Detailed Predictions for: Mt Tamalpais
Launch Altitude (f): 2040
LZ Altitude (f): 0
Sounding

Station:

KOAK

Date/Time:

23 SEP 2017

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 Sat 55 55 N 14 1106 2040 0 Blue 0
6 AM Sat 54 54 N 14 1106 2040 0 Blue 0
7 AM Sat 54 54 N 14 1106 2040 0 Blue 0
8 AM Sat 56 56 N 15 1106 2040 0 Blue 0
9 AM Sat 58 59 N 15 1374 2040 0 Blue 0
10 AM Sat 62 64 N 15 3871 2079 39 Blue 3
11 AM Sat 66 69 N 8 6738 4333 2293 Blue 8
12 Noon Sat 69 74 N 8 8448 7688 5648 White 13
1 PM Sat 71 76 N 8 8860 8860 6820 White 15
2 PM Sat 72 77 NW 18 9065 9065 7025 White 16
3 PM Sat 72 76 NW 18 8860 8860 6820 White 15
4 PM Sat 70 72 NW 18 8034 6662 4622 White 11
5 PM Sat 68 69 NW 18 6738 4333 2293 Blue 8
6 PM Sat 66 66 NW 18 4359 3102 1062 Blue 5
7 PM Sat 64 64 NW 18 3871 2079 39 Blue 3
8 PM Sat 62 62 NW 17 2643 2040 0 Blue 1
9 PM Sat 61 61 NW 17 2091 2040 0 Blue 0
10 PM Sat 60 60 NW 17 1734 2040 0 Blue 0
11 PM Sat 59 59 N 12 1374 2040 0 Blue 0
12 Midnight Sun 59 59 N 12 1374 2040 0 Blue 0
1 AM Sun 59 59 N 12 1374 2040 0 Blue 0
2 AM Sun 58 58 N 8 1106 2040 0 Blue 0
3 AM Sun 58 58 N 8 1106 2040 0 Blue 0
4 AM Sun 57 57 N 8 1106 2040 0 Blue 0
5 AM Sun 56 56 NE 9 1106 2040 0 Blue 0
6 AM Sun 56 56 NE 9 1106 2040 0 Blue 0
7 AM Sun 56 56 NE 9 1106 2040 0 Blue 0
8 AM Sun 58 58 N 10 1106 2040 0 Blue 0
9 AM Sun 60 61 N 10 2091 2040 0 Blue 0
10 AM Sun 63 65 N 10 4106 2634 594 Blue 4
11 AM Sun 67 70 W 6 7147 5145 3105 Blue 9
12 Noon Sun 70 74 W 6 8448 7688 5648 White 13
1 PM Sun 74 79 W 6 9473 9473 7433 White 18
2 PM Sun 76 80 W 12 9676 9676 7636 White 19
3 PM Sun 76 80 W 12 9676 9676 7636 White 19
4 PM Sun 76 78 W 12 9270 9270 7230 White 17
5 PM Sun 74 75 NW 20 8655 8354 6314 White 14
6 PM Sun 71 71 NW 20 7827 6088 4048 White 10
7 PM Sun 69 69 NW 20 6738 4333 2293 Blue 8
8 PM Sun 66 66 NW 20 4359 3102 1062 Blue 5
9 PM Sun 65 65 NW 20 4106 2634 594 Blue 4
10 PM Sun 63 63 NW 20 3162 2040 0 Blue 2
11 PM Sun 62 62 N 14 2643 2040 0 Blue 1
12 Midnight Mon 62 62 N 14 2643 2040 0 Blue 1
1 AM Mon 62 62 N 14 2643 2040 0 Blue 1
2 AM Mon 61 61 N 14 2091 2040 0 Blue 0
3 AM Mon 61 61 N 14 2091 2040 0 Blue 0
4 AM Mon 60 60 N 14 1734 2040 0 Blue 0
5 AM Mon 59 59 N 15 1374 2040 0 Blue 0
6 AM Mon 58 58 N 15 1106 2040 0 Blue 0
7 AM Mon 58 58 N 15 1106 2040 0 Blue 0
8 AM Mon 59 59 N 15 1374 2040 0 Blue 0
9 AM Mon 62 63 N 15 3162 2040 0 Blue 2
10 AM Mon 65 67 N 15 5466 3850 1810 Blue 6
11 AM Mon 69 72 NW 16 8034 6662 4622 White 11
12 Noon Mon 74 79 NW 16 9473 9473 7433 White 18
1 PM Mon 77 82 NW 16 10103 10103 8063 White 21
2 PM Mon 79 84 NW 16 10504 10504 8464 White 23
3 PM Mon 80 84 NW 16 10504 10504 8464 White 23
4 PM Mon 79 82 NW 16 10103 10103 8063 White 21
5 PM Mon 77 78 NW 16 9270 9270 7230 White 17
6 PM Mon 75 75 NW 16 8655 8354 6314 White 14
7 PM Mon 73 73 NW 16 8242 7066 5026 White 12
8 PM Mon 72 72 NW 16 8034 6662 4622 White 11
9 PM Mon 71 71 NW 16 7827 6088 4048 White 10
10 PM Mon 71 71 NW 16 7827 6088 4048 White 10
11 PM Mon 70 70 N 14 7147 5145 3105 Blue 9
12 Midnight Tue 69 69 N 14 6738 4333 2293 Blue 8
1 AM Tue 68 68 N 14 6155 4082 2042 Blue 7
2 AM Tue 67 67 N 14 5466 3850 1810 Blue 6
3 AM Tue 67 67 N 14 5466 3850 1810 Blue 6
