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:

250217/1200

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 Mon 44 44 WNW 10 14 2023 2821 0 Blue 0
1 AM Mon 44 44 WNW 10 14 2023 2821 0 Blue 0
2 AM Mon 42 42 NW 10 14 2023 2821 0 Blue 0
3 AM Mon 42 42 NW 10 14 2023 2821 0 Blue 0
4 AM Mon 41 41 NW 10 14 2023 2821 0 Blue 0
5 AM Mon 40 40 NW 9 14 2023 2821 0 Blue 0
6 AM Mon 41 41 NW 9 12 2023 2821 0 Blue 0
7 AM Mon 41 41 NW 8 11 2023 2821 0 Blue 0
8 AM Mon 41 41 NW 8 11 2023 2821 0 Blue 0
9 AM Mon 42 42 NW 6 11 2023 2821 0 Blue 0
10 AM Mon 43 44 WNW 6 11 2023 2821 0 Blue 0
11 AM Mon 44 45 WNW 6 11 2410 2821 0 Blue 0
12 Noon Mon 45 46 WNW 6 13 4111 2821 0 Blue 1
1 PM Mon 47 48 WNW 6 13 4847 2821 0 Blue 3
2 PM Mon 47 48 WNW 6 13 4847 2821 0 Blue 3
3 PM Mon 47 47 WNW 8 14 4745 2821 0 Blue 2
4 PM Mon 48 48 WNW 9 16 4847 2821 0 Blue 3
5 PM Mon 47 47 NW 9 14 4745 2821 0 Blue 2
6 PM Mon 46 46 NW 9 13 4111 2821 0 Blue 1
7 PM Mon 46 46 NW 9 13 4111 2821 0 Blue 1
8 PM Mon 44 44 NNW 9 13 2023 2821 0 Blue 0
9 PM Mon 44 44 NNW 9 13 2023 2821 0 Blue 0
10 PM Mon 43 43 N 9 14 2023 2821 0 Blue 0
11 PM Mon 43 43 N 9 14 2023 2821 0 Blue 0
12 Midnight Tue 43 43 N 9 14 2023 2821 0 Blue 0
1 AM Tue 42 42 N 9 14 2023 2821 0 Blue 0
2 AM Tue 42 42 N 9 13 2023 2821 0 Blue 0
3 AM Tue 41 41 NNW 9 13 2023 2821 0 Blue 0
4 AM Tue 40 40 N 9 13 2023 2821 0 Blue 0
5 AM Tue 41 41 NNW 9 13 2023 2821 0 Blue 0
6 AM Tue 41 41 NNW 9 12 2023 2821 0 Blue 0
7 AM Tue 41 41 NNW 9 12 2023 2821 0 Blue 0
8 AM Tue 43 43 NNW 9 12 2023 2821 0 Blue 0
9 AM Tue 44 45 N 9 13 2410 2821 0 Blue 0
10 AM Tue 46 48 N 8 12 4847 2821 0 Blue 3
11 AM Tue 48 50 N 8 12 4991 4718 1897 Blue 5
12 Noon Tue 49 52 N 8 12 5060 4922 2101 Blue 7
1 PM Tue 51 53 W 5 10 5095 4989 2168 Blue 8
2 PM Tue 52 54 W 5 10 5130 5023 2202 Blue 9
3 PM Tue 52 53 W 5 10 5095 4989 2168 Blue 8
4 PM Tue 51 51 SSW 5 11 5026 4841 2020 Blue 6
5 PM Tue 50 50 SSW 5 11 4991 4718 1897 Blue 5
6 PM Tue 49 49 SSW 5 11 4927 4076 1255 Blue 4
7 PM Tue 48 48 SW 6 11 4847 2821 0 Blue 3
8 PM Tue 48 48 SW 6 11 4847 2821 0 Blue 3
9 PM Tue 48 48 SW 6 11 4847 2821 0 Blue 3
10 PM Tue 47 47 WSW 5 9 4745 2821 0 Blue 2
