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

Station:

KOAK

Date/Time:

18 SEP 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 Wed 59 59 SW 3 652 2040 0 Blue 0
6 AM Wed 58 58 SW 3 404 2040 0 Blue 0
7 AM Wed 58 58 SW 3 404 2040 0 Blue 0
8 AM Wed 58 58 S 6 404 2040 0 Blue 0
9 AM Wed 58 58 S 6 404 2040 0 Blue 0
10 AM Wed 57 57 S 6 404 2040 0 Blue 0
11 AM Wed 60 61 SW 7 1274 2040 0 Blue 0
12 Noon Wed 63 65 SW 7 3576 2722 682 White 4
1 PM Wed 66 70 SW 7 4336 3944 1904 Blue 9
2 PM Wed 67 72 W 14 5030 4197 2157 Blue 11
3 PM Wed 66 70 W 14 4336 3944 1904 Blue 9
4 PM Wed 66 69 W 14 4209 3808 1768 Blue 8
5 PM Wed 65 66 NW 16 3793 3098 1058 White 5
6 PM Wed 68 68 NW 16 4082 3632 1592 Blue 7
7 PM Wed 64 64 NW 16 3358 2040 0 White 3
8 PM Wed 63 63 NW 16 3123 2040 0 Blue 2
9 PM Wed 62 62 NW 16 2742 2040 0 Blue 1
10 PM Wed 61 61 NW 16 1274 2040 0 Blue 0
11 PM Wed 60 60 NW 16 901 2040 0 Blue 0
12 Midnight Thu 60 60 NW 16 901 2040 0 Blue 0
1 AM Thu 60 60 NW 16 901 2040 0 Blue 0
2 AM Thu 58 58 N 14 404 2040 0 Blue 0
3 AM Thu 59 59 N 14 652 2040 0 Blue 0
4 AM Thu 58 58 N 14 404 2040 0 Blue 0
5 AM Thu 57 57 N 9 404 2040 0 Blue 0
6 AM Thu 56 56 N 9 404 2040 0 Blue 0
7 AM Thu 55 55 N 9 404 2040 0 Blue 0
8 AM Thu 57 57 W 0 404 2040 0 Blue 0
9 AM Thu 58 59 W 0 652 2040 0 Blue 0
10 AM Thu 59 61 W 0 1274 2040 0 Blue 0
11 AM Thu 62 66 W 7 3793 3098 1058 White 5
12 Noon Thu 65 70 W 7 4336 3944 1904 Blue 9
1 PM Thu 67 72 W 7 5030 4197 2157 Blue 11
2 PM Thu 68 73 W 10 5091 4323 2283 Blue 12
3 PM Thu 69 73 W 10 5091 4323 2283 Blue 12
4 PM Thu 69 72 W 10 5030 4197 2157 Blue 11
5 PM Thu 68 69 NW 10 4209 3808 1768 Blue 8
6 PM Thu 66 66 NW 10 3793 3098 1058 White 5
7 PM Thu 65 65 NW 10 3576 2722 682 White 4
8 PM Thu 63 63 N 10 3123 2040 0 Blue 2
9 PM Thu 62 62 N 10 2742 2040 0 Blue 1
10 PM Thu 62 62 N 10 2742 2040 0 Blue 1
11 PM Thu 62 62 N 9 2742 2040 0 Blue 1
12 Midnight Fri 61 61 N 9 1274 2040 0 Blue 0
1 AM Fri 60 60 N 9 901 2040 0 Blue 0
2 AM Fri 59 59 N 5 652 2040 0 Blue 0
3 AM Fri 58 58 N 5 404 2040 0 Blue 0
4 AM Fri 58 58 N 5 404 2040 0 Blue 0
5 AM Fri 57 57 N 6 404 2040 0 Blue 0
6 AM Fri 56 56 N 6 404 2040 0 Blue 0
7 AM Fri 56 56 N 6 404 2040 0 Blue 0
8 AM Fri 57 57 N 1 404 2040 0 Blue 0
9 AM Fri 59 59 N 1 652 2040 0 Blue 0
10 AM Fri 62 63 N 1 3123 2040 0 Blue 2
11 AM Fri 65 68 W 5 4082 3632 1592 Blue 7
12 Noon Fri 68 72 W 5 5030 4197 2157 Blue 11
1 PM Fri 70 75 W 5 5214 5022 2982 Blue 14
2 PM Fri 72 76 W 8 5316 5083 3043 Blue 15
3 PM Fri 73 76 W 8 5316 5083 3043 Blue 15
4 PM Fri 73 75 W 8 5214 5022 2982 Blue 14
5 PM Fri 72 73 NW 9 5091 4323 2283 Blue 12
6 PM Fri 70 70 NW 9 4336 3944 1904 Blue 9
7 PM Fri 68 68 NW 9 4082 3632 1592 Blue 7
8 PM Fri 65 65 NW 7 3576 2722 682 White 4
9 PM Fri 63 63 NW 7 3123 2040 0 Blue 2
10 PM Fri 62 62 NW 7 2742 2040 0 Blue 1
11 PM Fri 61 61 N 3 1274 2040 0 Blue 0
12 Midnight Sat 60 60 N 3 901 2040 0 Blue 0
1 AM Sat 59 59 N 3 652 2040 0 Blue 0
2 AM Sat 58 58 N 3 404 2040 0 Blue 0
3 AM Sat 58 58 N 3 404 2040 0 Blue 0
4 AM Sat 57 57 N 3 404 2040 0 Blue 0
