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

Station:

 KOAK

Date/Time:

 3 SEP 2010

Temp/Wind data from:

NOAA Digital Forecast

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 61 61 NW 5 981 2040 0 Blue 0
6 AM Fri 61 61 NW 5 981 2040 0 Blue 0
7 AM Fri 60 60 NW 5 981 2040 0 Blue 0
8 AM Fri 64 64 W 6 1019 2040 0 Blue 0
9 AM Fri 68 68 W 6 1250 2040 0 Blue 0
10 AM Fri 72 72 W 6 1481 2040 0 Blue 0
11 AM Fri 76 79 W 9 2039 2040 0 Blue 6
12 Noon Fri 79 83 W 9 2381 2122 82 Blue 10
1 PM Fri 81 86 W 9 2672 2377 337 Blue 13
2 PM Fri 82 87 W 12 2852 2462 422 Blue 14
3 PM Fri 82 86 W 12 2672 2377 337 Blue 13
4 PM Fri 81 84 W 12 2466 2207 167 Blue 11
5 PM Fri 77 78 NW 12 1954 2040 0 Blue 5
6 PM Fri 74 74 NW 12 1614 2040 0 Blue 1
7 PM Fri 70 70 NW 12 1366 2040 0 Blue 0
8 PM Fri 64 64 NW 10 1019 2040 0 Blue 0
9 PM Fri 61 61 NW 10 981 2040 0 Blue 0
10 PM Fri 60 60 NW 10 981 2040 0 Blue 0
11 PM Fri 60 60 NW 9 981 2040 0 Blue 0
12 Midnight Sat 59 59 NW 9 981 2040 0 Blue 0
1 AM Sat 59 59 NW 9 981 2040 0 Blue 0
2 AM Sat 57 57 NW 9 981 2040 0 Blue 0
3 AM Sat 57 57 NW 9 981 2040 0 Blue 0
4 AM Sat 56 56 NW 9 981 2040 0 Blue 0
5 AM Sat 56 56 NW 6 981 2040 0 Blue 0
6 AM Sat 56 56 NW 6 981 2040 0 Blue 0
7 AM Sat 55 55 NW 6 981 2040 0 Blue 0
8 AM Sat 58 58 W 7 981 2040 0 Blue 0
9 AM Sat 63 63 W 7 981 2040 0 Blue 0
10 AM Sat 66 66 W 7 1134 2040 0 Blue 0
11 AM Sat 70 73 W 10 1539 2040 0 Blue 0
12 Noon Sat 73 77 W 10 1869 2040 0 Blue 4
1 PM Sat 75 80 W 10 2125 2040 0 Blue 7
2 PM Sat 76 80 W 8 2125 2040 0 Blue 7
3 PM Sat 76 80 W 8 2125 2040 0 Blue 7
4 PM Sat 75 78 W 8 1954 2040 0 Blue 5
5 PM Sat 72 73 W 10 1539 2040 0 Blue 0
6 PM Sat 70 70 W 10 1366 2040 0 Blue 0
7 PM Sat 66 66 W 10 1134 2040 0 Blue 0
8 PM Sat 62 62 W 10 981 2040 0 Blue 0
9 PM Sat 59 59 W 10 981 2040 0 Blue 0
10 PM Sat 59 59 W 10 981 2040 0 Blue 0
11 PM Sat 58 58 W 9 981 2040 0 Blue 0
12 Midnight Sun 58 58 W 9 981 2040 0 Blue 0
1 AM Sun 57 57 W 9 981 2040 0 Blue 0
2 AM Sun 56 56 W 9 981 2040 0 Blue 0
3 AM Sun 56 56 W 9 981 2040 0 Blue 0
4 AM Sun 55 55 W 9 981 2040 0 Blue 0
5 AM Sun 56 56 W 8 981 2040 0 Blue 0
6 AM Sun 55 55 W 8 981 2040 0 Blue 0
7 AM Sun 55 55 W 8 981 2040 0 Blue 0
8 AM Sun 58 58 W 8 981 2040 0 Blue 0
9 AM Sun 64 64 W 8 1019 2040 0 Blue 0
10 AM Sun 67 67 W 8 1192 2040 0 Blue 0
11 AM Sun 72 75 W 5 1699 2040 0 Blue 2
12 Noon Sun 75 79 W 5 2039 2040 0 Blue 6
1 PM Sun 77 81 W 5 2210 2040 0 Blue 8
2 PM Sun 78 82 W 5 2295 2040 0 Blue 9
3 PM Sun 79 82 W 5 2295 2040 0 Blue 9
4 PM Sun 78 80 W 5 2125 2040 0 Blue 7
5 PM Sun 75 76 W 8 1784 2040 0 Blue 3
6 PM Sun 72 72 W 8 1481 2040 0 Blue 0
7 PM Sun 69 69 W 8 1308 2040 0 Blue 0
8 PM Sun 64 64 W 8 1019 2040 0 Blue 0
9 PM Sun 62 62 W 8 981 2040 0 Blue 0
10 PM Sun 61 61 W 8 981 2040 0 Blue 0
11 PM Sun 61 61 NW 8 981 2040 0 Blue 0
12 Midnight Mon 61 61 NW 8 981 2040 0 Blue 0
1 AM Mon 60 60 NW 8 981 2040 0 Blue 0
2 AM Mon 59 59 NW 8 981 2040 0 Blue 0
3 AM Mon 59 59 NW 8 981 2040 0 Blue 0
