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

Station:

 KOAK

Date/Time UTC:

 260911/1200

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 Fri 80 80 W 6 16 3548 2821 0 Blue 0
1 AM Fri 79 79 W 6 14 3280 2821 0 Blue 0
2 AM Fri 78 78 W 6 14 2993 2821 0 Blue 0
3 AM Fri 76 76 W 6 13 2585 2821 0 Blue 0
4 AM Fri 74 74 W 5 12 2585 2821 0 Blue 0
5 AM Fri 71 71 WNW 4 11 2585 2821 0 Blue 0
6 AM Fri 69 69 W 4 11 2585 2821 0 Blue 0
7 AM Fri 67 67 W 4 10 2585 2821 0 Blue 0
8 AM Fri 67 67 W 4 10 2585 2821 0 Blue 0
9 AM Fri 68 69 W 4 9 2585 2821 0 Blue 0
10 AM Fri 70 73 W 4 9 2585 2821 0 Blue 0
11 AM Fri 72 76 W 4 10 2585 2821 0 Blue 0
12 Noon Fri 74 80 WSW 4 11 3548 2821 0 Blue 0
1 PM Fri 75 81 WSW 5 13 3764 2990 169 Blue 1
2 PM Fri 76 82 WSW 8 16 3980 3274 453 Blue 2
3 PM Fri 77 82 WSW 8 17 3980 3274 453 Blue 2
4 PM Fri 75 78 WSW 8 17 2993 2821 0 Blue 0
5 PM Fri 74 76 WSW 8 17 2585 2821 0 Blue 0
6 PM Fri 73 73 WSW 6 16 2585 2821 0 Blue 0
7 PM Fri 70 70 WSW 5 14 2585 2821 0 Blue 0
8 PM Fri 69 69 W 5 13 2585 2821 0 Blue 0
9 PM Fri 69 69 W 5 13 2585 2821 0 Blue 0
10 PM Fri 70 70 W 5 13 2585 2821 0 Blue 0
11 PM Fri 70 70 W 4 13 2585 2821 0 Blue 0
12 Midnight Sat 70 70 W 4 13 2585 2821 0 Blue 0
1 AM Sat 70 70 W 4 12 2585 2821 0 Blue 0
2 AM Sat 70 70 W 5 12 2585 2821 0 Blue 0
3 AM Sat 68 68 W 5 12 2585 2821 0 Blue 0
4 AM Sat 67 67 W 5 12 2585 2821 0 Blue 0
5 AM Sat 65 65 W 6 14 2585 2821 0 Blue 0
6 AM Sat 64 64 W 6 14 2585 2821 0 Blue 0
7 AM Sat 62 62 W 6 14 2585 2821 0 Blue 0
8 AM Sat 62 62 W 9 18 2585 2821 0 Blue 0
9 AM Sat 63 64 W 9 18 2585 2821 0 Blue 0
10 AM Sat 64 66 W 9 18 2585 2821 0 Blue 0
11 AM Sat 66 70 WSW 12 21 2585 2821 0 Blue 0
12 Noon Sat 67 72 WSW 12 21 2585 2821 0 Blue 0
1 PM Sat 68 74 WSW 12 21 2585 2821 0 Blue 0
2 PM Sat 68 74 WSW 13 24 2585 2821 0 Blue 0
3 PM Sat 68 73 WSW 13 24 2585 2821 0 Blue 0
4 PM Sat 66 69 WSW 13 24 2585 2821 0 Blue 0
5 PM Sat 65 66 W 13 25 2585 2821 0 Blue 0
6 PM Sat 64 64 W 13 25 2585 2821 0 Blue 0
7 PM Sat 62 62 W 13 25 2585 2821 0 Blue 0
8 PM Sat 60 60 WSW 11 24 2585 2821 0 Blue 0
9 PM Sat 60 60 WSW 11 24 2585 2821 0 Blue 0
