Detailed Predictions for: Big Sur
Launch Altitude (f): 3200
LZ Altitude (f): 60
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 54 44 N 1 2746 3200 0 Blue 0
6 AM Tue 53 43 N 1 2746 3200 0 Blue 0
7 AM Tue 53 43 N 1 2746 3200 0 Blue 0
8 AM Tue 56 46 W 3 2746 3200 0 Blue 0
9 AM Tue 60 51 W 3 3110 3200 0 Blue 1
10 AM Tue 61 54 W 3 3181 3200 0 Blue 4
11 AM Tue 63 57 W 6 3252 3200 0 Blue 7
12 Noon Tue 63 58 W 6 3276 3205 5 Blue 8
1 PM Tue 64 60 W 6 3323 3252 52 Blue 10
2 PM Tue 64 60 W 6 3323 3252 52 Blue 10
3 PM Tue 65 60 W 6 3323 3252 52 Blue 10
4 PM Tue 66 59 W 6 3300 3228 28 Blue 9
5 PM Tue 66 57 W 5 3252 3200 0 Blue 7
6 PM Tue 67 57 W 5 3252 3200 0 Blue 7
7 PM Tue 65 55 W 5 3205 3200 0 Blue 5
8 PM Tue 61 51 W 2 3110 3200 0 Blue 1
9 PM Tue 61 51 W 2 3110 3200 0 Blue 1
10 PM Tue 62 52 W 2 3134 3200 0 Blue 2
11 PM Tue 61 51 NW 3 3110 3200 0 Blue 1
12 Midnight Wed 61 51 NW 3 3110 3200 0 Blue 1
1 AM Wed 61 51 NW 3 3110 3200 0 Blue 1
2 AM Wed 59 49 N 5 2746 3200 0 Blue 0
3 AM Wed 58 48 N 5 2746 3200 0 Blue 0
4 AM Wed 58 48 N 5 2746 3200 0 Blue 0
5 AM Wed 56 46 N 6 2746 3200 0 Blue 0
6 AM Wed 56 46 N 6 2746 3200 0 Blue 0
7 AM Wed 56 46 N 6 2746 3200 0 Blue 0
8 AM Wed 60 50 N 3 2996 3200 0 Blue 0
9 AM Wed 67 58 N 3 3276 3205 5 Blue 8
10 AM Wed 68 60 N 3 3323 3252 52 Blue 10
11 AM Wed 71 65 NW 3 3452 3370 170 Blue 15
12 Noon Wed 71 66 NW 3 3512 3394 194 Blue 16
1 PM Wed 73 69 NW 3 4154 3510 310 Blue 19
2 PM Wed 74 69 NW 3 4154 3510 310 Blue 19
3 PM Wed 75 69 NW 3 4154 3510 310 Blue 19
4 PM Wed 76 69 NW 3 4154 3510 310 Blue 19
5 PM Wed 77 68 N 15 3921 3451 251 Blue 18
6 PM Wed 78 68 N 15 3921 3451 251 Blue 18
7 PM Wed 76 66 N 15 3512 3394 194 Blue 16
8 PM Wed 71 61 N 15 3347 3276 76 Blue 11
9 PM Wed 71 61 N 15 3347 3276 76 Blue 11
10 PM Wed 72 62 N 15 3371 3299 99 Blue 12
11 PM Wed 71 61 N 14 3347 3276 76 Blue 11
12 Midnight Thu 70 60 N 14 3323 3252 52 Blue 10
1 AM Thu 70 60 N 14 3323 3252 52 Blue 10
2 AM Thu 68 58 N 14 3276 3205 5 Blue 8
3 AM Thu 66 56 N 14 3229 3200 0 Blue 6
4 AM Thu 67 57 N 14 3252 3200 0 Blue 7
5 AM Thu 64 54 N 9 3181 3200 0 Blue 4
6 AM Thu 64 54 N 9 3181 3200 0 Blue 4
7 AM Thu 64 54 N 9 3181 3200 0 Blue 4
8 AM Thu 68 58 N 9 3276 3205 5 Blue 8
9 AM Thu 74 65 N 9 3452 3370 170 Blue 15
10 AM Thu 75 67 N 9 3690 3418 218 Blue 17
11 AM Thu 78 72 NW 3 5652 4143 943 Blue 22
12 Noon Thu 78 73 NW 3 6064 4388 1188 Blue 23
1 PM Thu 79 75 NW 3 6739 5590 2390 Blue 25
2 PM Thu 80 76 NW 3 7079 6029 2829 Blue 26
3 PM Thu 81 76 NW 3 7079 6029 2829 Blue 26
4 PM Thu 82 75 NW 3 6739 5590 2390 Blue 25
5 PM Thu 82 73 N 7 6064 4388 1188 Blue 23
6 PM Thu 83 73 N 7 6064 4388 1188 Blue 23
7 PM Thu 80 70 N 7 4403 3683 483 Blue 20
8 PM Thu 74 64 N 7 3418 3347 147 Blue 14
9 PM Thu 74 64 N 7 3418 3347 147 Blue 14
10 PM Thu 75 65 N 7 3452 3370 170 Blue 15
11 PM Thu 74 64 NE 6 3418 3347 147 Blue 14
12 Midnight Fri 74 64 NE 6 3418 3347 147 Blue 14
1 AM Fri 73 63 NE 6 3394 3323 123 Blue 13
2 AM Fri 70 60 NE 6 3323 3252 52 Blue 10
3 AM Fri 69 59 NE 6 3300 3228 28 Blue 9