11 PM Tue 47 47 WSW 5 9 4745 2821 0 Blue 2
12 Midnight Wed 46 46 WSW 5 9 4111 2821 0 Blue 1
1 AM Wed 46 46 SW 6 10 4111 2821 0 Blue 1
2 AM Wed 45 45 SW 6 10 2410 2821 0 Blue 0
3 AM Wed 45 45 SW 6 10 2410 2821 0 Blue 0
4 AM Wed 44 44 SW 8 11 2023 2821 0 Blue 0
5 AM Wed 44 44 SW 8 11 2023 2821 0 Blue 0
6 AM Wed 45 45 SW 8 11 2410 2821 0 Blue 0
7 AM Wed 45 45 SSW 9 13 2410 2821 0 Blue 0
8 AM Wed 45 45 SSW 9 13 2410 2821 0 Blue 0
9 AM Wed 46 46 SSW 9 13 4111 2821 0 Blue 1
10 AM Wed 46 46 SW 11 18 4111 2821 0 Blue 1
11 AM Wed 47 47 SW 11 18 4745 2821 0 Blue 2
12 Noon Wed 48 49 SW 11 18 4927 4076 1255 Blue 4
1 PM Wed 49 50 WSW 11 19 4991 4718 1897 Blue 5
2 PM Wed 50 50 WSW 11 19 4991 4718 1897 Blue 5
3 PM Wed 49 49 WSW 11 19 4927 4076 1255 Blue 4
4 PM Wed 49 49 W 13 20 4927 4076 1255 Blue 4
5 PM Wed 48 48 W 13 20 4847 2821 0 Blue 3
6 PM Wed 48 48 W 13 20 4847 2821 0 Blue 3
7 PM Wed 47 47 WNW 13 19 4745 2821 0 Blue 2
8 PM Wed 46 46 WNW 13 19 4111 2821 0 Blue 1
9 PM Wed 46 46 WNW 13 19 4111 2821 0 Blue 1
10 PM Wed 45 45 NW 13 19 2410 2821 0 Blue 0
11 PM Wed 45 45 NW 13 19 2410 2821 0 Blue 0
12 Midnight Thu 45 45 NW 13 19 2410 2821 0 Blue 0
1 AM Thu 44 44 NNW 13 20 2023 2821 0 Blue 0
2 AM Thu 44 44 NNW 13 20 2023 2821 0 Blue 0
3 AM Thu 43 43 NNW 13 20 2023 2821 0 Blue 0
4 AM Thu 42 42 NNW 14 21 2023 2821 0 Blue 0
5 AM Thu 41 41 NNW 14 21 2023 2821 0 Blue 0
6 AM Thu 41 41 NNW 14 21 2023 2821 0 Blue 0
7 AM Thu 41 41 NNW 17 24 2023 2821 0 Blue 0
8 AM Thu 43 43 NNW 17 24 2023 2821 0 Blue 0
9 AM Thu 45 46 NNW 17 24 4111 2821 0 Blue 1
10 AM Thu 48 50 N 17 26 4991 4718 1897 Blue 5
11 AM Thu 49 52 N 17 26 5060 4922 2101 Blue 7
12 Noon Thu 50 53 N 17 26 5095 4989 2168 Blue 8
1 PM Thu 51 54 N 13 24 5130 5023 2202 Blue 9
2 PM Thu 52 54 N 13 24 5130 5023 2202 Blue 9
3 PM Thu 52 53 N 13 24 5095 4989 2168 Blue 8
4 PM Thu 52 52 NNW 16 25 5060 4922 2101 Blue 7
5 PM Thu 52 52 NNW 16 25 5060 4922 2101 Blue 7
6 PM Thu 51 51 NNW 16 25 5026 4841 2020 Blue 6
7 PM Thu 50 50 NNW 18 27 4991 4718 1897 Blue 5
8 PM Thu 50 50 NNW 18 27 4991 4718 1897 Blue 5
9 PM Thu 50 50 NNW 18 27 4991 4718 1897 Blue 5
10 PM Thu 49 49 NNW 21 32 4927 4076 1255 Blue 4
11 PM Thu 48 48 NNW 21 32 4847 2821 0 Blue 3
