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

Station:

KOAK

Date/Time:

20 JUN 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 Sun 58 58 SW 4 6 1407 2040 0 Blue 6
1 AM Sun 55 55 SW 4 6 1230 2040 0 Blue 3
2 AM Sun 56 56 WSW 5 8 1302 2040 0 Blue 4
3 AM Sun 55 55 WSW 5 9 1230 2040 0 Blue 3
4 AM Sun 54 54 WSW 5 8 1179 2040 0 Blue 2
5 AM Sun 54 54 WSW 5 8 1179 2040 0 Blue 2
6 AM Sun 52 52 WSW 4 6 1108 2040 0 White 0
7 AM Sun 52 52 SW 5 8 1108 2040 0 White 0
8 AM Sun 54 55 SW 5 8 1230 2040 0 Blue 3
9 AM Sun 55 56 SSW 5 8 1302 2040 0 Blue 4
10 AM Sun 56 59 SW 5 9 1433 2040 0 Blue 7
11 AM Sun 58 62 SW 6 10 1459 2040 0 Blue 10
12 Noon Sun 61 67 WSW 8 11 1488 2040 0 Blue 15
1 PM Sun 62 68 WSW 9 12 1494 2040 0 Blue 16
2 PM Sun 64 70 WSW 9 14 1510 2040 0 Blue 18
3 PM Sun 63 69 W 10 14 1500 2040 0 Blue 17
4 PM Sun 64 69 W 10 14 1500 2040 0 Blue 17
5 PM Sun 62 65 W 10 16 1477 2040 0 Blue 13
6 PM Sun 63 64 W 10 16 1471 2040 0 Blue 12
7 PM Sun 61 61 W 10 14 1453 2040 0 Blue 9
8 PM Sun 59 59 W 10 14 1433 2040 0 Blue 7
9 PM Sun 57 57 W 9 14 1367 2040 0 Blue 5
10 PM Sun 56 56 W 9 13 1302 2040 0 Blue 4
11 PM Sun 55 55 W 9 13 1230 2040 0 Blue 3
12 Midnight Mon 54 54 W 9 12 1179 2040 0 Blue 2
1 AM Mon 54 54 W 8 11 1179 2040 0 Blue 2
2 AM Mon 53 53 W 8 11 1156 2040 0 Blue 1
3 AM Mon 53 53 WSW 8 11 1156 2040 0 Blue 1
4 AM Mon 52 52 WSW 6 11 1108 2040 0 White 0
5 AM Mon 52 52 WSW 8 11 1108 2040 0 White 0
6 AM Mon 53 53 WSW 6 11 1156 2040 0 Blue 1
7 AM Mon 53 53 WSW 8 11 1156 2040 0 Blue 1
8 AM Mon 54 54 WSW 8 11 1179 2040 0 Blue 2
9 AM Mon 55 56 WSW 8 11 1302 2040 0 Blue 4
10 AM Mon 56 57 WSW 9 12 1367 2040 0 Blue 5
11 AM Mon 58 62 WSW 10 14 1459 2040 0 Blue 10
12 Noon Mon 60 65 WSW 10 14 1477 2040 0 Blue 13
1 PM Mon 62 67 WSW 10 14 1488 2040 0 Blue 15
2 PM Mon 63 69 WSW 11 18 1500 2040 0 Blue 17
3 PM Mon 63 68 WSW 11 18 1494 2040 0 Blue 16
4 PM Mon 63 67 WSW 11 18 1488 2040 0 Blue 15
5 PM Mon 62 64 W 12 18 1471 2040 0 Blue 12
6 PM Mon 61 62 W 12 18 1459 2040 0 Blue 10
7 PM Mon 60 60 W 12 18 1447 2040 0 Blue 8
8 PM Mon 59 59 W 10 16 1433 2040 0 Blue 7
9 PM Mon 58 58 W 10 16 1407 2040 0 Blue 6