5 AM Sat 56 56 N 5 404 2040 0 Blue 0
6 AM Sat 56 56 N 5 404 2040 0 Blue 0
7 AM Sat 57 57 N 5 404 2040 0 Blue 0
8 AM Sat 58 58 E 2 404 2040 0 Blue 0
9 AM Sat 61 62 E 2 2742 2040 0 Blue 1
10 AM Sat 63 65 E 2 3576 2722 682 White 4
11 AM Sat 67 71 SE 3 4887 4070 2030 White 10
12 Noon Sat 70 75 SE 3 5214 5022 2982 Blue 14
1 PM Sat 73 79 SE 3 6161 5297 3257 Blue 18
2 PM Sat 75 81 W 5 6973 5631 3591 Blue 20
3 PM Sat 76 81 W 5 6973 5631 3591 Blue 20
4 PM Sat 76 79 W 5 6161 5297 3257 Blue 18
5 PM Sat 74 75 W 8 5214 5022 2982 Blue 14
6 PM Sat 72 72 W 8 5030 4197 2157 Blue 11
7 PM Sat 70 70 W 8 4336 3944 1904 Blue 9
8 PM Sat 67 67 W 8 3955 3455 1415 Blue 6
9 PM Sat 65 65 W 8 3576 2722 682 White 4
10 PM Sat 64 64 W 8 3358 2040 0 White 3
11 PM Sat 62 62 W 7 2742 2040 0 Blue 1
12 Midnight Sun 62 62 W 7 2742 2040 0 Blue 1
1 AM Sun 61 61 W 7 1274 2040 0 Blue 0
2 AM Sun 60 60 W 6 901 2040 0 Blue 0
3 AM Sun 59 59 W 6 652 2040 0 Blue 0
4 AM Sun 58 58 W 6 404 2040 0 Blue 0
5 AM Sun 58 58 W 6 404 2040 0 Blue 0
6 AM Sun 57 57 W 6 404 2040 0 Blue 0
7 AM Sun 57 57 W 6 404 2040 0 Blue 0
8 AM Sun 57 57 W 7 404 2040 0 Blue 0
9 AM Sun 59 59 W 7 652 2040 0 Blue 0
10 AM Sun 61 63 W 7 3123 2040 0 Blue 2
11 AM Sun 63 65 W 12 3576 2722 682 White 4
12 Noon Sun 67 70 W 12 4336 3944 1904 Blue 9
1 PM Sun 70 73 W 12 5091 4323 2283 Blue 12
2 PM Sun 72 75 W 15 5214 5022 2982 Blue 14
3 PM Sun 73 75 W 15 5214 5022 2982 Blue 14
4 PM Sun 72 73 W 15 5091 4323 2283 Blue 12
5 PM Sun 71 72 W 17 5030 4197 2157 Blue 11
6 PM Sun 70 70 W 17 4336 3944 1904 Blue 9
7 PM Sun 69 69 W 17 4209 3808 1768 Blue 8
8 PM Sun 67 67 W 22 3955 3455 1415 Blue 6
9 PM Sun 66 66 W 22 3793 3098 1058 White 5
10 PM Sun 64 64 W 22 3358 2040 0 White 3
11 PM Sun 63 63 NW 21 3123 2040 0 Blue 2
12 Midnight Mon 62 62 NW 21 2742 2040 0 Blue 1
1 AM Mon 61 61 NW 21 1274 2040 0 Blue 0
2 AM Mon 60 60 NW 17 901 2040 0 Blue 0
3 AM Mon 59 59 NW 17 652 2040 0 Blue 0
4 AM Mon 58 58 NW 17 404 2040 0 Blue 0
5 AM Mon 57 57 N 13 404 2040 0 Blue 0
6 AM Mon 57 57 N 13 404 2040 0 Blue 0
7 AM Mon 57 57 N 13 404 2040 0 Blue 0
8 AM Mon 57 57 N 8 404 2040 0 Blue 0
9 AM Mon 59 60 N 8 901 2040 0 Blue 0
10 AM Mon 62 64 N 8 3358 2040 0 White 3
11 AM Mon 65 68 N 10 4082 3632 1592 Blue 7
12 Noon Mon 68 72 N 10 5030 4197 2157 Blue 11
1 PM Mon 71 76 N 10 5316 5083 3043 Blue 15
2 PM Mon 74 79 NW 12 6161 5297 3257 Blue 18
3 PM Mon 75 79 NW 12 6161 5297 3257 Blue 18
4 PM Mon 75 77 NW 12 5453 5145 3105 Blue 16
5 PM Mon 74 75 NW 14 5214 5022 2982 Blue 14
6 PM Mon 73 73 NW 14 5091 4323 2283 Blue 12
7 PM Mon 71 71 NW 14 4887 4070 2030 White 10
8 PM Mon 69 69 NW 13 4209 3808 1768 Blue 8
9 PM Mon 68 68 NW 13 4082 3632 1592 Blue 7
10 PM Mon 66 66 NW 13 3793 3098 1058 White 5
11 PM Mon 66 66 NW 13 3793 3098 1058 White 5
12 Midnight Tue 65 65 NW 13 3576 2722 682 White 4
1 AM Tue 65 65 NW 13 3576 2722 682 White 4
2 AM Tue 65 65 N 13 3576 2722 682 White 4
3 AM Tue 64 64 N 13 3358 2040 0 White 3
4 AM Tue 64 64 N 13 3358 2040 0 White 3

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