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

Station:

 KOAK

Date/Time UTC:

 260911/1200

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 Fri 65 65 WNW 9 16 1769 2040 0 Blue 9
1 AM Fri 64 64 WNW 10 17 1759 2040 0 Blue 8
2 AM Fri 63 63 WNW 10 18 1747 2040 0 Blue 7
3 AM Fri 64 64 WNW 9 16 1759 2040 0 Blue 8
4 AM Fri 62 62 WNW 9 14 1736 2040 0 Blue 6
5 AM Fri 61 61 WNW 8 13 1724 2040 0 Blue 5
6 AM Fri 60 60 W 8 13 1713 2040 0 Blue 4
7 AM Fri 59 59 W 8 13 1691 2040 0 Blue 3
8 AM Fri 59 59 W 6 12 1691 2040 0 Blue 3
9 AM Fri 59 60 W 6 11 1713 2040 0 Blue 4
10 AM Fri 60 62 W 6 11 1736 2040 0 Blue 6
11 AM Fri 61 64 W 6 12 1759 2040 0 Blue 8
12 Noon Fri 64 68 W 8 13 1794 2040 0 Blue 12
1 PM Fri 64 69 W 8 14 1802 2040 0 Blue 13
2 PM Fri 65 70 W 9 14 1810 2040 0 Blue 14
3 PM Fri 66 70 W 9 16 1810 2040 0 Blue 14
4 PM Fri 66 69 W 10 16 1802 2040 0 Blue 13
5 PM Fri 66 67 WNW 10 16 1785 2040 0 Blue 11
6 PM Fri 66 66 WNW 10 17 1777 2040 0 Blue 10
7 PM Fri 64 64 WNW 9 16 1759 2040 0 Blue 8
8 PM Fri 64 64 WNW 10 17 1759 2040 0 Blue 8
9 PM Fri 64 64 WNW 10 17 1759 2040 0 Blue 8
10 PM Fri 64 64 WNW 10 17 1759 2040 0 Blue 8
11 PM Fri 64 64 WNW 11 18 1759 2040 0 Blue 8
12 Midnight Sat 63 63 WNW 11 19 1747 2040 0 Blue 7
1 AM Sat 62 62 WNW 11 20 1736 2040 0 Blue 6
2 AM Sat 62 62 WNW 11 20 1736 2040 0 Blue 6
3 AM Sat 62 62 WNW 11 20 1736 2040 0 Blue 6
4 AM Sat 60 60 WNW 11 20 1713 2040 0 Blue 4
5 AM Sat 60 60 WNW 12 23 1713 2040 0 Blue 4
6 AM Sat 59 59 WNW 12 23 1691 2040 0 Blue 3
7 AM Sat 58 58 WNW 12 23 1655 2040 0 Blue 2
8 AM Sat 58 58 WNW 13 24 1655 2040 0 Blue 2
9 AM Sat 58 59 WNW 13 24 1691 2040 0 Blue 3
10 AM Sat 59 61 WNW 13 24 1724 2040 0 Blue 5
11 AM Sat 59 62 WNW 18 26 1736 2040 0 Blue 6
12 Noon Sat 60 65 WNW 18 26 1769 2040 0 Blue 9
1 PM Sat 61 66 WNW 18 26 1777 2040 0 Blue 10
2 PM Sat 61 66 WNW 19 27 1777 2040 0 Blue 10
3 PM Sat 62 66 WNW 19 27 1777 2040 0 Blue 10
4 PM Sat 61 64 WNW 19 27 1759 2040 0 Blue 8
5 PM Sat 61 62 WNW 18 27 1736 2040 0 Blue 6
6 PM Sat 61 61 WNW 18 27 1724 2040 0 Blue 5
7 PM Sat 60 60 WNW 18 27 1713 2040 0 Blue 4
8 PM Sat 60 60 WNW 14 24 1713 2040 0 Blue 4
9 PM Sat 61 61 WNW 14 24 1724 2040 0 Blue 5