10 PM Mon 58 58 W 10 16 1407 2040 0 Blue 6
11 PM Mon 58 58 WSW 8 12 1407 2040 0 Blue 6
12 Midnight Tue 59 59 WSW 8 12 1433 2040 0 Blue 7
1 AM Tue 59 59 WSW 8 12 1433 2040 0 Blue 7
2 AM Tue 59 59 SW 5 8 1433 2040 0 Blue 7
3 AM Tue 58 58 SW 5 8 1407 2040 0 Blue 6
4 AM Tue 57 57 SW 5 8 1367 2040 0 Blue 5
5 AM Tue 57 57 SSW 4 8 1367 2040 0 Blue 5
6 AM Tue 57 57 SSW 4 8 1367 2040 0 Blue 5
7 AM Tue 58 58 SSW 4 8 1407 2040 0 Blue 6
8 AM Tue 58 58 SSW 8 11 1407 2040 0 Blue 6
9 AM Tue 59 60 SSW 8 11 1447 2040 0 Blue 8
10 AM Tue 60 62 SSW 8 11 1459 2040 0 Blue 10
11 AM Tue 60 63 SW 9 13 1465 2040 0 Blue 11
12 Noon Tue 61 65 SW 9 13 1477 2040 0 Blue 13
1 PM Tue 63 67 SW 9 13 1488 2040 0 Blue 15
2 PM Tue 63 69 WSW 11 18 1500 2040 0 Blue 17
3 PM Tue 64 69 WSW 11 18 1500 2040 0 Blue 17
4 PM Tue 63 67 WSW 11 18 1488 2040 0 Blue 15
5 PM Tue 62 65 WSW 12 18 1477 2040 0 Blue 13
6 PM Tue 61 62 WSW 12 18 1459 2040 0 Blue 10
7 PM Tue 60 60 WSW 12 18 1447 2040 0 Blue 8
8 PM Tue 60 60 WSW 10 16 1447 2040 0 Blue 8
9 PM Tue 59 59 WSW 10 16 1433 2040 0 Blue 7
10 PM Tue 59 59 WSW 10 16 1433 2040 0 Blue 7
11 PM Tue 59 59 SW 8 11 1433 2040 0 Blue 7
12 Midnight Wed 59 59 SW 8 11 1433 2040 0 Blue 7
1 AM Wed 58 58 SW 8 11 1407 2040 0 Blue 6
2 AM Wed 57 57 SW 5 9 1367 2040 0 Blue 5
3 AM Wed 57 57 SW 5 9 1367 2040 0 Blue 5
4 AM Wed 56 56 SW 5 9 1302 2040 0 Blue 4
5 AM Wed 56 56 SW 5 8 1302 2040 0 Blue 4
6 AM Wed 55 55 SW 5 8 1230 2040 0 Blue 3
7 AM Wed 55 55 SW 5 8 1230 2040 0 Blue 3
8 AM Wed 55 55 SSW 3 5 1230 2040 0 Blue 3
9 AM Wed 56 57 SSW 3 5 1367 2040 0 Blue 5
10 AM Wed 57 59 SSW 3 5 1433 2040 0 Blue 7
11 AM Wed 59 63 SW 5 8 1465 2040 0 Blue 11
12 Noon Wed 60 64 SW 5 8 1471 2040 0 Blue 12
1 PM Wed 62 67 SW 5 8 1488 2040 0 Blue 15
2 PM Wed 64 71 SW 8 11 1525 2040 0 Blue 19
3 PM Wed 64 70 SW 8 11 1510 2040 0 Blue 18
4 PM Wed 64 68 SW 8 11 1494 2040 0 Blue 16
5 PM Wed 64 67 WSW 9 13 1488 2040 0 Blue 15
6 PM Wed 63 64 WSW 9 13 1471 2040 0 Blue 12
7 PM Wed 62 62 WSW 9 13 1459 2040 0 Blue 10
8 PM Wed 61 61 W 9 13 1453 2040 0 Blue 9
9 PM Wed 59 59 W 9 13 1433 2040 0 Blue 7
10 PM Wed 58 58 W 9 13 1407 2040 0 Blue 6
