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:

 241207/1200

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 Sat 53 53 N 2 5 2490 2821 0 Blue 0
1 AM Sat 52 52 NNE 2 6 2490 2821 0 Blue 0
2 AM Sat 51 51 N 2 5 2490 2821 0 Blue 0
3 AM Sat 51 51 N 2 5 2490 2821 0 Blue 0
4 AM Sat 50 50 NNE 2 5 2490 2821 0 Blue 0
5 AM Sat 51 51 N 2 5 2490 2821 0 Blue 0
6 AM Sat 50 50 N 2 5 2490 2821 0 Blue 0
7 AM Sat 50 50 NNE 3 5 2490 2821 0 Blue 0
8 AM Sat 49 49 NNE 2 5 2490 2821 0 Blue 0
9 AM Sat 50 50 NNE 2 5 2490 2821 0 Blue 0
10 AM Sat 51 52 NNW 2 5 2490 2821 0 Blue 0
11 AM Sat 52 53 NNW 2 5 2490 2821 0 Blue 0
12 Noon Sat 52 53 WNW 2 6 2490 2821 0 Blue 0
1 PM Sat 54 55 W 2 6 2490 2821 0 Blue 0
2 PM Sat 53 54 SW 2 5 2490 2821 0 Blue 0
3 PM Sat 53 53 SW 2 4 2490 2821 0 Blue 0
4 PM Sat 52 52 W 2 4 2490 2821 0 Blue 0
5 PM Sat 51 51 W 1 3 2490 2821 0 Blue 0
6 PM Sat 51 51 W 1 3 2490 2821 0 Blue 0
7 PM Sat 52 52 WNW 1 3 2490 2821 0 Blue 0
8 PM Sat 53 53 NW 1 3 2490 2821 0 Blue 0
9 PM Sat 53 53 NNW 2 4 2490 2821 0 Blue 0
10 PM Sat 53 53 NNW 2 5 2490 2821 0 Blue 0
11 PM Sat 52 52 N 2 5 2490 2821 0 Blue 0
12 Midnight Sun 53 53 N 2 6 2490 2821 0 Blue 0
1 AM Sun 52 52 N 3 8 2490 2821 0 Blue 0
2 AM Sun 52 52 N 4 9 2490 2821 0 Blue 0
3 AM Sun 52 52 N 5 10 2490 2821 0 Blue 0
4 AM Sun 52 52 N 5 11 2490 2821 0 Blue 0
5 AM Sun 51 51 N 6 12 2490 2821 0 Blue 0
6 AM Sun 50 50 N 8 13 2490 2821 0 Blue 0
7 AM Sun 50 50 NNW 9 14 2490 2821 0 Blue 0
8 AM Sun 50 50 N 9 16 2490 2821 0 Blue 0
9 AM Sun 50 50 N 10 17 2490 2821 0 Blue 0
10 AM Sun 51 51 N 9 16 2490 2821 0 Blue 0
11 AM Sun 52 53 N 9 16 2490 2821 0 Blue 0
12 Noon Sun 54 55 N 9 16 2490 2821 0 Blue 0
1 PM Sun 54 55 N 5 13 2490 2821 0 Blue 0
2 PM Sun 54 55 N 5 13 2490 2821 0 Blue 0
3 PM Sun 53 53 N 5 13 2490 2821 0 Blue 0
4 PM Sun 52 52 N 3 8 2490 2821 0 Blue 0
5 PM Sun 52 52 N 3 8 2490 2821 0 Blue 0
6 PM Sun 51 51 N 3 8 2490 2821 0 Blue 0
7 PM Sun 51 51 NNW 9 16 2490 2821 0 Blue 0
8 PM Sun 51 51 NNW 9 16 2490 2821 0 Blue 0
9 PM Sun 51 51 NNW 9 16 2490 2821 0 Blue 0
