Detailed Predictions for: Mt Tamalpais
Launch Lat, Long, Altitude (f): 37.90719, -122.62, 2040
LZ Altitude (f): 0
Sounding

Station:

 KOAK

Date/Time UTC:

 260912/1200

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 Sat 63 63 WNW 10 17 1782 2040 0 Blue 6
1 AM Sat 63 63 WNW 10 16 1782 2040 0 Blue 6
2 AM Sat 63 63 WNW 10 17 1782 2040 0 Blue 6
3 AM Sat 61 61 NW 10 17 1717 2040 0 Blue 4
4 AM Sat 61 61 WNW 10 17 1717 2040 0 Blue 4
5 AM Sat 61 61 WNW 10 17 1717 2040 0 Blue 4
6 AM Sat 58 58 WNW 10 17 1573 2040 0 Blue 1
7 AM Sat 59 59 WNW 10 17 1606 2040 0 Blue 2
8 AM Sat 60 60 WNW 12 19 1649 2040 0 Blue 3
9 AM Sat 60 60 WNW 12 19 1649 2040 0 Blue 3
10 AM Sat 61 63 WNW 13 20 1782 2040 0 Blue 6
11 AM Sat 61 65 WNW 14 20 1829 2040 0 Blue 8
12 Noon Sat 62 67 WNW 16 21 1866 2040 0 Blue 10
1 PM Sat 63 69 WNW 17 23 1903 2040 0 Blue 12
2 PM Sat 63 68 WNW 18 24 1885 2040 0 Blue 11
3 PM Sat 63 67 WNW 18 25 1866 2040 0 Blue 10
4 PM Sat 62 65 WNW 18 25 1829 2040 0 Blue 8
5 PM Sat 61 62 WNW 17 26 1758 2040 0 Blue 5
6 PM Sat 62 62 WNW 17 27 1758 2040 0 Blue 5
7 PM Sat 60 60 WNW 17 28 1649 2040 0 Blue 3
8 PM Sat 60 60 WNW 17 28 1649 2040 0 Blue 3
9 PM Sat 61 61 WNW 16 29 1717 2040 0 Blue 4
10 PM Sat 61 61 NW 17 32 1717 2040 0 Blue 4
11 PM Sat 61 61 NW 17 32 1717 2040 0 Blue 4
12 Midnight Sun 61 61 NW 17 31 1717 2040 0 Blue 4
1 AM Sun 60 60 NW 16 29 1649 2040 0 Blue 3
2 AM Sun 60 60 NW 14 29 1649 2040 0 Blue 3
3 AM Sun 60 60 NW 14 28 1649 2040 0 Blue 3
4 AM Sun 60 60 NW 16 28 1649 2040 0 Blue 3
5 AM Sun 59 59 NW 14 28 1606 2040 0 Blue 2
6 AM Sun 57 57 NW 14 28 1482 2040 0 Blue 0
7 AM Sun 57 57 NW 14 28 1482 2040 0 Blue 0
8 AM Sun 57 57 NW 11 20 1482 2040 0 Blue 0
9 AM Sun 58 59 NW 11 20 1606 2040 0 Blue 2
10 AM Sun 60 62 NW 11 20 1758 2040 0 Blue 5
11 AM Sun 61 65 WNW 11 18 1829 2040 0 Blue 8
12 Noon Sun 63 68 WNW 11 18 1885 2040 0 Blue 11
1 PM Sun 64 70 WNW 11 18 1921 2040 0 Blue 13
2 PM Sun 65 70 WNW 13 20 1921 2040 0 Blue 13
3 PM Sun 65 69 WNW 13 20 1903 2040 0 Blue 12
4 PM Sun 65 68 WNW 13 20 1885 2040 0 Blue 11
5 PM Sun 64 65 WNW 13 21 1829 2040 0 Blue 8
6 PM Sun 64 64 WNW 13 21 1805 2040 0 Blue 7
