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

Station:

KOAK

Date/Time:

14 APR 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 Sun 39 39 E 13 19 2507 2821 0 Blue 0
1 AM Sun 39 39 E 12 18 2507 2821 0 Blue 0
2 AM Sun 40 40 ESE 12 19 2684 2821 0 Blue 0
3 AM Sun 38 38 E 16 20 2507 2821 0 Blue 0
4 AM Sun 39 39 E 14 20 2507 2821 0 Blue 0
5 AM Sun 39 39 E 14 19 2507 2821 0 Blue 0
6 AM Sun 39 39 E 11 16 2507 2821 0 Blue 0
7 AM Sun 40 40 E 11 16 2684 2821 0 Blue 0
8 AM Sun 40 40 E 11 13 2684 2821 0 Blue 0
9 AM Sun 39 39 E 8 11 2507 2821 0 Blue 0
10 AM Sun 38 38 E 4 8 2507 2821 0 Blue 0
11 AM Sun 39 40 S 3 5 2684 2821 0 Blue 0
12 Noon Sun 41 43 S 3 5 4223 2821 0 White 1
1 PM Sun 43 45 SSW 4 6 4671 4216 1395 White 3
2 PM Sun 44 45 SW 5 8 4671 4216 1395 White 3
3 PM Sun 45 46 W 8 10 4891 4557 1736 White 4
4 PM Sun 44 44 WSW 8 10 4446 3475 654 White 2
5 PM Sun 44 44 W 9 12 4446 3475 654 White 2
6 PM Sun 44 44 W 9 11 4446 3475 654 White 2
7 PM Sun 44 44 W 9 12 4446 3475 654 White 2
8 PM Sun 45 45 WNW 6 11 4671 4216 1395 White 3
9 PM Sun 45 45 NW 5 11 4671 4216 1395 White 3
10 PM Sun 44 44 NW 5 11 4446 3475 654 White 2
11 PM Sun 44 44 NW 4 11 4446 3475 654 White 2
12 Midnight Mon 44 44 NW 4 10 4446 3475 654 White 2
1 AM Mon 44 44 NNW 5 9 4446 3475 654 White 2
2 AM Mon 44 44 N 6 9 4446 3475 654 White 2
3 AM Mon 43 43 N 6 8 4223 2821 0 White 1
4 AM Mon 42 42 NNE 6 9 4003 2821 0 White 0
5 AM Mon 41 41 N 8 11 3498 2821 0 Blue 0
6 AM Mon 41 41 N 6 10 3498 2821 0 Blue 0
7 AM Mon 42 42 N 6 10 4003 2821 0 White 0
8 AM Mon 43 43 NNE 6 10 4223 2821 0 White 1
9 AM Mon 45 46 NNE 5 9 4891 4557 1736 White 4
10 AM Mon 47 50 N 4 6 5752 5752 2931 White 8
11 AM Mon 49 53 NW 3 8 6390 6390 3569 White 11
12 Noon Mon 50 55 NW 3 8 6813 6813 3992 White 13
1 PM Mon 52 57 NW 3 8 7232 7232 4411 White 15
2 PM Mon 53 58 W 4 9 7442 7442 4621 White 16
3 PM Mon 54 58 W 4 9 7442 7442 4621 White 16
4 PM Mon 55 58 W 4 9 7442 7442 4621 White 16
5 PM Mon 54 55 WSW 5 9 6813 6813 3992 White 13
6 PM Mon 54 54 WSW 5 9 6602 6602 3781 White 12
7 PM Mon 53 53 WSW 5 9 6390 6390 3569 White 11
8 PM Mon 51 51 WSW 9 12 5966 5966 3145 White 9
9 PM Mon 50 50 WSW 9 12 5752 5752 2931 White 8
10 PM Mon 49 49 WSW 9 12 5537 5537 2716 White 7
11 PM Mon 48 48 WSW 8 12 5322 5322 2501 White 6
