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

Station:

KOAK

Date/Time:

21 SEP 2021

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 Tue 73 73 NE 8 12 758 2040 0 Blue 0
1 AM Tue 70 70 NE 9 13 758 2040 0 Blue 0
2 AM Tue 71 71 NE 10 14 758 2040 0 Blue 0
3 AM Tue 71 71 NE 11 18 758 2040 0 Blue 0
4 AM Tue 70 70 NE 14 21 758 2040 0 Blue 0
5 AM Tue 69 69 ENE 14 23 758 2040 0 Blue 0
6 AM Tue 68 68 NE 16 24 758 2040 0 Blue 0
7 AM Tue 67 67 NE 16 24 758 2040 0 Blue 0
8 AM Tue 69 69 NE 16 25 758 2040 0 Blue 0
9 AM Tue 72 73 NE 16 24 758 2040 0 Blue 0
10 AM Tue 78 80 ENE 12 18 1827 2040 0 Blue 0
11 AM Tue 81 85 E 6 11 4031 3399 1359 Blue 5
12 Noon Tue 84 89 SE 6 11 4794 4341 2301 Blue 9
1 PM Tue 83 88 S 3 4 4686 4000 1960 Blue 8
2 PM Tue 82 87 WSW 5 8 4578 3897 1857 Blue 7
3 PM Tue 81 85 W 6 9 4031 3399 1359 Blue 5
4 PM Tue 80 82 W 6 10 3485 2040 0 Blue 2
5 PM Tue 79 80 W 6 11 1827 2040 0 Blue 0
6 PM Tue 78 78 W 8 11 1236 2040 0 Blue 0
7 PM Tue 76 76 W 6 10 758 2040 0 Blue 0
8 PM Tue 68 68 W 5 9 758 2040 0 Blue 0
9 PM Tue 71 71 W 5 9 758 2040 0 Blue 0
10 PM Tue 69 69 W 5 8 758 2040 0 Blue 0
11 PM Tue 68 68 W 4 6 758 2040 0 Blue 0
12 Midnight Wed 67 67 W 4 6 758 2040 0 Blue 0
1 AM Wed 65 65 W 5 8 758 2040 0 Blue 0
2 AM Wed 64 64 W 5 8 758 2040 0 Blue 0
3 AM Wed 63 63 W 5 8 758 2040 0 Blue 0
4 AM Wed 62 62 W 5 9 758 2040 0 Blue 0
5 AM Wed 61 61 W 5 9 758 2040 0 Blue 0
6 AM Wed 60 60 WSW 5 9 758 2040 0 Blue 0
7 AM Wed 58 58 WSW 5 9 758 2040 0 Blue 0
8 AM Wed 59 59 WSW 5 8 758 2040 0 Blue 0
9 AM Wed 59 59 WSW 5 9 758 2040 0 Blue 0
10 AM Wed 62 63 SW 6 9 758 2040 0 Blue 0
11 AM Wed 64 66 WSW 6 10 758 2040 0 Blue 0
12 Noon Wed 64 67 WSW 6 10 758 2040 0 Blue 0
1 PM Wed 66 69 WSW 6 10 758 2040 0 Blue 0
2 PM Wed 67 70 W 8 12 758 2040 0 Blue 0
3 PM Wed 67 70 W 8 12 758 2040 0 Blue 0
4 PM Wed 66 68 W 8 12 758 2040 0 Blue 0
5 PM Wed 65 66 WNW 9 12 758 2040 0 Blue 0
6 PM Wed 65 65 WNW 9 12 758 2040 0 Blue 0
7 PM Wed 64 64 WNW 9 12 758 2040 0 Blue 0
8 PM Wed 64 64 NW 6 11 758 2040 0 Blue 0
9 PM Wed 62 62 NW 6 11 758 2040 0 Blue 0
