Detailed Predictions for: St John
Launch Altitude (f): 6350
LZ Altitude (f): 1185
Sounding

Station:

KOAK

Date/Time:

23 SEP 2017

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
5 AM Sat 45 45 N 12 4081 6350 0 Blue 0
6 AM Sat 45 45 N 12 4081 6350 0 Blue 0
7 AM Sat 45 45 N 12 4081 6350 0 Blue 0
8 AM Sat 47 47 N 15 4116 6350 0 Blue 0
9 AM Sat 50 51 N 15 6871 6350 0 Blue 2
10 AM Sat 53 55 N 15 9208 7335 985 White 6
11 AM Sat 56 59 N 15 10085 9853 3503 White 10
12 Noon Sat 58 62 N 15 10718 10718 4368 White 13
1 PM Sat 60 65 N 15 11345 11345 4995 White 16
2 PM Sat 60 65 N 15 11345 11345 4995 White 16
3 PM Sat 61 65 N 15 11345 11345 4995 White 16
4 PM Sat 61 63 N 15 10928 10928 4578 White 14
5 PM Sat 59 60 N 12 10296 10240 3890 White 11
6 PM Sat 56 56 N 12 9422 8069 1719 White 7
7 PM Sat 52 52 N 12 7410 6350 0 Blue 3
8 PM Sat 49 49 N 10 5824 6350 0 Blue 0
9 PM Sat 48 48 N 10 4381 6350 0 Blue 0
10 PM Sat 48 48 N 10 4381 6350 0 Blue 0
11 PM Sat 48 48 N 12 4381 6350 0 Blue 0
12 Midnight Sun 48 48 N 12 4381 6350 0 Blue 0
1 AM Sun 47 47 N 12 4116 6350 0 Blue 0
2 AM Sun 47 47 N 10 4116 6350 0 Blue 0
3 AM Sun 46 46 N 10 4081 6350 0 Blue 0
4 AM Sun 47 47 N 10 4116 6350 0 Blue 0
5 AM Sun 47 47 N 12 4116 6350 0 Blue 0
6 AM Sun 46 46 N 12 4081 6350 0 Blue 0
7 AM Sun 46 46 N 12 4081 6350 0 Blue 0
8 AM Sun 47 47 N 12 4116 6350 0 Blue 0
9 AM Sun 51 52 N 12 7410 6350 0 Blue 3
10 AM Sun 55 57 N 12 9636 8720 2370 White 8
11 AM Sun 59 62 NE 12 10718 10718 4368 White 13
12 Noon Sun 62 66 NE 12 11554 11554 5204 White 17
1 PM Sun 64 69 NE 12 12173 12173 5823 White 20
2 PM Sun 65 69 NE 10 12173 12173 5823 White 20
3 PM Sun 65 68 NE 10 11966 11966 5616 White 19
4 PM Sun 65 67 NE 10 11761 11761 5411 White 18
5 PM Sun 63 64 N 9 11137 11137 4787 White 15
6 PM Sun 61 61 N 9 10507 10507 4157 White 12
7 PM Sun 58 58 N 9 9860 9201 2851 White 9
8 PM Sun 56 56 N 9 9422 8069 1719 White 7
9 PM Sun 54 54 N 9 8789 6836 486 Blue 5
10 PM Sun 54 54 N 9 8789 6836 486 Blue 5
11 PM Sun 53 53 N 10 8158 6350 0 Blue 4
12 Midnight Mon 53 53 N 10 8158 6350 0 Blue 4
1 AM Mon 53 53 N 10 8158 6350 0 Blue 4
2 AM Mon 52 52 N 10 7410 6350 0 Blue 3
3 AM Mon 52 52 N 10 7410 6350 0 Blue 3
4 AM Mon 52 52 N 10 7410 6350 0 Blue 3
5 AM Mon 51 51 N 9 6871 6350 0 Blue 2
6 AM Mon 51 51 N 9 6871 6350 0 Blue 2
7 AM Mon 51 51 N 9 6871 6350 0 Blue 2
8 AM Mon 53 53 N 9 8158 6350 0 Blue 4
9 AM Mon 57 58 N 9 9860 9201 2851 White 9
10 AM Mon 62 64 N 9 11137 11137 4787 White 15
11 AM Mon 67 71 N 12 12585 12585 6235 White 22
12 Noon Mon 70 75 N 12 13405 13405 7055 White 26
1 PM Mon 71 76 N 12 13608 13608 7258 White 27
2 PM Mon 72 77 N 12 13811 13811 7461 White 28
3 PM Mon 73 77 N 12 13811 13811 7461 White 28
4 PM Mon 73 76 N 12 13608 13608 7258 White 27
5 PM Mon 72 73 N 10 12995 12995 6645 White 24
6 PM Mon 69 69 N 10 12173 12173 5823 White 20
7 PM Mon 65 65 N 10 11345 11345 4995 White 16
8 PM Mon 62 62 N 10 10718 10718 4368 White 13
9 PM Mon 59 59 N 10 10085 9853 3503 White 10
10 PM Mon 58 58 N 10 9860 9201 2851 White 9
11 PM Mon 57 57 N 12 9636 8720 2370 White 8
12 Midnight Tue 57 57 N 12 9636 8720 2370 White 8
1 AM Tue 57 57 N 12 9636 8720 2370 White 8
2 AM Tue 57 57 N 12 9636 8720 2370 White 8
3 AM Tue 56 56 N 12 9422 8069 1719 White 7
4 AM Tue 56 56 N 12 9422 8069 1719 White 7
5 AM Tue 56 56 N 13 9422 8069 1719 White 7
6 AM Tue 55 55 N 13 9208 7335 985 White 6
