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

Station:

KOAK

Date/Time:

18 SEP 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 Tue 46 46 N 6 4380 6350 0 Blue 0
6 AM Tue 46 46 N 6 4380 6350 0 Blue 0
7 AM Tue 47 47 N 6 4380 6350 0 Blue 0
8 AM Tue 48 48 N 3 4380 6350 0 Blue 0
9 AM Tue 52 53 N 3 4380 6350 0 Blue 0
10 AM Tue 56 58 N 3 4380 6350 0 Blue 0
11 AM Tue 60 63 E 5 5579 6350 0 Blue 1
12 Noon Tue 63 67 E 5 7079 6350 0 Blue 5
1 PM Tue 65 70 E 5 7723 7049 699 Blue 8
2 PM Tue 66 71 E 5 7920 7310 960 Blue 9
3 PM Tue 66 70 E 5 7723 7049 699 Blue 8
4 PM Tue 65 67 E 5 7079 6350 0 Blue 5
5 PM Tue 64 65 W 2 6381 6350 0 Blue 3
6 PM Tue 60 60 W 2 4380 6350 0 Blue 0
7 PM Tue 56 56 W 2 4380 6350 0 Blue 0
8 PM Tue 53 53 NW 7 4380 6350 0 Blue 0
9 PM Tue 51 51 NW 7 4380 6350 0 Blue 0
10 PM Tue 51 51 NW 7 4380 6350 0 Blue 0
11 PM Tue 51 51 NW 6 4380 6350 0 Blue 0
12 Midnight Wed 50 50 NW 6 4380 6350 0 Blue 0
1 AM Wed 50 50 NW 6 4380 6350 0 Blue 0
2 AM Wed 49 49 N 6 4380 6350 0 Blue 0
3 AM Wed 49 49 N 6 4380 6350 0 Blue 0
4 AM Wed 49 49 N 6 4380 6350 0 Blue 0
5 AM Wed 48 48 N 6 4380 6350 0 Blue 0
6 AM Wed 48 48 N 6 4380 6350 0 Blue 0
7 AM Wed 48 48 N 6 4380 6350 0 Blue 0
8 AM Wed 50 50 N 5 4380 6350 0 Blue 0
9 AM Wed 54 55 N 5 4380 6350 0 Blue 0
10 AM Wed 59 61 N 5 4380 6350 0 Blue 0
11 AM Wed 64 68 NE 6 7328 6360 10 Blue 6
12 Noon Wed 67 72 NE 6 8305 7506 1156 Blue 10
1 PM Wed 69 74 NE 6 9099 7898 1548 Blue 12
2 PM Wed 70 75 N 5 9487 8254 1904 Blue 13
3 PM Wed 70 74 N 5 9099 7898 1548 Blue 12
4 PM Wed 70 73 N 5 8705 7702 1352 Blue 11
5 PM Wed 68 69 N 6 7526 6704 354 Blue 7
6 PM Wed 65 65 N 6 6381 6350 0 Blue 3
7 PM Wed 61 61 N 6 4380 6350 0 Blue 0
8 PM Wed 58 58 N 6 4380 6350 0 Blue 0
9 PM Wed 56 56 N 6 4380 6350 0 Blue 0
10 PM Wed 54 54 N 6 4380 6350 0 Blue 0
11 PM Wed 54 54 SW 8 4380 6350 0 Blue 0
12 Midnight Thu 53 53 SW 8 4380 6350 0 Blue 0
1 AM Thu 53 53 SW 8 4380 6350 0 Blue 0
2 AM Thu 52 52 SW 8 4380 6350 0 Blue 0
3 AM Thu 52 52 SW 8 4380 6350 0 Blue 0
4 AM Thu 52 52 SW 8 4380 6350 0 Blue 0
5 AM Thu 51 51 N 9 4380 6350 0 Blue 0
6 AM Thu 51 51 N 9 4380 6350 0 Blue 0
7 AM Thu 51 51 N 9 4380 6350 0 Blue 0
8 AM Thu 53 53 N 9 4380 6350 0 Blue 0
9 AM Thu 58 59 N 9 4380 6350 0 Blue 0
10 AM Thu 63 65 N 9 6381 6350 0 Blue 3
11 AM Thu 67 71 N 9 7920 7310 960 Blue 9
12 Noon Thu 70 75 N 9 9487 8254 1904 Blue 13
1 PM Thu 71 76 N 9 9870 8650 2300 Blue 14
2 PM Thu 72 77 N 9 10237 9040 2690 Blue 15
3 PM Thu 73 77 N 9 10237 9040 2690 Blue 15
4 PM Thu 73 76 N 9 9870 8650 2300 Blue 14
5 PM Thu 71 72 NW 6 8305 7506 1156 Blue 10
6 PM Thu 68 68 NW 6 7328 6360 10 Blue 6
7 PM Thu 64 64 NW 6 6038 6350 0 Blue 2
8 PM Thu 60 60 NW 6 4380 6350 0 Blue 0
9 PM Thu 58 58 NW 6 4380 6350 0 Blue 0
10 PM Thu 57 57 NW 6 4380 6350 0 Blue 0
11 PM Thu 57 57 NW 6 4380 6350 0 Blue 0
12 Midnight Fri 56 56 NW 6 4380 6350 0 Blue 0
1 AM Fri 56 56 NW 6 4380 6350 0 Blue 0
2 AM Fri 55 55 NW 6 4380 6350 0 Blue 0
3 AM Fri 55 55 NW 6 4380 6350 0 Blue 0