4 AM Fri 69 59 NE 6 3300 3228 28 Blue 9
5 AM Fri 66 56 E 7 3229 3200 0 Blue 6
6 AM Fri 65 55 E 7 3205 3200 0 Blue 5
7 AM Fri 66 56 E 7 3229 3200 0 Blue 6
8 AM Fri 67 57 E 7 3252 3200 0 Blue 7
9 AM Fri 70 61 E 7 3347 3276 76 Blue 11
10 AM Fri 71 63 E 7 3394 3323 123 Blue 13
11 AM Fri 72 66 SW 7 3512 3394 194 Blue 16
12 Noon Fri 72 67 SW 7 3690 3418 218 Blue 17
1 PM Fri 73 69 SW 7 4154 3510 310 Blue 19
2 PM Fri 73 69 SW 7 4154 3510 310 Blue 19
3 PM Fri 74 68 SW 7 3921 3451 251 Blue 18
4 PM Fri 74 67 SW 7 3690 3418 218 Blue 17
5 PM Fri 74 65 W 9 3452 3370 170 Blue 15
6 PM Fri 75 65 W 9 3452 3370 170 Blue 15
7 PM Fri 73 63 W 9 3394 3323 123 Blue 13
8 PM Fri 68 58 W 9 3276 3205 5 Blue 8
9 PM Fri 68 58 W 9 3276 3205 5 Blue 8
10 PM Fri 69 59 W 9 3300 3228 28 Blue 9
11 PM Fri 68 58 N 6 3276 3205 5 Blue 8
12 Midnight Sat 68 58 N 6 3276 3205 5 Blue 8
1 AM Sat 68 58 N 6 3276 3205 5 Blue 8
2 AM Sat 66 56 N 6 3229 3200 0 Blue 6
3 AM Sat 64 54 N 6 3181 3200 0 Blue 4
4 AM Sat 65 55 N 6 3205 3200 0 Blue 5
5 AM Sat 63 53 N 5 3158 3200 0 Blue 3
6 AM Sat 62 52 N 5 3134 3200 0 Blue 2
7 AM Sat 62 52 N 5 3134 3200 0 Blue 2
8 AM Sat 65 55 N 5 3205 3200 0 Blue 5
9 AM Sat 68 59 N 5 3300 3228 28 Blue 9
10 AM Sat 69 61 N 5 3347 3276 76 Blue 11
11 AM Sat 71 65 W 8 3452 3370 170 Blue 15
12 Noon Sat 71 66 W 8 3512 3394 194 Blue 16
1 PM Sat 72 68 W 8 3921 3451 251 Blue 18
2 PM Sat 72 68 W 8 3921 3451 251 Blue 18
3 PM Sat 73 67 W 8 3690 3418 218 Blue 17
4 PM Sat 74 67 W 8 3690 3418 218 Blue 17
5 PM Sat 74 65 NW 9 3452 3370 170 Blue 15
6 PM Sat 74 64 NW 9 3418 3347 147 Blue 14
7 PM Sat 73 63 NW 9 3394 3323 123 Blue 13
8 PM Sat 69 59 NW 9 3300 3228 28 Blue 9
9 PM Sat 69 59 NW 9 3300 3228 28 Blue 9
10 PM Sat 70 60 NW 9 3323 3252 52 Blue 10
11 PM Sat 69 59 N 7 3300 3228 28 Blue 9
12 Midnight Sun 69 59 N 7 3300 3228 28 Blue 9
1 AM Sun 69 59 N 7 3300 3228 28 Blue 9
2 AM Sun 67 57 N 7 3252 3200 0 Blue 7
3 AM Sun 66 56 N 7 3229 3200 0 Blue 6
4 AM Sun 66 56 N 7 3229 3200 0 Blue 6
5 AM Sun 64 54 N 6 3181 3200 0 Blue 4
6 AM Sun 64 54 N 6 3181 3200 0 Blue 4
7 AM Sun 64 54 N 6 3181 3200 0 Blue 4
8 AM Sun 66 56 N 6 3229 3200 0 Blue 6
9 AM Sun 69 59 N 6 3300 3228 28 Blue 9
10 AM Sun 70 61 N 6 3347 3276 76 Blue 11
11 AM Sun 71 65 NW 9 3452 3370 170 Blue 15
12 Noon Sun 71 66 NW 9 3512 3394 194 Blue 16
1 PM Sun 72 68 NW 9 3921 3451 251 Blue 18
2 PM Sun 72 68 NW 9 3921 3451 251 Blue 18
3 PM Sun 73 67 NW 9 3690 3418 218 Blue 17
4 PM Sun 73 66 NW 9 3512 3394 194 Blue 16
5 PM Sun 74 65 NW 9 3452 3370 170 Blue 15
6 PM Sun 74 64 NW 9 3418 3347 147 Blue 14
7 PM Sun 72 62 NW 9 3371 3299 99 Blue 12
8 PM Sun 68 58 NW 9 3276 3205 5 Blue 8
9 PM Sun 68 58 NW 9 3276 3205 5 Blue 8
10 PM Sun 69 59 NW 9 3300 3228 28 Blue 9
11 PM Sun 68 58 N 9 3276 3205 5 Blue 8
12 Midnight Mon 68 58 N 9 3276 3205 5 Blue 8
1 AM Mon 68 58 N 9 3276 3205 5 Blue 8
2 AM Mon 66 56 N 9 3229 3200 0 Blue 6
3 AM Mon 65 55 N 9 3205 3200 0 Blue 5
4 AM Mon 65 55 N 9 3205 3200 0 Blue 5

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