Detailed Predictions for: Mt Vaca
Launch Altitude (f): 2821
LZ Altitude (f): 2000
Sounding

Station:

KOAK

Date/Time:

24 AUG 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 Sat 65 65 SW 13 2526 2821 0 Blue 0
6 AM Sat 66 66 SW 13 2526 2821 0 Blue 0
7 AM Sat 65 65 SW 13 2526 2821 0 Blue 0
8 AM Sat 67 67 SW 14 2526 2821 0 Blue 0
9 AM Sat 68 69 SW 14 2526 2821 0 Blue 0
10 AM Sat 70 73 SW 14 2526 2821 0 Blue 0
11 AM Sat 72 77 SW 15 2919 2821 0 Blue 2
12 Noon Sat 75 82 SW 15 4411 3136 315 Blue 7
1 PM Sat 76 83 SW 15 4828 3392 571 Blue 8
2 PM Sat 78 85 SW 16 5652 4343 1522 Blue 10
3 PM Sat 78 84 SW 16 5420 3532 711 Blue 9
4 PM Sat 78 82 SW 16 4411 3136 315 Blue 7
5 PM Sat 77 79 SW 17 3138 2821 0 Blue 4
6 PM Sat 75 76 SW 17 2809 2821 0 Blue 1
7 PM Sat 74 74 SW 17 2526 2821 0 Blue 0
8 PM Sat 73 73 W 14 2526 2821 0 Blue 0
9 PM Sat 72 72 W 14 2526 2821 0 Blue 0
10 PM Sat 70 70 W 14 2526 2821 0 Blue 0
11 PM Sat 70 70 SW 13 2526 2821 0 Blue 0
12 Midnight Sun 71 71 SW 13 2526 2821 0 Blue 0
1 AM Sun 69 69 SW 13 2526 2821 0 Blue 0
2 AM Sun 70 70 W 12 2526 2821 0 Blue 0
3 AM Sun 69 69 W 12 2526 2821 0 Blue 0
4 AM Sun 68 68 W 12 2526 2821 0 Blue 0
5 AM Sun 68 68 W 10 2526 2821 0 Blue 0
6 AM Sun 69 69 W 10 2526 2821 0 Blue 0
7 AM Sun 68 68 W 10 2526 2821 0 Blue 0
8 AM Sun 72 72 W 8 2526 2821 0 Blue 0
9 AM Sun 74 76 W 8 2809 2821 0 Blue 1
10 AM Sun 76 79 W 8 3138 2821 0 Blue 4
11 AM Sun 77 82 SW 9 4411 3136 315 Blue 7
12 Noon Sun 81 86 SW 9 5884 4800 1979 Blue 11
1 PM Sun 82 88 SW 9 7152 5630 2809 Blue 13
2 PM Sun 83 90 SW 13 7430 6173 3352 Blue 15
3 PM Sun 83 89 SW 13 7291 5861 3040 Blue 14
4 PM Sun 82 86 SW 13 5884 4800 1979 Blue 11
5 PM Sun 81 83 SW 15 4828 3392 571 Blue 8
6 PM Sun 80 81 SW 15 3536 3027 206 Blue 6
7 PM Sun 78 78 SW 15 3028 2821 0 Blue 3
8 PM Sun 76 76 SW 10 2809 2821 0 Blue 1
9 PM Sun 74 74 SW 10 2526 2821 0 Blue 0
10 PM Sun 72 72 SW 10 2526 2821 0 Blue 0
11 PM Sun 71 71 SW 9 2526 2821 0 Blue 0
12 Midnight Mon 70 70 SW 9 2526 2821 0 Blue 0
1 AM Mon 70 70 SW 9 2526 2821 0 Blue 0
2 AM Mon 70 70 W 9 2526 2821 0 Blue 0
3 AM Mon 69 69 W 9 2526 2821 0 Blue 0
4 AM Mon 68 68 W 9 2526 2821 0 Blue 0
5 AM Mon 68 68 W 9 2526 2821 0 Blue 0
6 AM Mon 68 68 W 9 2526 2821 0 Blue 0
7 AM Mon 69 69 W 9 2526 2821 0 Blue 0
8 AM Mon 70 70 W 7 2526 2821 0 Blue 0
9 AM Mon 73 74 W 7 2526 2821 0 Blue 0
10 AM Mon 75 78 W 7 3028 2821 0 Blue 3
11 AM Mon 78 83 SW 7 4828 3392 571 Blue 8
12 Noon Mon 80 87 SW 7 6759 5399 2578 Blue 12
1 PM Mon 83 90 SW 7 7430 6173 3352 Blue 15
2 PM Mon 84 91 SW 9 7569 7132 4311 Blue 16
3 PM Mon 85 91 SW 9 7569 7132 4311 Blue 16
4 PM Mon 84 88 SW 9 7152 5630 2809 Blue 13
5 PM Mon 83 85 SW 14 5652 4343 1522 Blue 10
6 PM Mon 82 83 SW 14 4828 3392 571 Blue 8
7 PM Mon 80 80 SW 14 3396 2917 96 Blue 5
8 PM Mon 77 77 SW 10 2919 2821 0 Blue 2
9 PM Mon 75 75 SW 10 2683 2821 0 Blue 0
10 PM Mon 73 73 SW 10 2526 2821 0 Blue 0
11 PM Mon 72 72 SW 9 2526 2821 0 Blue 0
12 Midnight Tue 71 71 SW 9 2526 2821 0 Blue 0
1 AM Tue 71 71 SW 9 2526 2821 0 Blue 0
2 AM Tue 71 71 SW 9 2526 2821 0 Blue 0