12 Midnight Tue 48 48 WSW 8 12 5322 5322 2501 White 6
1 AM Tue 47 47 WSW 8 12 5107 4923 2102 White 5
2 AM Tue 47 47 W 9 12 5107 4923 2102 White 5
3 AM Tue 47 47 W 9 12 5107 4923 2102 White 5
4 AM Tue 46 46 W 9 12 4891 4557 1736 White 4
5 AM Tue 47 47 WNW 8 11 5107 4923 2102 White 5
6 AM Tue 47 47 WNW 8 11 5107 4923 2102 White 5
7 AM Tue 48 48 WNW 8 11 5322 5322 2501 White 6
8 AM Tue 50 50 WNW 8 11 5752 5752 2931 White 8
9 AM Tue 51 52 WNW 8 11 6179 6179 3358 White 10
10 AM Tue 53 56 WNW 8 11 7023 7023 4202 White 14
11 AM Tue 55 60 W 6 11 7860 7860 5039 White 18
12 Noon Tue 57 63 W 6 11 8483 8483 5662 White 21
1 PM Tue 58 65 W 6 11 8893 8893 6072 White 23
2 PM Tue 60 66 SW 8 11 9097 9097 6276 White 24
3 PM Tue 60 65 SW 8 11 8893 8893 6072 White 23
4 PM Tue 61 64 SW 8 11 8688 8688 5867 White 22
5 PM Tue 61 62 WSW 9 13 8273 8273 5452 White 20
6 PM Tue 60 60 WSW 9 13 7860 7860 5039 White 18
7 PM Tue 59 59 WSW 9 13 7652 7652 4831 White 17
8 PM Tue 58 58 WSW 9 14 7442 7442 4621 White 16
9 PM Tue 56 56 WSW 9 14 7023 7023 4202 White 14
10 PM Tue 55 55 WSW 9 14 6813 6813 3992 White 13
11 PM Tue 54 54 WNW 9 13 6602 6602 3781 White 12
12 Midnight Wed 53 53 WNW 9 13 6390 6390 3569 White 11
1 AM Wed 53 53 WNW 9 13 6390 6390 3569 White 11
2 AM Wed 52 52 NW 9 12 6179 6179 3358 White 10
3 AM Wed 52 52 NW 9 12 6179 6179 3358 White 10
4 AM Wed 52 52 NW 9 12 6179 6179 3358 White 10
5 AM Wed 52 52 NNW 10 16 6179 6179 3358 White 10
6 AM Wed 52 52 NNW 10 16 6179 6179 3358 White 10
7 AM Wed 53 53 NNW 10 16 6390 6390 3569 White 11
8 AM Wed 55 55 N 10 14 6813 6813 3992 White 13
9 AM Wed 56 57 N 10 14 7232 7232 4411 White 15
10 AM Wed 58 61 N 10 14 8066 8066 5245 White 19
11 AM Wed 60 64 N 10 14 8688 8688 5867 White 22
12 Noon Wed 62 67 N 10 14 9301 9301 6480 White 25
1 PM Wed 64 69 N 10 14 9706 9706 6885 White 27
2 PM Wed 65 70 N 10 14 9929 9929 7108 White 28
3 PM Wed 66 70 N 10 14 9929 9929 7108 White 28
4 PM Wed 67 70 N 10 14 9929 9929 7108 White 28
5 PM Wed 67 68 NW 9 13 9505 9505 6684 White 26
6 PM Wed 66 66 NW 9 13 9097 9097 6276 White 24
7 PM Wed 64 64 NW 9 13 8688 8688 5867 White 22
8 PM Wed 62 62 WSW 6 11 8273 8273 5452 White 20
9 PM Wed 61 61 WSW 6 11 8066 8066 5245 White 19
10 PM Wed 59 59 WSW 6 11 7652 7652 4831 White 17
11 PM Wed 58 58 W 8 11 7442 7442 4621 White 16
