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

Station:

KOAK

Date/Time:

18 SEP 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 Tue 53 53 NW 10 1646 2040 0 Blue 1
6 AM Tue 52 52 NW 10 778 2040 0 Blue 0
7 AM Tue 52 52 NW 10 778 2040 0 Blue 0
8 AM Tue 52 52 W 9 778 2040 0 Blue 0
9 AM Tue 54 55 W 9 2299 2040 0 White 3
10 AM Tue 56 58 W 9 2683 2480 440 Blue 6
11 AM Tue 58 61 W 12 3126 2680 640 Blue 9
12 Noon Tue 63 67 W 12 3265 3194 1154 Blue 15
1 PM Tue 65 70 W 12 3335 3263 1223 Blue 18
2 PM Tue 65 70 W 15 3335 3263 1223 Blue 18
3 PM Tue 66 70 W 15 3335 3263 1223 Blue 18
4 PM Tue 66 69 W 15 3312 3240 1200 Blue 17
5 PM Tue 65 66 NW 14 3242 3171 1131 Blue 14
6 PM Tue 63 63 NW 14 3172 3101 1061 Blue 11
7 PM Tue 61 61 NW 14 3126 2680 640 Blue 9
8 PM Tue 60 60 NW 17 3103 2618 578 Blue 8
9 PM Tue 59 59 NW 17 2745 2557 517 Blue 7
10 PM Tue 58 58 NW 17 2683 2480 440 Blue 6
11 PM Tue 57 57 N 14 2622 2104 64 Blue 5
12 Midnight Wed 56 56 N 14 2530 2040 0 White 4
1 AM Wed 56 56 N 14 2530 2040 0 White 4
2 AM Wed 56 56 N 13 2530 2040 0 White 4
3 AM Wed 54 54 N 13 2080 2040 0 White 2
4 AM Wed 54 54 N 13 2080 2040 0 White 2
5 AM Wed 54 54 N 9 2080 2040 0 White 2
6 AM Wed 53 53 N 9 1646 2040 0 Blue 1
7 AM Wed 53 53 N 9 1646 2040 0 Blue 1
8 AM Wed 53 53 N 5 1646 2040 0 Blue 1
9 AM Wed 56 56 N 5 2530 2040 0 White 4
10 AM Wed 59 60 N 5 3103 2618 578 Blue 8
11 AM Wed 62 66 W 12 3242 3171 1131 Blue 14
12 Noon Wed 69 74 W 12 3428 3356 1316 Blue 22
1 PM Wed 71 77 W 12 3770 3426 1386 Blue 25
2 PM Wed 72 77 W 13 3770 3426 1386 Blue 25
3 PM Wed 73 77 W 13 3770 3426 1386 Blue 25
4 PM Wed 73 76 W 13 3543 3403 1363 Blue 24
5 PM Wed 71 72 N 14 3381 3310 1270 Blue 20
6 PM Wed 69 69 N 14 3312 3240 1200 Blue 17
7 PM Wed 66 66 N 14 3242 3171 1131 Blue 14
8 PM Wed 64 64 N 14 3195 3124 1084 Blue 12
9 PM Wed 62 62 N 14 3149 2742 702 Blue 10
10 PM Wed 61 61 N 14 3126 2680 640 Blue 9
11 PM Wed 59 59 N 10 2745 2557 517 Blue 7
12 Midnight Thu 58 58 N 10 2683 2480 440 Blue 6
1 AM Thu 58 58 N 10 2683 2480 440 Blue 6
2 AM Thu 58 58 N 10 2683 2480 440 Blue 6
3 AM Thu 56 56 N 10 2530 2040 0 White 4
4 AM Thu 55 55 N 10 2299 2040 0 White 3
5 AM Thu 55 55 N 12 2299 2040 0 White 3
6 AM Thu 54 54 N 12 2080 2040 0 White 2
7 AM Thu 54 54 N 12 2080 2040 0 White 2
8 AM Thu 54 54 N 12 2080 2040 0 White 2
9 AM Thu 57 57 N 12 2622 2104 64 Blue 5
10 AM Thu 61 62 N 12 3149 2742 702 Blue 10
11 AM Thu 65 69 W 13 3312 3240 1200 Blue 17
12 Noon Thu 73 78 W 13 3996 3471 1431 Blue 26
1 PM Thu 76 82 W 13 5790 4203 2163 Blue 30
2 PM Thu 77 82 W 13 5790 4203 2163 Blue 30
3 PM Thu 78 82 W 13 5790 4203 2163 Blue 30
4 PM Thu 78 81 W 13 5117 3975 1935 Blue 29
5 PM Thu 76 77 NW 13 3770 3426 1386 Blue 25
6 PM Thu 73 73 NW 13 3405 3333 1293 Blue 21
7 PM Thu 69 69 NW 13 3312 3240 1200 Blue 17
8 PM Thu 66 66 NW 13 3242 3171 1131 Blue 14
9 PM Thu 65 65 NW 13 3219 3147 1107 Blue 13
10 PM Thu 63 63 NW 13 3172 3101 1061 Blue 11
11 PM Thu 61 61 N 5 3126 2680 640 Blue 9
12 Midnight Fri 60 60 N 5 3103 2618 578 Blue 8
1 AM Fri 59 59 N 5 2745 2557 517 Blue 7
2 AM Fri 59 59 N 5 2745 2557 517 Blue 7
3 AM Fri 57 57 N 5 2622 2104 64 Blue 5
