Detailed Predictions for: Elk Mountain
Launch Lat, Long, Altitude (f): 39.2820, -122.93, 4000
LZ Altitude (f): 1600
Sounding

Station:

KOAK

Date/Time:

21 SEP 2021

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Wind
Gust
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
12 Midnight Tue 66 66 NE 9 13 2621 4000 0 Blue 0
1 AM Tue 66 66 NE 9 13 2621 4000 0 Blue 0
2 AM Tue 66 66 ENE 5 8 2621 4000 0 Blue 0
3 AM Tue 66 66 ENE 5 8 2621 4000 0 Blue 0
4 AM Tue 66 66 ENE 5 8 2621 4000 0 Blue 0
5 AM Tue 66 66 ENE 5 8 2621 4000 0 Blue 0
6 AM Tue 66 66 ENE 5 8 2621 4000 0 Blue 0
7 AM Tue 69 69 ENE 5 8 2621 4000 0 Blue 0
8 AM Tue 70 70 E 4 5 2621 4000 0 Blue 0
9 AM Tue 77 78 E 4 5 4537 4000 0 Blue 4
10 AM Tue 81 83 E 4 5 5055 4749 749 Blue 9
11 AM Tue 84 88 S 6 9 6956 5336 1336 Blue 14
12 Noon Tue 85 90 S 6 9 7363 6409 2409 Blue 16
1 PM Tue 87 92 S 6 9 7841 7131 3131 Blue 18
2 PM Tue 88 93 S 6 9 7976 7333 3333 Blue 19
3 PM Tue 90 94 S 6 9 8078 7557 3557 Blue 20
4 PM Tue 90 93 S 6 9 7976 7333 3333 Blue 19
5 PM Tue 88 89 SSW 8 10 7160 5880 1880 Blue 15
6 PM Tue 84 84 SSW 8 10 5115 4858 858 Blue 10
7 PM Tue 78 78 SSW 8 10 4537 4000 0 Blue 4
8 PM Tue 71 71 SE 1 1 2621 4000 0 Blue 0
9 PM Tue 71 71 SE 1 1 2621 4000 0 Blue 0
10 PM Tue 72 72 SE 1 1 2621 4000 0 Blue 0
11 PM Tue 72 72 ESE 1 1 2621 4000 0 Blue 0
12 Midnight Wed 70 70 ESE 1 1 2621 4000 0 Blue 0
1 AM Wed 70 70 ESE 1 1 2621 4000 0 Blue 0
2 AM Wed 70 70 ESE 2 3 2621 4000 0 Blue 0
3 AM Wed 70 70 ESE 2 3 2621 4000 0 Blue 0
4 AM Wed 70 70 ESE 2 3 2621 4000 0 Blue 0
5 AM Wed 69 69 ESE 2 3 2621 4000 0 Blue 0
6 AM Wed 68 68 ESE 2 3 2621 4000 0 Blue 0
7 AM Wed 67 67 ESE 2 3 2621 4000 0 Blue 0
8 AM Wed 68 68 S 2 3 2621 4000 0 Blue 0
9 AM Wed 73 74 S 2 3 3794 4000 0 Blue 0
10 AM Wed 77 79 S 2 3 4646 4000 0 Blue 5
11 AM Wed 79 82 SSW 5 8 4976 4640 640 Blue 8
12 Noon Wed 80 85 SSW 5 8 5383 4968 968 Blue 11
1 PM Wed 81 86 SSW 5 8 5936 5050 1050 Blue 12
2 PM Wed 83 88 WSW 5 8 6956 5336 1336 Blue 14
3 PM Wed 84 88 WSW 5 8 6956 5336 1336 Blue 14
4 PM Wed 84 87 WSW 5 8 6471 5111 1111 Blue 13
5 PM Wed 82 83 WNW 5 8 5055 4749 749 Blue 9
6 PM Wed 76 76 WNW 5 8 3946 4000 0 Blue 2
7 PM Wed 70 70 WNW 5 8 2621 4000 0 Blue 0
