Detailed Predictions for: Elk Mountain
Launch Altitude (f): 4000
LZ Altitude (f): 1600
Sounding

Station:

KOAK

Date/Time:

21 JUL 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 Sat 69 69 S 3 2589 4000 0 Blue 0
6 AM Sat 69 69 S 3 2589 4000 0 Blue 0
7 AM Sat 71 71 S 3 2620 4000 0 Blue 0
8 AM Sat 73 73 SE 3 2901 4000 0 Blue 2
9 AM Sat 76 78 SE 3 3562 4000 0 Blue 7
10 AM Sat 80 83 SE 3 4378 4000 0 Blue 12
11 AM Sat 83 87 S 6 5690 4958 958 Blue 16
12 Noon Sat 86 91 S 6 7594 5871 1871 Blue 20
1 PM Sat 87 93 S 6 8670 6914 2914 Blue 22
2 PM Sat 88 94 S 9 10144 7505 3505 Blue 23
3 PM Sat 89 94 S 9 10144 7505 3505 Blue 23
4 PM Sat 89 93 S 9 8670 6914 2914 Blue 22
5 PM Sat 88 90 S 9 6996 5671 1671 Blue 19
6 PM Sat 85 86 S 9 5478 4344 344 Blue 15
7 PM Sat 81 81 S 9 4032 4000 0 Blue 10
8 PM Sat 78 78 NW 6 3562 4000 0 Blue 7
9 PM Sat 75 75 NW 6 3089 4000 0 Blue 4
10 PM Sat 73 73 NW 6 2901 4000 0 Blue 2
11 PM Sat 72 72 W 5 2803 4000 0 Blue 1
12 Midnight Sun 72 72 W 5 2803 4000 0 Blue 1
1 AM Sun 71 71 W 5 2620 4000 0 Blue 0
2 AM Sun 71 71 SW 5 2620 4000 0 Blue 0
3 AM Sun 70 70 SW 5 2589 4000 0 Blue 0
4 AM Sun 70 70 SW 5 2589 4000 0 Blue 0
5 AM Sun 70 70 S 3 2589 4000 0 Blue 0
6 AM Sun 70 70 S 3 2589 4000 0 Blue 0
7 AM Sun 71 71 S 3 2620 4000 0 Blue 0
8 AM Sun 73 73 E 2 2901 4000 0 Blue 2
9 AM Sun 76 78 E 2 3562 4000 0 Blue 7
10 AM Sun 80 83 E 2 4378 4000 0 Blue 12
11 AM Sun 83 88 SE 6 5891 5216 1216 Blue 17
12 Noon Sun 85 91 SE 6 7594 5871 1871 Blue 20
1 PM Sun 87 94 SE 6 10144 7505 3505 Blue 23
2 PM Sun 88 94 SE 9 10144 7505 3505 Blue 23
3 PM Sun 89 95 SE 9 10782 8074 4074 Blue 24
4 PM Sun 89 93 SE 9 8670 6914 2914 Blue 22
5 PM Sun 88 91 SW 10 7594 5871 1871 Blue 20
6 PM Sun 85 86 SW 10 5478 4344 344 Blue 15
7 PM Sun 83 83 SW 10 4378 4000 0 Blue 12
8 PM Sun 80 80 SW 10 3878 4000 0 Blue 9
9 PM Sun 78 78 SW 10 3562 4000 0 Blue 7
10 PM Sun 77 77 SW 10 3324 4000 0 Blue 6
11 PM Sun 76 76 SW 5 3200 4000 0 Blue 5
12 Midnight Mon 75 75 SW 5 3089 4000 0 Blue 4
1 AM Mon 74 74 SW 5 2981 4000 0 Blue 3
2 AM Mon 73 73 SW 5 2901 4000 0 Blue 2
3 AM Mon 73 73 SW 5 2901 4000 0 Blue 2
4 AM Mon 72 72 SW 5 2803 4000 0 Blue 1
5 AM Mon 72 72 SE 2 2803 4000 0 Blue 1
6 AM Mon 73 73 SE 2 2901 4000 0 Blue 2
7 AM Mon 74 74 SE 2 2981 4000 0 Blue 3
8 AM Mon 76 77 SE 2 3324 4000 0 Blue 6
9 AM Mon 80 82 SE 2 4186 4000 0 Blue 11
10 AM Mon 84 88 SE 2 5891 5216 1216 Blue 17
11 AM Mon 88 93 E 6 8670 6914 2914 Blue 22
12 Noon Mon 91 98 E 6 12575 10675 6675 Blue 27
1 PM Mon 93 100 E 6 13242 11498 7498 Blue 29
2 PM Mon 95 102 E 6 14607 12913 8913 White 31
3 PM Mon 96 102 E 6 14607 12913 8913 White 31
4 PM Mon 96 101 E 6 14407 12323 8323 White 30
5 PM Mon 95 98 W 9 12575 10675 6675 Blue 27
6 PM Mon 91 92 W 9 8162 6071 2071 Blue 21
7 PM Mon 87 87 W 9 5690 4958 958 Blue 16
8 PM Mon 83 83 W 9 4378 4000 0 Blue 12
9 PM Mon 80 80 W 9 3878 4000 0 Blue 9
10 PM Mon 79 79 W 9 3724 4000 0 Blue 8
11 PM Mon 77 77 NW 5 3324 4000 0 Blue 6
12 Midnight Tue 76 76 NW 5 3200 4000 0 Blue 5
1 AM Tue 75 75 NW 5 3089 4000 0 Blue 4
2 AM Tue 74 74 NW 5 2981 4000 0 Blue 3
3 AM Tue 73 73 NW 5 2901 4000 0 Blue 2
