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

Station:

KOAK

Date/Time:

25 AUG 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 Sun 59 59 NW 5 784 2040 0 Blue 0
6 AM Sun 60 60 NW 5 813 2040 0 Blue 0
7 AM Sun 58 58 NW 5 784 2040 0 Blue 0
8 AM Sun 60 60 W 5 813 2040 0 Blue 0
9 AM Sun 62 63 W 5 953 2040 0 Blue 0
10 AM Sun 63 65 W 5 1046 2040 0 Blue 0
11 AM Sun 66 69 W 7 1234 2040 0 Blue 0
12 Noon Sun 68 73 W 7 1427 2040 0 Blue 2
1 PM Sun 70 76 W 7 1577 2040 0 Blue 5
2 PM Sun 72 78 W 9 1676 2040 0 Blue 7
3 PM Sun 74 79 W 9 1726 2040 0 Blue 8
4 PM Sun 74 78 W 9 1676 2040 0 Blue 7
5 PM Sun 74 76 W 9 1577 2040 0 Blue 5
6 PM Sun 74 75 W 9 1527 2040 0 Blue 4
7 PM Sun 71 71 W 9 1328 2040 0 Blue 0
8 PM Sun 67 67 NW 7 1140 2040 0 Blue 0
9 PM Sun 66 66 NW 7 1093 2040 0 Blue 0
10 PM Sun 64 64 NW 7 1000 2040 0 Blue 0
11 PM Sun 63 63 NW 5 953 2040 0 Blue 0
12 Midnight Mon 61 61 NW 5 859 2040 0 Blue 0
1 AM Mon 61 61 NW 5 859 2040 0 Blue 0
2 AM Mon 60 60 NW 5 813 2040 0 Blue 0
3 AM Mon 61 61 NW 5 859 2040 0 Blue 0
4 AM Mon 58 58 NW 5 784 2040 0 Blue 0
5 AM Mon 58 58 NW 3 784 2040 0 Blue 0
6 AM Mon 58 58 NW 3 784 2040 0 Blue 0
7 AM Mon 58 58 NW 3 784 2040 0 Blue 0
8 AM Mon 60 60 W 5 813 2040 0 Blue 0
9 AM Mon 62 63 W 5 953 2040 0 Blue 0
10 AM Mon 64 66 W 5 1093 2040 0 Blue 0
11 AM Mon 66 70 W 6 1281 2040 0 Blue 0
12 Noon Mon 69 74 W 6 1477 2040 0 Blue 3
1 PM Mon 72 78 W 6 1676 2040 0 Blue 7
2 PM Mon 74 79 W 8 1726 2040 0 Blue 8
3 PM Mon 74 79 W 8 1726 2040 0 Blue 8
4 PM Mon 74 77 W 8 1626 2040 0 Blue 6
5 PM Mon 73 74 W 9 1477 2040 0 Blue 3
6 PM Mon 71 71 W 9 1328 2040 0 Blue 0
7 PM Mon 68 68 W 9 1187 2040 0 Blue 0
8 PM Mon 66 66 NW 9 1093 2040 0 Blue 0
9 PM Mon 64 64 NW 9 1000 2040 0 Blue 0
10 PM Mon 63 63 NW 9 953 2040 0 Blue 0
11 PM Mon 62 62 NW 7 906 2040 0 Blue 0
12 Midnight Tue 62 62 NW 7 906 2040 0 Blue 0
1 AM Tue 61 61 NW 7 859 2040 0 Blue 0
2 AM Tue 60 60 NW 6 813 2040 0 Blue 0
3 AM Tue 60 60 NW 6 813 2040 0 Blue 0
4 AM Tue 59 59 NW 6 784 2040 0 Blue 0
5 AM Tue 59 59 NW 5 784 2040 0 Blue 0
6 AM Tue 58 58 NW 5 784 2040 0 Blue 0
7 AM Tue 58 58 NW 5 784 2040 0 Blue 0
8 AM Tue 59 59 W 5 784 2040 0 Blue 0
9 AM Tue 60 60 W 5 813 2040 0 Blue 0
10 AM Tue 63 64 W 5 1000 2040 0 Blue 0
11 AM Tue 65 69 W 7 1234 2040 0 Blue 0
12 Noon Tue 68 73 W 7 1427 2040 0 Blue 2
1 PM Tue 71 76 W 7 1577 2040 0 Blue 5
2 PM Tue 73 78 W 9 1676 2040 0 Blue 7
3 PM Tue 73 77 W 9 1626 2040 0 Blue 6
4 PM Tue 73 76 W 9 1577 2040 0 Blue 5
5 PM Tue 71 73 W 10 1427 2040 0 Blue 2
6 PM Tue 69 70 W 10 1281 2040 0 Blue 0
7 PM Tue 67 67 W 10 1140 2040 0 Blue 0
8 PM Tue 65 65 NW 10 1046 2040 0 Blue 0
9 PM Tue 64 64 NW 10 1000 2040 0 Blue 0
10 PM Tue 64 64 NW 10 1000 2040 0 Blue 0
11 PM Tue 64 64 NW 9 1000 2040 0 Blue 0
12 Midnight Wed 63 63 NW 9 953 2040 0 Blue 0
1 AM Wed 62 62 NW 9 906 2040 0 Blue 0
2 AM Wed 61 61 NW 8 859 2040 0 Blue 0
3 AM Wed 60 60 NW 8 813 2040 0 Blue 0
