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:

250217/1200

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 Mon 48 48 NW 6 11 1278 2040 0 Blue 1
1 AM Mon 48 48 NW 6 11 1278 2040 0 Blue 1
2 AM Mon 47 47 NW 6 11 1195 2040 0 Blue 0
3 AM Mon 47 47 NW 6 11 1195 2040 0 Blue 0
4 AM Mon 47 47 NW 6 11 1195 2040 0 Blue 0
5 AM Mon 46 46 NW 6 11 991 2040 0 Blue 0
6 AM Mon 46 46 NW 6 11 991 2040 0 Blue 0
7 AM Mon 47 47 NW 6 11 1195 2040 0 Blue 0
8 AM Mon 47 47 NW 6 12 1195 2040 0 Blue 0
9 AM Mon 48 48 NW 6 13 1278 2040 0 Blue 1
10 AM Mon 48 49 NW 8 16 1362 2040 0 Blue 2
11 AM Mon 49 50 NW 9 16 1482 2040 0 Blue 3
12 Noon Mon 50 51 NW 10 18 1629 2040 0 Blue 4
1 PM Mon 50 51 WNW 10 19 1629 2040 0 Blue 4
2 PM Mon 50 51 WNW 11 20 1629 2040 0 Blue 4
3 PM Mon 50 51 WNW 12 20 1629 2040 0 Blue 4
4 PM Mon 50 50 WNW 12 20 1482 2040 0 Blue 3
5 PM Mon 49 49 NW 12 20 1362 2040 0 Blue 2
6 PM Mon 48 48 NW 12 20 1278 2040 0 Blue 1
7 PM Mon 47 47 NW 12 19 1195 2040 0 Blue 0
8 PM Mon 47 47 NW 12 19 1195 2040 0 Blue 0
9 PM Mon 47 47 NNW 11 19 1195 2040 0 Blue 0
10 PM Mon 47 47 NW 11 19 1195 2040 0 Blue 0
11 PM Mon 47 47 NNW 11 18 1195 2040 0 Blue 0
12 Midnight Tue 47 47 NNW 10 17 1195 2040 0 Blue 0
1 AM Tue 46 46 NNW 10 16 991 2040 0 Blue 0
2 AM Tue 46 46 NNW 9 14 991 2040 0 Blue 0
3 AM Tue 46 46 NNW 8 13 991 2040 0 Blue 0
4 AM Tue 45 45 NNW 6 12 898 2040 0 Blue 0
5 AM Tue 46 46 NNW 6 10 991 2040 0 Blue 0
6 AM Tue 45 45 N 4 9 898 2040 0 Blue 0
7 AM Tue 45 45 N 4 8 898 2040 0 Blue 0
8 AM Tue 47 47 N 3 6 1195 2040 0 Blue 0
9 AM Tue 49 50 N 2 5 1482 2040 0 Blue 3
10 AM Tue 50 51 N 2 5 1629 2040 0 Blue 4
11 AM Tue 51 53 N 2 5 2193 2040 0 Blue 6
12 Noon Tue 52 54 N 2 5 3246 2040 0 White 7
1 PM Tue 52 54 W 4 8 3246 2040 0 White 7
2 PM Tue 52 54 W 4 8 3246 2040 0 White 7
3 PM Tue 52 53 W 4 8 2193 2040 0 Blue 6
4 PM Tue 52 52 W 6 11 1839 2040 0 Blue 5
5 PM Tue 51 51 W 6 11 1629 2040 0 Blue 4
6 PM Tue 50 50 W 6 11 1482 2040 0 Blue 3
7 PM Tue 50 50 WNW 5 8 1482 2040 0 Blue 3
8 PM Tue 50 50 WNW 5 8 1482 2040 0 Blue 3
9 PM Tue 50 50 WNW 5 8 1482 2040 0 Blue 3
10 PM Tue 49 49 W 3 6 1362 2040 0 Blue 2
