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

Station:

KOAK

Date/Time:

26 MAY 2019

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 Sun 36 36 N 16 4673 6350 0 Blue 0
6 AM Sun 36 36 N 16 4673 6350 0 Blue 0
7 AM Sun 37 37 N 16 4882 6350 0 Blue 1
8 AM Sun 38 38 NW 13 5090 6350 0 Blue 2
9 AM Sun 38 39 NW 13 5298 6350 0 Blue 3
10 AM Sun 38 39 NW 13 5298 6350 0 Blue 3
11 AM Sun 38 41 N 12 5712 6350 0 Blue 5
12 Noon Sun 39 43 N 12 7113 6350 0 Blue 7
1 PM Sun 40 44 N 12 7397 6350 0 White 8
2 PM Sun 42 46 NE 9 7831 7047 697 White 10
3 PM Sun 43 46 NE 9 7831 7047 697 White 10
4 PM Sun 44 46 NE 9 7831 7047 697 White 10
5 PM Sun 44 45 N 7 7614 6350 0 White 9
6 PM Sun 44 44 N 7 7397 6350 0 White 8
7 PM Sun 43 43 N 7 7113 6350 0 Blue 7
8 PM Sun 43 43 SE 7 7113 6350 0 Blue 7
9 PM Sun 43 43 SE 7 7113 6350 0 Blue 7
10 PM Sun 43 43 SE 7 7113 6350 0 Blue 7
11 PM Sun 43 43 W 9 7113 6350 0 Blue 7
12 Midnight Mon 42 42 W 9 6360 6350 0 Blue 6
1 AM Mon 42 42 W 9 6360 6350 0 Blue 6
2 AM Mon 42 42 N 8 6360 6350 0 Blue 6
3 AM Mon 41 41 N 8 5712 6350 0 Blue 5
4 AM Mon 41 41 N 8 5712 6350 0 Blue 5
5 AM Mon 41 41 NE 7 5712 6350 0 Blue 5
6 AM Mon 42 42 NE 7 6360 6350 0 Blue 6
7 AM Mon 43 43 NE 7 7113 6350 0 Blue 7
8 AM Mon 44 44 NE 7 7397 6350 0 White 8
9 AM Mon 46 47 NE 7 8047 7567 1217 White 11
10 AM Mon 48 50 NE 7 8694 8544 2194 White 14
11 AM Mon 50 51 E 10 8913 8913 2563 White 15
12 Noon Mon 51 53 E 10 9351 9351 3001 White 17
1 PM Mon 52 54 E 10 9569 9569 3219 White 18
2 PM Mon 52 54 SE 9 9569 9569 3219 White 18
3 PM Mon 52 54 SE 9 9569 9569 3219 White 18
4 PM Mon 52 53 SE 9 9351 9351 3001 White 17
5 PM Mon 52 53 S 12 9351 9351 3001 White 17
6 PM Mon 51 51 S 12 8913 8913 2563 White 15
7 PM Mon 50 50 S 12 8694 8544 2194 White 14
8 PM Mon 49 49 S 12 8478 8231 1881 White 13
9 PM Mon 48 48 S 12 8263 7914 1564 White 12
10 PM Mon 48 48 S 12 8263 7914 1564 White 12
11 PM Mon 47 47 NW 9 8047 7567 1217 White 11
12 Midnight Tue 47 47 NW 9 8047 7567 1217 White 11
1 AM Tue 46 46 NW 9 7831 7047 697 White 10
2 AM Tue 46 46 NW 9 7831 7047 697 White 10
3 AM Tue 45 45 NW 9 7614 6350 0 White 9
4 AM Tue 45 45 NW 9 7614 6350 0 White 9
5 AM Tue 45 45 N 12 7614 6350 0 White 9
6 AM Tue 46 46 N 12 7831 7047 697 White 10
7 AM Tue 48 48 N 12 8263 7914 1564 White 12
8 AM Tue 50 51 N 12 8913 8913 2563 White 15
9 AM Tue 53 55 N 12 9782 9782 3432 White 19
10 AM Tue 56 60 N 12 10829 10829 4479 White 24
11 AM Tue 58 62 N 13 11246 11246 4896 White 26
12 Noon Tue 59 64 N 13 11663 11522 5172 White 28
1 PM Tue 60 66 N 13 12078 11683 5333 White 30
2 PM Tue 60 65 N 13 11871 11598 5248 White 29
3 PM Tue 60 65 N 13 11871 11598 5248 White 29
4 PM Tue 61 64 N 13 11663 11522 5172 White 28
5 PM Tue 61 63 N 12 11453 11447 5097 White 27
6 PM Tue 59 60 N 12 10829 10829 4479 White 24
7 PM Tue 57 57 N 12 10202 10202 3852 White 21
8 PM Tue 55 55 N 12 9782 9782 3432 White 19
9 PM Tue 54 54 N 12 9569 9569 3219 White 18
10 PM Tue 53 53 N 12 9351 9351 3001 White 17
11 PM Tue 53 53 N 12 9351 9351 3001 White 17
12 Midnight Wed 52 52 N 12 9132 9132 2782 White 16
1 AM Wed 52 52 N 12 9132 9132 2782 White 16
2 AM Wed 51 51 N 12 8913 8913 2563 White 15
3 AM Wed 50 50 N 12 8694 8544 2194 White 14
4 AM Wed 50 50 N 12 8694 8544 2194 White 14
5 AM Wed 50 50 N 12 8694 8544 2194 White 14