7 AM Tue 55 55 N 13 9208 7335 985 White 6
8 AM Tue 56 56 N 13 9422 8069 1719 White 7
9 AM Tue 60 61 N 13 10507 10507 4157 White 12
10 AM Tue 64 66 N 13 11554 11554 5204 White 17
11 AM Tue 68 72 N 12 12790 12790 6440 White 23
12 Noon Tue 71 76 N 12 13608 13608 7258 White 27
1 PM Tue 72 77 N 12 13811 13811 7461 White 28
2 PM Tue 73 78 N 12 14014 14014 7664 White 29
3 PM Tue 73 77 N 12 13811 13811 7461 White 28
4 PM Tue 73 76 N 12 13608 13608 7258 White 27
5 PM Tue 71 72 N 6 12790 12790 6440 White 23
6 PM Tue 68 68 N 6 11966 11966 5616 White 19
7 PM Tue 64 64 N 6 11137 11137 4787 White 15
8 PM Tue 61 61 N 6 10507 10507 4157 White 12
9 PM Tue 59 59 N 6 10085 9853 3503 White 10
10 PM Tue 59 59 N 6 10085 9853 3503 White 10
11 PM Tue 59 59 E 8 10085 9853 3503 White 10
12 Midnight Wed 58 58 E 8 9860 9201 2851 White 9
1 AM Wed 58 58 E 8 9860 9201 2851 White 9
2 AM Wed 58 58 E 8 9860 9201 2851 White 9
3 AM Wed 58 58 E 8 9860 9201 2851 White 9
4 AM Wed 58 58 E 8 9860 9201 2851 White 9
5 AM Wed 57 57 NE 8 9636 8720 2370 White 8
6 AM Wed 56 56 NE 8 9422 8069 1719 White 7
7 AM Wed 56 56 NE 8 9422 8069 1719 White 7
8 AM Wed 57 57 NE 8 9636 8720 2370 White 8
9 AM Wed 62 63 NE 8 10928 10928 4578 White 14
10 AM Wed 67 69 NE 8 12173 12173 5823 White 20
11 AM Wed 72 75 NE 9 13405 13405 7055 White 26
12 Noon Wed 74 78 NE 9 14014 14014 7664 White 29
1 PM Wed 75 79 NE 9 14217 14217 7867 White 30
2 PM Wed 75 79 NE 9 14217 14217 7867 White 30
3 PM Wed 75 78 NE 9 14014 14014 7664 White 29
4 PM Wed 75 77 NE 9 13811 13811 7461 White 28
5 PM Wed 73 74 SE 3 13200 13200 6850 White 25
6 PM Wed 69 69 SE 3 12173 12173 5823 White 20
7 PM Wed 65 65 SE 3 11345 11345 4995 White 16
8 PM Wed 61 61 SE 3 10507 10507 4157 White 12
9 PM Wed 59 59 SE 3 10085 9853 3503 White 10
10 PM Wed 58 58 SE 3 9860 9201 2851 White 9
11 PM Wed 58 58 SE 5 9860 9201 2851 White 9
12 Midnight Thu 58 58 SE 5 9860 9201 2851 White 9
1 AM Thu 58 58 SE 5 9860 9201 2851 White 9
2 AM Thu 57 57 SE 5 9636 8720 2370 White 8
3 AM Thu 57 57 SE 5 9636 8720 2370 White 8
4 AM Thu 58 58 SE 5 9860 9201 2851 White 9
5 AM Thu 57 57 E 3 9636 8720 2370 White 8
6 AM Thu 56 56 E 3 9422 8069 1719 White 7
7 AM Thu 56 56 E 3 9422 8069 1719 White 7
8 AM Thu 57 57 E 3 9636 8720 2370 White 8
9 AM Thu 61 61 E 3 10507 10507 4157 White 12
10 AM Thu 65 67 E 3 11761 11761 5411 White 18
11 AM Thu 69 72 E 6 12790 12790 6440 White 23
12 Noon Thu 72 76 E 6 13608 13608 7258 White 27
1 PM Thu 73 77 E 6 13811 13811 7461 White 28
2 PM Thu 74 78 E 6 14014 14014 7664 White 29
3 PM Thu 74 77 E 6 13811 13811 7461 White 28
4 PM Thu 73 75 E 6 13405 13405 7055 White 26
5 PM Thu 71 72 S 6 12790 12790 6440 White 23
6 PM Thu 68 68 S 6 11966 11966 5616 White 19
7 PM Thu 64 64 S 6 11137 11137 4787 White 15
8 PM Thu 60 60 S 6 10296 10240 3890 White 11
9 PM Thu 59 59 S 6 10085 9853 3503 White 10
10 PM Thu 59 59 S 6 10085 9853 3503 White 10
11 PM Thu 59 59 W 6 10085 9853 3503 White 10
12 Midnight Fri 58 58 W 6 9860 9201 2851 White 9
1 AM Fri 58 58 W 6 9860 9201 2851 White 9
2 AM Fri 58 58 W 6 9860 9201 2851 White 9
3 AM Fri 58 58 W 6 9860 9201 2851 White 9
4 AM Fri 58 58 W 6 9860 9201 2851 White 9

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 website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service 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 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