11 PM Wed 61 61 W 4 4 4229 6350 0 Blue 0
12 Midnight Thu 63 63 W 4 4 4229 6350 0 Blue 0
1 AM Thu 60 60 W 4 4 4229 6350 0 Blue 0
2 AM Thu 60 60 SE 4 4 4229 6350 0 Blue 0
3 AM Thu 57 57 SE 4 4 4229 6350 0 Blue 0
4 AM Thu 57 57 SE 4 4 4229 6350 0 Blue 0
5 AM Thu 56 56 NW 4 4 4229 6350 0 Blue 0
6 AM Thu 57 57 NW 4 4 4229 6350 0 Blue 0
7 AM Thu 59 59 NW 4 4 4229 6350 0 Blue 0
8 AM Thu 62 63 NNE 3 3 4229 6350 0 Blue 0
9 AM Thu 65 67 NNE 3 3 4882 6350 0 Blue 0
10 AM Thu 67 71 NNE 3 3 7298 6350 0 Blue 4
11 AM Thu 68 74 ESE 5 9 9208 7188 838 Blue 7
12 Noon Thu 69 76 ESE 5 9 9583 8613 2263 Blue 9
1 PM Thu 71 79 ESE 5 9 12105 9451 3101 Blue 12
2 PM Thu 72 79 ESE 11 17 12105 9451 3101 Blue 12
3 PM Thu 73 79 ESE 11 17 12105 9451 3101 Blue 12
4 PM Thu 73 77 ESE 11 17 10380 9147 2797 Blue 10
5 PM Thu 72 74 SSE 5 9 9208 7188 838 Blue 7
6 PM Thu 70 71 SSE 5 9 7298 6350 0 Blue 4
7 PM Thu 68 68 SSE 5 9 5561 6350 0 Blue 1
8 PM Thu 66 66 ESE 9 13 4229 6350 0 Blue 0
9 PM Thu 64 64 ESE 9 13 4229 6350 0 Blue 0
10 PM Thu 62 62 ESE 9 13 4229 6350 0 Blue 0
11 PM Thu 60 60 ESE 10 16 4229 6350 0 Blue 0
12 Midnight Fri 59 59 ESE 10 16 4229 6350 0 Blue 0
1 AM Fri 58 58 ESE 10 16 4229 6350 0 Blue 0
2 AM Fri 57 57 ENE 9 13 4229 6350 0 Blue 0
3 AM Fri 56 56 ENE 9 13 4229 6350 0 Blue 0
4 AM Fri 55 55 ENE 9 13 4229 6350 0 Blue 0
5 AM Fri 55 55 N 8 12 4229 6350 0 Blue 0
6 AM Fri 56 56 N 8 12 4229 6350 0 Blue 0
7 AM Fri 57 57 N 8 12 4229 6350 0 Blue 0
8 AM Fri 59 60 E 8 12 4229 6350 0 Blue 0
9 AM Fri 61 63 E 8 12 4229 6350 0 Blue 0
10 AM Fri 63 66 E 8 12 4229 6350 0 Blue 0
11 AM Fri 65 70 E 6 10 6136 6350 0 Blue 3
12 Noon Fri 67 73 E 6 10 8688 6350 0 Blue 6
1 PM Fri 68 75 E 6 10 9311 8242 1892 Blue 8
2 PM Fri 69 75 E 8 12 9311 8242 1892 Blue 8
3 PM Fri 69 74 E 8 12 9208 7188 838 Blue 7
4 PM Fri 69 73 E 8 12 8688 6350 0 Blue 6
5 PM Fri 68 70 E 8 12 6136 6350 0 Blue 3
6 PM Fri 66 67 E 8 12 4882 6350 0 Blue 0
7 PM Fri 64 64 E 8 12 4229 6350 0 Blue 0
8 PM Fri 62 62 NW 10 16 4229 6350 0 Blue 0
9 PM Fri 60 60 NW 10 16 4229 6350 0 Blue 0
10 PM Fri 59 59 NW 10 16 4229 6350 0 Blue 0
11 PM Fri 58 58 NNW 12 19 4229 6350 0 Blue 0
12 Midnight Sat 57 57 NNW 12 19 4229 6350 0 Blue 0
1 AM Sat 56 56 NNW 12 19 4229 6350 0 Blue 0
2 AM Sat 55 55 N 12 19 4229 6350 0 Blue 0
3 AM Sat 54 54 N 12 19 4229 6350 0 Blue 0
4 AM Sat 53 53 N 12 19 4229 6350 0 Blue 0
5 AM Sat 52 52 N 11 17 4229 6350 0 Blue 0
6 AM Sat 53 53 N 11 17 4229 6350 0 Blue 0
7 AM Sat 54 54 N 11 17 4229 6350 0 Blue 0
8 AM Sat 56 57 NNE 11 17 4229 6350 0 Blue 0
9 AM Sat 58 60 NNE 11 17 4229 6350 0 Blue 0
10 AM Sat 59 63 NNE 11 17 4229 6350 0 Blue 0
11 AM Sat 61 67 NE 10 16 4882 6350 0 Blue 0