4 AM Tue 72 72 NW 5 2803 4000 0 Blue 1
5 AM Tue 72 72 N 5 2803 4000 0 Blue 1
6 AM Tue 72 72 N 5 2803 4000 0 Blue 1
7 AM Tue 74 74 N 5 2981 4000 0 Blue 3
8 AM Tue 76 77 N 5 3324 4000 0 Blue 6
9 AM Tue 80 82 N 5 4186 4000 0 Blue 11
10 AM Tue 84 88 N 5 5891 5216 1216 Blue 17
11 AM Tue 88 94 SW 6 10144 7505 3505 Blue 23
12 Noon Tue 91 98 SW 6 12575 10675 6675 Blue 27
1 PM Tue 93 101 SW 6 14407 12323 8323 White 30
2 PM Tue 94 102 SW 6 14607 12913 8913 White 31
3 PM Tue 95 102 SW 6 14607 12913 8913 White 31
4 PM Tue 95 100 SW 6 13242 11498 7498 Blue 29
5 PM Tue 94 97 W 10 11748 9838 5838 Blue 26
6 PM Tue 91 92 W 10 8162 6071 2071 Blue 21
7 PM Tue 88 88 W 10 5891 5216 1216 Blue 17
8 PM Tue 85 85 W 10 5235 4179 179 Blue 14
9 PM Tue 82 82 W 10 4186 4000 0 Blue 11
10 PM Tue 80 80 W 10 3878 4000 0 Blue 9
11 PM Tue 79 79 NW 7 3724 4000 0 Blue 8
12 Midnight Wed 78 78 NW 7 3562 4000 0 Blue 7
1 AM Wed 77 77 NW 7 3324 4000 0 Blue 6
2 AM Wed 76 76 NW 7 3200 4000 0 Blue 5
3 AM Wed 75 75 NW 7 3089 4000 0 Blue 4
4 AM Wed 74 74 NW 7 2981 4000 0 Blue 3
5 AM Wed 74 74 N 7 2981 4000 0 Blue 3
6 AM Wed 75 75 N 7 3089 4000 0 Blue 4
7 AM Wed 76 76 N 7 3200 4000 0 Blue 5
8 AM Wed 79 80 N 7 3878 4000 0 Blue 9
9 AM Wed 83 85 N 7 5235 4179 179 Blue 14
10 AM Wed 88 92 N 7 8162 6071 2071 Blue 21
11 AM Wed 92 97 W 6 11748 9838 5838 Blue 26
12 Noon Wed 95 101 W 6 14407 12323 8323 White 30
1 PM Wed 97 104 W 6 15008 13401 9401 White 33
2 PM Wed 98 105 W 6 15208 15208 11208 White 34
3 PM Wed 98 104 W 6 15008 13401 9401 White 33
4 PM Wed 98 102 W 6 14607 12913 8913 White 31
5 PM Wed 96 99 W 10 12996 11084 7084 Blue 28
6 PM Wed 93 94 W 10 10144 7505 3505 Blue 23
7 PM Wed 89 89 W 10 6092 5456 1456 Blue 18
8 PM Wed 85 85 W 10 5235 4179 179 Blue 14
9 PM Wed 82 82 W 10 4186 4000 0 Blue 11
10 PM Wed 80 80 W 10 3878 4000 0 Blue 9
11 PM Wed 78 78 NW 6 3562 4000 0 Blue 7
12 Midnight Thu 77 77 NW 6 3324 4000 0 Blue 6
1 AM Thu 76 76 NW 6 3200 4000 0 Blue 5
2 AM Thu 75 75 NW 6 3089 4000 0 Blue 4
3 AM Thu 73 73 NW 6 2901 4000 0 Blue 2
4 AM Thu 72 72 NW 6 2803 4000 0 Blue 1
5 AM Thu 72 72 N 7 2803 4000 0 Blue 1
6 AM Thu 72 72 N 7 2803 4000 0 Blue 1
7 AM Thu 74 74 N 7 2981 4000 0 Blue 3
8 AM Thu 77 77 N 7 3324 4000 0 Blue 6
9 AM Thu 80 82 N 7 4186 4000 0 Blue 11
10 AM Thu 84 87 N 7 5690 4958 958 Blue 16
11 AM Thu 88 94 NW 7 10144 7505 3505 Blue 23
12 Noon Thu 92 99 NW 7 12996 11084 7084 Blue 28
1 PM Thu 94 102 NW 7 14607 12913 8913 White 31
2 PM Thu 96 104 NW 7 15008 13401 9401 White 33
3 PM Thu 96 103 NW 7 14808 13158 9158 White 32
4 PM Thu 95 100 NW 7 13242 11498 7498 Blue 29
5 PM Thu 94 97 W 12 11748 9838 5838 Blue 26
6 PM Thu 91 93 W 12 8670 6914 2914 Blue 22
7 PM Thu 88 88 W 12 5891 5216 1216 Blue 17
8 PM Thu 85 85 W 12 5235 4179 179 Blue 14
9 PM Thu 82 82 W 12 4186 4000 0 Blue 11
10 PM Thu 79 79 W 12 3724 4000 0 Blue 8
11 PM Thu 77 77 NW 8 3324 4000 0 Blue 6
12 Midnight Fri 76 76 NW 8 3200 4000 0 Blue 5
1 AM Fri 74 74 NW 8 2981 4000 0 Blue 3
2 AM Fri 73 73 NW 8 2901 4000 0 Blue 2
3 AM Fri 72 72 NW 8 2803 4000 0 Blue 1
4 AM Fri 71 71 NW 8 2620 4000 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