Detailed Predictions for: Elk Mountain
Launch Altitude (f): 4000
LZ Altitude (f): 1600
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 56 56 N 5 3211 4000 0 Blue 6
6 AM Tue 56 56 N 5 3211 4000 0 Blue 6
7 AM Tue 56 56 N 5 3211 4000 0 Blue 6
8 AM Tue 58 58 N 3 3258 4000 0 Blue 8
9 AM Tue 62 63 N 3 3376 4000 0 Blue 13
10 AM Tue 66 68 N 3 3744 4000 0 Blue 18
11 AM Tue 71 74 SW 3 6139 4456 456 Blue 24
12 Noon Tue 74 78 SW 3 7365 6431 2431 Blue 28
1 PM Tue 76 81 SW 3 7946 7336 3336 Blue 31
2 PM Tue 77 82 W 5 8340 7527 3527 Blue 32
3 PM Tue 78 82 W 5 8340 7527 3527 Blue 32
4 PM Tue 78 81 W 5 7946 7336 3336 Blue 31
5 PM Tue 76 77 W 8 7152 6101 2101 Blue 27
6 PM Tue 73 73 W 8 5802 4198 198 Blue 23
7 PM Tue 68 68 W 8 3744 4000 0 Blue 18
8 PM Tue 64 64 NW 7 3400 4000 0 Blue 14
9 PM Tue 62 62 NW 7 3353 4000 0 Blue 12
10 PM Tue 61 61 NW 7 3329 4000 0 Blue 11
11 PM Tue 60 60 N 6 3305 4000 0 Blue 10
12 Midnight Wed 59 59 N 6 3282 4000 0 Blue 9
1 AM Wed 59 59 N 6 3282 4000 0 Blue 9
2 AM Wed 58 58 N 6 3258 4000 0 Blue 8
3 AM Wed 58 58 N 6 3258 4000 0 Blue 8
4 AM Wed 57 57 N 6 3235 4000 0 Blue 7
5 AM Wed 57 57 N 5 3235 4000 0 Blue 7
6 AM Wed 56 56 N 5 3211 4000 0 Blue 6
7 AM Wed 56 56 N 5 3211 4000 0 Blue 6
8 AM Wed 58 58 NE 3 3258 4000 0 Blue 8
9 AM Wed 63 64 NE 3 3400 4000 0 Blue 14
10 AM Wed 68 70 NE 3 4211 4000 0 Blue 20
11 AM Wed 73 77 W 5 7152 6101 2101 Blue 27
12 Noon Wed 77 82 W 5 8340 7527 3527 Blue 32
1 PM Wed 80 85 W 5 9488 8268 4268 Blue 35
2 PM Wed 81 86 W 6 9860 8653 4653 Blue 36
3 PM Wed 82 86 W 6 9860 8653 4653 Blue 36
4 PM Wed 82 85 W 6 9488 8268 4268 Blue 35
5 PM Wed 80 81 NW 8 7946 7336 3336 Blue 31
6 PM Wed 77 77 NW 8 7152 6101 2101 Blue 27
7 PM Wed 73 73 NW 8 5802 4198 198 Blue 23
8 PM Wed 69 69 NW 8 3975 4000 0 Blue 19
9 PM Wed 67 67 NW 8 3526 4000 0 Blue 17
10 PM Wed 65 65 NW 8 3424 4000 0 Blue 15
11 PM Wed 64 64 NE 3 3400 4000 0 Blue 14
12 Midnight Thu 63 63 NE 3 3376 4000 0 Blue 13
1 AM Thu 63 63 NE 3 3376 4000 0 Blue 13
2 AM Thu 62 62 NE 3 3353 4000 0 Blue 12
3 AM Thu 62 62 NE 3 3353 4000 0 Blue 12
4 AM Thu 61 61 NE 3 3329 4000 0 Blue 11
5 AM Thu 61 61 N 5 3329 4000 0 Blue 11
6 AM Thu 60 60 N 5 3305 4000 0 Blue 10
7 AM Thu 60 60 N 5 3305 4000 0 Blue 10
8 AM Thu 62 62 N 5 3353 4000 0 Blue 12
9 AM Thu 67 68 N 5 3744 4000 0 Blue 18
10 AM Thu 72 74 N 5 6139 4456 456 Blue 24
11 AM Thu 78 82 NE 5 8340 7527 3527 Blue 32
12 Noon Thu 82 87 NE 5 10220 9031 5031 Blue 37
1 PM Thu 84 89 NE 5 11738 9774 5774 Blue 39
2 PM Thu 86 91 NE 5 12328 10446 6446 Blue 41
3 PM Thu 87 91 NE 5 12328 10446 6446 Blue 41
4 PM Thu 87 90 NE 5 12071 10138 6138 Blue 40
5 PM Thu 85 86 W 6 9860 8653 4653 Blue 36
6 PM Thu 82 82 W 6 8340 7527 3527 Blue 32
7 PM Thu 77 77 W 6 7152 6101 2101 Blue 27
8 PM Thu 73 73 W 6 5802 4198 198 Blue 23
9 PM Thu 71 71 W 6 4474 4000 0 Blue 21
10 PM Thu 69 69 W 6 3975 4000 0 Blue 19
11 PM Thu 69 69 N 5 3975 4000 0 Blue 19
12 Midnight Fri 68 68 N 5 3744 4000 0 Blue 18
1 AM Fri 67 67 N 5 3526 4000 0 Blue 17
2 AM Fri 66 66 N 5 3466 4000 0 Blue 16
3 AM Fri 66 66 N 5 3466 4000 0 Blue 16
