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

Station:

 KOAK

Date/Time:

 18 MAY 2012

Temp/Wind data from:

NOAA Digital Forecast

Time
(Local)		 High
Temp
Puddle
Temp
Wind
 (mph)		 Thermal
Ceiling
(ft)		 Soaring
Ceiling
(ft)		 Above
Launch
(ft)		 Thermal
Type		 Thermal
Index
(F)
5 AM Fri 50 50 N 7 3848 6350 0 Blue 0
6 AM Fri 51 51 N 7 3848 6350 0 Blue 0
7 AM Fri 53 53 N 7 3848 6350 0 Blue 0
8 AM Fri 55 56 N 7 7102 6350 0 Blue 1
9 AM Fri 58 60 N 7 7994 7587 1237 Blue 5
10 AM Fri 62 66 N 7 10217 8772 2422 Blue 11
11 AM Fri 65 71 NE 6 12857 11033 4683 Blue 16
12 Noon Fri 66 73 NE 6 13321 12221 5871 Blue 18
1 PM Fri 68 76 NE 6 14011 13252 6902 Blue 21
2 PM Fri 68 75 E 5 13782 13022 6672 Blue 20
3 PM Fri 69 75 E 5 13782 13022 6672 Blue 20
4 PM Fri 70 74 E 5 13552 12781 6431 Blue 19
5 PM Fri 69 71 SE 5 12857 11033 4683 Blue 16
6 PM Fri 67 68 SE 5 11173 9971 3621 Blue 13
7 PM Fri 64 64 SE 5 9818 8157 1807 Blue 9
8 PM Fri 61 61 NE 2 8196 7796 1446 Blue 6
9 PM Fri 59 59 NE 2 7888 7031 681 Blue 4
10 PM Fri 58 58 NE 2 7805 6350 0 Blue 3
11 PM Fri 57 57 N 3 7627 6350 0 Blue 2
12 Midnight Sat 56 56 N 3 7102 6350 0 Blue 1
1 AM Sat 56 56 N 3 7102 6350 0 Blue 1
2 AM Sat 55 55 SE 2 4570 6350 0 Blue 0
3 AM Sat 54 54 SE 2 3848 6350 0 Blue 0
4 AM Sat 53 53 SE 2 3848 6350 0 Blue 0
5 AM Sat 53 53 N 2 3848 6350 0 Blue 0
6 AM Sat 54 54 N 2 3848 6350 0 Blue 0
7 AM Sat 57 57 N 2 7627 6350 0 Blue 2
8 AM Sat 60 61 E 2 8196 7796 1446 Blue 6
9 AM Sat 63 65 E 2 10005 8466 2116 Blue 10
10 AM Sat 66 70 E 2 12374 10398 4048 Blue 15
11 AM Sat 69 75 E 6 13782 13022 6672 Blue 20
12 Noon Sat 71 78 E 6 15314 13709 7359 Blue 23
1 PM Sat 72 79 E 6 15731 13936 7586 White 24
2 PM Sat 73 80 SE 7 15930 14318 7968 White 25
3 PM Sat 73 79 SE 7 15731 13936 7586 White 24
4 PM Sat 73 77 SE 7 14580 13481 7131 Blue 22
5 PM Sat 72 74 SE 2 13552 12781 6431 Blue 19
6 PM Sat 70 71 SE 2 12857 11033 4683 Blue 16
7 PM Sat 68 68 SE 2 11173 9971 3621 Blue 13
8 PM Sat 65 65 SE 2 10005 8466 2116 Blue 10
9 PM Sat 64 64 SE 2 9818 8157 1807 Blue 9
10 PM Sat 62 62 SE 2 8508 7879 1529 Blue 7
11 PM Sat 62 62 NW 1 8508 7879 1529 Blue 7
12 Midnight Sun 62 62 NW 1 8508 7879 1529 Blue 7