8 PM Wed 66 66 N 10 13 2621 4000 0 Blue 0
9 PM Wed 65 65 N 10 13 2621 4000 0 Blue 0
10 PM Wed 66 66 N 10 13 2621 4000 0 Blue 0
11 PM Wed 68 68 NNE 10 13 2621 4000 0 Blue 0
12 Midnight Thu 68 68 NNE 10 13 2621 4000 0 Blue 0
1 AM Thu 68 68 NNE 10 13 2621 4000 0 Blue 0
2 AM Thu 67 67 NE 12 16 2621 4000 0 Blue 0
3 AM Thu 67 67 NE 12 16 2621 4000 0 Blue 0
4 AM Thu 67 67 NE 12 16 2621 4000 0 Blue 0
5 AM Thu 67 67 NNE 10 13 2621 4000 0 Blue 0
6 AM Thu 66 66 NNE 10 13 2621 4000 0 Blue 0
7 AM Thu 66 66 NNE 10 13 2621 4000 0 Blue 0
8 AM Thu 67 67 N 10 13 2621 4000 0 Blue 0
9 AM Thu 71 72 N 10 13 2621 4000 0 Blue 0
10 AM Thu 77 79 N 10 13 4646 4000 0 Blue 5
11 AM Thu 82 85 NE 2 3 5383 4968 968 Blue 11
12 Noon Thu 85 89 NE 2 3 7160 5880 1880 Blue 15
1 PM Thu 87 92 NE 2 3 7841 7131 3131 Blue 18
2 PM Thu 89 94 NE 2 3 8078 7557 3557 Blue 20
3 PM Thu 90 94 NE 2 3 8078 7557 3557 Blue 20
4 PM Thu 90 93 NE 2 3 7976 7333 3333 Blue 19
5 PM Thu 88 89 WNW 5 8 7160 5880 1880 Blue 15
6 PM Thu 82 82 WNW 5 8 4976 4640 640 Blue 8
7 PM Thu 76 76 WNW 5 8 3946 4000 0 Blue 2
8 PM Thu 71 71 N 4 5 2621 4000 0 Blue 0
9 PM Thu 70 70 N 4 5 2621 4000 0 Blue 0
10 PM Thu 71 71 N 4 5 2621 4000 0 Blue 0
11 PM Thu 72 72 N 3 4 2621 4000 0 Blue 0
12 Midnight Fri 73 73 N 3 4 2859 4000 0 Blue 0
1 AM Fri 72 72 N 3 4 2621 4000 0 Blue 0
2 AM Fri 71 71 NNE 4 5 2621 4000 0 Blue 0
3 AM Fri 71 71 NNE 4 5 2621 4000 0 Blue 0
4 AM Fri 71 71 NNE 4 5 2621 4000 0 Blue 0
5 AM Fri 70 70 NE 3 4 2621 4000 0 Blue 0
6 AM Fri 69 69 NE 3 4 2621 4000 0 Blue 0
7 AM Fri 68 68 NE 3 4 2621 4000 0 Blue 0
8 AM Fri 69 69 NE 3 4 2621 4000 0 Blue 0
9 AM Fri 74 75 NE 3 4 3870 4000 0 Blue 1
10 AM Fri 80 82 NE 3 4 4976 4640 640 Blue 8
11 AM Fri 85 89 W 2 3 7160 5880 1880 Blue 15
12 Noon Fri 88 93 W 2 3 7976 7333 3333 Blue 19
1 PM Fri 89 94 W 2 3 8078 7557 3557 Blue 20
2 PM Fri 90 95 W 2 3 8606 7801 3801 Blue 21
3 PM Fri 91 95 W 2 3 8606 7801 3801 Blue 21
4 PM Fri 91 94 W 2 3 8078 7557 3557 Blue 20
5 PM Fri 88 89 WSW 5 8 7160 5880 1880 Blue 15
6 PM Fri 82 82 WSW 5 8 4976 4640 640 Blue 8
7 PM Fri 75 75 WSW 5 8 3870 4000 0 Blue 1
8 PM Fri 70 70 WSW 5 8 2621 4000 0 Blue 0
9 PM Fri 69 69 WSW 5 8 2621 4000 0 Blue 0
10 PM Fri 70 70 WSW 5 8 2621 4000 0 Blue 0