4 AM Fri 65 65 N 5 3424 4000 0 Blue 15
5 AM Fri 65 65 NE 6 3424 4000 0 Blue 15
6 AM Fri 64 64 NE 6 3400 4000 0 Blue 14
7 AM Fri 64 64 NE 6 3400 4000 0 Blue 14
8 AM Fri 65 65 NE 6 3424 4000 0 Blue 15
9 AM Fri 69 70 NE 6 4211 4000 0 Blue 20
10 AM Fri 74 76 NE 6 6813 5737 1737 Blue 26
11 AM Fri 78 82 W 3 8340 7527 3527 Blue 32
12 Noon Fri 82 87 W 3 10220 9031 5031 Blue 37
1 PM Fri 84 89 W 3 11738 9774 5774 Blue 39
2 PM Fri 86 91 W 3 12328 10446 6446 Blue 41
3 PM Fri 86 90 W 3 12071 10138 6138 Blue 40
4 PM Fri 85 88 W 3 10524 9405 5405 Blue 38
5 PM Fri 83 84 W 10 9111 7910 3910 Blue 34
6 PM Fri 78 78 W 10 7365 6431 2431 Blue 28
7 PM Fri 73 73 W 10 5802 4198 198 Blue 23
8 PM Fri 69 69 W 10 3975 4000 0 Blue 19
9 PM Fri 65 65 W 10 3424 4000 0 Blue 15
10 PM Fri 63 63 W 10 3376 4000 0 Blue 13
11 PM Fri 62 62 NW 7 3353 4000 0 Blue 12
12 Midnight Sat 61 61 NW 7 3329 4000 0 Blue 11
1 AM Sat 60 60 NW 7 3305 4000 0 Blue 10
2 AM Sat 59 59 NW 7 3282 4000 0 Blue 9
3 AM Sat 59 59 NW 7 3282 4000 0 Blue 9
4 AM Sat 58 58 NW 7 3258 4000 0 Blue 8
5 AM Sat 57 57 N 5 3235 4000 0 Blue 7
6 AM Sat 57 57 N 5 3235 4000 0 Blue 7
7 AM Sat 57 57 N 5 3235 4000 0 Blue 7
8 AM Sat 59 59 N 5 3282 4000 0 Blue 9
9 AM Sat 63 63 N 5 3376 4000 0 Blue 13
10 AM Sat 69 71 N 5 4474 4000 0 Blue 21
11 AM Sat 73 76 W 9 6813 5737 1737 Blue 26
12 Noon Sat 77 81 W 9 7946 7336 3336 Blue 31
1 PM Sat 79 83 W 9 8728 7719 3719 Blue 33
2 PM Sat 80 84 W 9 9111 7910 3910 Blue 34
3 PM Sat 81 84 W 9 9111 7910 3910 Blue 34
4 PM Sat 81 83 W 9 8728 7719 3719 Blue 33
5 PM Sat 78 79 W 8 7558 6767 2767 Blue 29
6 PM Sat 75 75 W 8 6471 5054 1054 Blue 25
7 PM Sat 70 70 W 8 4211 4000 0 Blue 20
8 PM Sat 66 66 W 8 3466 4000 0 Blue 16
9 PM Sat 63 63 W 8 3376 4000 0 Blue 13
10 PM Sat 61 61 W 8 3329 4000 0 Blue 11
11 PM Sat 60 60 NW 6 3305 4000 0 Blue 10
12 Midnight Sun 59 59 NW 6 3282 4000 0 Blue 9
1 AM Sun 58 58 NW 6 3258 4000 0 Blue 8
2 AM Sun 58 58 NW 6 3258 4000 0 Blue 8
3 AM Sun 57 57 NW 6 3235 4000 0 Blue 7
4 AM Sun 56 56 NW 6 3211 4000 0 Blue 6
5 AM Sun 56 56 NW 6 3211 4000 0 Blue 6
6 AM Sun 55 55 NW 6 3187 4000 0 Blue 5
7 AM Sun 55 55 NW 6 3187 4000 0 Blue 5
8 AM Sun 57 57 NW 6 3235 4000 0 Blue 7
9 AM Sun 60 60 NW 6 3305 4000 0 Blue 10
10 AM Sun 64 65 NW 6 3424 4000 0 Blue 15
11 AM Sun 68 71 W 9 4474 4000 0 Blue 21
12 Noon Sun 71 75 W 9 6471 5054 1054 Blue 25
1 PM Sun 73 77 W 9 7152 6101 2101 Blue 27
2 PM Sun 74 78 W 9 7365 6431 2431 Blue 28
3 PM Sun 75 78 W 9 7365 6431 2431 Blue 28
4 PM Sun 74 76 W 9 6813 5737 1737 Blue 26
5 PM Sun 73 74 W 9 6139 4456 456 Blue 24
6 PM Sun 69 69 W 9 3975 4000 0 Blue 19
7 PM Sun 65 65 W 9 3424 4000 0 Blue 15
8 PM Sun 61 61 W 9 3329 4000 0 Blue 11
9 PM Sun 59 59 W 9 3282 4000 0 Blue 9
10 PM Sun 57 57 W 9 3235 4000 0 Blue 7
11 PM Sun 56 56 N 6 3211 4000 0 Blue 6
12 Midnight Mon 55 55 N 6 3187 4000 0 Blue 5
1 AM Mon 54 54 N 6 3164 4000 0 Blue 4
2 AM Mon 53 53 N 6 3140 4000 0 Blue 3
3 AM Mon 53 53 N 6 3140 4000 0 Blue 3
4 AM Mon 53 53 N 6 3140 4000 0 Blue 3

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