Detailed Predictions for: Mt Vaca
Launch Lat, Long, Altitude (f): 38.400316, -122.106135, 2821
LZ Altitude (f): 2000
Sounding

Station:

KOAK

Date/Time:

24 JUL 2024

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Wind
Gust
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
12 Midnight Wed 75 75 WSW 7 16 2710 2821 0 Blue 0
1 AM Wed 73 73 WSW 7 16 2710 2821 0 Blue 0
2 AM Wed 71 71 WSW 7 15 2710 2821 0 Blue 0
3 AM Wed 70 70 WSW 7 15 2710 2821 0 Blue 0
4 AM Wed 70 70 WSW 6 14 2710 2821 0 Blue 0
5 AM Wed 69 69 WSW 6 12 2710 2821 0 Blue 0
6 AM Wed 70 70 WSW 5 12 2710 2821 0 Blue 0
7 AM Wed 74 74 WSW 5 11 2710 2821 0 Blue 0
8 AM Wed 80 81 WSW 5 8 2710 2821 0 Blue 0
9 AM Wed 86 88 WSW 4 5 3977 3607 786 Blue 4
10 AM Wed 92 96 SW 4 5 7376 5483 2662 Blue 12
11 AM Wed 96 102 SW 6 7 14281 11213 8392 Blue 18
12 Noon Wed 99 106 SW 8 9 15606 14472 11651 Blue 22
1 PM Wed 101 109 SW 10 11 17840 15338 12517 Blue 25
2 PM Wed 101 109 SW 11 13 17840 15338 12517 Blue 25
3 PM Wed 101 108 WSW 13 15 16907 14801 11980 Blue 24
4 PM Wed 99 104 WSW 14 16 14733 12212 9391 Blue 20
5 PM Wed 97 100 WSW 15 17 11990 9577 6756 Blue 16
6 PM Wed 94 95 WSW 14 16 6791 4966 2145 Blue 11
7 PM Wed 89 89 WSW 12 14 4205 3739 918 Blue 5
8 PM Wed 83 83 SW 9 15 2710 2821 0 Blue 0
9 PM Wed 79 79 SW 8 16 2710 2821 0 Blue 0
10 PM Wed 76 76 WSW 7 16 2710 2821 0 Blue 0
11 PM Wed 73 73 WSW 7 15 2710 2821 0 Blue 0
12 Midnight Thu 71 71 WSW 6 14 2710 2821 0 Blue 0
1 AM Thu 69 69 WSW 6 14 2710 2821 0 Blue 0
2 AM Thu 68 68 WSW 7 15 2710 2821 0 Blue 0
3 AM Thu 67 67 WSW 7 15 2710 2821 0 Blue 0
4 AM Thu 66 66 WSW 7 16 2710 2821 0 Blue 0
5 AM Thu 65 65 WSW 7 15 2710 2821 0 Blue 0
6 AM Thu 66 66 WSW 6 14 2710 2821 0 Blue 0
7 AM Thu 70 70 WSW 6 13 2710 2821 0 Blue 0
8 AM Thu 75 76 WSW 7 9 2710 2821 0 Blue 0
9 AM Thu 80 82 WSW 7 8 2710 2821 0 Blue 0
10 AM Thu 85 89 SW 7 8 4205 3739 918 Blue 5
11 AM Thu 89 95 SW 8 10 6791 4966 2145 Blue 11
12 Noon Thu 93 100 SW 9 11 11990 9577 6756 Blue 16
1 PM Thu 96 104 SW 10 12 14733 12212 9391 Blue 20
2 PM Thu 97 105 SW 11 13 14946 14137 11316 Blue 21
3 PM Thu 98 105 SW 12 13 14946 14137 11316 Blue 21
4 PM Thu 97 102 SW 12 14 14281 11213 8392 Blue 18
5 PM Thu 94 97 WSW 13 15 9995 6115 3294 Blue 13
6 PM Thu 91 93 WSW 13 14 5537 4388 1567 Blue 9
7 PM Thu 85 85 WSW 11 14 3615 2821 0 Blue 1
8 PM Thu 79 79 SW 9 18 2710 2821 0 Blue 0
9 PM Thu 73 73 WSW 9 19 2710 2821 0 Blue 0
10 PM Thu 69 69 WSW 9 19 2710 2821 0 Blue 0
11 PM Thu 66 66 WSW 8 17 2710 2821 0 Blue 0
12 Midnight Fri 63 63 WSW 7 16 2710 2821 0 Blue 0
1 AM Fri 61 61 WSW 7 15 2710 2821 0 Blue 0
2 AM Fri 60 60 WSW 7 16 2710 2821 0 Blue 0
3 AM Fri 59 59 WSW 7 16 2710 2821 0 Blue 0
4 AM Fri 58 58 WSW 7 16 2710 2821 0 Blue 0
5 AM Fri 57 57 WSW 7 15 2710 2821 0 Blue 0
6 AM Fri 57 57 WSW 6 14 2710 2821 0 Blue 0
7 AM Fri 62 62 WSW 6 13 2710 2821 0 Blue 0
8 AM Fri 67 68 WSW 6 7 2710 2821 0 Blue 0
9 AM Fri 72 74 WSW 5 6 2710 2821 0 Blue 0
10 AM Fri 77 81 WSW 6 7 2710 2821 0 Blue 0
11 AM Fri 81 87 SW 7 8 3860 3226 405 Blue 3
12 Noon Fri 85 93 SW 8 10 5537 4388 1567 Blue 9
1 PM Fri 87 95 SW 10 12 6791 4966 2145 Blue 11
2 PM Fri 87 95 SW 12 14 6791 4966 2145 Blue 11
3 PM Fri 86 93 SW 14 17 5537 4388 1567 Blue 9
4 PM Fri 85 90 SW 15 17 4397 3856 1035 Blue 6
5 PM Fri 83 86 SW 15 17 3742 2821 0 Blue 2
6 PM Fri 80 82 SW 15 17 2710 2821 0 Blue 0
7 PM Fri 74 74 SW 14 17 2710 2821 0 Blue 0
8 PM Fri 68 68 SW 13 21 2710 2821 0 Blue 0
9 PM Fri 63 63 SW 13 25 2710 2821 0 Blue 0
10 PM Fri 59 59 SW 12 23 2710 2821 0 Blue 0
11 PM Fri 57 57 SW 11 22 2710 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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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 [email protected]