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

Station:

KOAK

Date/Time:

27 MAY 2018

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 50 50 N 7 886 2040 0 Blue 0
6 AM Sun 50 50 N 7 886 2040 0 Blue 0
7 AM Sun 50 50 N 7 886 2040 0 Blue 0
8 AM Sun 52 52 W 7 1034 2040 0 Blue 0
9 AM Sun 56 58 W 7 1621 2040 0 Blue 1
10 AM Sun 60 63 W 7 1867 2040 0 Blue 6
11 AM Sun 63 69 W 14 3254 2302 262 Blue 12
12 Noon Sun 66 73 W 14 4706 3727 1687 Blue 16
1 PM Sun 70 77 W 14 7146 4904 2864 Blue 20
2 PM Sun 71 78 W 15 7550 5438 3398 Blue 21
3 PM Sun 71 77 W 15 7146 4904 2864 Blue 20
4 PM Sun 70 74 W 15 4941 4223 2183 Blue 17
5 PM Sun 68 71 NW 15 4261 2717 677 Blue 14
6 PM Sun 65 66 NW 15 2309 2040 0 Blue 9
7 PM Sun 61 61 NW 15 1768 2040 0 Blue 4
8 PM Sun 58 58 NW 14 1621 2040 0 Blue 1
9 PM Sun 57 57 NW 14 1553 2040 0 Blue 0
10 PM Sun 56 56 NW 14 1449 2040 0 Blue 0
11 PM Sun 55 55 NW 8 1345 2040 0 Blue 0
12 Midnight Mon 55 55 NW 8 1345 2040 0 Blue 0
1 AM Mon 57 57 NW 8 1553 2040 0 Blue 0
2 AM Mon 56 56 NW 6 1449 2040 0 Blue 0
3 AM Mon 55 55 NW 6 1345 2040 0 Blue 0
4 AM Mon 54 54 NW 6 1242 2040 0 Blue 0
5 AM Mon 52 52 N 7 1034 2040 0 Blue 0
6 AM Mon 52 52 N 7 1034 2040 0 Blue 0
7 AM Mon 52 52 N 7 1034 2040 0 Blue 0
8 AM Mon 54 55 N 6 1345 2040 0 Blue 0
9 AM Mon 58 61 N 6 1768 2040 0 Blue 4
10 AM Mon 63 68 N 6 2734 2120 80 Blue 11
11 AM Mon 66 72 W 9 4484 3219 1179 Blue 15
12 Noon Mon 69 76 W 9 6076 4681 2641 Blue 19
1 PM Mon 74 82 W 9 7848 7609 5569 Blue 25
2 PM Mon 74 81 NW 15 7774 7534 5494 Blue 24
3 PM Mon 74 80 NW 15 7699 6930 4890 Blue 23
4 PM Mon 74 78 NW 15 7550 5438 3398 Blue 21
5 PM Mon 71 74 NW 15 4941 4223 2183 Blue 17
6 PM Mon 68 69 NW 15 3254 2302 262 Blue 12
7 PM Mon 64 64 NW 15 1942 2040 0 Blue 7
8 PM Mon 61 61 NW 15 1768 2040 0 Blue 4
9 PM Mon 59 59 NW 15 1670 2040 0 Blue 2
10 PM Mon 58 58 NW 15 1621 2040 0 Blue 1
11 PM Mon 57 57 NW 7 1553 2040 0 Blue 0
12 Midnight Tue 57 57 NW 7 1553 2040 0 Blue 0
1 AM Tue 59 59 NW 7 1670 2040 0 Blue 2
2 AM Tue 58 58 NW 7 1621 2040 0 Blue 1
3 AM Tue 57 57 NW 7 1553 2040 0 Blue 0
4 AM Tue 56 56 NW 7 1449 2040 0 Blue 0
5 AM Tue 54 54 W 6 1242 2040 0 Blue 0
6 AM Tue 53 53 W 6 1138 2040 0 Blue 0
7 AM Tue 53 53 W 6 1138 2040 0 Blue 0
8 AM Tue 55 55 W 6 1345 2040 0 Blue 0
9 AM Tue 57 58 W 6 1621 2040 0 Blue 1
10 AM Tue 60 62 W 6 1817 2040 0 Blue 5
11 AM Tue 62 68 W 12 2734 2120 80 Blue 11
12 Noon Tue 64 71 W 12 4261 2717 677 Blue 14
1 PM Tue 67 75 W 12 5519 4460 2420 Blue 18
2 PM Tue 68 75 W 12 5519 4460 2420 Blue 18
3 PM Tue 68 74 W 12 4941 4223 2183 Blue 17
4 PM Tue 67 72 W 12 4484 3219 1179 Blue 15
5 PM Tue 65 68 NW 18 2734 2120 80 Blue 11
6 PM Tue 62 63 NW 18 1867 2040 0 Blue 6
7 PM Tue 59 59 NW 18 1670 2040 0 Blue 2
8 PM Tue 56 56 NW 18 1449 2040 0 Blue 0
9 PM Tue 55 55 NW 18 1345 2040 0 Blue 0
10 PM Tue 54 54 NW 18 1242 2040 0 Blue 0
11 PM Tue 54 54 NW 13 1242 2040 0 Blue 0
12 Midnight Wed 53 53 NW 13 1138 2040 0 Blue 0
1 AM Wed 55 55 NW 13 1345 2040 0 Blue 0
2 AM Wed 54 54 NW 13 1242 2040 0 Blue 0