11 PM Fri 71 71 WNW 3 4 2621 4000 0 Blue 0
12 Midnight Sat 71 71 WNW 3 4 2621 4000 0 Blue 0
1 AM Sat 71 71 WNW 3 4 2621 4000 0 Blue 0
2 AM Sat 70 70 WNW 3 4 2621 4000 0 Blue 0
3 AM Sat 70 70 WNW 3 4 2621 4000 0 Blue 0
4 AM Sat 70 70 WNW 3 4 2621 4000 0 Blue 0
5 AM Sat 69 69 NNW 3 4 2621 4000 0 Blue 0
6 AM Sat 68 68 NNW 3 4 2621 4000 0 Blue 0
7 AM Sat 67 67 NNW 3 4 2621 4000 0 Blue 0
8 AM Sat 68 68 NNW 3 4 2621 4000 0 Blue 0
9 AM Sat 72 73 NNW 3 4 2859 4000 0 Blue 0
10 AM Sat 77 79 NNW 3 4 4646 4000 0 Blue 5
11 AM Sat 82 85 W 4 5 5383 4968 968 Blue 11
12 Noon Sat 85 89 W 4 5 7160 5880 1880 Blue 15
1 PM Sat 86 91 W 4 5 7595 6923 2923 Blue 17
2 PM Sat 86 91 W 4 5 7595 6923 2923 Blue 17
3 PM Sat 87 91 W 4 5 7595 6923 2923 Blue 17
4 PM Sat 87 90 W 4 5 7363 6409 2409 Blue 16
5 PM Sat 84 85 W 5 8 5383 4968 968 Blue 11
6 PM Sat 79 79 W 5 8 4646 4000 0 Blue 5
7 PM Sat 72 72 W 5 8 2621 4000 0 Blue 0
8 PM Sat 67 67 W 5 8 2621 4000 0 Blue 0
9 PM Sat 66 66 W 5 8 2621 4000 0 Blue 0
10 PM Sat 67 67 W 5 8 2621 4000 0 Blue 0
11 PM Sat 68 68 NNW 3 4 2621 4000 0 Blue 0
12 Midnight Sun 69 69 NNW 3 4 2621 4000 0 Blue 0
1 AM Sun 68 68 NNW 3 4 2621 4000 0 Blue 0
2 AM Sun 67 67 NNW 3 4 2621 4000 0 Blue 0
3 AM Sun 67 67 NNW 3 4 2621 4000 0 Blue 0
4 AM Sun 67 67 NNW 3 4 2621 4000 0 Blue 0
5 AM Sun 66 66 NNE 2 3 2621 4000 0 Blue 0
6 AM Sun 65 65 NNE 2 3 2621 4000 0 Blue 0
7 AM Sun 65 65 NNE 2 3 2621 4000 0 Blue 0
8 AM Sun 66 66 NNE 2 3 2621 4000 0 Blue 0
9 AM Sun 70 70 NNE 2 3 2621 4000 0 Blue 0
10 AM Sun 74 76 NNE 2 3 3946 4000 0 Blue 2
11 AM Sun 78 81 W 3 4 4866 4530 530 Blue 7
12 Noon Sun 81 85 W 3 4 5383 4968 968 Blue 11
1 PM Sun 83 87 W 3 4 6471 5111 1111 Blue 13
2 PM Sun 84 88 W 3 4 6956 5336 1336 Blue 14
3 PM Sun 84 87 W 3 4 6471 5111 1111 Blue 13
4 PM Sun 83 85 W 3 4 5383 4968 968 Blue 11
5 PM Sun 80 81 WSW 5 8 4866 4530 530 Blue 7
6 PM Sun 75 75 WSW 5 8 3870 4000 0 Blue 1
7 PM Sun 69 69 WSW 5 8 2621 4000 0 Blue 0
8 PM Sun 65 65 WSW 5 8 2621 4000 0 Blue 0
9 PM Sun 64 64 WSW 5 8 2621 4000 0 Blue 0
10 PM Sun 65 65 WSW 5 8 2621 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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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]