7 PM Sun 63 63 WNW 13 21 1782 2040 0 Blue 6
8 PM Sun 62 62 WNW 12 20 1758 2040 0 Blue 5
9 PM Sun 62 62 WNW 12 20 1758 2040 0 Blue 5
10 PM Sun 62 62 WNW 12 20 1758 2040 0 Blue 5
11 PM Sun 62 62 NW 8 13 1758 2040 0 Blue 5
12 Midnight Mon 61 61 NW 8 13 1717 2040 0 Blue 4
1 AM Mon 59 59 NW 8 13 1606 2040 0 Blue 2
2 AM Mon 58 58 NW 5 10 1573 2040 0 Blue 1
3 AM Mon 57 57 NW 5 10 1482 2040 0 Blue 0
4 AM Mon 56 56 NW 5 10 351 2040 0 Blue 0
5 AM Mon 55 55 NW 3 5 351 2040 0 Blue 0
6 AM Mon 55 55 NW 3 5 351 2040 0 Blue 0
7 AM Mon 55 55 NW 3 5 351 2040 0 Blue 0
8 AM Mon 56 56 WNW 2 4 351 2040 0 Blue 0
9 AM Mon 58 59 WNW 2 4 1606 2040 0 Blue 2
10 AM Mon 61 63 WNW 2 4 1782 2040 0 Blue 6
11 AM Mon 64 68 W 4 8 1885 2040 0 Blue 11
12 Noon Mon 66 71 W 4 8 1974 2040 0 Blue 14
1 PM Mon 67 73 W 4 8 2080 2040 0 Blue 16
2 PM Mon 68 74 W 8 13 2133 2040 0 Blue 17
3 PM Mon 68 73 W 8 13 2080 2040 0 Blue 16
4 PM Mon 68 71 W 8 13 1974 2040 0 Blue 14
5 PM Mon 67 69 W 10 17 1903 2040 0 Blue 12
6 PM Mon 66 66 W 10 17 1848 2040 0 Blue 9
7 PM Mon 63 63 W 10 17 1782 2040 0 Blue 6
8 PM Mon 61 61 WNW 9 14 1717 2040 0 Blue 4
9 PM Mon 60 60 WNW 9 14 1649 2040 0 Blue 3
10 PM Mon 60 60 WNW 9 14 1649 2040 0 Blue 3
11 PM Mon 60 60 WNW 6 12 1649 2040 0 Blue 3
12 Midnight Tue 59 59 WNW 6 12 1606 2040 0 Blue 2
1 AM Tue 58 58 WNW 6 12 1573 2040 0 Blue 1
2 AM Tue 58 58 WNW 5 10 1573 2040 0 Blue 1
3 AM Tue 57 57 WNW 5 10 1482 2040 0 Blue 0
4 AM Tue 57 57 WNW 5 10 1482 2040 0 Blue 0
5 AM Tue 56 56 W 4 8 351 2040 0 Blue 0
6 AM Tue 56 56 W 4 8 351 2040 0 Blue 0
7 AM Tue 55 55 W 4 8 351 2040 0 Blue 0
8 AM Tue 55 55 W 3 8 351 2040 0 Blue 0
9 AM Tue 56 56 W 3 8 351 2040 0 Blue 0
10 AM Tue 57 58 W 3 8 1573 2040 0 Blue 1
11 AM Tue 58 61 SW 4 9 1717 2040 0 Blue 4
12 Noon Tue 60 64 SW 4 9 1805 2040 0 Blue 7
1 PM Tue 61 66 SW 4 9 1848 2040 0 Blue 9
2 PM Tue 62 67 WSW 5 11 1866 2040 0 Blue 10
3 PM Tue 63 67 WSW 5 11 1866 2040 0 Blue 10
4 PM Tue 63 66 WSW 5 11 1848 2040 0 Blue 9
5 PM Tue 64 65 W 5 12 1829 2040 0 Blue 8
6 PM Tue 62 62 W 5 12 1758 2040 0 Blue 5
7 PM Tue 60 60 W 5 12 1649 2040 0 Blue 3
8 PM Tue 60 60 W 3 8 1649 2040 0 Blue 3
9 PM Tue 59 59 W 3 8 1606 2040 0 Blue 2