12 Midnight Fri 47 47 NNW 21 32 4745 2821 0 Blue 2
1 AM Fri 46 46 N 20 29 4111 2821 0 Blue 1
2 AM Fri 45 45 N 20 29 2410 2821 0 Blue 0
3 AM Fri 44 44 N 20 29 2023 2821 0 Blue 0
4 AM Fri 43 43 N 18 26 2023 2821 0 Blue 0
5 AM Fri 42 42 N 18 26 2023 2821 0 Blue 0
6 AM Fri 43 43 N 18 26 2023 2821 0 Blue 0
7 AM Fri 44 44 N 14 21 2023 2821 0 Blue 0
8 AM Fri 45 45 N 14 21 2410 2821 0 Blue 0
9 AM Fri 47 48 N 14 21 4847 2821 0 Blue 3
10 AM Fri 49 51 N 12 19 5026 4841 2020 Blue 6
11 AM Fri 50 53 N 12 19 5095 4989 2168 Blue 8
12 Noon Fri 52 55 N 12 19 5164 5058 2237 Blue 10
1 PM Fri 53 56 NNE 9 16 5199 5092 2271 Blue 11
2 PM Fri 54 56 NNE 9 16 5199 5092 2271 Blue 11
3 PM Fri 54 55 NNE 9 16 5164 5058 2237 Blue 10
4 PM Fri 54 54 NNE 8 13 5130 5023 2202 Blue 9
5 PM Fri 53 53 NNE 8 13 5095 4989 2168 Blue 8
6 PM Fri 52 52 NNE 8 13 5060 4922 2101 Blue 7
7 PM Fri 50 50 WNW 5 9 4991 4718 1897 Blue 5
8 PM Fri 49 49 WNW 5 9 4927 4076 1255 Blue 4
9 PM Fri 48 48 WNW 5 9 4847 2821 0 Blue 3
10 PM Fri 48 48 NW 5 9 4847 2821 0 Blue 3
11 PM Fri 47 47 NW 5 9 4745 2821 0 Blue 2
12 Midnight Sat 46 46 NW 5 9 4111 2821 0 Blue 1
1 AM Sat 46 46 NW 6 9 4111 2821 0 Blue 1
2 AM Sat 45 45 NW 6 9 2410 2821 0 Blue 0
3 AM Sat 44 44 NW 6 9 2023 2821 0 Blue 0
4 AM Sat 44 44 NNW 8 10 2023 2821 0 Blue 0
5 AM Sat 44 44 NNW 8 10 2023 2821 0 Blue 0
6 AM Sat 44 44 NNW 8 10 2023 2821 0 Blue 0
7 AM Sat 45 45 NNW 6 9 2410 2821 0 Blue 0
8 AM Sat 47 47 NNW 6 9 4745 2821 0 Blue 2
9 AM Sat 49 50 NNW 6 9 4991 4718 1897 Blue 5
10 AM Sat 51 53 NE 5 11 5095 4989 2168 Blue 8
11 AM Sat 52 54 NE 5 11 5130 5023 2202 Blue 9
12 Noon Sat 54 57 NE 5 11 5233 5127 2306 Blue 12
1 PM Sat 55 57 E 5 10 5233 5127 2306 Blue 12
2 PM Sat 56 58 E 5 10 5269 5161 2340 Blue 13
3 PM Sat 56 57 E 5 10 5233 5127 2306 Blue 12
4 PM Sat 56 56 SSE 6 10 5199 5092 2271 Blue 11
5 PM Sat 55 55 SSE 6 10 5164 5058 2237 Blue 10
6 PM Sat 54 54 SSE 6 10 5130 5023 2202 Blue 9
7 PM Sat 53 53 SW 6 9 5095 4989 2168 Blue 8
8 PM Sat 52 52 SW 6 9 5060 4922 2101 Blue 7
9 PM Sat 51 51 SW 6 9 5026 4841 2020 Blue 6
10 PM Sat 50 50 W 8 9 4991 4718 1897 Blue 5

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]