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

Station:

 KOAK

Date/Time:

 20 MAR 2023

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)
7 AM Mon 42 42 WSW 18 23 3256 2821 0 White 3
8 AM Mon 42 42 WSW 19 25 3256 2821 0 White 3
9 AM Mon 42 42 WSW 21 26 3256 2821 0 White 3
10 AM Mon 41 41 W 19 25 3034 2821 0 White 2
11 AM Mon 40 40 W 18 24 2813 2821 0 White 1
12 Noon Mon 38 39 W 17 23 2503 2821 0 Blue 0
1 PM Mon 38 40 W 16 21 2813 2821 0 White 1
2 PM Mon 37 40 W 14 21 2813 2821 0 White 1
3 PM Mon 37 39 W 14 19 2503 2821 0 Blue 0
4 PM Mon 38 39 W 14 18 2503 2821 0 Blue 0
5 PM Mon 39 39 W 12 16 2503 2821 0 Blue 0
6 PM Mon 41 41 W 10 14 3034 2821 0 White 2
7 PM Mon 43 43 WSW 10 13 3476 2876 55 White 4
8 PM Mon 43 43 SW 11 13 3476 2876 55 White 4
9 PM Mon 44 44 SW 10 13 3696 3257 436 White 5
10 PM Mon 45 45 SW 10 14 3916 3463 642 White 6
11 PM Mon 44 44 SW 9 13 3696 3257 436 White 5
12 Midnight Tue 44 44 SW 10 13 3696 3257 436 White 5
1 AM Tue 43 43 SW 10 13 3476 2876 55 White 4
2 AM Tue 40 40 SW 11 14 2813 2821 0 White 1
3 AM Tue 39 39 SW 9 12 2503 2821 0 Blue 0
4 AM Tue 39 39 SW 9 11 2503 2821 0 Blue 0
5 AM Tue 39 39 W 8 10 2503 2821 0 Blue 0
6 AM Tue 39 39 SSW 8 11 2503 2821 0 Blue 0
7 AM Tue 39 39 S 8 11 2503 2821 0 Blue 0
8 AM Tue 39 39 ENE 8 11 2503 2821 0 Blue 0
9 AM Tue 39 39 ENE 9 13 2503 2821 0 Blue 0
10 AM Tue 38 38 NE 10 16 2503 2821 0 Blue 0
11 AM Tue 38 38 NE 13 17 2503 2821 0 Blue 0
12 Noon Tue 36 36 NE 18 23 2503 2821 0 Blue 0
1 PM Tue 37 37 NE 20 25 2503 2821 0 Blue 0
2 PM Tue 37 37 NE 23 29 2503 2821 0 Blue 0
3 PM Tue 37 37 NE 24 29 2503 2821 0 Blue 0
4 PM Tue 36 36 NE 24 29 2503 2821 0 Blue 0
5 PM Tue 36 36 NE 23 29 2503 2821 0 Blue 0
6 PM Tue 37 37 NE 21 27 2503 2821 0 Blue 0
7 PM Tue 37 37 NE 21 27 2503 2821 0 Blue 0
8 PM Tue 38 38 NE 21 27 2503 2821 0 Blue 0
9 PM Tue 39 39 NE 21 27 2503 2821 0 Blue 0
10 PM Tue 39 39 NE 21 27 2503 2821 0 Blue 0
11 PM Tue 39 39 NE 21 27 2503 2821 0 Blue 0
12 Midnight Wed 38 38 E 19 24 2503 2821 0 Blue 0
1 AM Wed 38 38 E 19 24 2503 2821 0 Blue 0
2 AM Wed 38 38 E 19 24 2503 2821 0 Blue 0
3 AM Wed 38 38 ESE 18 25 2503 2821 0 Blue 0
4 AM Wed 39 39 ESE 18 25 2503 2821 0 Blue 0
5 AM Wed 39 39 ESE 18 25 2503 2821 0 Blue 0
6 AM Wed 39 39 E 17 21 2503 2821 0 Blue 0
7 AM Wed 38 38 E 17 21 2503 2821 0 Blue 0
8 AM Wed 38 38 E 17 21 2503 2821 0 Blue 0
9 AM Wed 38 38 E 17 23 2503 2821 0 Blue 0
10 AM Wed 38 38 E 17 23 2503 2821 0 Blue 0
11 AM Wed 38 38 E 17 23 2503 2821 0 Blue 0
12 Noon Wed 38 39 E 12 18 2503 2821 0 Blue 0
1 PM Wed 39 40 E 12 18 2813 2821 0 White 1
2 PM Wed 40 41 E 12 18 3034 2821 0 White 2
3 PM Wed 40 40 ENE 11 17 2813 2821 0 White 1
4 PM Wed 41 41 ENE 11 17 3034 2821 0 White 2
5 PM Wed 41 41 ENE 11 17 3034 2821 0 White 2
6 PM Wed 41 41 SE 9 14 3034 2821 0 White 2
7 PM Wed 42 42 SE 9 14 3256 2821 0 White 3
8 PM Wed 43 43 SE 9 14 3476 2876 55 White 4
9 PM Wed 44 44 WSW 9 13 3696 3257 436 White 5
10 PM Wed 44 44 WSW 9 13 3696 3257 436 White 5
11 PM Wed 45 45 WSW 9 13 3916 3463 642 White 6
12 Midnight Thu 45 45 WSW 10 13 3916 3463 642 White 6
1 AM Thu 44 44 WSW 10 13 3696 3257 436 White 5
2 AM Thu 44 44 WSW 10 13 3696 3257 436 White 5
3 AM Thu 43 43 WSW 10 14 3476 2876 55 White 4
4 AM Thu 42 42 WSW 10 14 3256 2821 0 White 3
5 AM Thu 42 42 WSW 10 14 3256 2821 0 White 3