10 PM Wed 61 61 NW 6 11 758 2040 0 Blue 0
11 PM Wed 60 60 NW 8 11 758 2040 0 Blue 0
12 Midnight Thu 59 59 NW 8 11 758 2040 0 Blue 0
1 AM Thu 59 59 NW 8 11 758 2040 0 Blue 0
2 AM Thu 58 58 NNW 6 11 758 2040 0 Blue 0
3 AM Thu 58 58 NNW 6 11 758 2040 0 Blue 0
4 AM Thu 58 58 NNW 6 11 758 2040 0 Blue 0
5 AM Thu 58 58 N 5 9 758 2040 0 Blue 0
6 AM Thu 57 57 N 5 9 758 2040 0 Blue 0
7 AM Thu 58 58 N 5 9 758 2040 0 Blue 0
8 AM Thu 58 58 N 5 8 758 2040 0 Blue 0
9 AM Thu 61 62 N 5 8 758 2040 0 Blue 0
10 AM Thu 64 66 N 5 8 758 2040 0 Blue 0
11 AM Thu 68 71 NNW 6 9 758 2040 0 Blue 0
12 Noon Thu 70 74 NNW 6 9 758 2040 0 Blue 0
1 PM Thu 71 75 NNW 6 9 758 2040 0 Blue 0
2 PM Thu 72 75 NW 9 13 758 2040 0 Blue 0
3 PM Thu 73 76 NW 9 13 758 2040 0 Blue 0
4 PM Thu 72 74 NW 9 13 758 2040 0 Blue 0
5 PM Thu 72 73 NW 12 18 758 2040 0 Blue 0
6 PM Thu 71 71 NW 12 18 758 2040 0 Blue 0
7 PM Thu 70 70 NW 12 18 758 2040 0 Blue 0
8 PM Thu 69 69 NW 8 12 758 2040 0 Blue 0
9 PM Thu 67 67 NW 8 12 758 2040 0 Blue 0
10 PM Thu 66 66 NW 8 12 758 2040 0 Blue 0
11 PM Thu 64 64 NNW 4 6 758 2040 0 Blue 0
12 Midnight Fri 63 63 NNW 4 6 758 2040 0 Blue 0
1 AM Fri 62 62 NNW 4 6 758 2040 0 Blue 0
2 AM Fri 61 61 WNW 4 5 758 2040 0 Blue 0
3 AM Fri 61 61 WNW 4 5 758 2040 0 Blue 0
4 AM Fri 60 60 WNW 4 5 758 2040 0 Blue 0
5 AM Fri 60 60 W 4 5 758 2040 0 Blue 0
6 AM Fri 59 59 W 4 5 758 2040 0 Blue 0
7 AM Fri 59 59 W 4 5 758 2040 0 Blue 0
8 AM Fri 60 60 SSW 2 2 758 2040 0 Blue 0
9 AM Fri 62 63 SSW 2 2 758 2040 0 Blue 0
10 AM Fri 64 66 SSW 2 2 758 2040 0 Blue 0
11 AM Fri 66 69 SSW 4 6 758 2040 0 Blue 0
12 Noon Fri 68 72 SSW 4 6 758 2040 0 Blue 0
1 PM Fri 69 73 SSW 4 6 758 2040 0 Blue 0
2 PM Fri 70 74 SW 4 6 758 2040 0 Blue 0
3 PM Fri 70 73 SW 4 6 758 2040 0 Blue 0
4 PM Fri 69 71 SW 4 6 758 2040 0 Blue 0
5 PM Fri 68 69 WSW 6 10 758 2040 0 Blue 0
6 PM Fri 68 68 WSW 6 10 758 2040 0 Blue 0
7 PM Fri 67 67 WSW 6 10 758 2040 0 Blue 0
8 PM Fri 66 66 WSW 5 8 758 2040 0 Blue 0
9 PM Fri 65 65 WSW 5 8 758 2040 0 Blue 0
10 PM Fri 64 64 WSW 5 8 758 2040 0 Blue 0
