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

Station:

KOAK

Date/Time:

20 OCT 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 55 55 N 7 949 2040 0 Blue 0
6 AM Sun 52 52 N 7 528 2040 0 Blue 0
7 AM Sun 52 52 N 7 528 2040 0 Blue 0
8 AM Sun 52 52 N 7 528 2040 0 Blue 0
9 AM Sun 54 54 N 7 746 2040 0 Blue 0
10 AM Sun 58 59 N 7 1425 2040 0 Blue 3
11 AM Sun 62 64 NW 9 1881 2040 0 Blue 8
12 Noon Sun 64 67 NW 9 3138 2040 0 Blue 11
1 PM Sun 66 70 NW 9 4813 3119 1079 Blue 14
2 PM Sun 66 69 NW 14 4430 2821 781 Blue 13
3 PM Sun 66 69 NW 14 4430 2821 781 Blue 13
4 PM Sun 66 67 NW 14 3138 2040 0 Blue 11
5 PM Sun 66 66 NW 15 2838 2040 0 Blue 10
6 PM Sun 62 62 NW 15 1606 2040 0 Blue 6
7 PM Sun 59 59 NW 15 1425 2040 0 Blue 3
8 PM Sun 58 58 N 18 1338 2040 0 Blue 2
9 PM Sun 58 58 N 18 1338 2040 0 Blue 2
10 PM Sun 57 57 N 18 1249 2040 0 Blue 1
11 PM Sun 56 56 N 9 1151 2040 0 Blue 0
12 Midnight Mon 56 56 N 9 1151 2040 0 Blue 0
1 AM Mon 56 56 N 9 1151 2040 0 Blue 0
2 AM Mon 56 56 N 2 1151 2040 0 Blue 0
3 AM Mon 56 56 N 2 1151 2040 0 Blue 0
4 AM Mon 55 55 N 2 949 2040 0 Blue 0
5 AM Mon 54 54 NW 2 746 2040 0 Blue 0
6 AM Mon 54 54 NW 2 746 2040 0 Blue 0
7 AM Mon 53 53 NW 2 542 2040 0 Blue 0
8 AM Mon 54 54 N 2 746 2040 0 Blue 0
9 AM Mon 56 56 N 2 1151 2040 0 Blue 0
10 AM Mon 60 61 N 2 1546 2040 0 Blue 5
11 AM Mon 66 68 W 2 3436 2300 260 Blue 12
12 Noon Mon 69 72 W 2 5414 4397 2357 Blue 16
1 PM Mon 71 75 W 2 6318 5370 3330 Blue 19
2 PM Mon 71 74 W 6 6022 5052 3012 Blue 18
3 PM Mon 71 74 W 6 6022 5052 3012 Blue 18
4 PM Mon 71 72 W 6 5414 4397 2357 Blue 16
5 PM Mon 70 70 N 9 4813 3119 1079 Blue 14
6 PM Mon 66 66 N 9 2838 2040 0 Blue 10
7 PM Mon 63 63 N 9 1699 2040 0 Blue 7
8 PM Mon 62 62 N 9 1606 2040 0 Blue 6
9 PM Mon 61 61 N 9 1546 2040 0 Blue 5
10 PM Mon 60 60 N 9 1485 2040 0 Blue 4
11 PM Mon 60 60 N 3 1485 2040 0 Blue 4
12 Midnight Tue 60 60 N 3 1485 2040 0 Blue 4
1 AM Tue 59 59 N 3 1425 2040 0 Blue 3
2 AM Tue 59 59 N 3 1425 2040 0 Blue 3
3 AM Tue 59 59 N 3 1425 2040 0 Blue 3
4 AM Tue 58 58 N 3 1338 2040 0 Blue 2
5 AM Tue 57 57 NE 3 1249 2040 0 Blue 1
6 AM Tue 56 56 NE 3 1151 2040 0 Blue 0
7 AM Tue 56 56 NE 3 1151 2040 0 Blue 0
8 AM Tue 56 56 N 3 1151 2040 0 Blue 0
9 AM Tue 58 58 N 3 1338 2040 0 Blue 2
10 AM Tue 63 64 N 3 1881 2040 0 Blue 8
11 AM Tue 68 70 N 2 4813 3119 1079 Blue 14
12 Noon Tue 71 74 N 2 6022 5052 3012 Blue 18
1 PM Tue 73 77 N 2 7036 5975 3935 Blue 21
2 PM Tue 73 76 NW 7 6611 5680 3640 Blue 20
3 PM Tue 74 76 NW 7 6611 5680 3640 Blue 20
4 PM Tue 73 74 NW 7 6022 5052 3012 Blue 18
5 PM Tue 72 72 NW 7 5414 4397 2357 Blue 16
6 PM Tue 68 68 NW 7 3436 2300 260 Blue 12
7 PM Tue 64 64 NW 7 1881 2040 0 Blue 8
8 PM Tue 63 63 N 5 1699 2040 0 Blue 7
9 PM Tue 62 62 N 5 1606 2040 0 Blue 6
10 PM Tue 61 61 N 5 1546 2040 0 Blue 5
11 PM Tue 60 60 NE 5 1485 2040 0 Blue 4
12 Midnight Wed 60 60 NE 5 1485 2040 0 Blue 4
1 AM Wed 60 60 NE 5 1485 2040 0 Blue 4
2 AM Wed 60 60 N 5 1485 2040 0 Blue 4
3 AM Wed 60 60 N 5 1485 2040 0 Blue 4
4 AM Wed 59 59 N 5 1425 2040 0 Blue 3