4 AM Mon 58 58 NW 8 981 2040 0 Blue 0
5 AM Mon 58 58 N 8 981 2040 0 Blue 0
6 AM Mon 58 58 N 8 981 2040 0 Blue 0
7 AM Mon 58 58 N 8 981 2040 0 Blue 0
8 AM Mon 61 61 N 8 981 2040 0 Blue 0
9 AM Mon 66 66 N 8 1134 2040 0 Blue 0
10 AM Mon 70 70 N 8 1366 2040 0 Blue 0
11 AM Mon 74 78 NW 5 1954 2040 0 Blue 5
12 Noon Mon 77 83 NW 5 2381 2122 82 Blue 10
1 PM Mon 79 85 NW 5 2551 2292 252 Blue 12
2 PM Mon 80 86 NW 5 2672 2377 337 Blue 13
3 PM Mon 80 85 NW 5 2551 2292 252 Blue 12
4 PM Mon 79 83 NW 5 2381 2122 82 Blue 10
5 PM Mon 76 78 W 9 1954 2040 0 Blue 5
6 PM Mon 72 73 W 9 1539 2040 0 Blue 0
7 PM Mon 68 68 W 9 1250 2040 0 Blue 0
8 PM Mon 63 63 W 9 981 2040 0 Blue 0
9 PM Mon 61 61 W 9 981 2040 0 Blue 0
10 PM Mon 60 60 W 9 981 2040 0 Blue 0
11 PM Mon 59 59 W 10 981 2040 0 Blue 0
12 Midnight Tue 59 59 W 10 981 2040 0 Blue 0
1 AM Tue 58 58 W 10 981 2040 0 Blue 0
2 AM Tue 57 57 W 10 981 2040 0 Blue 0
3 AM Tue 57 57 W 10 981 2040 0 Blue 0
4 AM Tue 56 56 W 10 981 2040 0 Blue 0
5 AM Tue 56 56 W 9 981 2040 0 Blue 0
6 AM Tue 56 56 W 9 981 2040 0 Blue 0
7 AM Tue 55 55 W 9 981 2040 0 Blue 0
8 AM Tue 58 58 W 9 981 2040 0 Blue 0
9 AM Tue 61 61 W 9 981 2040 0 Blue 0
10 AM Tue 63 63 W 9 981 2040 0 Blue 0
11 AM Tue 66 69 W 10 1308 2040 0 Blue 0
12 Noon Tue 68 72 W 10 1481 2040 0 Blue 0
1 PM Tue 70 74 W 10 1614 2040 0 Blue 1
2 PM Tue 71 75 W 10 1699 2040 0 Blue 2
3 PM Tue 71 74 W 10 1614 2040 0 Blue 1
4 PM Tue 70 72 W 10 1481 2040 0 Blue 0
5 PM Tue 67 68 W 21 1250 2040 0 Blue 0
6 PM Tue 64 64 W 21 1019 2040 0 Blue 0
7 PM Tue 61 61 W 21 981 2040 0 Blue 0
8 PM Tue 57 57 W 21 981 2040 0 Blue 0
9 PM Tue 54 54 W 21 981 2040 0 Blue 0
10 PM Tue 54 54 W 21 981 2040 0 Blue 0
11 PM Tue 53 53 W 16 981 2040 0 Blue 0
12 Midnight Wed 53 53 W 16 981 2040 0 Blue 0
1 AM Wed 53 53 W 16 981 2040 0 Blue 0
2 AM Wed 52 52 W 16 981 2040 0 Blue 0
3 AM Wed 52 52 W 16 981 2040 0 Blue 0
4 AM Wed 51 51 W 16 981 2040 0 Blue 0
5 AM Wed 51 51 W 14 981 2040 0 Blue 0
6 AM Wed 50 50 W 14 981 2040 0 Blue 0
7 AM Wed 50 50 W 14 981 2040 0 Blue 0
8 AM Wed 53 53 W 14 981 2040 0 Blue 0
9 AM Wed 57 57 W 14 981 2040 0 Blue 0
10 AM Wed 60 60 W 14 981 2040 0 Blue 0
11 AM Wed 64 66 W 9 1134 2040 0 Blue 0
12 Noon Wed 66 69 W 9 1308 2040 0 Blue 0
1 PM Wed 68 72 W 9 1481 2040 0 Blue 0
2 PM Wed 69 72 W 9 1481 2040 0 Blue 0
3 PM Wed 69 72 W 9 1481 2040 0 Blue 0
4 PM Wed 68 70 W 9 1366 2040 0 Blue 0
5 PM Wed 66 67 W 13 1192 2040 0 Blue 0
6 PM Wed 64 64 W 13 1019 2040 0 Blue 0
7 PM Wed 61 61 W 13 981 2040 0 Blue 0
8 PM Wed 57 57 W 13 981 2040 0 Blue 0
9 PM Wed 55 55 W 13 981 2040 0 Blue 0
10 PM Wed 54 54 W 13 981 2040 0 Blue 0
11 PM Wed 54 54 W 7 981 2040 0 Blue 0
12 Midnight Thu 54 54 W 7 981 2040 0 Blue 0
1 AM Thu 53 53 W 7 981 2040 0 Blue 0
2 AM Thu 53 53 W 7 981 2040 0 Blue 0
3 AM Thu 53 53 W 7 981 2040 0 Blue 0
4 AM Thu 52 52 W 7 981 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 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