11 PM Tue 49 49 W 3 6 1362 2040 0 Blue 2
12 Midnight Wed 49 49 W 3 6 1362 2040 0 Blue 2
1 AM Wed 49 49 SW 3 5 1362 2040 0 Blue 2
2 AM Wed 49 49 SW 3 5 1362 2040 0 Blue 2
3 AM Wed 49 49 SW 3 5 1362 2040 0 Blue 2
4 AM Wed 49 49 SSW 3 8 1362 2040 0 Blue 2
5 AM Wed 50 50 SSW 3 8 1482 2040 0 Blue 3
6 AM Wed 50 50 SSW 3 8 1482 2040 0 Blue 3
7 AM Wed 51 51 S 6 11 1629 2040 0 Blue 4
8 AM Wed 51 51 S 6 11 1629 2040 0 Blue 4
9 AM Wed 52 52 S 6 11 1839 2040 0 Blue 5
10 AM Wed 52 52 SW 9 16 1839 2040 0 Blue 5
11 AM Wed 52 53 SW 9 16 2193 2040 0 Blue 6
12 Noon Wed 52 53 SW 9 16 2193 2040 0 Blue 6
1 PM Wed 52 53 W 10 18 2193 2040 0 Blue 6
2 PM Wed 52 53 W 10 18 2193 2040 0 Blue 6
3 PM Wed 52 52 W 10 18 1839 2040 0 Blue 5
4 PM Wed 52 52 WNW 11 19 1839 2040 0 Blue 5
5 PM Wed 51 51 WNW 11 19 1629 2040 0 Blue 4
6 PM Wed 50 50 WNW 11 19 1482 2040 0 Blue 3
7 PM Wed 50 50 WNW 11 20 1482 2040 0 Blue 3
8 PM Wed 50 50 WNW 11 20 1482 2040 0 Blue 3
9 PM Wed 50 50 WNW 11 20 1482 2040 0 Blue 3
10 PM Wed 50 50 NW 12 20 1482 2040 0 Blue 3
11 PM Wed 50 50 NW 12 20 1482 2040 0 Blue 3
12 Midnight Thu 50 50 NW 12 20 1482 2040 0 Blue 3
1 AM Thu 50 50 NW 12 20 1482 2040 0 Blue 3
2 AM Thu 49 49 NW 12 20 1362 2040 0 Blue 2
3 AM Thu 48 48 NW 12 20 1278 2040 0 Blue 1
4 AM Thu 48 48 NNW 11 19 1278 2040 0 Blue 1
5 AM Thu 47 47 NNW 11 19 1195 2040 0 Blue 0
6 AM Thu 46 46 NNW 11 19 991 2040 0 Blue 0
7 AM Thu 46 46 NNW 9 14 991 2040 0 Blue 0
8 AM Thu 47 47 NNW 9 14 1195 2040 0 Blue 0
9 AM Thu 49 50 NNW 9 14 1482 2040 0 Blue 3
10 AM Thu 50 52 NNW 6 12 1839 2040 0 Blue 5
11 AM Thu 52 55 NNW 6 12 3464 2040 0 White 8
12 Noon Thu 53 56 NNW 6 12 3681 2146 106 White 9
1 PM Thu 54 57 NW 9 16 3896 3896 1856 White 10
2 PM Thu 55 57 NW 9 16 3896 3896 1856 White 10
3 PM Thu 55 56 NW 9 16 3681 2146 106 White 9
4 PM Thu 55 55 NW 10 18 3464 2040 0 White 8
5 PM Thu 54 54 NW 10 18 3246 2040 0 White 7
6 PM Thu 52 52 NW 10 18 1839 2040 0 Blue 5
7 PM Thu 51 51 NW 10 16 1629 2040 0 Blue 4
8 PM Thu 51 51 NW 10 16 1629 2040 0 Blue 4
9 PM Thu 50 50 NW 10 16 1482 2040 0 Blue 3
10 PM Thu 50 50 NNW 6 12 1482 2040 0 Blue 3