11 PM Fri 62 62 SW 5 8 758 2040 0 Blue 0
12 Midnight Sat 62 62 SW 5 8 758 2040 0 Blue 0
1 AM Sat 61 61 SW 5 8 758 2040 0 Blue 0
2 AM Sat 61 61 SW 4 6 758 2040 0 Blue 0
3 AM Sat 61 61 SW 4 6 758 2040 0 Blue 0
4 AM Sat 61 61 SW 4 6 758 2040 0 Blue 0
5 AM Sat 60 60 SW 4 6 758 2040 0 Blue 0
6 AM Sat 60 60 SW 4 6 758 2040 0 Blue 0
7 AM Sat 60 60 SW 4 6 758 2040 0 Blue 0
8 AM Sat 60 60 SW 3 4 758 2040 0 Blue 0
9 AM Sat 60 60 SW 3 4 758 2040 0 Blue 0
10 AM Sat 62 63 SW 3 4 758 2040 0 Blue 0
11 AM Sat 63 65 SW 6 9 758 2040 0 Blue 0
12 Noon Sat 64 67 SW 6 9 758 2040 0 Blue 0
1 PM Sat 65 69 SW 6 9 758 2040 0 Blue 0
2 PM Sat 65 68 SW 8 11 758 2040 0 Blue 0
3 PM Sat 66 69 SW 8 11 758 2040 0 Blue 0
4 PM Sat 65 67 SW 8 11 758 2040 0 Blue 0
5 PM Sat 65 66 WSW 9 14 758 2040 0 Blue 0
6 PM Sat 64 64 WSW 9 14 758 2040 0 Blue 0
7 PM Sat 64 64 WSW 9 14 758 2040 0 Blue 0
8 PM Sat 63 63 WSW 6 11 758 2040 0 Blue 0
9 PM Sat 62 62 WSW 6 11 758 2040 0 Blue 0
10 PM Sat 62 62 WSW 6 11 758 2040 0 Blue 0
11 PM Sat 61 61 WSW 6 9 758 2040 0 Blue 0
12 Midnight Sun 61 61 WSW 6 9 758 2040 0 Blue 0
1 AM Sun 60 60 WSW 6 9 758 2040 0 Blue 0
2 AM Sun 60 60 WSW 6 9 758 2040 0 Blue 0
3 AM Sun 60 60 WSW 6 9 758 2040 0 Blue 0
4 AM Sun 59 59 WSW 6 9 758 2040 0 Blue 0
5 AM Sun 59 59 WSW 5 8 758 2040 0 Blue 0
6 AM Sun 58 58 WSW 5 8 758 2040 0 Blue 0
7 AM Sun 58 58 WSW 5 8 758 2040 0 Blue 0
8 AM Sun 58 58 WSW 4 6 758 2040 0 Blue 0
9 AM Sun 58 58 WSW 4 6 758 2040 0 Blue 0
10 AM Sun 59 60 WSW 4 6 758 2040 0 Blue 0
11 AM Sun 60 62 WSW 6 11 758 2040 0 Blue 0
12 Noon Sun 61 63 WSW 6 11 758 2040 0 Blue 0
1 PM Sun 62 64 WSW 6 11 758 2040 0 Blue 0
2 PM Sun 63 66 WSW 9 13 758 2040 0 Blue 0
3 PM Sun 63 65 WSW 9 13 758 2040 0 Blue 0
4 PM Sun 62 63 WSW 9 13 758 2040 0 Blue 0
5 PM Sun 62 63 W 9 14 758 2040 0 Blue 0
6 PM Sun 62 62 W 9 14 758 2040 0 Blue 0
7 PM Sun 62 62 W 9 14 758 2040 0 Blue 0
8 PM Sun 61 61 W 6 11 758 2040 0 Blue 0
9 PM Sun 60 60 W 6 11 758 2040 0 Blue 0
10 PM Sun 60 60 W 6 11 758 2040 0 Blue 0

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]