4 AM Wed 60 60 NW 8 813 2040 0 Blue 0
5 AM Wed 60 60 NW 8 813 2040 0 Blue 0
6 AM Wed 60 60 NW 8 813 2040 0 Blue 0
7 AM Wed 60 60 NW 8 813 2040 0 Blue 0
8 AM Wed 60 60 SW 9 813 2040 0 Blue 0
9 AM Wed 61 62 SW 9 906 2040 0 Blue 0
10 AM Wed 63 65 SW 9 1046 2040 0 Blue 0
11 AM Wed 65 69 SW 12 1234 2040 0 Blue 0
12 Noon Wed 67 73 SW 12 1427 2040 0 Blue 2
1 PM Wed 70 76 SW 12 1577 2040 0 Blue 5
2 PM Wed 71 78 SW 12 1676 2040 0 Blue 7
3 PM Wed 72 78 SW 12 1676 2040 0 Blue 7
4 PM Wed 72 76 SW 12 1577 2040 0 Blue 5
5 PM Wed 71 73 SW 13 1427 2040 0 Blue 2
6 PM Wed 69 70 SW 13 1281 2040 0 Blue 0
7 PM Wed 67 67 SW 13 1140 2040 0 Blue 0
8 PM Wed 65 65 SW 12 1046 2040 0 Blue 0
9 PM Wed 65 65 SW 12 1046 2040 0 Blue 0
10 PM Wed 64 64 SW 12 1000 2040 0 Blue 0
11 PM Wed 64 64 W 10 1000 2040 0 Blue 0
12 Midnight Thu 64 64 W 10 1000 2040 0 Blue 0
1 AM Thu 64 64 W 10 1000 2040 0 Blue 0
2 AM Thu 63 63 W 9 953 2040 0 Blue 0
3 AM Thu 62 62 W 9 906 2040 0 Blue 0
4 AM Thu 61 61 W 9 859 2040 0 Blue 0
5 AM Thu 61 61 SW 12 859 2040 0 Blue 0
6 AM Thu 60 60 SW 12 813 2040 0 Blue 0
7 AM Thu 60 60 SW 12 813 2040 0 Blue 0
8 AM Thu 60 60 W 10 813 2040 0 Blue 0
9 AM Thu 61 61 W 10 859 2040 0 Blue 0
10 AM Thu 62 63 W 10 953 2040 0 Blue 0
11 AM Thu 64 69 W 13 1234 2040 0 Blue 0
12 Noon Thu 66 72 W 13 1377 2040 0 Blue 1
1 PM Thu 69 76 W 13 1577 2040 0 Blue 5
2 PM Thu 70 76 W 13 1577 2040 0 Blue 5
3 PM Thu 71 77 W 13 1626 2040 0 Blue 6
4 PM Thu 71 75 W 13 1527 2040 0 Blue 4
5 PM Thu 70 72 W 14 1377 2040 0 Blue 1
6 PM Thu 69 70 W 14 1281 2040 0 Blue 0
7 PM Thu 67 67 W 14 1140 2040 0 Blue 0
8 PM Thu 66 66 W 14 1093 2040 0 Blue 0
9 PM Thu 65 65 W 14 1046 2040 0 Blue 0
10 PM Thu 65 65 W 14 1046 2040 0 Blue 0
11 PM Thu 64 64 W 12 1000 2040 0 Blue 0
12 Midnight Fri 63 63 W 12 953 2040 0 Blue 0
1 AM Fri 62 62 W 12 906 2040 0 Blue 0
2 AM Fri 62 62 W 10 906 2040 0 Blue 0
3 AM Fri 61 61 W 10 859 2040 0 Blue 0
4 AM Fri 60 60 W 10 813 2040 0 Blue 0
5 AM Fri 60 60 W 10 813 2040 0 Blue 0
6 AM Fri 60 60 W 10 813 2040 0 Blue 0
7 AM Fri 59 59 W 10 784 2040 0 Blue 0
8 AM Fri 59 59 W 10 784 2040 0 Blue 0
9 AM Fri 60 61 W 10 859 2040 0 Blue 0
10 AM Fri 62 64 W 10 1000 2040 0 Blue 0
11 AM Fri 64 69 W 12 1234 2040 0 Blue 0
12 Noon Fri 66 72 W 12 1377 2040 0 Blue 1
1 PM Fri 69 76 W 12 1577 2040 0 Blue 5
2 PM Fri 71 78 W 14 1676 2040 0 Blue 7
3 PM Fri 72 78 W 14 1676 2040 0 Blue 7
4 PM Fri 72 76 W 14 1577 2040 0 Blue 5
5 PM Fri 71 73 W 16 1427 2040 0 Blue 2
6 PM Fri 69 70 W 16 1281 2040 0 Blue 0
7 PM Fri 66 66 W 16 1093 2040 0 Blue 0
8 PM Fri 64 64 W 16 1000 2040 0 Blue 0
9 PM Fri 63 63 W 16 953 2040 0 Blue 0
10 PM Fri 63 63 W 16 953 2040 0 Blue 0
11 PM Fri 63 63 W 14 953 2040 0 Blue 0
12 Midnight Sat 62 62 W 14 906 2040 0 Blue 0
1 AM Sat 61 61 W 14 859 2040 0 Blue 0
2 AM Sat 60 60 W 12 813 2040 0 Blue 0
3 AM Sat 59 59 W 12 784 2040 0 Blue 0
4 AM Sat 58 58 W 12 784 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