11 PM Thu 50 50 NNW 6 12 1482 2040 0 Blue 3
12 Midnight Fri 49 49 NNW 6 12 1362 2040 0 Blue 2
1 AM Fri 49 49 N 5 10 1362 2040 0 Blue 2
2 AM Fri 48 48 N 5 10 1278 2040 0 Blue 1
3 AM Fri 47 47 N 5 10 1195 2040 0 Blue 0
4 AM Fri 46 46 NNE 4 9 991 2040 0 Blue 0
5 AM Fri 46 46 NNE 4 9 991 2040 0 Blue 0
6 AM Fri 46 46 NNE 4 9 991 2040 0 Blue 0
7 AM Fri 47 47 NE 4 9 1195 2040 0 Blue 0
8 AM Fri 48 48 NE 4 9 1278 2040 0 Blue 1
9 AM Fri 50 51 NE 4 9 1629 2040 0 Blue 4
10 AM Fri 52 54 NE 4 10 3246 2040 0 White 7
11 AM Fri 53 55 NE 4 10 3464 2040 0 White 8
12 Noon Fri 54 57 NE 4 10 3896 3896 1856 White 10
1 PM Fri 55 58 N 4 9 4110 4110 2070 White 11
2 PM Fri 56 58 N 4 9 4110 4110 2070 White 11
3 PM Fri 56 57 N 4 9 3896 3896 1856 White 10
4 PM Fri 55 55 WNW 5 10 3464 2040 0 White 8
5 PM Fri 54 54 WNW 5 10 3246 2040 0 White 7
6 PM Fri 53 53 WNW 5 10 2193 2040 0 Blue 6
7 PM Fri 52 52 NW 5 9 1839 2040 0 Blue 5
8 PM Fri 51 51 NW 5 9 1629 2040 0 Blue 4
9 PM Fri 50 50 NW 5 9 1482 2040 0 Blue 3
10 PM Fri 50 50 NNW 4 8 1482 2040 0 Blue 3
11 PM Fri 49 49 NNW 4 8 1362 2040 0 Blue 2
12 Midnight Sat 49 49 NNW 4 8 1362 2040 0 Blue 2
1 AM Sat 49 49 N 3 6 1362 2040 0 Blue 2
2 AM Sat 48 48 N 3 6 1278 2040 0 Blue 1
3 AM Sat 48 48 N 3 6 1278 2040 0 Blue 1
4 AM Sat 47 47 NNE 4 8 1195 2040 0 Blue 0
5 AM Sat 47 47 NNE 4 8 1195 2040 0 Blue 0
6 AM Sat 48 48 NNE 4 8 1278 2040 0 Blue 1
7 AM Sat 49 49 NNE 3 6 1362 2040 0 Blue 2
8 AM Sat 50 50 NNE 3 6 1482 2040 0 Blue 3
9 AM Sat 51 51 NNE 3 6 1629 2040 0 Blue 4
10 AM Sat 52 53 NNE 3 8 2193 2040 0 Blue 6
11 AM Sat 54 56 NNE 3 8 3681 2146 106 White 9
12 Noon Sat 55 57 NNE 3 8 3896 3896 1856 White 10
1 PM Sat 56 58 N 3 6 4110 4110 2070 White 11
2 PM Sat 57 59 N 3 6 4325 4325 2285 White 12
3 PM Sat 57 58 N 3 6 4110 4110 2070 White 11
4 PM Sat 57 57 WNW 4 9 3896 3896 1856 White 10
5 PM Sat 56 56 WNW 4 9 3681 2146 106 White 9
6 PM Sat 54 54 WNW 4 9 3246 2040 0 White 7
7 PM Sat 53 53 NW 5 8 2193 2040 0 Blue 6
8 PM Sat 52 52 NW 5 8 1839 2040 0 Blue 5
9 PM Sat 52 52 NW 5 8 1839 2040 0 Blue 5
10 PM Sat 52 52 NW 5 8 1839 2040 0 Blue 5

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]