12 Midnight Thu 57 57 W 8 11 7232 7232 4411 White 15
1 AM Thu 56 56 W 8 11 7023 7023 4202 White 14
2 AM Thu 55 55 NW 8 12 6813 6813 3992 White 13
3 AM Thu 54 54 NW 8 12 6602 6602 3781 White 12
4 AM Thu 53 53 NW 8 12 6390 6390 3569 White 11
5 AM Thu 53 53 NNW 9 12 6390 6390 3569 White 11
6 AM Thu 53 53 NNW 9 12 6390 6390 3569 White 11
7 AM Thu 54 54 NNW 9 12 6602 6602 3781 White 12
8 AM Thu 56 56 N 9 12 7023 7023 4202 White 14
9 AM Thu 57 58 N 9 12 7442 7442 4621 White 16
10 AM Thu 59 61 N 9 12 8066 8066 5245 White 19
11 AM Thu 61 64 NNE 8 11 8688 8688 5867 White 22
12 Noon Thu 63 67 NNE 8 11 9301 9301 6480 White 25
1 PM Thu 65 69 NNE 8 11 9706 9706 6885 White 27
2 PM Thu 66 70 WSW 8 12 9929 9929 7108 White 28
3 PM Thu 67 70 WSW 8 12 9929 9929 7108 White 28
4 PM Thu 67 69 WSW 8 12 9706 9706 6885 White 27
5 PM Thu 67 68 WSW 9 13 9505 9505 6684 White 26
6 PM Thu 66 66 WSW 9 13 9097 9097 6276 White 24
7 PM Thu 64 64 WSW 9 13 8688 8688 5867 White 22
8 PM Thu 62 62 WSW 9 13 8273 8273 5452 White 20
9 PM Thu 60 60 WSW 9 13 7860 7860 5039 White 18
10 PM Thu 58 58 WSW 9 13 7442 7442 4621 White 16
11 PM Thu 57 57 W 9 12 7232 7232 4411 White 15
12 Midnight Fri 55 55 W 9 12 6813 6813 3992 White 13
1 AM Fri 54 54 W 9 12 6602 6602 3781 White 12
2 AM Fri 53 53 W 8 12 6390 6390 3569 White 11
3 AM Fri 52 52 W 8 12 6179 6179 3358 White 10
4 AM Fri 52 52 W 8 12 6179 6179 3358 White 10
5 AM Fri 52 52 W 9 12 6179 6179 3358 White 10
6 AM Fri 52 52 W 9 12 6179 6179 3358 White 10
7 AM Fri 53 53 W 9 12 6390 6390 3569 White 11
8 AM Fri 54 54 W 9 13 6602 6602 3781 White 12
9 AM Fri 56 57 W 9 13 7232 7232 4411 White 15
10 AM Fri 58 61 W 9 13 8066 8066 5245 White 19
11 AM Fri 60 65 WSW 8 12 8893 8893 6072 White 23
12 Noon Fri 62 68 WSW 8 12 9505 9505 6684 White 26
1 PM Fri 63 69 WSW 8 12 9706 9706 6885 White 27
2 PM Fri 64 70 SW 10 16 9929 9929 7108 White 28
3 PM Fri 65 70 SW 10 16 9929 9929 7108 White 28
4 PM Fri 65 68 SW 10 16 9505 9505 6684 White 26
5 PM Fri 64 66 SW 13 17 9097 9097 6276 White 24
6 PM Fri 63 63 SW 13 17 8483 8483 5662 White 21
7 PM Fri 61 61 SW 13 17 8066 8066 5245 White 19
8 PM Fri 58 58 WSW 11 16 7442 7442 4621 White 16
9 PM Fri 57 57 WSW 11 16 7232 7232 4411 White 15
10 PM Fri 55 55 WSW 11 16 6813 6813 3992 White 13

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]