6 AM Thu 41 41 WNW 9 14 3034 2821 0 White 2
7 AM Thu 41 41 WNW 9 14 3034 2821 0 White 2
8 AM Thu 40 40 WNW 9 14 2813 2821 0 White 1
9 AM Thu 39 39 NW 10 16 2503 2821 0 Blue 0
10 AM Thu 39 40 NW 10 16 2813 2821 0 White 1
11 AM Thu 39 41 NW 10 16 3034 2821 0 White 2
12 Noon Thu 39 41 NNW 9 14 3034 2821 0 White 2
1 PM Thu 39 41 NNW 9 14 3034 2821 0 White 2
2 PM Thu 39 41 NNW 9 14 3034 2821 0 White 2
3 PM Thu 39 41 W 10 14 3034 2821 0 White 2
4 PM Thu 41 42 W 10 14 3256 2821 0 White 3
5 PM Thu 43 43 W 10 14 3476 2876 55 White 4
6 PM Thu 45 45 W 10 14 3916 3463 642 White 6
7 PM Thu 47 47 W 10 14 4355 4024 1203 White 8
8 PM Thu 48 48 W 10 14 4575 4575 1754 White 9
9 PM Thu 48 48 W 10 16 4575 4575 1754 White 9
10 PM Thu 48 48 W 10 16 4575 4575 1754 White 9
11 PM Thu 48 48 W 10 16 4575 4575 1754 White 9
12 Midnight Fri 46 46 WSW 11 17 4134 3669 848 White 7
1 AM Fri 45 45 WSW 11 17 3916 3463 642 White 6
2 AM Fri 44 44 WSW 11 17 3696 3257 436 White 5
3 AM Fri 43 43 WSW 11 17 3476 2876 55 White 4
4 AM Fri 42 42 WSW 11 17 3256 2821 0 White 3
5 AM Fri 41 41 WSW 11 17 3034 2821 0 White 2
6 AM Fri 41 41 W 11 17 3034 2821 0 White 2
7 AM Fri 40 40 W 11 17 2813 2821 0 White 1
8 AM Fri 39 39 W 11 17 2503 2821 0 Blue 0
9 AM Fri 38 38 W 11 17 2503 2821 0 Blue 0
10 AM Fri 37 38 W 11 17 2503 2821 0 Blue 0
11 AM Fri 37 39 W 11 17 2503 2821 0 Blue 0
12 Noon Fri 36 40 W 11 17 2813 2821 0 White 1
1 PM Fri 36 40 W 11 17 2813 2821 0 White 1
2 PM Fri 37 41 W 11 17 3034 2821 0 White 2
3 PM Fri 38 41 WNW 11 18 3034 2821 0 White 2
4 PM Fri 39 41 WNW 11 18 3034 2821 0 White 2
5 PM Fri 41 42 WNW 11 18 3256 2821 0 White 3
6 PM Fri 43 43 NW 12 18 3476 2876 55 White 4
7 PM Fri 45 45 NW 12 18 3916 3463 642 White 6
8 PM Fri 46 46 NW 12 18 4134 3669 848 White 7
9 PM Fri 46 46 WNW 13 20 4134 3669 848 White 7
10 PM Fri 46 46 WNW 13 20 4134 3669 848 White 7
11 PM Fri 46 46 WNW 13 20 4134 3669 848 White 7
12 Midnight Sat 45 45 W 13 20 3916 3463 642 White 6
1 AM Sat 44 44 W 13 20 3696 3257 436 White 5
2 AM Sat 42 42 W 13 20 3256 2821 0 White 3
3 AM Sat 41 41 W 13 18 3034 2821 0 White 2
4 AM Sat 40 40 W 13 18 2813 2821 0 White 1
5 AM Sat 39 39 W 13 18 2503 2821 0 Blue 0
6 AM Sat 38 38 WNW 13 18 2503 2821 0 Blue 0
7 AM Sat 37 37 WNW 13 18 2503 2821 0 Blue 0
8 AM Sat 36 36 WNW 13 18 2503 2821 0 Blue 0
9 AM Sat 36 37 WNW 14 19 2503 2821 0 Blue 0
10 AM Sat 35 37 WNW 14 19 2503 2821 0 Blue 0
11 AM Sat 34 38 WNW 14 19 2503 2821 0 Blue 0
12 Noon Sat 34 38 WNW 12 18 2503 2821 0 Blue 0
1 PM Sat 34 39 WNW 12 18 2503 2821 0 Blue 0
2 PM Sat 35 40 WNW 12 18 2813 2821 0 White 1
3 PM Sat 36 40 NW 14 19 2813 2821 0 White 1
4 PM Sat 38 40 NW 14 19 2813 2821 0 White 1
5 PM Sat 40 41 NW 14 19 3034 2821 0 White 2
6 PM Sat 43 43 NNW 14 18 3476 2876 55 White 4
7 PM Sat 44 44 NNW 14 18 3696 3257 436 White 5
8 PM Sat 45 45 NNW 14 18 3916 3463 642 White 6
9 PM Sat 46 46 NW 13 18 4134 3669 848 White 7
10 PM Sat 46 46 NW 13 18 4134 3669 848 White 7
11 PM Sat 46 46 NW 13 18 4134 3669 848 White 7
12 Midnight Sun 45 45 WNW 13 18 3916 3463 642 White 6
1 AM Sun 43 43 WNW 13 18 3476 2876 55 White 4
2 AM Sun 42 42 WNW 13 18 3256 2821 0 White 3
3 AM Sun 40 40 WNW 12 17 2813 2821 0 White 1
4 AM Sun 39 39 WNW 12 17 2503 2821 0 Blue 0
5 AM Sun 38 38 WNW 12 17 2503 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]