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

Station:

KOAK

Date/Time:

27 MAY 2018

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 49 49 N 8 4252 6350 0 Blue 0
6 AM Sun 50 50 N 8 4252 6350 0 Blue 0
7 AM Sun 52 52 N 8 4252 6350 0 Blue 0
8 AM Sun 55 56 N 10 5103 6350 0 Blue 0
9 AM Sun 60 63 N 10 7824 7583 1233 Blue 7
10 AM Sun 64 68 N 10 8695 7970 1620 Blue 12
11 AM Sun 68 74 N 10 10741 9633 3283 Blue 18
12 Noon Sun 70 77 N 10 11829 10693 4343 Blue 21
1 PM Sun 72 80 N 10 12679 11705 5355 Blue 24
2 PM Sun 72 80 N 9 12679 11705 5355 Blue 24
3 PM Sun 73 79 N 9 12504 11275 4925 Blue 23
4 PM Sun 73 78 N 9 12169 10958 4608 Blue 22
5 PM Sun 72 75 NE 10 11027 10175 3825 Blue 19
6 PM Sun 70 71 NE 10 9729 8650 2300 Blue 15
7 PM Sun 68 68 NE 10 8695 7970 1620 Blue 12
8 PM Sun 65 65 NE 9 7979 7738 1388 Blue 9
9 PM Sun 63 63 NE 9 7824 7583 1233 Blue 7
10 PM Sun 61 61 NE 9 7669 6384 34 Blue 5
11 PM Sun 61 61 N 10 7669 6384 34 Blue 5
12 Midnight Mon 61 61 N 10 7669 6384 34 Blue 5
1 AM Mon 61 61 N 10 7669 6384 34 Blue 5
2 AM Mon 61 61 N 10 7669 6384 34 Blue 5
3 AM Mon 60 60 N 10 7591 6350 0 Blue 4
4 AM Mon 59 59 N 10 7514 6350 0 Blue 3
5 AM Mon 58 58 N 10 6471 6350 0 Blue 2
6 AM Mon 59 59 N 10 7514 6350 0 Blue 3
7 AM Mon 60 60 N 10 7591 6350 0 Blue 4
8 AM Mon 63 64 N 13 7901 7660 1310 Blue 8
9 AM Mon 66 69 N 13 9017 8047 1697 Blue 13
10 AM Mon 69 74 N 13 10741 9633 3283 Blue 18
11 AM Mon 72 78 N 12 12169 10958 4608 Blue 22
12 Noon Mon 74 82 N 12 13022 12415 6065 Blue 26
1 PM Mon 74 82 N 12 13022 12415 6065 Blue 26
2 PM Mon 75 83 N 12 13424 12632 6282 White 27
3 PM Mon 76 82 N 12 13022 12415 6065 Blue 26
4 PM Mon 76 81 N 12 12851 12082 5732 Blue 25
5 PM Mon 75 78 NE 8 12169 10958 4608 Blue 22
6 PM Mon 73 74 NE 8 10741 9633 3283 Blue 18
7 PM Mon 70 70 NE 8 9336 8329 1979 Blue 14
8 PM Mon 68 68 NE 8 8695 7970 1620 Blue 12
9 PM Mon 66 66 NE 8 8057 7815 1465 Blue 10
10 PM Mon 65 65 NE 8 7979 7738 1388 Blue 9
11 PM Mon 64 64 N 8 7901 7660 1310 Blue 8
12 Midnight Tue 64 64 N 8 7901 7660 1310 Blue 8
1 AM Tue 63 63 N 8 7824 7583 1233 Blue 7
2 AM Tue 62 62 N 8 7746 7506 1156 Blue 6
3 AM Tue 62 62 N 8 7746 7506 1156 Blue 6
4 AM Tue 61 61 N 8 7669 6384 34 Blue 5
5 AM Tue 61 61 N 7 7669 6384 34 Blue 5
6 AM Tue 62 62 N 7 7746 7506 1156 Blue 6
7 AM Tue 63 63 N 7 7824 7583 1233 Blue 7
8 AM Tue 65 66 N 7 8057 7815 1465 Blue 10
9 AM Tue 68 70 N 7 9336 8329 1979 Blue 14
10 AM Tue 71 75 N 7 11027 10175 3825 Blue 19
11 AM Tue 73 79 SE 13 12504 11275 4925 Blue 23
12 Noon Tue 75 82 SE 13 13022 12415 6065 Blue 26
1 PM Tue 75 82 SE 13 13022 12415 6065 Blue 26
2 PM Tue 75 82 SE 13 13022 12415 6065 Blue 26
3 PM Tue 75 81 SE 13 12851 12082 5732 Blue 25
4 PM Tue 74 78 SE 13 12169 10958 4608 Blue 22
5 PM Tue 72 74 W 13 10741 9633 3283 Blue 18
6 PM Tue 70 71 W 13 9729 8650 2300 Blue 15
7 PM Tue 66 66 W 13 8057 7815 1465 Blue 10
8 PM Tue 63 63 W 13 7824 7583 1233 Blue 7
9 PM Tue 60 60 W 13 7591 6350 0 Blue 4
10 PM Tue 58 58 W 13 6471 6350 0 Blue 2
11 PM Tue 57 57 N 13 5713 6350 0 Blue 1
12 Midnight Wed 56 56 N 13 5103 6350 0 Blue 0