12 Noon Sat 63 70 NE 10 16 6136 6350 0 Blue 3
1 PM Sat 64 72 NE 10 16 8283 6350 0 Blue 5
2 PM Sat 66 72 NE 9 13 8283 6350 0 Blue 5
3 PM Sat 67 72 NE 9 13 8283 6350 0 Blue 5
4 PM Sat 67 71 NE 9 13 7298 6350 0 Blue 4
5 PM Sat 67 69 NNE 9 13 5849 6350 0 Blue 2
6 PM Sat 66 67 NNE 9 13 4882 6350 0 Blue 0
7 PM Sat 65 65 NNE 9 13 4229 6350 0 Blue 0
8 PM Sat 63 63 NW 8 12 4229 6350 0 Blue 0
9 PM Sat 61 61 NW 8 12 4229 6350 0 Blue 0
10 PM Sat 59 59 NW 8 12 4229 6350 0 Blue 0
11 PM Sat 58 58 NNW 10 16 4229 6350 0 Blue 0
12 Midnight Sun 57 57 NNW 10 16 4229 6350 0 Blue 0
1 AM Sun 57 57 NNW 10 16 4229 6350 0 Blue 0
2 AM Sun 57 57 NW 10 16 4229 6350 0 Blue 0
3 AM Sun 56 56 NW 10 16 4229 6350 0 Blue 0
4 AM Sun 55 55 NW 10 16 4229 6350 0 Blue 0
5 AM Sun 54 54 N 9 13 4229 6350 0 Blue 0
6 AM Sun 55 55 N 9 13 4229 6350 0 Blue 0
7 AM Sun 57 57 N 9 13 4229 6350 0 Blue 0
8 AM Sun 59 60 NE 9 13 4229 6350 0 Blue 0
9 AM Sun 62 64 NE 9 13 4229 6350 0 Blue 0
10 AM Sun 64 68 NE 9 13 5561 6350 0 Blue 1
11 AM Sun 66 72 ENE 5 9 8283 6350 0 Blue 5
12 Noon Sun 68 75 ENE 5 9 9311 8242 1892 Blue 8
1 PM Sun 69 77 ENE 5 9 10380 9147 2797 Blue 10
2 PM Sun 70 77 SSE 6 10 10380 9147 2797 Blue 10
3 PM Sun 71 77 SSE 6 10 10380 9147 2797 Blue 10
4 PM Sun 71 75 SSE 6 10 9311 8242 1892 Blue 8
5 PM Sun 70 73 WSW 8 12 8688 6350 0 Blue 6
6 PM Sun 69 70 WSW 8 12 6136 6350 0 Blue 3
7 PM Sun 67 67 WSW 8 12 4882 6350 0 Blue 0
8 PM Sun 65 65 W 9 13 4229 6350 0 Blue 0
9 PM Sun 63 63 W 9 13 4229 6350 0 Blue 0
10 PM Sun 62 62 W 9 13 4229 6350 0 Blue 0
11 PM Sun 60 60 WSW 8 12 4229 6350 0 Blue 0
12 Midnight Mon 59 59 WSW 8 12 4229 6350 0 Blue 0
1 AM Mon 57 57 WSW 8 12 4229 6350 0 Blue 0
2 AM Mon 56 56 NW 9 13 4229 6350 0 Blue 0
3 AM Mon 55 55 NW 9 13 4229 6350 0 Blue 0
4 AM Mon 53 53 NW 9 13 4229 6350 0 Blue 0
5 AM Mon 53 53 NW 5 9 4229 6350 0 Blue 0
6 AM Mon 53 53 NW 5 9 4229 6350 0 Blue 0
7 AM Mon 55 55 NW 5 9 4229 6350 0 Blue 0
8 AM Mon 56 57 NE 6 10 4229 6350 0 Blue 0
9 AM Mon 58 61 NE 6 10 4229 6350 0 Blue 0
10 AM Mon 59 63 NE 6 10 4229 6350 0 Blue 0
11 AM Mon 61 67 WSW 6 10 4882 6350 0 Blue 0
12 Noon Mon 63 71 WSW 6 10 7298 6350 0 Blue 4
1 PM Mon 65 73 WSW 6 10 8688 6350 0 Blue 6
2 PM Mon 66 73 S 6 10 8688 6350 0 Blue 6
3 PM Mon 67 73 S 6 10 8688 6350 0 Blue 6
4 PM Mon 67 71 S 6 10 7298 6350 0 Blue 4
5 PM Mon 66 68 WSW 8 12 5561 6350 0 Blue 1
6 PM Mon 65 66 WSW 8 12 4229 6350 0 Blue 0
7 PM Mon 63 63 WSW 8 12 4229 6350 0 Blue 0
8 PM Mon 61 61 W 10 16 4229 6350 0 Blue 0
9 PM Mon 59 59 W 10 16 4229 6350 0 Blue 0
10 PM Mon 57 57 W 10 16 4229 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 ac_soaring@yahoo.com