10 PM Sun 52 52 NNW 16 31 2490 2821 0 Blue 0
11 PM Sun 52 52 NNW 16 31 2490 2821 0 Blue 0
12 Midnight Mon 51 51 NNW 16 31 2490 2821 0 Blue 0
1 AM Mon 51 51 N 24 39 2490 2821 0 Blue 0
2 AM Mon 50 50 N 24 39 2490 2821 0 Blue 0
3 AM Mon 49 49 N 24 39 2490 2821 0 Blue 0
4 AM Mon 48 48 N 29 41 2490 2821 0 Blue 0
5 AM Mon 48 48 N 29 41 2490 2821 0 Blue 0
6 AM Mon 48 48 N 29 41 2490 2821 0 Blue 0
7 AM Mon 48 48 N 29 43 2490 2821 0 Blue 0
8 AM Mon 48 48 N 29 43 2490 2821 0 Blue 0
9 AM Mon 47 47 N 29 43 2490 2821 0 Blue 0
10 AM Mon 47 48 N 21 35 2490 2821 0 Blue 0
11 AM Mon 48 50 N 21 35 2490 2821 0 Blue 0
12 Noon Mon 49 51 N 21 35 2490 2821 0 Blue 0
1 PM Mon 50 52 N 14 29 2490 2821 0 Blue 0
2 PM Mon 50 51 N 14 29 2490 2821 0 Blue 0
3 PM Mon 49 49 N 14 29 2490 2821 0 Blue 0
4 PM Mon 49 49 N 11 23 2490 2821 0 Blue 0
5 PM Mon 48 48 N 11 23 2490 2821 0 Blue 0
6 PM Mon 47 47 N 11 23 2490 2821 0 Blue 0
7 PM Mon 47 47 N 10 18 2490 2821 0 Blue 0
8 PM Mon 48 48 N 10 18 2490 2821 0 Blue 0
9 PM Mon 48 48 N 10 18 2490 2821 0 Blue 0
10 PM Mon 49 49 N 13 21 2490 2821 0 Blue 0
11 PM Mon 48 48 N 13 21 2490 2821 0 Blue 0
12 Midnight Tue 48 48 N 13 21 2490 2821 0 Blue 0
1 AM Tue 46 46 N 14 23 2490 2821 0 Blue 0
2 AM Tue 45 45 N 14 23 2490 2821 0 Blue 0
3 AM Tue 44 44 N 14 23 2490 2821 0 Blue 0
4 AM Tue 43 43 N 13 20 2490 2821 0 Blue 0
5 AM Tue 43 43 N 13 20 2490 2821 0 Blue 0
6 AM Tue 42 42 N 13 20 2490 2821 0 Blue 0
7 AM Tue 42 42 N 11 18 2490 2821 0 Blue 0
8 AM Tue 42 42 N 11 18 2490 2821 0 Blue 0
9 AM Tue 42 42 N 11 18 2490 2821 0 Blue 0
10 AM Tue 42 42 NNE 9 14 2490 2821 0 Blue 0
11 AM Tue 43 44 NNE 9 14 2490 2821 0 Blue 0
12 Noon Tue 44 45 NNE 9 14 2490 2821 0 Blue 0
1 PM Tue 45 46 NE 5 12 2490 2821 0 Blue 0
2 PM Tue 45 45 NE 5 12 2490 2821 0 Blue 0
3 PM Tue 44 44 NE 5 12 2490 2821 0 Blue 0
4 PM Tue 44 44 NE 3 6 2490 2821 0 Blue 0
5 PM Tue 44 44 NE 3 6 2490 2821 0 Blue 0
6 PM Tue 44 44 NE 3 6 2490 2821 0 Blue 0
7 PM Tue 44 44 N 2 6 2490 2821 0 Blue 0
8 PM Tue 45 45 N 2 6 2490 2821 0 Blue 0
9 PM Tue 46 46 N 2 6 2490 2821 0 Blue 0