10 PM Sat 61 61 WNW 14 24 1724 2040 0 Blue 5
11 PM Sat 62 62 WNW 16 26 1736 2040 0 Blue 6
12 Midnight Sun 61 61 WNW 16 26 1724 2040 0 Blue 5
1 AM Sun 60 60 WNW 16 26 1713 2040 0 Blue 4
2 AM Sun 59 59 WNW 14 26 1691 2040 0 Blue 3
3 AM Sun 58 58 WNW 14 26 1655 2040 0 Blue 2
4 AM Sun 58 58 WNW 14 26 1655 2040 0 Blue 2
5 AM Sun 57 57 NW 12 21 1618 2040 0 Blue 1
6 AM Sun 56 56 NW 12 21 1456 2040 0 White 0
7 AM Sun 55 55 NW 12 21 1013 2040 0 Blue 0
8 AM Sun 55 55 NW 10 17 1013 2040 0 Blue 0
9 AM Sun 56 57 NW 10 17 1618 2040 0 Blue 1
10 AM Sun 58 60 NW 10 17 1713 2040 0 Blue 4
11 AM Sun 60 64 WNW 8 14 1759 2040 0 Blue 8
12 Noon Sun 62 68 WNW 8 14 1794 2040 0 Blue 12
1 PM Sun 63 69 WNW 8 14 1802 2040 0 Blue 13
2 PM Sun 64 70 WNW 12 18 1810 2040 0 Blue 14
3 PM Sun 65 70 WNW 12 18 1810 2040 0 Blue 14
4 PM Sun 65 68 WNW 12 18 1794 2040 0 Blue 12
5 PM Sun 64 66 WNW 12 19 1777 2040 0 Blue 10
6 PM Sun 64 64 WNW 12 19 1759 2040 0 Blue 8
7 PM Sun 63 63 WNW 12 19 1747 2040 0 Blue 7
8 PM Sun 62 62 WNW 12 20 1736 2040 0 Blue 6
9 PM Sun 62 62 WNW 12 20 1736 2040 0 Blue 6
10 PM Sun 62 62 WNW 12 20 1736 2040 0 Blue 6
11 PM Sun 62 62 NW 9 13 1736 2040 0 Blue 6
12 Midnight Mon 61 61 NW 9 13 1724 2040 0 Blue 5
1 AM Mon 60 60 NW 9 13 1713 2040 0 Blue 4
2 AM Mon 59 59 WNW 6 11 1691 2040 0 Blue 3
3 AM Mon 58 58 WNW 6 11 1655 2040 0 Blue 2
4 AM Mon 57 57 WNW 6 11 1618 2040 0 Blue 1
5 AM Mon 56 56 NW 4 6 1456 2040 0 White 0
6 AM Mon 56 56 NW 4 6 1456 2040 0 White 0
7 AM Mon 55 55 NW 4 6 1013 2040 0 Blue 0
8 AM Mon 55 55 WNW 2 5 1013 2040 0 Blue 0
9 AM Mon 57 58 WNW 2 5 1655 2040 0 Blue 2
10 AM Mon 60 62 WNW 2 5 1736 2040 0 Blue 6
11 AM Mon 63 67 W 4 6 1785 2040 0 Blue 11
12 Noon Mon 65 70 W 4 6 1810 2040 0 Blue 14
1 PM Mon 66 72 W 4 6 1827 2040 0 Blue 16
2 PM Mon 67 73 W 9 13 1835 2040 0 Blue 17
3 PM Mon 68 73 W 9 13 1835 2040 0 Blue 17
4 PM Mon 67 70 W 9 13 1810 2040 0 Blue 14
5 PM Mon 68 69 WNW 11 18 1802 2040 0 Blue 13
6 PM Mon 66 66 WNW 11 18 1777 2040 0 Blue 10
7 PM Mon 64 64 WNW 11 18 1759 2040 0 Blue 8
8 PM Mon 62 62 WNW 10 17 1736 2040 0 Blue 6
9 PM Mon 61 61 WNW 10 17 1724 2040 0 Blue 5
10 PM Mon 61 61 WNW 10 17 1724 2040 0 Blue 5