1 AM Sun 62 62 NW 1 8508 7879 1529 Blue 7
2 AM Sun 62 62 NW 1 8508 7879 1529 Blue 7
3 AM Sun 60 60 NW 1 7994 7587 1237 Blue 5
4 AM Sun 58 58 NW 1 7805 6350 0 Blue 3
5 AM Sun 57 57 NW 1 7627 6350 0 Blue 2
6 AM Sun 58 58 NW 1 7805 6350 0 Blue 3
7 AM Sun 61 61 NW 1 8196 7796 1446 Blue 6
8 AM Sun 64 65 NW 1 10005 8466 2116 Blue 10
9 AM Sun 68 70 NW 1 12374 10398 4048 Blue 15
10 AM Sun 71 75 NW 1 13782 13022 6672 Blue 20
11 AM Sun 74 78 SE 6 15314 13709 7359 Blue 23
12 Noon Sun 75 80 SE 6 15930 14318 7968 White 25
1 PM Sun 76 82 SE 6 16330 15663 9313 White 27
2 PM Sun 76 81 SE 6 16130 15051 8701 White 26
3 PM Sun 76 80 SE 6 15930 14318 7968 White 25
4 PM Sun 76 79 SE 6 15731 13936 7586 White 24
5 PM Sun 75 77 S 8 14580 13481 7131 Blue 22
6 PM Sun 72 73 S 8 13321 12221 5871 Blue 18
7 PM Sun 69 69 S 8 11786 10175 3825 Blue 14
8 PM Sun 66 66 S 8 10217 8772 2422 Blue 11
9 PM Sun 64 64 S 8 9818 8157 1807 Blue 9
10 PM Sun 63 63 S 8 8816 7980 1630 Blue 8
11 PM Sun 62 62 SE 5 8508 7879 1529 Blue 7
12 Midnight Mon 61 61 SE 5 8196 7796 1446 Blue 6
1 AM Mon 61 61 SE 5 8196 7796 1446 Blue 6
2 AM Mon 60 60 SE 5 7994 7587 1237 Blue 5
3 AM Mon 59 59 SE 5 7888 7031 681 Blue 4
4 AM Mon 58 58 SE 5 7805 6350 0 Blue 3
5 AM Mon 57 57 W 3 7627 6350 0 Blue 2
6 AM Mon 58 58 W 3 7805 6350 0 Blue 3
7 AM Mon 60 60 W 3 7994 7587 1237 Blue 5
8 AM Mon 62 62 W 3 8508 7879 1529 Blue 7
9 AM Mon 63 64 W 3 9818 8157 1807 Blue 9
10 AM Mon 65 67 W 3 10530 9784 3434 Blue 12
11 AM Mon 66 70 W 5 12374 10398 4048 Blue 15
12 Noon Mon 67 72 W 5 13090 11640 5290 Blue 17
1 PM Mon 67 72 W 5 13090 11640 5290 Blue 17
2 PM Mon 67 72 W 5 13090 11640 5290 Blue 17
3 PM Mon 67 71 W 5 12857 11033 4683 Blue 16
4 PM Mon 67 70 W 5 12374 10398 4048 Blue 15
5 PM Mon 66 68 W 14 11173 9971 3621 Blue 13
6 PM Mon 63 63 W 14 8816 7980 1630 Blue 8
7 PM Mon 61 61 W 14 8196 7796 1446 Blue 6
8 PM Mon 58 58 W 14 7805 6350 0 Blue 3
9 PM Mon 56 56 W 14 7102 6350 0 Blue 1
10 PM Mon 54 54 W 14 3848 6350 0 Blue 0
11 PM Mon 53 53 NW 12 3848 6350 0 Blue 0
12 Midnight Tue 52 52 NW 12 3848 6350 0 Blue 0
1 AM Tue 52 52 NW 12 3848 6350 0 Blue 0
2 AM Tue 52 52 NW 12 3848 6350 0 Blue 0
3 AM Tue 51 51 NW 12 3848 6350 0 Blue 0
