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

Station:

KOAK

Date/Time:

23 JUN 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 Wed 54 54 WSW 1 2 3724 4000 0 Blue 1
1 AM Wed 50 50 S 1 2 3659 4000 0 Blue 0
2 AM Wed 46 46 ESE 1 2 3632 4000 0 Blue 0
3 AM Wed 45 45 ESE 1 2 3632 4000 0 Blue 0
4 AM Wed 45 45 E 1 3 3632 4000 0 Blue 0
5 AM Wed 45 45 E 1 3 3632 4000 0 Blue 0
6 AM Wed 50 50 SE 2 3 3659 4000 0 Blue 0
7 AM Wed 55 55 S 2 2 3763 4000 0 Blue 2
8 AM Wed 60 61 SSW 2 2 3925 4000 0 Blue 8
9 AM Wed 66 69 SW 2 3 4399 4128 128 Blue 16
10 AM Wed 72 77 SW 3 4 7139 5745 1745 Blue 24
11 AM Wed 78 84 SW 4 4 11471 11471 7471 White 31
12 Noon Wed 80 88 SW 6 6 12302 12302 8302 White 35
1 PM Wed 82 90 WSW 7 9 12712 12712 8712 White 37
2 PM Wed 84 92 WSW 9 11 13125 13125 9125 White 39
3 PM Wed 81 88 W 9 10 12302 12302 8302 White 35
4 PM Wed 78 83 W 8 10 11260 11260 7260 White 30
5 PM Wed 75 78 W 8 9 7735 6131 2131 Blue 25
6 PM Wed 73 74 W 6 8 5772 4878 878 Blue 21
7 PM Wed 71 71 W 5 6 4882 4225 225 Blue 18
8 PM Wed 69 69 W 3 4 4399 4128 128 Blue 16
9 PM Wed 67 67 S 2 4 4177 4024 24 Blue 14
10 PM Wed 64 64 E 2 4 4025 4000 0 Blue 11
11 PM Wed 62 62 NNE 1 3 3949 4000 0 Blue 9
12 Midnight Thu 58 58 NNE 1 3 3855 4000 0 Blue 5
1 AM Thu 54 54 NNE 1 3 3724 4000 0 Blue 1
2 AM Thu 49 49 NNE 1 2 3648 4000 0 Blue 0
3 AM Thu 49 49 NE 1 2 3648 4000 0 Blue 0
4 AM Thu 48 48 E 1 2 3637 4000 0 Blue 0
5 AM Thu 48 48 SE 1 2 3637 4000 0 Blue 0
6 AM Thu 54 54 SSW 0 1 3724 4000 0 Blue 1
7 AM Thu 60 60 W 0 0 3902 4000 0 Blue 7
8 AM Thu 66 67 NNW 0 0 4177 4024 24 Blue 14
9 AM Thu 72 75 WNW 1 1 6155 4986 986 Blue 22
10 AM Thu 78 83 W 2 3 11260 11260 7260 White 30
11 AM Thu 84 91 SW 4 4 12918 12918 8918 White 38
12 Noon Thu 86 94 WSW 6 7 13531 13531 9531 White 41
1 PM Thu 87 95 WSW 8 9 13735 13735 9735 White 42
2 PM Thu 88 96 W 10 12 13936 13936 9936 White 43
3 PM Thu 86 93 W 9 11 13328 13328 9328 White 40
4 PM Thu 83 88 W 8 10 12302 12302 8302 White 35
5 PM Thu 81 84 W 8 9 11471 11471 7471 White 31
6 PM Thu 79 80 W 6 7 10629 7060 3060 White 27
7 PM Thu 76 76 W 5 6 6463 5180 1180 Blue 23
8 PM Thu 74 74 WSW 3 4 5772 4878 878 Blue 21
9 PM Thu 71 71 SSW 3 4 4882 4225 225 Blue 18
10 PM Thu 69 69 S 2 4 4399 4128 128 Blue 16
11 PM Thu 66 66 SE 1 3 4129 4000 0 Blue 13
12 Midnight Fri 62 62 SSW 1 3 3949 4000 0 Blue 9
1 AM Fri 58 58 WNW 1 2 3855 4000 0 Blue 5
2 AM Fri 53 53 N 1 2 3692 4000 0 Blue 0
3 AM Fri 54 54 WSW 1 3 3724 4000 0 Blue 1
4 AM Fri 54 54 SSE 2 4 3724 4000 0 Blue 1
5 AM Fri 54 54 NE 2 5 3724 4000 0 Blue 1
6 AM Fri 60 60 ESE 2 4 3902 4000 0 Blue 7
7 AM Fri 67 67 SSE 1 2 4177 4024 24 Blue 14
8 AM Fri 74 75 SW 1 1 6155 4986 986 Blue 22
9 AM Fri 79 81 SW 2 2 10840 7663 3663 White 28
10 AM Fri 84 88 WSW 3 3 12302 12302 8302 White 35
11 AM Fri 89 94 WSW 4 5 13531 13531 9531 White 41
12 Noon Fri 90 97 W 6 7 14137 14137 10137 White 44
1 PM Fri 92 100 W 8 9 14736 14736 10736 White 47
2 PM Fri 93 101 W 10 12 14933 14933 10933 White 48
3 PM Fri 91 98 W 9 11 14338 14338 10338 White 45
4 PM Fri 90 95 W 8 9 13735 13735 9735 White 42
5 PM Fri 88 91 W 7 8 12918 12918 8918 White 38
6 PM Fri 87 88 W 6 7 12302 12302 8302 White 35
7 PM Fri 86 86 W 4 7 11889 11889 7889 White 33
8 PM Fri 85 85 WSW 3 6 11680 11680 7680 White 32
9 PM Fri 83 83 WNW 3 7 11260 11260 7260 White 30
10 PM Fri 82 82 NW 4 8 11050 9782 5782 White 29
11 PM Fri 81 81 NNW 4 9 10840 7663 3663 White 28

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]