Detailed Predictions for: Mt Vaca
Launch Altitude (f): 2821
LZ Altitude (f): 2000
Sounding

Station:

KOAK

Date/Time:

18 OCT 2019

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
5 AM Fri 52 52 NW 12 2388 2821 0 Blue 0
6 AM Fri 50 50 NW 12 1923 2821 0 Blue 0
7 AM Fri 50 50 NW 12 1923 2821 0 Blue 0
8 AM Fri 50 50 NW 13 1923 2821 0 Blue 0
9 AM Fri 52 52 NW 13 2388 2821 0 Blue 0
10 AM Fri 54 55 NW 13 3164 2821 0 Blue 2
11 AM Fri 56 58 W 13 3487 3162 341 Blue 5
12 Noon Fri 58 61 W 13 4370 3484 663 Blue 8
1 PM Fri 60 64 W 13 5869 4347 1526 Blue 11
2 PM Fri 61 65 W 14 6333 4849 2028 Blue 12
3 PM Fri 61 64 W 14 5869 4347 1526 Blue 11
4 PM Fri 60 61 W 14 4370 3484 663 Blue 8
5 PM Fri 59 59 W 14 3594 3269 448 Blue 6
6 PM Fri 57 57 W 14 3379 3055 234 Blue 4
7 PM Fri 55 55 W 14 3164 2821 0 Blue 2
8 PM Fri 54 54 W 10 3057 2821 0 Blue 1
9 PM Fri 53 53 W 10 2619 2821 0 Blue 0
10 PM Fri 52 52 W 10 2388 2821 0 Blue 0
11 PM Fri 51 51 W 10 2156 2821 0 Blue 0
12 Midnight Sat 53 53 W 10 2619 2821 0 Blue 0
1 AM Sat 52 52 W 10 2388 2821 0 Blue 0
2 AM Sat 52 52 NW 14 2388 2821 0 Blue 0
3 AM Sat 53 53 NW 14 2619 2821 0 Blue 0
4 AM Sat 52 52 NW 14 2388 2821 0 Blue 0
5 AM Sat 52 52 W 14 2388 2821 0 Blue 0
6 AM Sat 53 53 W 14 2619 2821 0 Blue 0
7 AM Sat 52 52 W 14 2388 2821 0 Blue 0
8 AM Sat 52 52 W 14 2388 2821 0 Blue 0
9 AM Sat 54 54 W 14 3057 2821 0 Blue 1
10 AM Sat 56 57 W 14 3379 3055 234 Blue 4
11 AM Sat 58 59 W 15 3594 3269 448 Blue 6
12 Noon Sat 60 62 W 15 4893 3591 770 Blue 9
1 PM Sat 62 64 W 15 5869 4347 1526 Blue 11
2 PM Sat 62 64 W 18 5869 4347 1526 Blue 11
3 PM Sat 62 63 W 18 5391 3936 1115 Blue 10
4 PM Sat 61 62 W 18 4893 3591 770 Blue 9
5 PM Sat 60 60 W 18 3955 3377 556 Blue 7
6 PM Sat 58 58 W 18 3487 3162 341 Blue 5
7 PM Sat 56 56 W 18 3272 2821 0 Blue 3
8 PM Sat 55 55 W 13 3164 2821 0 Blue 2
9 PM Sat 54 54 W 13 3057 2821 0 Blue 1
10 PM Sat 54 54 W 13 3057 2821 0 Blue 1
11 PM Sat 54 54 W 12 3057 2821 0 Blue 1
12 Midnight Sun 54 54 W 12 3057 2821 0 Blue 1
1 AM Sun 54 54 W 12 3057 2821 0 Blue 1
2 AM Sun 54 54 NW 12 3057 2821 0 Blue 1
3 AM Sun 54 54 NW 12 3057 2821 0 Blue 1
4 AM Sun 54 54 NW 12 3057 2821 0 Blue 1
5 AM Sun 54 54 NW 13 3057 2821 0 Blue 1
6 AM Sun 53 53 NW 13 2619 2821 0 Blue 0
7 AM Sun 52 52 NW 13 2388 2821 0 Blue 0
8 AM Sun 53 53 NW 13 2619 2821 0 Blue 0
9 AM Sun 54 54 NW 13 3057 2821 0 Blue 1
10 AM Sun 56 57 NW 13 3379 3055 234 Blue 4
11 AM Sun 58 61 NW 14 4370 3484 663 Blue 8
12 Noon Sun 60 63 NW 14 5391 3936 1115 Blue 10
1 PM Sun 62 66 NW 14 6787 5347 2526 Blue 13
2 PM Sun 64 67 NW 14 7164 5819 2998 Blue 14
3 PM Sun 65 67 NW 14 7164 5819 2998 Blue 14
4 PM Sun 65 66 NW 14 6787 5347 2526 Blue 13
5 PM Sun 64 64 NW 13 5869 4347 1526 Blue 11
6 PM Sun 62 62 NW 13 4893 3591 770 Blue 9
7 PM Sun 60 60 NW 13 3955 3377 556 Blue 7
8 PM Sun 57 57 NW 9 3379 3055 234 Blue 4
9 PM Sun 57 57 NW 9 3379 3055 234 Blue 4
10 PM Sun 57 57 NW 9 3379 3055 234 Blue 4
11 PM Sun 57 57 NW 9 3379 3055 234 Blue 4
12 Midnight Mon 57 57 NW 9 3379 3055 234 Blue 4
1 AM Mon 58 58 NW 9 3487 3162 341 Blue 5
2 AM Mon 58 58 NW 10 3487 3162 341 Blue 5
3 AM Mon 58 58 NW 10 3487 3162 341 Blue 5
4 AM Mon 59 59 NW 10 3594 3269 448 Blue 6
5 AM Mon 58 58 NW 13 3487 3162 341 Blue 5
6 AM Mon 57 57 NW 13 3379 3055 234 Blue 4