10 PM Sat 60 60 WSW 11 24 2585 2821 0 Blue 0
11 PM Sat 61 61 W 11 24 2585 2821 0 Blue 0
12 Midnight Sun 61 61 W 11 24 2585 2821 0 Blue 0
1 AM Sun 60 60 W 11 24 2585 2821 0 Blue 0
2 AM Sun 60 60 W 6 17 2585 2821 0 Blue 0
3 AM Sun 59 59 W 6 17 2585 2821 0 Blue 0
4 AM Sun 58 58 W 6 17 2585 2821 0 Blue 0
5 AM Sun 58 58 W 6 17 2585 2821 0 Blue 0
6 AM Sun 57 57 W 6 17 2585 2821 0 Blue 0
7 AM Sun 56 56 W 6 17 2585 2821 0 Blue 0
8 AM Sun 56 56 WNW 8 18 2585 2821 0 Blue 0
9 AM Sun 58 59 WNW 8 18 2585 2821 0 Blue 0
10 AM Sun 60 63 WNW 8 18 2585 2821 0 Blue 0
11 AM Sun 62 66 N 6 16 2585 2821 0 Blue 0
12 Noon Sun 64 70 N 6 16 2585 2821 0 Blue 0
1 PM Sun 66 72 N 6 16 2585 2821 0 Blue 0
2 PM Sun 67 73 NW 4 11 2585 2821 0 Blue 0
3 PM Sun 68 73 NW 4 11 2585 2821 0 Blue 0
4 PM Sun 69 72 NW 4 11 2585 2821 0 Blue 0
5 PM Sun 69 71 W 2 9 2585 2821 0 Blue 0
6 PM Sun 67 67 W 2 9 2585 2821 0 Blue 0
7 PM Sun 65 65 W 2 9 2585 2821 0 Blue 0
8 PM Sun 64 64 WSW 1 6 2585 2821 0 Blue 0
9 PM Sun 64 64 WSW 1 6 2585 2821 0 Blue 0
10 PM Sun 64 64 WSW 1 6 2585 2821 0 Blue 0
11 PM Sun 66 66 W 3 10 2585 2821 0 Blue 0
12 Midnight Mon 68 68 W 3 10 2585 2821 0 Blue 0
1 AM Mon 70 70 W 3 10 2585 2821 0 Blue 0
2 AM Mon 71 71 W 3 11 2585 2821 0 Blue 0
3 AM Mon 71 71 W 3 11 2585 2821 0 Blue 0
4 AM Mon 71 71 W 3 11 2585 2821 0 Blue 0
5 AM Mon 70 70 W 2 12 2585 2821 0 Blue 0
6 AM Mon 69 69 W 2 12 2585 2821 0 Blue 0
7 AM Mon 68 68 W 2 12 2585 2821 0 Blue 0
8 AM Mon 67 67 W 5 16 2585 2821 0 Blue 0
9 AM Mon 68 69 W 5 16 2585 2821 0 Blue 0
10 AM Mon 69 72 W 5 16 2585 2821 0 Blue 0
11 AM Mon 70 74 NW 5 13 2585 2821 0 Blue 0
12 Noon Mon 72 77 NW 5 13 2705 2821 0 Blue 0
1 PM Mon 73 79 NW 5 13 3280 2821 0 Blue 0
2 PM Mon 74 80 WSW 4 11 3548 2821 0 Blue 0
3 PM Mon 74 79 WSW 4 11 3280 2821 0 Blue 0
4 PM Mon 74 77 WSW 4 11 2705 2821 0 Blue 0
5 PM Mon 73 75 SW 6 16 2585 2821 0 Blue 0
6 PM Mon 70 70 SW 6 16 2585 2821 0 Blue 0
7 PM Mon 67 67 SW 6 16 2585 2821 0 Blue 0
8 PM Mon 65 65 SW 2 11 2585 2821 0 Blue 0
9 PM Mon 65 65 SW 2 11 2585 2821 0 Blue 0
10 PM Mon 65 65 SW 2 11 2585 2821 0 Blue 0