11 PM Mon 60 60 WNW 9 13 1713 2040 0 Blue 4
12 Midnight Tue 60 60 WNW 9 13 1713 2040 0 Blue 4
1 AM Tue 59 59 WNW 9 13 1691 2040 0 Blue 3
2 AM Tue 58 58 WNW 6 12 1655 2040 0 Blue 2
3 AM Tue 58 58 WNW 6 12 1655 2040 0 Blue 2
4 AM Tue 57 57 WNW 6 12 1618 2040 0 Blue 1
5 AM Tue 57 57 W 5 10 1618 2040 0 Blue 1
6 AM Tue 57 57 W 5 10 1618 2040 0 Blue 1
7 AM Tue 57 57 W 5 10 1618 2040 0 Blue 1
8 AM Tue 57 57 W 5 9 1618 2040 0 Blue 1
9 AM Tue 58 58 W 5 9 1655 2040 0 Blue 2
10 AM Tue 59 60 W 5 9 1713 2040 0 Blue 4
11 AM Tue 60 62 SW 4 9 1736 2040 0 Blue 6
12 Noon Tue 62 65 SW 4 9 1769 2040 0 Blue 9
1 PM Tue 63 66 SW 4 9 1777 2040 0 Blue 10
2 PM Tue 64 67 WSW 5 11 1785 2040 0 Blue 11
3 PM Tue 64 67 WSW 5 11 1785 2040 0 Blue 11
4 PM Tue 63 65 WSW 5 11 1769 2040 0 Blue 9
5 PM Tue 62 63 W 6 12 1747 2040 0 Blue 7
6 PM Tue 61 61 W 6 12 1724 2040 0 Blue 5
7 PM Tue 60 60 W 6 12 1713 2040 0 Blue 4
8 PM Tue 59 59 W 4 10 1691 2040 0 Blue 3
9 PM Tue 59 59 W 4 10 1691 2040 0 Blue 3
10 PM Tue 59 59 W 4 10 1691 2040 0 Blue 3
11 PM Tue 60 60 W 4 9 1713 2040 0 Blue 4
12 Midnight Wed 59 59 W 4 9 1691 2040 0 Blue 3
1 AM Wed 59 59 W 4 9 1691 2040 0 Blue 3
2 AM Wed 59 59 WSW 4 9 1691 2040 0 Blue 3
3 AM Wed 59 59 WSW 4 9 1691 2040 0 Blue 3
4 AM Wed 59 59 WSW 4 9 1691 2040 0 Blue 3
5 AM Wed 59 59 WSW 4 8 1691 2040 0 Blue 3
6 AM Wed 59 59 WSW 4 8 1691 2040 0 Blue 3
7 AM Wed 58 58 WSW 4 8 1655 2040 0 Blue 2
8 AM Wed 58 58 WSW 3 6 1655 2040 0 Blue 2
9 AM Wed 57 57 WSW 3 6 1618 2040 0 Blue 1
10 AM Wed 57 58 WSW 3 6 1655 2040 0 Blue 2
11 AM Wed 58 60 SW 4 8 1713 2040 0 Blue 4
12 Noon Wed 58 61 SW 4 8 1724 2040 0 Blue 5
1 PM Wed 60 63 SW 4 8 1747 2040 0 Blue 7
2 PM Wed 61 64 WSW 4 11 1759 2040 0 Blue 8
3 PM Wed 61 63 WSW 4 11 1747 2040 0 Blue 7
4 PM Wed 61 63 WSW 4 11 1747 2040 0 Blue 7
5 PM Wed 60 61 W 5 11 1724 2040 0 Blue 5
6 PM Wed 60 60 W 5 11 1713 2040 0 Blue 4
7 PM Wed 59 59 W 5 11 1691 2040 0 Blue 3
8 PM Wed 58 58 W 3 8 1655 2040 0 Blue 2
9 PM Wed 59 59 W 3 8 1691 2040 0 Blue 3
10 PM Wed 59 59 W 3 8 1691 2040 0 Blue 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 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]