7 AM Mon 56 56 NW 13 3272 2821 0 Blue 3
8 AM Mon 57 57 N 12 3379 3055 234 Blue 4
9 AM Mon 58 58 N 12 3487 3162 341 Blue 5
10 AM Mon 60 61 N 12 4370 3484 663 Blue 8
11 AM Mon 63 66 N 13 6787 5347 2526 Blue 13
12 Noon Mon 66 69 N 13 7660 6726 3905 Blue 16
1 PM Mon 68 72 N 13 8396 7619 4798 Blue 19
2 PM Mon 70 74 N 13 8862 8107 5286 Blue 21
3 PM Mon 71 74 N 13 8862 8107 5286 Blue 21
4 PM Mon 71 72 N 13 8396 7619 4798 Blue 19
5 PM Mon 70 70 N 12 7907 7127 4306 Blue 17
6 PM Mon 68 68 N 12 7413 6278 3457 Blue 15
7 PM Mon 66 66 N 12 6787 5347 2526 Blue 13
8 PM Mon 64 64 N 7 5869 4347 1526 Blue 11
9 PM Mon 62 62 N 7 4893 3591 770 Blue 9
10 PM Mon 62 62 N 7 4893 3591 770 Blue 9
11 PM Mon 62 62 N 9 4893 3591 770 Blue 9
12 Midnight Tue 62 62 N 9 4893 3591 770 Blue 9
1 AM Tue 62 62 N 9 4893 3591 770 Blue 9
2 AM Tue 62 62 N 9 4893 3591 770 Blue 9
3 AM Tue 62 62 N 9 4893 3591 770 Blue 9
4 AM Tue 61 61 N 9 4370 3484 663 Blue 8
5 AM Tue 60 60 N 12 3955 3377 556 Blue 7
6 AM Tue 59 59 N 12 3594 3269 448 Blue 6
7 AM Tue 58 58 N 12 3487 3162 341 Blue 5
8 AM Tue 58 58 N 10 3487 3162 341 Blue 5
9 AM Tue 60 60 N 10 3955 3377 556 Blue 7
10 AM Tue 63 64 N 10 5869 4347 1526 Blue 11
11 AM Tue 66 69 N 10 7660 6726 3905 Blue 16
12 Noon Tue 68 71 N 10 8152 7373 4552 Blue 18
1 PM Tue 70 74 N 10 8862 8107 5286 Blue 21
2 PM Tue 72 75 N 12 9126 8350 5529 Blue 22
3 PM Tue 73 76 N 12 9484 8591 5770 Blue 23
4 PM Tue 73 74 N 12 8862 8107 5286 Blue 21
5 PM Tue 72 72 N 9 8396 7619 4798 Blue 19
6 PM Tue 70 70 N 9 7907 7127 4306 Blue 17
7 PM Tue 67 67 N 9 7164 5819 2998 Blue 14
8 PM Tue 65 65 W 7 6333 4849 2028 Blue 12
9 PM Tue 64 64 W 7 5869 4347 1526 Blue 11
10 PM Tue 63 63 W 7 5391 3936 1115 Blue 10
11 PM Tue 63 63 W 8 5391 3936 1115 Blue 10
12 Midnight Wed 63 63 W 8 5391 3936 1115 Blue 10
1 AM Wed 63 63 W 8 5391 3936 1115 Blue 10
2 AM Wed 63 63 W 9 5391 3936 1115 Blue 10
3 AM Wed 63 63 W 9 5391 3936 1115 Blue 10
4 AM Wed 63 63 W 9 5391 3936 1115 Blue 10
5 AM Wed 62 62 N 12 4893 3591 770 Blue 9
6 AM Wed 61 61 N 12 4370 3484 663 Blue 8
7 AM Wed 60 60 N 12 3955 3377 556 Blue 7
8 AM Wed 60 60 N 12 3955 3377 556 Blue 7
9 AM Wed 61 61 N 12 4370 3484 663 Blue 8
10 AM Wed 63 64 N 12 5869 4347 1526 Blue 11
11 AM Wed 66 69 N 14 7660 6726 3905 Blue 16
12 Noon Wed 69 72 N 14 8396 7619 4798 Blue 19
1 PM Wed 71 75 N 14 9126 8350 5529 Blue 22
2 PM Wed 72 75 N 13 9126 8350 5529 Blue 22
3 PM Wed 73 76 N 13 9484 8591 5770 Blue 23
4 PM Wed 73 74 N 13 8862 8107 5286 Blue 21
5 PM Wed 72 72 N 14 8396 7619 4798 Blue 19
6 PM Wed 70 70 N 14 7907 7127 4306 Blue 17
7 PM Wed 68 68 N 14 7413 6278 3457 Blue 15
8 PM Wed 66 66 N 12 6787 5347 2526 Blue 13
9 PM Wed 65 65 N 12 6333 4849 2028 Blue 12
10 PM Wed 64 64 N 12 5869 4347 1526 Blue 11
11 PM Wed 64 64 N 17 5869 4347 1526 Blue 11
12 Midnight Thu 64 64 N 17 5869 4347 1526 Blue 11
1 AM Thu 64 64 N 17 5869 4347 1526 Blue 11
2 AM Thu 64 64 N 16 5869 4347 1526 Blue 11
3 AM Thu 64 64 N 16 5869 4347 1526 Blue 11
4 AM Thu 63 63 N 16 5391 3936 1115 Blue 10

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 website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service 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 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 ac_soaring@yahoo.com