11 PM Mon 65 65 WSW 2 8 2585 2821 0 Blue 0
12 Midnight Tue 65 65 WSW 2 8 2585 2821 0 Blue 0
1 AM Tue 64 64 WSW 2 8 2585 2821 0 Blue 0
2 AM Tue 63 63 WSW 2 8 2585 2821 0 Blue 0
3 AM Tue 62 62 WSW 2 8 2585 2821 0 Blue 0
4 AM Tue 62 62 WSW 2 8 2585 2821 0 Blue 0
5 AM Tue 61 61 WSW 1 6 2585 2821 0 Blue 0
6 AM Tue 60 60 WSW 1 6 2585 2821 0 Blue 0
7 AM Tue 59 59 WSW 1 6 2585 2821 0 Blue 0
8 AM Tue 60 60 WSW 1 6 2585 2821 0 Blue 0
9 AM Tue 61 62 WSW 1 6 2585 2821 0 Blue 0
10 AM Tue 63 65 WSW 1 6 2585 2821 0 Blue 0
11 AM Tue 65 69 SSW 3 8 2585 2821 0 Blue 0
12 Noon Tue 67 72 SSW 3 8 2585 2821 0 Blue 0
1 PM Tue 68 73 SSW 3 8 2585 2821 0 Blue 0
2 PM Tue 69 74 SSW 4 11 2585 2821 0 Blue 0
3 PM Tue 69 73 SSW 4 11 2585 2821 0 Blue 0
4 PM Tue 69 72 SSW 4 11 2585 2821 0 Blue 0
5 PM Tue 67 68 SW 5 13 2585 2821 0 Blue 0
6 PM Tue 64 64 SW 5 13 2585 2821 0 Blue 0
7 PM Tue 61 61 SW 5 13 2585 2821 0 Blue 0
8 PM Tue 59 59 SW 4 12 2585 2821 0 Blue 0
9 PM Tue 59 59 SW 4 12 2585 2821 0 Blue 0
10 PM Tue 59 59 SW 4 12 2585 2821 0 Blue 0
11 PM Tue 60 60 WSW 3 12 2585 2821 0 Blue 0
12 Midnight Wed 60 60 WSW 3 12 2585 2821 0 Blue 0
1 AM Wed 60 60 WSW 3 12 2585 2821 0 Blue 0
2 AM Wed 60 60 WSW 2 10 2585 2821 0 Blue 0
3 AM Wed 61 61 WSW 2 10 2585 2821 0 Blue 0
4 AM Wed 61 61 WSW 2 10 2585 2821 0 Blue 0
5 AM Wed 61 61 WSW 2 9 2585 2821 0 Blue 0
6 AM Wed 60 60 WSW 2 9 2585 2821 0 Blue 0
7 AM Wed 59 59 WSW 2 9 2585 2821 0 Blue 0
8 AM Wed 58 58 WSW 1 6 2585 2821 0 Blue 0
9 AM Wed 59 60 WSW 1 6 2585 2821 0 Blue 0
10 AM Wed 61 63 WSW 1 6 2585 2821 0 Blue 0
11 AM Wed 62 66 SSW 2 6 2585 2821 0 Blue 0
12 Noon Wed 64 69 SSW 2 6 2585 2821 0 Blue 0
1 PM Wed 65 70 SSW 2 6 2585 2821 0 Blue 0
2 PM Wed 65 70 SW 4 10 2585 2821 0 Blue 0
3 PM Wed 65 69 SW 4 10 2585 2821 0 Blue 0
4 PM Wed 65 68 SW 4 10 2585 2821 0 Blue 0
5 PM Wed 64 66 SW 5 13 2585 2821 0 Blue 0
6 PM Wed 62 62 SW 5 13 2585 2821 0 Blue 0
7 PM Wed 60 60 SW 5 13 2585 2821 0 Blue 0
8 PM Wed 58 58 SW 3 12 2585 2821 0 Blue 0
9 PM Wed 58 58 SW 3 12 2585 2821 0 Blue 0
10 PM Wed 58 58 SW 3 12 2585 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]