4 AM Fri 54 54 NW 6 4380 6350 0 Blue 0
5 AM Fri 54 54 N 7 4380 6350 0 Blue 0
6 AM Fri 53 53 N 7 4380 6350 0 Blue 0
7 AM Fri 53 53 N 7 4380 6350 0 Blue 0
8 AM Fri 55 55 N 7 4380 6350 0 Blue 0
9 AM Fri 59 60 N 7 4380 6350 0 Blue 0
10 AM Fri 64 66 N 7 6729 6350 0 Blue 4
11 AM Fri 69 72 N 5 8305 7506 1156 Blue 10
12 Noon Fri 71 76 N 5 9870 8650 2300 Blue 14
1 PM Fri 72 77 N 5 10237 9040 2690 Blue 15
2 PM Fri 73 78 N 5 10549 9424 3074 Blue 16
3 PM Fri 73 77 N 5 10237 9040 2690 Blue 15
4 PM Fri 73 76 N 5 9870 8650 2300 Blue 14
5 PM Fri 71 72 SW 9 8305 7506 1156 Blue 10
6 PM Fri 67 67 SW 9 7079 6350 0 Blue 5
7 PM Fri 63 63 SW 9 5579 6350 0 Blue 1
8 PM Fri 59 59 SW 9 4380 6350 0 Blue 0
9 PM Fri 57 57 SW 9 4380 6350 0 Blue 0
10 PM Fri 56 56 SW 9 4380 6350 0 Blue 0
11 PM Fri 56 56 NW 8 4380 6350 0 Blue 0
12 Midnight Sat 56 56 NW 8 4380 6350 0 Blue 0
1 AM Sat 55 55 NW 8 4380 6350 0 Blue 0
2 AM Sat 54 54 NW 8 4380 6350 0 Blue 0
3 AM Sat 54 54 NW 8 4380 6350 0 Blue 0
4 AM Sat 53 53 NW 8 4380 6350 0 Blue 0
5 AM Sat 52 52 NW 6 4380 6350 0 Blue 0
6 AM Sat 52 52 NW 6 4380 6350 0 Blue 0
7 AM Sat 53 53 NW 6 4380 6350 0 Blue 0
8 AM Sat 54 54 NW 6 4380 6350 0 Blue 0
9 AM Sat 57 57 NW 6 4380 6350 0 Blue 0
10 AM Sat 60 61 NW 6 4380 6350 0 Blue 0
11 AM Sat 64 67 NW 12 7079 6350 0 Blue 5
12 Noon Sat 65 69 NW 12 7526 6704 354 Blue 7
1 PM Sat 66 70 NW 12 7723 7049 699 Blue 8
2 PM Sat 67 71 NW 12 7920 7310 960 Blue 9
3 PM Sat 67 70 NW 12 7723 7049 699 Blue 8
4 PM Sat 67 69 NW 12 7526 6704 354 Blue 7
5 PM Sat 65 66 SW 9 6729 6350 0 Blue 4
6 PM Sat 62 62 SW 9 4665 6350 0 Blue 0
7 PM Sat 59 59 SW 9 4380 6350 0 Blue 0
8 PM Sat 56 56 SW 9 4380 6350 0 Blue 0
9 PM Sat 54 54 SW 9 4380 6350 0 Blue 0
10 PM Sat 54 54 SW 9 4380 6350 0 Blue 0
11 PM Sat 54 54 W 7 4380 6350 0 Blue 0
12 Midnight Sun 54 54 W 7 4380 6350 0 Blue 0
1 AM Sun 53 53 W 7 4380 6350 0 Blue 0
2 AM Sun 53 53 W 7 4380 6350 0 Blue 0
3 AM Sun 52 52 W 7 4380 6350 0 Blue 0
4 AM Sun 52 52 W 7 4380 6350 0 Blue 0
5 AM Sun 51 51 NW 6 4380 6350 0 Blue 0
6 AM Sun 51 51 NW 6 4380 6350 0 Blue 0
7 AM Sun 51 51 NW 6 4380 6350 0 Blue 0
8 AM Sun 53 53 NW 6 4380 6350 0 Blue 0
9 AM Sun 55 55 NW 6 4380 6350 0 Blue 0
10 AM Sun 58 59 NW 6 4380 6350 0 Blue 0
11 AM Sun 60 63 NW 13 5579 6350 0 Blue 1
12 Noon Sun 62 66 NW 13 6729 6350 0 Blue 4
1 PM Sun 63 67 NW 13 7079 6350 0 Blue 5
2 PM Sun 64 68 NW 13 7328 6360 10 Blue 6
3 PM Sun 64 67 NW 13 7079 6350 0 Blue 5
4 PM Sun 64 66 NW 13 6729 6350 0 Blue 4
5 PM Sun 62 63 SW 12 5579 6350 0 Blue 1
6 PM Sun 59 59 SW 12 4380 6350 0 Blue 0
7 PM Sun 56 56 SW 12 4380 6350 0 Blue 0
8 PM Sun 53 53 SW 12 4380 6350 0 Blue 0
9 PM Sun 51 51 SW 12 4380 6350 0 Blue 0
10 PM Sun 51 51 SW 12 4380 6350 0 Blue 0
11 PM Sun 50 50 NE 8 4380 6350 0 Blue 0
12 Midnight Mon 50 50 NE 8 4380 6350 0 Blue 0
1 AM Mon 49 49 NE 8 4380 6350 0 Blue 0
2 AM Mon 49 49 NE 8 4380 6350 0 Blue 0
3 AM Mon 49 49 NE 8 4380 6350 0 Blue 0
4 AM Mon 48 48 NE 8 4380 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