4 AM Fri 56 56 N 5 2530 2040 0 White 4
5 AM Fri 55 55 N 5 2299 2040 0 White 3
6 AM Fri 54 54 N 5 2080 2040 0 White 2
7 AM Fri 54 54 N 5 2080 2040 0 White 2
8 AM Fri 54 54 N 5 2080 2040 0 White 2
9 AM Fri 56 56 N 5 2530 2040 0 White 4
10 AM Fri 60 61 N 5 3126 2680 640 Blue 9
11 AM Fri 63 67 W 12 3265 3194 1154 Blue 15
12 Noon Fri 70 75 W 12 3475 3380 1340 Blue 23
1 PM Fri 72 77 W 12 3770 3426 1386 Blue 25
2 PM Fri 72 77 W 12 3770 3426 1386 Blue 25
3 PM Fri 73 77 W 12 3770 3426 1386 Blue 25
4 PM Fri 73 76 W 12 3543 3403 1363 Blue 24
5 PM Fri 72 73 W 16 3405 3333 1293 Blue 21
6 PM Fri 69 69 W 16 3312 3240 1200 Blue 17
7 PM Fri 66 66 W 16 3242 3171 1131 Blue 14
8 PM Fri 64 64 W 16 3195 3124 1084 Blue 12
9 PM Fri 62 62 W 16 3149 2742 702 Blue 10
10 PM Fri 61 61 W 16 3126 2680 640 Blue 9
11 PM Fri 60 60 NW 12 3103 2618 578 Blue 8
12 Midnight Sat 58 58 NW 12 2683 2480 440 Blue 6
1 AM Sat 58 58 NW 12 2683 2480 440 Blue 6
2 AM Sat 58 58 NW 12 2683 2480 440 Blue 6
3 AM Sat 56 56 NW 12 2530 2040 0 White 4
4 AM Sat 55 55 NW 12 2299 2040 0 White 3
5 AM Sat 55 55 W 8 2299 2040 0 White 3
6 AM Sat 54 54 W 8 2080 2040 0 White 2
7 AM Sat 54 54 W 8 2080 2040 0 White 2
8 AM Sat 54 54 W 8 2080 2040 0 White 2
9 AM Sat 56 56 W 8 2530 2040 0 White 4
10 AM Sat 58 59 W 8 2745 2557 517 Blue 7
11 AM Sat 61 65 W 13 3219 3147 1107 Blue 13
12 Noon Sat 66 71 W 13 3358 3287 1247 Blue 19
1 PM Sat 68 74 W 13 3428 3356 1316 Blue 22
2 PM Sat 68 73 W 13 3405 3333 1293 Blue 21
3 PM Sat 69 73 W 13 3405 3333 1293 Blue 21
4 PM Sat 69 72 W 13 3381 3310 1270 Blue 20
5 PM Sat 68 69 W 15 3312 3240 1200 Blue 17
6 PM Sat 66 66 W 15 3242 3171 1131 Blue 14
7 PM Sat 63 63 W 15 3172 3101 1061 Blue 11
8 PM Sat 62 62 W 15 3149 2742 702 Blue 10
9 PM Sat 60 60 W 15 3103 2618 578 Blue 8
10 PM Sat 59 59 W 15 2745 2557 517 Blue 7
11 PM Sat 58 58 W 12 2683 2480 440 Blue 6
12 Midnight Sun 57 57 W 12 2622 2104 64 Blue 5
1 AM Sun 57 57 W 12 2622 2104 64 Blue 5
2 AM Sun 57 57 W 12 2622 2104 64 Blue 5
3 AM Sun 56 56 W 12 2530 2040 0 White 4
4 AM Sun 55 55 W 12 2299 2040 0 White 3
5 AM Sun 55 55 W 8 2299 2040 0 White 3
6 AM Sun 54 54 W 8 2080 2040 0 White 2
7 AM Sun 54 54 W 8 2080 2040 0 White 2
8 AM Sun 54 54 W 8 2080 2040 0 White 2
9 AM Sun 56 56 W 8 2530 2040 0 White 4
10 AM Sun 58 58 W 8 2683 2480 440 Blue 6
11 AM Sun 60 64 W 14 3195 3124 1084 Blue 12
12 Noon Sun 65 70 W 14 3335 3263 1223 Blue 18
1 PM Sun 66 72 W 14 3381 3310 1270 Blue 20
2 PM Sun 67 72 W 14 3381 3310 1270 Blue 20
3 PM Sun 68 72 W 14 3381 3310 1270 Blue 20
4 PM Sun 68 71 W 14 3358 3287 1247 Blue 19
5 PM Sun 66 67 W 16 3265 3194 1154 Blue 15
6 PM Sun 64 64 W 16 3195 3124 1084 Blue 12
7 PM Sun 62 62 W 16 3149 2742 702 Blue 10
8 PM Sun 60 60 W 16 3103 2618 578 Blue 8
9 PM Sun 60 60 W 16 3103 2618 578 Blue 8
10 PM Sun 58 58 W 16 2683 2480 440 Blue 6
11 PM Sun 57 57 W 12 2622 2104 64 Blue 5
12 Midnight Mon 56 56 W 12 2530 2040 0 White 4
1 AM Mon 56 56 W 12 2530 2040 0 White 4
2 AM Mon 56 56 W 12 2530 2040 0 White 4
3 AM Mon 55 55 W 12 2299 2040 0 White 3
4 AM Mon 54 54 W 12 2080 2040 0 White 2

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