5 AM Wed 58 58 N 9 1338 2040 0 Blue 2
6 AM Wed 57 57 N 9 1249 2040 0 Blue 1
7 AM Wed 56 56 N 9 1151 2040 0 Blue 0
8 AM Wed 57 57 NE 9 1249 2040 0 Blue 1
9 AM Wed 58 58 NE 9 1338 2040 0 Blue 2
10 AM Wed 63 64 NE 9 1881 2040 0 Blue 8
11 AM Wed 68 71 N 9 5093 3414 1374 Blue 15
12 Noon Wed 71 74 N 9 6022 5052 3012 Blue 18
1 PM Wed 73 77 N 9 7036 5975 3935 Blue 21
2 PM Wed 73 77 W 12 7036 5975 3935 Blue 21
3 PM Wed 73 76 W 12 6611 5680 3640 Blue 20
4 PM Wed 72 73 W 12 5724 4774 2734 Blue 17
5 PM Wed 72 72 NW 9 5414 4397 2357 Blue 16
6 PM Wed 68 68 NW 9 3436 2300 260 Blue 12
7 PM Wed 65 65 NW 9 2317 2040 0 Blue 9
8 PM Wed 64 64 NW 12 1881 2040 0 Blue 8
9 PM Wed 63 63 NW 12 1699 2040 0 Blue 7
10 PM Wed 62 62 NW 12 1606 2040 0 Blue 6
11 PM Wed 62 62 N 8 1606 2040 0 Blue 6
12 Midnight Thu 62 62 N 8 1606 2040 0 Blue 6
1 AM Thu 61 61 N 8 1546 2040 0 Blue 5
2 AM Thu 61 61 NE 8 1546 2040 0 Blue 5
3 AM Thu 61 61 NE 8 1546 2040 0 Blue 5
4 AM Thu 60 60 NE 8 1485 2040 0 Blue 4
5 AM Thu 59 59 NE 9 1425 2040 0 Blue 3
6 AM Thu 59 59 NE 9 1425 2040 0 Blue 3
7 AM Thu 58 58 NE 9 1338 2040 0 Blue 2
8 AM Thu 58 58 NE 12 1338 2040 0 Blue 2
9 AM Thu 60 60 NE 12 1485 2040 0 Blue 4
10 AM Thu 65 66 NE 12 2838 2040 0 Blue 10
11 AM Thu 70 72 NE 12 5414 4397 2357 Blue 16
12 Noon Thu 73 76 NE 12 6611 5680 3640 Blue 20
1 PM Thu 76 80 NE 12 7577 6941 4901 Blue 24
2 PM Thu 76 79 NE 9 7416 6558 4518 Blue 23
3 PM Thu 76 78 NE 9 7254 6268 4228 Blue 22
4 PM Thu 75 76 NE 9 6611 5680 3640 Blue 20
5 PM Thu 75 75 NE 7 6318 5370 3330 Blue 19
6 PM Thu 70 70 NE 7 4813 3119 1079 Blue 14
7 PM Thu 66 66 NE 7 2838 2040 0 Blue 10
8 PM Thu 64 64 N 6 1881 2040 0 Blue 8
9 PM Thu 63 63 N 6 1699 2040 0 Blue 7
10 PM Thu 62 62 N 6 1606 2040 0 Blue 6
11 PM Thu 62 62 NE 5 1606 2040 0 Blue 6
12 Midnight Fri 62 62 NE 5 1606 2040 0 Blue 6
1 AM Fri 61 61 NE 5 1546 2040 0 Blue 5
2 AM Fri 61 61 E 6 1546 2040 0 Blue 5
3 AM Fri 61 61 E 6 1546 2040 0 Blue 5
4 AM Fri 60 60 E 6 1485 2040 0 Blue 4
5 AM Fri 59 59 NE 6 1425 2040 0 Blue 3
6 AM Fri 58 58 NE 6 1338 2040 0 Blue 2
7 AM Fri 57 57 NE 6 1249 2040 0 Blue 1
8 AM Fri 58 58 NE 6 1338 2040 0 Blue 2
9 AM Fri 59 59 NE 6 1425 2040 0 Blue 3
10 AM Fri 64 65 NE 6 2317 2040 0 Blue 9
11 AM Fri 69 71 NE 7 5093 3414 1374 Blue 15
12 Noon Fri 72 75 NE 7 6318 5370 3330 Blue 19
1 PM Fri 74 78 NE 7 7254 6268 4228 Blue 22
2 PM Fri 74 77 W 5 7036 5975 3935 Blue 21
3 PM Fri 75 78 W 5 7254 6268 4228 Blue 22
4 PM Fri 74 75 W 5 6318 5370 3330 Blue 19
5 PM Fri 73 73 W 5 5724 4774 2734 Blue 17
6 PM Fri 68 68 W 5 3436 2300 260 Blue 12
7 PM Fri 64 64 W 5 1881 2040 0 Blue 8
8 PM Fri 62 62 W 6 1606 2040 0 Blue 6
9 PM Fri 61 61 W 6 1546 2040 0 Blue 5
10 PM Fri 60 60 W 6 1485 2040 0 Blue 4
11 PM Fri 59 59 NW 6 1425 2040 0 Blue 3
12 Midnight Sat 59 59 NW 6 1425 2040 0 Blue 3
1 AM Sat 58 58 NW 6 1338 2040 0 Blue 2
2 AM Sat 58 58 W 6 1338 2040 0 Blue 2
3 AM Sat 58 58 W 6 1338 2040 0 Blue 2
4 AM Sat 57 57 W 6 1249 2040 0 Blue 1

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 [email protected]