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

Station:

KOAK

Date/Time:

25 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 Sun 68 68 W 10 2287 2821 0 Blue 0
6 AM Sun 71 71 W 10 2287 2821 0 Blue 0
7 AM Sun 67 67 W 10 2287 2821 0 Blue 0
8 AM Sun 70 70 W 9 2287 2821 0 Blue 0
9 AM Sun 73 74 W 9 2287 2821 0 Blue 0
10 AM Sun 75 78 W 9 2883 2821 0 Blue 1
11 AM Sun 77 82 SW 12 4202 3055 234 Blue 5
12 Noon Sun 80 87 SW 12 6477 5070 2249 Blue 10
1 PM Sun 82 89 SW 12 7091 5982 3161 Blue 12
2 PM Sun 83 90 SW 14 7313 6424 3603 Blue 13
3 PM Sun 84 90 SW 14 7313 6424 3603 Blue 13
4 PM Sun 84 88 SW 14 6826 5531 2710 Blue 11
5 PM Sun 82 84 SW 15 5106 3902 1081 Blue 7
6 PM Sun 80 81 SW 15 3914 2882 61 Blue 4
7 PM Sun 78 78 SW 15 2883 2821 0 Blue 1
8 PM Sun 77 77 SW 10 2471 2821 0 Blue 0
9 PM Sun 74 74 SW 10 2287 2821 0 Blue 0
10 PM Sun 72 72 SW 10 2287 2821 0 Blue 0
11 PM Sun 70 70 W 9 2287 2821 0 Blue 0
12 Midnight Mon 71 71 W 9 2287 2821 0 Blue 0
1 AM Mon 70 70 W 9 2287 2821 0 Blue 0
2 AM Mon 70 70 W 9 2287 2821 0 Blue 0
3 AM Mon 69 69 W 9 2287 2821 0 Blue 0
4 AM Mon 68 68 W 9 2287 2821 0 Blue 0
5 AM Mon 67 67 W 9 2287 2821 0 Blue 0
6 AM Mon 69 69 W 9 2287 2821 0 Blue 0
7 AM Mon 69 69 W 9 2287 2821 0 Blue 0
8 AM Mon 72 72 W 7 2287 2821 0 Blue 0
9 AM Mon 75 76 W 7 2287 2821 0 Blue 0
10 AM Mon 77 80 W 7 3625 2821 0 Blue 3
11 AM Mon 79 84 S 6 5106 3902 1081 Blue 7
12 Noon Mon 82 89 S 6 7091 5982 3161 Blue 12
1 PM Mon 84 91 S 6 7421 6791 3970 Blue 14
2 PM Mon 86 93 SW 9 8244 7297 4476 Blue 16
3 PM Mon 86 92 SW 9 7529 7054 4233 Blue 15
4 PM Mon 85 89 SW 9 7091 5982 3161 Blue 12
5 PM Mon 84 86 SW 14 6030 4401 1580 Blue 9
6 PM Mon 82 83 SW 14 4411 3616 795 Blue 6
7 PM Mon 79 79 SW 14 3062 2821 0 Blue 2
8 PM Mon 77 77 SW 10 2471 2821 0 Blue 0
9 PM Mon 74 74 SW 10 2287 2821 0 Blue 0
10 PM Mon 73 73 SW 10 2287 2821 0 Blue 0
11 PM Mon 71 71 SW 9 2287 2821 0 Blue 0
12 Midnight Tue 71 71 SW 9 2287 2821 0 Blue 0
1 AM Tue 71 71 SW 9 2287 2821 0 Blue 0
2 AM Tue 70 70 SW 9 2287 2821 0 Blue 0
3 AM Tue 69 69 SW 9 2287 2821 0 Blue 0
4 AM Tue 68 68 SW 9 2287 2821 0 Blue 0
5 AM Tue 67 67 W 9 2287 2821 0 Blue 0
6 AM Tue 68 68 W 9 2287 2821 0 Blue 0
7 AM Tue 69 69 W 9 2287 2821 0 Blue 0
8 AM Tue 71 71 W 8 2287 2821 0 Blue 0
9 AM Tue 73 73 W 8 2287 2821 0 Blue 0
10 AM Tue 75 76 W 8 2287 2821 0 Blue 0
11 AM Tue 78 82 SW 7 4202 3055 234 Blue 5
12 Noon Tue 81 86 SW 7 6030 4401 1580 Blue 9
1 PM Tue 83 88 SW 7 6826 5531 2710 Blue 11
2 PM Tue 85 92 SW 10 7529 7054 4233 Blue 15
3 PM Tue 85 91 SW 10 7421 6791 3970 Blue 14
4 PM Tue 84 88 SW 10 6826 5531 2710 Blue 11
5 PM Tue 82 84 SW 15 5106 3902 1081 Blue 7
6 PM Tue 80 81 SW 15 3914 2882 61 Blue 4
7 PM Tue 78 78 SW 15 2883 2821 0 Blue 1
8 PM Tue 76 76 SW 10 2287 2821 0 Blue 0
9 PM Tue 74 74 SW 10 2287 2821 0 Blue 0
10 PM Tue 72 72 SW 10 2287 2821 0 Blue 0
11 PM Tue 71 71 SW 9 2287 2821 0 Blue 0
12 Midnight Wed 70 70 SW 9 2287 2821 0 Blue 0
1 AM Wed 71 71 SW 9 2287 2821 0 Blue 0
2 AM Wed 71 71 SW 10 2287 2821 0 Blue 0
3 AM Wed 70 70 SW 10 2287 2821 0 Blue 0