6 AM Wed 51 51 N 12 8913 8913 2563 White 15
7 AM Wed 53 53 N 12 9351 9351 3001 White 17
8 AM Wed 55 55 N 12 9782 9782 3432 White 19
9 AM Wed 57 58 N 12 10411 10411 4061 White 22
10 AM Wed 58 60 N 12 10829 10829 4479 White 24
11 AM Wed 59 62 NW 10 11246 11246 4896 White 26
12 Noon Wed 60 64 NW 10 11663 11522 5172 White 28
1 PM Wed 61 65 NW 10 11871 11598 5248 White 29
2 PM Wed 62 66 NW 10 12078 11683 5333 White 30
3 PM Wed 62 65 NW 10 11871 11598 5248 White 29
4 PM Wed 62 64 NW 10 11663 11522 5172 White 28
5 PM Wed 61 63 W 12 11453 11447 5097 White 27
6 PM Wed 60 61 W 12 11036 11036 4686 White 25
7 PM Wed 58 58 W 12 10411 10411 4061 White 22
8 PM Wed 56 56 W 12 9992 9992 3642 White 20
9 PM Wed 55 55 W 12 9782 9782 3432 White 19
10 PM Wed 54 54 W 12 9569 9569 3219 White 18
11 PM Wed 53 53 NW 9 9351 9351 3001 White 17
12 Midnight Thu 53 53 NW 9 9351 9351 3001 White 17
1 AM Thu 52 52 NW 9 9132 9132 2782 White 16
2 AM Thu 52 52 NW 9 9132 9132 2782 White 16
3 AM Thu 51 51 NW 9 8913 8913 2563 White 15
4 AM Thu 51 51 NW 9 8913 8913 2563 White 15
5 AM Thu 51 51 N 7 8913 8913 2563 White 15
6 AM Thu 52 52 N 7 9132 9132 2782 White 16
7 AM Thu 52 52 N 7 9132 9132 2782 White 16
8 AM Thu 54 55 N 7 9782 9782 3432 White 19
9 AM Thu 55 57 N 7 10202 10202 3852 White 21
10 AM Thu 56 59 N 7 10620 10620 4270 White 23
11 AM Thu 58 61 N 8 11036 11036 4686 White 25
12 Noon Thu 59 63 N 8 11453 11447 5097 White 27
1 PM Thu 59 63 N 8 11453 11447 5097 White 27
2 PM Thu 60 64 N 8 11663 11522 5172 White 28
3 PM Thu 60 63 N 8 11453 11447 5097 White 27
4 PM Thu 60 62 N 8 11246 11246 4896 White 26
5 PM Thu 60 61 N 9 11036 11036 4686 White 25
6 PM Thu 59 59 N 9 10620 10620 4270 White 23
7 PM Thu 57 57 N 9 10202 10202 3852 White 21
8 PM Thu 56 56 N 9 9992 9992 3642 White 20
9 PM Thu 55 55 N 9 9782 9782 3432 White 19
10 PM Thu 54 54 N 9 9569 9569 3219 White 18
11 PM Thu 54 54 N 9 9569 9569 3219 White 18
12 Midnight Fri 53 53 N 9 9351 9351 3001 White 17
1 AM Fri 53 53 N 9 9351 9351 3001 White 17
2 AM Fri 52 52 N 9 9132 9132 2782 White 16
3 AM Fri 52 52 N 9 9132 9132 2782 White 16
4 AM Fri 51 51 N 9 8913 8913 2563 White 15
5 AM Fri 51 51 NW 9 8913 8913 2563 White 15
6 AM Fri 52 52 NW 9 9132 9132 2782 White 16
7 AM Fri 53 53 NW 9 9351 9351 3001 White 17
8 AM Fri 55 55 NW 9 9782 9782 3432 White 19
9 AM Fri 57 59 NW 9 10620 10620 4270 White 23
10 AM Fri 59 62 NW 9 11246 11246 4896 White 26
11 AM Fri 60 64 SW 9 11663 11522 5172 White 28
12 Noon Fri 61 66 SW 9 12078 11683 5333 White 30
1 PM Fri 61 66 SW 9 12078 11683 5333 White 30
2 PM Fri 62 67 SW 9 12286 11946 5596 White 31
3 PM Fri 62 66 SW 9 12078 11683 5333 White 30
4 PM Fri 62 65 SW 9 11871 11598 5248 White 29
5 PM Fri 62 63 W 10 11453 11447 5097 White 27
6 PM Fri 61 61 W 10 11036 11036 4686 White 25
7 PM Fri 59 59 W 10 10620 10620 4270 White 23
8 PM Fri 58 58 W 10 10411 10411 4061 White 22
9 PM Fri 57 57 W 10 10202 10202 3852 White 21
10 PM Fri 56 56 W 10 9992 9992 3642 White 20
11 PM Fri 55 55 W 10 9782 9782 3432 White 19
12 Midnight Sat 54 54 W 10 9569 9569 3219 White 18
1 AM Sat 54 54 W 10 9569 9569 3219 White 18
2 AM Sat 53 53 W 10 9351 9351 3001 White 17
3 AM Sat 53 53 W 10 9351 9351 3001 White 17
4 AM Sat 53 53 W 10 9351 9351 3001 White 17

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