3 AM Wed 53 53 NW 13 1138 2040 0 Blue 0
4 AM Wed 52 52 NW 13 1034 2040 0 Blue 0
5 AM Wed 51 51 NW 16 930 2040 0 Blue 0
6 AM Wed 50 50 NW 16 886 2040 0 Blue 0
7 AM Wed 50 50 NW 16 886 2040 0 Blue 0
8 AM Wed 51 51 NW 16 930 2040 0 Blue 0
9 AM Wed 53 54 NW 16 1242 2040 0 Blue 0
10 AM Wed 56 57 NW 16 1553 2040 0 Blue 0
11 AM Wed 57 62 W 16 1817 2040 0 Blue 5
12 Noon Wed 58 64 W 16 1942 2040 0 Blue 7
1 PM Wed 60 67 W 16 2493 2040 0 Blue 10
2 PM Wed 61 67 W 16 2493 2040 0 Blue 10
3 PM Wed 61 66 W 16 2309 2040 0 Blue 9
4 PM Wed 60 64 W 16 1942 2040 0 Blue 7
5 PM Wed 59 61 W 22 1768 2040 0 Blue 4
6 PM Wed 57 58 W 22 1621 2040 0 Blue 1
7 PM Wed 54 54 W 22 1242 2040 0 Blue 0
8 PM Wed 53 53 W 22 1138 2040 0 Blue 0
9 PM Wed 51 51 W 22 930 2040 0 Blue 0
10 PM Wed 51 51 W 22 930 2040 0 Blue 0
11 PM Wed 50 50 W 18 886 2040 0 Blue 0
12 Midnight Thu 50 50 W 18 886 2040 0 Blue 0
1 AM Thu 52 52 W 18 1034 2040 0 Blue 0
2 AM Thu 51 51 W 18 930 2040 0 Blue 0
3 AM Thu 50 50 W 18 886 2040 0 Blue 0
4 AM Thu 50 50 W 18 886 2040 0 Blue 0
5 AM Thu 49 49 W 22 886 2040 0 Blue 0
6 AM Thu 48 48 W 22 886 2040 0 Blue 0
7 AM Thu 48 48 W 22 886 2040 0 Blue 0
8 AM Thu 49 50 W 22 886 2040 0 Blue 0
9 AM Thu 51 53 W 22 1138 2040 0 Blue 0
10 AM Thu 54 57 W 22 1553 2040 0 Blue 0
11 AM Thu 55 61 W 20 1768 2040 0 Blue 4
12 Noon Thu 57 64 W 20 1942 2040 0 Blue 7
1 PM Thu 59 66 W 20 2309 2040 0 Blue 9
2 PM Thu 59 66 W 20 2309 2040 0 Blue 9
3 PM Thu 59 65 W 20 2126 2040 0 Blue 8
4 PM Thu 59 63 W 20 1867 2040 0 Blue 6
5 PM Thu 58 60 W 25 1719 2040 0 Blue 3
6 PM Thu 56 57 W 25 1553 2040 0 Blue 0
7 PM Thu 54 54 W 25 1242 2040 0 Blue 0
8 PM Thu 52 52 W 25 1034 2040 0 Blue 0
9 PM Thu 51 51 W 25 930 2040 0 Blue 0
10 PM Thu 50 50 W 25 886 2040 0 Blue 0
11 PM Thu 50 50 NW 21 886 2040 0 Blue 0
12 Midnight Fri 50 50 NW 21 886 2040 0 Blue 0
1 AM Fri 51 51 NW 21 930 2040 0 Blue 0
2 AM Fri 51 51 NW 21 930 2040 0 Blue 0
3 AM Fri 50 50 NW 21 886 2040 0 Blue 0
4 AM Fri 50 50 NW 21 886 2040 0 Blue 0
5 AM Fri 49 49 NW 15 886 2040 0 Blue 0
6 AM Fri 48 48 NW 15 886 2040 0 Blue 0
7 AM Fri 48 48 NW 15 886 2040 0 Blue 0
8 AM Fri 50 51 NW 15 930 2040 0 Blue 0
9 AM Fri 52 54 NW 15 1242 2040 0 Blue 0
10 AM Fri 55 58 NW 15 1621 2040 0 Blue 1
11 AM Fri 57 63 NW 9 1867 2040 0 Blue 6
12 Noon Fri 59 66 NW 9 2309 2040 0 Blue 9
1 PM Fri 61 68 NW 9 2734 2120 80 Blue 11
2 PM Fri 62 69 NW 9 3254 2302 262 Blue 12
3 PM Fri 62 68 NW 9 2734 2120 80 Blue 11
4 PM Fri 61 65 NW 9 2126 2040 0 Blue 8
5 PM Fri 60 62 W 16 1817 2040 0 Blue 5
6 PM Fri 58 59 W 16 1670 2040 0 Blue 2
7 PM Fri 55 55 W 16 1345 2040 0 Blue 0
8 PM Fri 54 54 W 16 1242 2040 0 Blue 0
9 PM Fri 52 52 W 16 1034 2040 0 Blue 0
10 PM Fri 52 52 W 16 1034 2040 0 Blue 0
11 PM Fri 52 52 NW 14 1034 2040 0 Blue 0
12 Midnight Sat 51 51 NW 14 930 2040 0 Blue 0
1 AM Sat 53 53 NW 14 1138 2040 0 Blue 0
2 AM Sat 52 52 NW 14 1034 2040 0 Blue 0
3 AM Sat 51 51 NW 14 930 2040 0 Blue 0
4 AM Sat 50 50 NW 14 886 2040 0 Blue 0

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