1 AM Wed 55 55 N 13 4756 6350 0 Blue 0
2 AM Wed 55 55 N 13 4756 6350 0 Blue 0
3 AM Wed 54 54 N 13 4524 6350 0 Blue 0
4 AM Wed 53 53 N 13 4291 6350 0 Blue 0
5 AM Wed 53 53 N 8 4291 6350 0 Blue 0
6 AM Wed 53 53 N 8 4291 6350 0 Blue 0
7 AM Wed 54 54 N 8 4524 6350 0 Blue 0
8 AM Wed 55 56 N 8 5103 6350 0 Blue 0
9 AM Wed 58 60 N 8 7591 6350 0 Blue 4
10 AM Wed 60 63 N 8 7824 7583 1233 Blue 7
11 AM Wed 63 67 NE 15 8370 7892 1542 Blue 11
12 Noon Wed 64 69 NE 15 9017 8047 1697 Blue 13
1 PM Wed 65 71 NE 15 9729 8650 2300 Blue 15
2 PM Wed 65 70 NE 15 9336 8329 1979 Blue 14
3 PM Wed 65 70 NE 15 9336 8329 1979 Blue 14
4 PM Wed 64 67 NE 15 8370 7892 1542 Blue 11
5 PM Wed 63 65 S 12 7979 7738 1388 Blue 9
6 PM Wed 60 61 S 12 7669 6384 34 Blue 5
7 PM Wed 58 58 S 12 6471 6350 0 Blue 2
8 PM Wed 55 55 S 12 4756 6350 0 Blue 0
9 PM Wed 53 53 S 12 4291 6350 0 Blue 0
10 PM Wed 52 52 S 12 4252 6350 0 Blue 0
11 PM Wed 51 51 NW 7 4252 6350 0 Blue 0
12 Midnight Thu 51 51 NW 7 4252 6350 0 Blue 0
1 AM Thu 50 50 NW 7 4252 6350 0 Blue 0
2 AM Thu 50 50 NW 7 4252 6350 0 Blue 0
3 AM Thu 49 49 NW 7 4252 6350 0 Blue 0
4 AM Thu 48 48 NW 7 4252 6350 0 Blue 0
5 AM Thu 48 48 NW 7 4252 6350 0 Blue 0
6 AM Thu 48 48 NW 7 4252 6350 0 Blue 0
7 AM Thu 48 48 NW 7 4252 6350 0 Blue 0
8 AM Thu 49 50 NW 7 4252 6350 0 Blue 0
9 AM Thu 49 51 NW 7 4252 6350 0 Blue 0
10 AM Thu 50 53 NW 7 4291 6350 0 Blue 0
11 AM Thu 51 56 W 7 5103 6350 0 Blue 0
12 Noon Thu 51 57 W 7 5713 6350 0 Blue 1
1 PM Thu 52 58 W 7 6471 6350 0 Blue 2
2 PM Thu 52 58 W 7 6471 6350 0 Blue 2
3 PM Thu 52 57 W 7 5713 6350 0 Blue 1
4 PM Thu 52 55 W 7 4756 6350 0 Blue 0
5 PM Thu 51 53 W 9 4291 6350 0 Blue 0
6 PM Thu 50 51 W 9 4252 6350 0 Blue 0
7 PM Thu 48 48 W 9 4252 6350 0 Blue 0
8 PM Thu 47 47 W 9 4252 6350 0 Blue 0
9 PM Thu 46 46 W 9 4252 6350 0 Blue 0
10 PM Thu 45 45 W 9 4252 6350 0 Blue 0
11 PM Thu 45 45 NW 9 4252 6350 0 Blue 0
12 Midnight Fri 44 44 NW 9 4252 6350 0 Blue 0
1 AM Fri 44 44 NW 9 4252 6350 0 Blue 0
2 AM Fri 44 44 NW 9 4252 6350 0 Blue 0
3 AM Fri 44 44 NW 9 4252 6350 0 Blue 0
4 AM Fri 44 44 NW 9 4252 6350 0 Blue 0
5 AM Fri 44 44 NW 10 4252 6350 0 Blue 0
6 AM Fri 45 45 NW 10 4252 6350 0 Blue 0
7 AM Fri 47 47 NW 10 4252 6350 0 Blue 0
8 AM Fri 49 50 NW 10 4252 6350 0 Blue 0
9 AM Fri 51 53 NW 10 4291 6350 0 Blue 0
10 AM Fri 53 56 NW 10 5103 6350 0 Blue 0
11 AM Fri 55 60 SW 6 7591 6350 0 Blue 4
12 Noon Fri 57 64 SW 6 7901 7660 1310 Blue 8
1 PM Fri 58 65 SW 6 7979 7738 1388 Blue 9
2 PM Fri 59 66 SW 6 8057 7815 1465 Blue 10
3 PM Fri 59 65 SW 6 7979 7738 1388 Blue 9
4 PM Fri 59 63 SW 6 7824 7583 1233 Blue 7
5 PM Fri 58 60 SW 7 7591 6350 0 Blue 4
6 PM Fri 56 57 SW 7 5713 6350 0 Blue 1
7 PM Fri 54 54 SW 7 4524 6350 0 Blue 0
8 PM Fri 52 52 SW 7 4252 6350 0 Blue 0
9 PM Fri 51 51 SW 7 4252 6350 0 Blue 0
10 PM Fri 50 50 SW 7 4252 6350 0 Blue 0
11 PM Fri 50 50 NW 6 4252 6350 0 Blue 0
12 Midnight Sat 50 50 NW 6 4252 6350 0 Blue 0
1 AM Sat 49 49 NW 6 4252 6350 0 Blue 0
2 AM Sat 49 49 NW 6 4252 6350 0 Blue 0
3 AM Sat 48 48 NW 6 4252 6350 0 Blue 0
4 AM Sat 48 48 NW 6 4252 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