10 PM Tue 46 46 N 3 8 2490 2821 0 Blue 0
11 PM Tue 46 46 N 3 8 2490 2821 0 Blue 0
12 Midnight Wed 46 46 N 3 8 2490 2821 0 Blue 0
1 AM Wed 46 46 N 4 8 2490 2821 0 Blue 0
2 AM Wed 45 45 N 4 8 2490 2821 0 Blue 0
3 AM Wed 44 44 N 4 8 2490 2821 0 Blue 0
4 AM Wed 44 44 N 5 9 2490 2821 0 Blue 0
5 AM Wed 44 44 N 5 9 2490 2821 0 Blue 0
6 AM Wed 44 44 N 5 9 2490 2821 0 Blue 0
7 AM Wed 44 44 N 5 8 2490 2821 0 Blue 0
8 AM Wed 44 44 N 5 8 2490 2821 0 Blue 0
9 AM Wed 44 44 N 5 8 2490 2821 0 Blue 0
10 AM Wed 44 44 NNE 4 9 2490 2821 0 Blue 0
11 AM Wed 45 46 NNE 4 9 2490 2821 0 Blue 0
12 Noon Wed 46 47 NNE 4 9 2490 2821 0 Blue 0
1 PM Wed 46 47 NNE 3 8 2490 2821 0 Blue 0
2 PM Wed 46 47 NNE 3 8 2490 2821 0 Blue 0
3 PM Wed 46 46 NNE 3 8 2490 2821 0 Blue 0
4 PM Wed 46 46 SE 2 4 2490 2821 0 Blue 0
5 PM Wed 46 46 SE 2 4 2490 2821 0 Blue 0
6 PM Wed 46 46 SE 2 4 2490 2821 0 Blue 0
7 PM Wed 46 46 W 2 5 2490 2821 0 Blue 0
8 PM Wed 47 47 W 2 5 2490 2821 0 Blue 0
9 PM Wed 48 48 W 2 5 2490 2821 0 Blue 0
10 PM Wed 48 48 W 2 5 2490 2821 0 Blue 0
11 PM Wed 49 49 W 2 5 2490 2821 0 Blue 0
12 Midnight Thu 49 49 W 2 5 2490 2821 0 Blue 0
1 AM Thu 49 49 W 3 6 2490 2821 0 Blue 0
2 AM Thu 49 49 W 3 6 2490 2821 0 Blue 0
3 AM Thu 48 48 W 3 6 2490 2821 0 Blue 0
4 AM Thu 48 48 W 4 9 2490 2821 0 Blue 0
5 AM Thu 47 47 W 4 9 2490 2821 0 Blue 0
6 AM Thu 47 47 W 4 9 2490 2821 0 Blue 0
7 AM Thu 46 46 W 4 9 2490 2821 0 Blue 0
8 AM Thu 46 46 W 4 9 2490 2821 0 Blue 0
9 AM Thu 45 45 W 4 9 2490 2821 0 Blue 0
10 AM Thu 45 45 W 4 9 2490 2821 0 Blue 0
11 AM Thu 46 47 W 4 9 2490 2821 0 Blue 0
12 Noon Thu 46 47 W 4 9 2490 2821 0 Blue 0
1 PM Thu 47 48 W 4 10 2490 2821 0 Blue 0
2 PM Thu 47 47 W 4 10 2490 2821 0 Blue 0
3 PM Thu 47 47 W 4 10 2490 2821 0 Blue 0
4 PM Thu 46 46 WSW 3 8 2490 2821 0 Blue 0
5 PM Thu 46 46 WSW 3 8 2490 2821 0 Blue 0
6 PM Thu 46 46 WSW 3 8 2490 2821 0 Blue 0
7 PM Thu 46 46 WSW 3 8 2490 2821 0 Blue 0
8 PM Thu 47 47 WSW 3 8 2490 2821 0 Blue 0
9 PM Thu 48 48 WSW 3 8 2490 2821 0 Blue 0
10 PM Thu 48 48 W 4 9 2490 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]