4 AM Tue 51 51 NW 12 3848 6350 0 Blue 0
5 AM Tue 51 51 NW 12 3848 6350 0 Blue 0
6 AM Tue 52 52 NW 12 3848 6350 0 Blue 0
7 AM Tue 54 54 NW 12 3848 6350 0 Blue 0
8 AM Tue 55 55 NW 12 4570 6350 0 Blue 0
9 AM Tue 57 58 NW 12 7805 6350 0 Blue 3
10 AM Tue 60 63 NW 12 8816 7980 1630 Blue 8
11 AM Tue 62 68 NW 9 11173 9971 3621 Blue 13
12 Noon Tue 63 70 NW 9 12374 10398 4048 Blue 15
1 PM Tue 64 71 NW 9 12857 11033 4683 Blue 16
2 PM Tue 64 71 NW 9 12857 11033 4683 Blue 16
3 PM Tue 65 71 NW 9 12857 11033 4683 Blue 16
4 PM Tue 65 69 NW 9 11786 10175 3825 Blue 14
5 PM Tue 65 67 N 5 10530 9784 3434 Blue 12
6 PM Tue 63 64 N 5 9818 8157 1807 Blue 9
7 PM Tue 60 60 N 5 7994 7587 1237 Blue 5
8 PM Tue 58 58 N 5 7805 6350 0 Blue 3
9 PM Tue 57 57 N 5 7627 6350 0 Blue 2
10 PM Tue 56 56 N 5 7102 6350 0 Blue 1
11 PM Tue 55 55 N 9 4570 6350 0 Blue 0
12 Midnight Wed 55 55 N 9 4570 6350 0 Blue 0
1 AM Wed 55 55 N 9 4570 6350 0 Blue 0
2 AM Wed 55 55 N 9 4570 6350 0 Blue 0
3 AM Wed 54 54 N 9 3848 6350 0 Blue 0
4 AM Wed 54 54 N 9 3848 6350 0 Blue 0
5 AM Wed 54 54 N 15 3848 6350 0 Blue 0
6 AM Wed 55 55 N 15 4570 6350 0 Blue 0
7 AM Wed 56 56 N 15 7102 6350 0 Blue 1
8 AM Wed 58 59 N 15 7888 7031 681 Blue 4
9 AM Wed 60 62 N 15 8508 7879 1529 Blue 7
10 AM Wed 64 68 N 15 11173 9971 3621 Blue 13
11 AM Wed 66 71 N 14 12857 11033 4683 Blue 16
12 Noon Wed 67 73 N 14 13321 12221 5871 Blue 18
1 PM Wed 67 73 N 14 13321 12221 5871 Blue 18
2 PM Wed 67 73 N 14 13321 12221 5871 Blue 18
3 PM Wed 67 72 N 14 13090 11640 5290 Blue 17
4 PM Wed 68 71 N 14 12857 11033 4683 Blue 16
5 PM Wed 68 70 N 12 12374 10398 4048 Blue 15
6 PM Wed 66 67 N 12 10530 9784 3434 Blue 12
7 PM Wed 64 64 N 12 9818 8157 1807 Blue 9
8 PM Wed 62 62 N 12 8508 7879 1529 Blue 7
9 PM Wed 61 61 N 12 8196 7796 1446 Blue 6
10 PM Wed 60 60 N 12 7994 7587 1237 Blue 5
11 PM Wed 59 59 N 14 7888 7031 681 Blue 4
12 Midnight Thu 59 59 N 14 7888 7031 681 Blue 4
1 AM Thu 58 58 N 14 7805 6350 0 Blue 3
2 AM Thu 58 58 N 14 7805 6350 0 Blue 3
3 AM Thu 57 57 N 14 7627 6350 0 Blue 2
4 AM Thu 55 55 N 14 4570 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 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