3 AM Tue 70 70 SW 9 2526 2821 0 Blue 0
4 AM Tue 68 68 SW 9 2526 2821 0 Blue 0
5 AM Tue 68 68 W 9 2526 2821 0 Blue 0
6 AM Tue 69 69 W 9 2526 2821 0 Blue 0
7 AM Tue 70 70 W 9 2526 2821 0 Blue 0
8 AM Tue 72 72 SW 7 2526 2821 0 Blue 0
9 AM Tue 74 75 SW 7 2683 2821 0 Blue 0
10 AM Tue 75 77 SW 7 2919 2821 0 Blue 2
11 AM Tue 77 81 SW 7 3536 3027 206 Blue 6
12 Noon Tue 80 86 SW 7 5884 4800 1979 Blue 11
1 PM Tue 82 88 SW 7 7152 5630 2809 Blue 13
2 PM Tue 83 89 SW 10 7291 5861 3040 Blue 14
3 PM Tue 84 89 SW 10 7291 5861 3040 Blue 14
4 PM Tue 83 87 SW 10 6759 5399 2578 Blue 12
5 PM Tue 82 84 SW 15 5420 3532 711 Blue 9
6 PM Tue 80 81 SW 15 3536 3027 206 Blue 6
7 PM Tue 78 78 SW 15 3028 2821 0 Blue 3
8 PM Tue 76 76 SW 10 2809 2821 0 Blue 1
9 PM Tue 74 74 SW 10 2526 2821 0 Blue 0
10 PM Tue 72 72 SW 10 2526 2821 0 Blue 0
11 PM Tue 71 71 SW 9 2526 2821 0 Blue 0
12 Midnight Wed 70 70 SW 9 2526 2821 0 Blue 0
1 AM Wed 70 70 SW 9 2526 2821 0 Blue 0
2 AM Wed 70 70 SW 10 2526 2821 0 Blue 0
3 AM Wed 70 70 SW 10 2526 2821 0 Blue 0
4 AM Wed 69 69 SW 10 2526 2821 0 Blue 0
5 AM Wed 69 69 SW 9 2526 2821 0 Blue 0
6 AM Wed 69 69 SW 9 2526 2821 0 Blue 0
7 AM Wed 70 70 SW 9 2526 2821 0 Blue 0
8 AM Wed 71 71 SW 9 2526 2821 0 Blue 0
9 AM Wed 72 73 SW 9 2526 2821 0 Blue 0
10 AM Wed 74 76 SW 9 2809 2821 0 Blue 1
11 AM Wed 75 79 SW 9 3138 2821 0 Blue 4
12 Noon Wed 77 82 SW 9 4411 3136 315 Blue 7
1 PM Wed 79 85 SW 9 5652 4343 1522 Blue 10
2 PM Wed 80 86 SW 13 5884 4800 1979 Blue 11
3 PM Wed 80 85 SW 13 5652 4343 1522 Blue 10
4 PM Wed 80 83 SW 13 4828 3392 571 Blue 8
5 PM Wed 79 81 SW 17 3536 3027 206 Blue 6
6 PM Wed 78 79 SW 17 3138 2821 0 Blue 4
7 PM Wed 76 76 SW 17 2809 2821 0 Blue 1
8 PM Wed 74 74 SW 13 2526 2821 0 Blue 0
9 PM Wed 72 72 SW 13 2526 2821 0 Blue 0
10 PM Wed 71 71 SW 13 2526 2821 0 Blue 0
11 PM Wed 69 69 SW 12 2526 2821 0 Blue 0
12 Midnight Thu 69 69 SW 12 2526 2821 0 Blue 0
1 AM Thu 70 70 SW 12 2526 2821 0 Blue 0
2 AM Thu 70 70 SW 13 2526 2821 0 Blue 0
3 AM Thu 70 70 SW 13 2526 2821 0 Blue 0
4 AM Thu 69 69 SW 13 2526 2821 0 Blue 0
5 AM Thu 69 69 SW 12 2526 2821 0 Blue 0
6 AM Thu 69 69 SW 12 2526 2821 0 Blue 0
7 AM Thu 69 69 SW 12 2526 2821 0 Blue 0
8 AM Thu 70 70 SW 9 2526 2821 0 Blue 0
9 AM Thu 70 71 SW 9 2526 2821 0 Blue 0
10 AM Thu 71 74 SW 9 2526 2821 0 Blue 0
11 AM Thu 73 78 SW 9 3028 2821 0 Blue 3
12 Noon Thu 74 80 SW 9 3396 2917 96 Blue 5
1 PM Thu 76 83 SW 9 4828 3392 571 Blue 8
2 PM Thu 78 85 SW 14 5652 4343 1522 Blue 10
3 PM Thu 78 84 SW 14 5420 3532 711 Blue 9
4 PM Thu 77 81 SW 14 3536 3027 206 Blue 6
5 PM Thu 76 78 SW 16 3028 2821 0 Blue 3
6 PM Thu 76 77 SW 16 2919 2821 0 Blue 2
7 PM Thu 74 74 SW 16 2526 2821 0 Blue 0
8 PM Thu 73 73 SW 12 2526 2821 0 Blue 0
9 PM Thu 72 72 SW 12 2526 2821 0 Blue 0
10 PM Thu 70 70 SW 12 2526 2821 0 Blue 0
11 PM Thu 69 69 SW 9 2526 2821 0 Blue 0
12 Midnight Fri 69 69 SW 9 2526 2821 0 Blue 0
1 AM Fri 69 69 SW 9 2526 2821 0 Blue 0
2 AM Fri 69 69 SW 10 2526 2821 0 Blue 0
3 AM Fri 68 68 SW 10 2526 2821 0 Blue 0
4 AM Fri 68 68 SW 10 2526 2821 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