4 AM Tue 67 67 N 14 5466 3850 1810 Blue 6
5 AM Tue 66 66 NE 14 4359 3102 1062 Blue 5
6 AM Tue 64 64 NE 14 3871 2079 39 Blue 3
7 AM Tue 61 61 NE 14 2091 2040 0 Blue 0
8 AM Tue 61 61 NE 14 2091 2040 0 Blue 0
9 AM Tue 64 65 NE 14 4106 2634 594 Blue 4
10 AM Tue 69 71 NE 14 7827 6088 4048 White 10
11 AM Tue 74 78 NE 7 9270 9270 7230 White 17
12 Noon Tue 77 82 NE 7 10103 10103 8063 White 21
1 PM Tue 79 84 NE 7 10504 10504 8464 White 23
2 PM Tue 80 85 NE 7 10703 10703 8663 White 24
3 PM Tue 81 85 NE 7 10703 10703 8663 White 24
4 PM Tue 81 84 NE 7 10504 10504 8464 White 23
5 PM Tue 80 81 W 8 9894 9894 7854 White 20
6 PM Tue 76 76 W 8 8860 8860 6820 White 15
7 PM Tue 71 71 W 8 7827 6088 4048 White 10
8 PM Tue 68 68 W 8 6155 4082 2042 Blue 7
9 PM Tue 68 68 W 8 6155 4082 2042 Blue 7
10 PM Tue 70 70 W 8 7147 5145 3105 Blue 9
11 PM Tue 71 71 NW 7 7827 6088 4048 White 10
12 Midnight Wed 68 68 NW 7 6155 4082 2042 Blue 7
1 AM Wed 64 64 NW 7 3871 2079 39 Blue 3
2 AM Wed 62 62 NW 7 2643 2040 0 Blue 1
3 AM Wed 62 62 NW 7 2643 2040 0 Blue 1
4 AM Wed 64 64 NW 7 3871 2079 39 Blue 3
5 AM Wed 65 65 NE 5 4106 2634 594 Blue 4
6 AM Wed 63 63 NE 5 3162 2040 0 Blue 2
7 AM Wed 61 61 NE 5 2091 2040 0 Blue 0
8 AM Wed 61 61 NE 5 2091 2040 0 Blue 0
9 AM Wed 65 65 NE 5 4106 2634 594 Blue 4
10 AM Wed 71 73 NE 5 8242 7066 5026 White 12
11 AM Wed 77 80 NE 7 9676 9676 7636 White 19
12 Noon Wed 81 85 NE 7 10703 10703 8663 White 24
1 PM Wed 83 87 NE 7 11102 11102 9062 White 26
2 PM Wed 84 88 NE 7 11300 11300 9260 White 27
3 PM Wed 85 88 NE 7 11300 11300 9260 White 27
4 PM Wed 85 87 NE 7 11102 11102 9062 White 26
5 PM Wed 83 84 W 5 10504 10504 8464 White 23
6 PM Wed 79 79 W 5 9473 9473 7433 White 18
7 PM Wed 75 75 W 5 8655 8354 6314 White 14
8 PM Wed 71 71 W 5 7827 6088 4048 White 10
9 PM Wed 71 71 W 5 7827 6088 4048 White 10
10 PM Wed 71 71 W 5 7827 6088 4048 White 10
11 PM Wed 70 70 NW 3 7147 5145 3105 Blue 9
12 Midnight Thu 68 68 NW 3 6155 4082 2042 Blue 7
1 AM Thu 64 64 NW 3 3871 2079 39 Blue 3
2 AM Thu 62 62 NW 3 2643 2040 0 Blue 1
3 AM Thu 63 63 NW 3 3162 2040 0 Blue 2
4 AM Thu 65 65 NW 3 4106 2634 594 Blue 4
5 AM Thu 66 66 NE 1 4359 3102 1062 Blue 5
6 AM Thu 64 64 NE 1 3871 2079 39 Blue 3
7 AM Thu 61 61 NE 1 2091 2040 0 Blue 0
8 AM Thu 61 61 NE 1 2091 2040 0 Blue 0
9 AM Thu 65 65 NE 1 4106 2634 594 Blue 4
10 AM Thu 72 73 NE 1 8242 7066 5026 White 12
11 AM Thu 78 81 NE 2 9894 9894 7854 White 20
12 Noon Thu 81 85 NE 2 10703 10703 8663 White 24
1 PM Thu 82 86 NE 2 10903 10903 8863 White 25
2 PM Thu 83 87 NE 2 11102 11102 9062 White 26
3 PM Thu 84 87 NE 2 11102 11102 9062 White 26
4 PM Thu 84 86 NE 2 10903 10903 8863 White 25
5 PM Thu 83 84 W 8 10504 10504 8464 White 23
6 PM Thu 78 78 W 8 9270 9270 7230 White 17
7 PM Thu 73 73 W 8 8242 7066 5026 White 12
8 PM Thu 69 69 W 8 6738 4333 2293 Blue 8
9 PM Thu 69 69 W 8 6738 4333 2293 Blue 8
10 PM Thu 70 70 W 8 7147 5145 3105 Blue 9
11 PM Thu 71 71 W 7 7827 6088 4048 White 10
12 Midnight Fri 68 68 W 7 6155 4082 2042 Blue 7
1 AM Fri 64 64 W 7 3871 2079 39 Blue 3
2 AM Fri 62 62 W 7 2643 2040 0 Blue 1
3 AM Fri 62 62 W 7 2643 2040 0 Blue 1
4 AM Fri 65 65 W 7 4106 2634 594 Blue 4

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