4 AM Wed 69 69 SW 10 2287 2821 0 Blue 0
5 AM Wed 69 69 SW 10 2287 2821 0 Blue 0
6 AM Wed 69 69 SW 10 2287 2821 0 Blue 0
7 AM Wed 70 70 SW 10 2287 2821 0 Blue 0
8 AM Wed 72 72 SW 9 2287 2821 0 Blue 0
9 AM Wed 73 75 SW 9 2287 2821 0 Blue 0
10 AM Wed 75 78 SW 9 2883 2821 0 Blue 1
11 AM Wed 76 80 SW 9 3625 2821 0 Blue 3
12 Noon Wed 78 84 SW 9 5106 3902 1081 Blue 7
1 PM Wed 80 86 SW 9 6030 4401 1580 Blue 9
2 PM Wed 81 88 SW 14 6826 5531 2710 Blue 11
3 PM Wed 81 87 SW 14 6477 5070 2249 Blue 10
4 PM Wed 80 84 SW 14 5106 3902 1081 Blue 7
5 PM Wed 79 81 SW 17 3914 2882 61 Blue 4
6 PM Wed 77 78 SW 17 2883 2821 0 Blue 1
7 PM Wed 75 75 SW 17 2287 2821 0 Blue 0
8 PM Wed 73 73 SW 13 2287 2821 0 Blue 0
9 PM Wed 71 71 SW 13 2287 2821 0 Blue 0
10 PM Wed 69 69 SW 13 2287 2821 0 Blue 0
11 PM Wed 68 68 SW 10 2287 2821 0 Blue 0
12 Midnight Thu 68 68 SW 10 2287 2821 0 Blue 0
1 AM Thu 69 69 SW 10 2287 2821 0 Blue 0
2 AM Thu 69 69 SW 12 2287 2821 0 Blue 0
3 AM Thu 68 68 SW 12 2287 2821 0 Blue 0
4 AM Thu 68 68 SW 12 2287 2821 0 Blue 0
5 AM Thu 67 67 SW 12 2287 2821 0 Blue 0
6 AM Thu 67 67 SW 12 2287 2821 0 Blue 0
7 AM Thu 68 68 SW 12 2287 2821 0 Blue 0
8 AM Thu 69 69 SW 10 2287 2821 0 Blue 0
9 AM Thu 70 72 SW 10 2287 2821 0 Blue 0
10 AM Thu 71 74 SW 10 2287 2821 0 Blue 0
11 AM Thu 73 78 SW 9 2883 2821 0 Blue 1
12 Noon Thu 75 82 SW 9 4202 3055 234 Blue 5
1 PM Thu 78 85 SW 9 5573 4187 1366 Blue 8
2 PM Thu 79 86 SW 14 6030 4401 1580 Blue 9
3 PM Thu 79 85 SW 14 5573 4187 1366 Blue 8
4 PM Thu 78 82 SW 14 4202 3055 234 Blue 5
5 PM Thu 77 79 SW 17 3062 2821 0 Blue 2
6 PM Thu 76 77 SW 17 2471 2821 0 Blue 0
7 PM Thu 74 74 SW 17 2287 2821 0 Blue 0
8 PM Thu 72 72 SW 12 2287 2821 0 Blue 0
9 PM Thu 70 70 SW 12 2287 2821 0 Blue 0
10 PM Thu 68 68 SW 12 2287 2821 0 Blue 0
11 PM Thu 67 67 SW 9 2287 2821 0 Blue 0
12 Midnight Fri 67 67 SW 9 2287 2821 0 Blue 0
1 AM Fri 68 68 SW 9 2287 2821 0 Blue 0
2 AM Fri 68 68 SW 10 2287 2821 0 Blue 0
3 AM Fri 67 67 SW 10 2287 2821 0 Blue 0
4 AM Fri 66 66 SW 10 2287 2821 0 Blue 0
5 AM Fri 66 66 SW 10 2287 2821 0 Blue 0
6 AM Fri 66 66 SW 10 2287 2821 0 Blue 0
7 AM Fri 66 66 SW 10 2287 2821 0 Blue 0
8 AM Fri 67 67 SW 9 2287 2821 0 Blue 0
9 AM Fri 68 70 SW 9 2287 2821 0 Blue 0
10 AM Fri 70 73 SW 9 2287 2821 0 Blue 0
11 AM Fri 72 77 SW 9 2471 2821 0 Blue 0
12 Noon Fri 75 82 SW 9 4202 3055 234 Blue 5
1 PM Fri 77 84 SW 9 5106 3902 1081 Blue 7
2 PM Fri 79 86 SW 13 6030 4401 1580 Blue 9
3 PM Fri 79 85 SW 13 5573 4187 1366 Blue 8
4 PM Fri 78 82 SW 13 4202 3055 234 Blue 5
5 PM Fri 77 79 SW 15 3062 2821 0 Blue 2
6 PM Fri 75 76 SW 15 2287 2821 0 Blue 0
7 PM Fri 73 73 SW 15 2287 2821 0 Blue 0
8 PM Fri 71 71 SW 10 2287 2821 0 Blue 0
9 PM Fri 70 70 SW 10 2287 2821 0 Blue 0
10 PM Fri 68 68 SW 10 2287 2821 0 Blue 0
11 PM Fri 66 66 SW 9 2287 2821 0 Blue 0
12 Midnight Sat 66 66 SW 9 2287 2821 0 Blue 0
1 AM Sat 66 66 SW 9 2287 2821 0 Blue 0
2 AM Sat 65 65 SW 10 2287 2821 0 Blue 0
3 AM Sat 65 65 SW 10 2287 2821 0 Blue 0
4 AM Sat 64 64 SW 10 2287 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