10 PM Tue 60 60 W 3 8 1649 2040 0 Blue 3
11 PM Tue 60 60 WSW 3 8 1649 2040 0 Blue 3
12 Midnight Wed 59 59 WSW 3 8 1606 2040 0 Blue 2
1 AM Wed 59 59 WSW 3 8 1606 2040 0 Blue 2
2 AM Wed 58 58 SW 3 8 1573 2040 0 Blue 1
3 AM Wed 59 59 SW 3 8 1606 2040 0 Blue 2
4 AM Wed 59 59 SW 3 8 1606 2040 0 Blue 2
5 AM Wed 59 59 SSW 3 6 1606 2040 0 Blue 2
6 AM Wed 59 59 SSW 3 6 1606 2040 0 Blue 2
7 AM Wed 59 59 SSW 3 6 1606 2040 0 Blue 2
8 AM Wed 59 59 SSW 4 8 1606 2040 0 Blue 2
9 AM Wed 59 59 SSW 4 8 1606 2040 0 Blue 2
10 AM Wed 60 61 SSW 4 8 1717 2040 0 Blue 4
11 AM Wed 60 62 SSW 4 9 1758 2040 0 Blue 5
12 Noon Wed 62 65 SSW 4 9 1829 2040 0 Blue 8
1 PM Wed 64 67 SSW 4 9 1866 2040 0 Blue 10
2 PM Wed 65 68 SW 4 11 1885 2040 0 Blue 11
3 PM Wed 65 68 SW 4 11 1885 2040 0 Blue 11
4 PM Wed 64 66 SW 4 11 1848 2040 0 Blue 9
5 PM Wed 64 65 WSW 5 11 1829 2040 0 Blue 8
6 PM Wed 62 62 WSW 5 11 1758 2040 0 Blue 5
7 PM Wed 62 62 WSW 5 11 1758 2040 0 Blue 5
8 PM Wed 61 61 W 2 6 1717 2040 0 Blue 4
9 PM Wed 61 61 W 2 6 1717 2040 0 Blue 4
10 PM Wed 61 61 W 2 6 1717 2040 0 Blue 4
11 PM Wed 61 61 W 2 5 1717 2040 0 Blue 4
12 Midnight Thu 60 60 W 2 5 1649 2040 0 Blue 3
1 AM Thu 60 60 W 2 5 1649 2040 0 Blue 3
2 AM Thu 59 59 W 2 4 1606 2040 0 Blue 2
3 AM Thu 59 59 W 2 4 1606 2040 0 Blue 2
4 AM Thu 60 60 W 2 4 1649 2040 0 Blue 3
5 AM Thu 60 60 W 2 4 1649 2040 0 Blue 3
6 AM Thu 60 60 W 2 4 1649 2040 0 Blue 3
7 AM Thu 59 59 W 2 4 1606 2040 0 Blue 2
8 AM Thu 59 59 W 2 4 1606 2040 0 Blue 2
9 AM Thu 60 60 W 2 4 1649 2040 0 Blue 3
10 AM Thu 61 62 W 2 4 1758 2040 0 Blue 5
11 AM Thu 62 64 WSW 3 6 1805 2040 0 Blue 7
12 Noon Thu 64 67 WSW 3 6 1866 2040 0 Blue 10
1 PM Thu 65 68 WSW 3 6 1885 2040 0 Blue 11
2 PM Thu 66 69 WSW 4 10 1903 2040 0 Blue 12
3 PM Thu 67 70 WSW 4 10 1921 2040 0 Blue 13
4 PM Thu 66 68 WSW 4 10 1885 2040 0 Blue 11
5 PM Thu 65 66 W 5 11 1848 2040 0 Blue 9
6 PM Thu 64 64 W 5 11 1805 2040 0 Blue 7
7 PM Thu 63 63 W 5 11 1782 2040 0 Blue 6
8 PM Thu 62 62 W 3 9 1758 2040 0 Blue 5
9 PM Thu 61 61 W 3 9 1717 2040 0 Blue 4
10 PM Thu 61 61 W 3 9 1717 2040 0 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 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]