11 PM Wed 57 57 W 8 11 1367 2040 0 Blue 5
12 Midnight Thu 56 56 W 8 11 1302 2040 0 Blue 4
1 AM Thu 55 55 W 8 11 1230 2040 0 Blue 3
2 AM Thu 55 55 W 6 9 1230 2040 0 Blue 3
3 AM Thu 54 54 W 6 9 1179 2040 0 Blue 2
4 AM Thu 54 54 W 6 9 1179 2040 0 Blue 2
5 AM Thu 54 54 W 4 6 1179 2040 0 Blue 2
6 AM Thu 53 53 W 4 6 1156 2040 0 Blue 1
7 AM Thu 54 54 W 4 6 1179 2040 0 Blue 2
8 AM Thu 54 55 SW 3 5 1230 2040 0 Blue 3
9 AM Thu 56 58 SW 3 5 1407 2040 0 Blue 6
10 AM Thu 58 61 SW 3 5 1453 2040 0 Blue 9
11 AM Thu 60 65 SW 4 6 1477 2040 0 Blue 13
12 Noon Thu 62 69 SW 4 6 1500 2040 0 Blue 17
1 PM Thu 64 71 SW 4 6 1525 2040 0 Blue 19
2 PM Thu 65 73 WSW 6 11 1555 2040 0 Blue 21
3 PM Thu 66 73 WSW 6 11 1555 2040 0 Blue 21
4 PM Thu 66 71 WSW 6 11 1525 2040 0 Blue 19
5 PM Thu 65 68 W 9 13 1494 2040 0 Blue 16
6 PM Thu 64 65 W 9 13 1477 2040 0 Blue 13
7 PM Thu 63 63 W 9 13 1465 2040 0 Blue 11
8 PM Thu 61 61 W 6 10 1453 2040 0 Blue 9
9 PM Thu 60 60 W 6 10 1447 2040 0 Blue 8
10 PM Thu 58 58 W 6 10 1407 2040 0 Blue 6
11 PM Thu 57 57 WSW 6 9 1367 2040 0 Blue 5
12 Midnight Fri 56 56 WSW 6 9 1302 2040 0 Blue 4
1 AM Fri 56 56 WSW 6 9 1302 2040 0 Blue 4
2 AM Fri 56 56 SW 4 6 1302 2040 0 Blue 4
3 AM Fri 55 55 SW 4 6 1230 2040 0 Blue 3
4 AM Fri 55 55 SW 4 6 1230 2040 0 Blue 3
5 AM Fri 55 55 SW 4 6 1230 2040 0 Blue 3
6 AM Fri 55 55 SW 4 6 1230 2040 0 Blue 3
7 AM Fri 56 56 SW 4 6 1302 2040 0 Blue 4
8 AM Fri 57 58 SSW 4 6 1407 2040 0 Blue 6
9 AM Fri 59 61 SSW 4 6 1453 2040 0 Blue 9
10 AM Fri 61 65 SSW 4 6 1477 2040 0 Blue 13
11 AM Fri 64 70 SSW 5 8 1510 2040 0 Blue 18
12 Noon Fri 66 73 SSW 5 8 1555 2040 0 Blue 21
1 PM Fri 68 76 SSW 5 8 1600 2040 0 Blue 24
2 PM Fri 69 77 SW 6 11 1615 2040 0 Blue 25
3 PM Fri 70 77 SW 6 11 1615 2040 0 Blue 25
4 PM Fri 69 74 SW 6 11 1570 2040 0 Blue 22
5 PM Fri 68 71 WSW 9 13 1525 2040 0 Blue 19
6 PM Fri 67 68 WSW 9 13 1494 2040 0 Blue 16
7 PM Fri 66 66 WSW 9 13 1483 2040 0 Blue 14
8 PM Fri 64 64 SW 6 10 1471 2040 0 Blue 12
9 PM Fri 62 62 SW 6 10 1459 2040 0 Blue 10
10 PM Fri 61 61 SW 6 10 1453 2040 0 Blue 9

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]