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

Station:

KOAK

Date/Time:

13 JUL 2024

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 Sat 68 68 NE 3 6 3022 4000 0 Blue 0
1 AM Sat 68 68 NE 2 5 3022 4000 0 Blue 0
2 AM Sat 67 67 NNE 3 6 3022 4000 0 Blue 0
3 AM Sat 67 67 NNE 3 6 3022 4000 0 Blue 0
4 AM Sat 67 67 NE 2 4 3022 4000 0 Blue 0
5 AM Sat 66 66 NE 2 5 3022 4000 0 Blue 0
6 AM Sat 64 64 N 2 5 3022 4000 0 Blue 0
7 AM Sat 77 77 NE 2 4 3022 4000 0 Blue 0
8 AM Sat 85 86 NE 1 1 3492 4000 0 Blue 0
9 AM Sat 92 93 SSW 2 2 6148 4230 230 Blue 6
10 AM Sat 98 100 SSW 4 4 17374 13285 9285 White 13
11 AM Sat 102 105 SSW 4 5 18371 18371 14371 White 18
12 Noon Sat 106 109 SSW 5 6 19145 19145 15145 White 22
1 PM Sat 107 111 SW 6 7 19588 19588 15588 White 24
2 PM Sat 106 110 WSW 9 10 19373 19373 15373 White 23
3 PM Sat 103 108 WSW 10 11 18953 18953 14953 White 21
4 PM Sat 100 105 W 10 12 18371 18371 14371 White 18
5 PM Sat 97 100 W 8 9 17374 13285 9285 White 13
6 PM Sat 95 96 WNW 6 7 12699 6076 2076 Blue 9
7 PM Sat 86 86 WNW 4 5 3492 4000 0 Blue 0
8 PM Sat 78 78 WNW 3 7 3022 4000 0 Blue 0
9 PM Sat 72 72 WNW 1 3 3022 4000 0 Blue 0
10 PM Sat 68 68 SW 0 0 3022 4000 0 Blue 0
11 PM Sat 65 65 E 0 0 3022 4000 0 Blue 0
12 Midnight Sun 64 64 ESE 1 2 3022 4000 0 Blue 0
1 AM Sun 63 63 ENE 0 1 3022 4000 0 Blue 0
2 AM Sun 62 62 ENE 0 1 3022 4000 0 Blue 0
3 AM Sun 62 62 SE 1 3 3022 4000 0 Blue 0
4 AM Sun 62 62 ENE 1 2 3022 4000 0 Blue 0
5 AM Sun 63 63 ESE 1 2 3022 4000 0 Blue 0
6 AM Sun 64 64 SE 1 2 3022 4000 0 Blue 0
7 AM Sun 67 67 SSE 2 4 3022 4000 0 Blue 0
8 AM Sun 74 74 SE 1 2 3022 4000 0 Blue 0
9 AM Sun 80 81 SSE 1 1 3022 4000 0 Blue 0
10 AM Sun 86 88 SSW 3 3 3843 4000 0 Blue 1
11 AM Sun 91 94 SSW 3 3 7865 4671 671 Blue 7
12 Noon Sun 95 100 S 3 4 17374 13285 9285 White 13
1 PM Sun 98 102 SSW 5 6 17774 15676 11676 White 15
2 PM Sun 98 104 SW 6 7 18173 18173 14173 White 17
3 PM Sun 96 102 WSW 6 8 17774 15676 11676 White 15
4 PM Sun 94 99 W 8 9 17173 12452 8452 White 12
5 PM Sun 91 95 W 7 9 10563 5051 1051 Blue 8
6 PM Sun 88 90 W 6 7 4237 4000 0 Blue 3
7 PM Sun 80 80 W 5 5 3022 4000 0 Blue 0
8 PM Sun 72 72 W 3 8 3022 4000 0 Blue 0
9 PM Sun 67 67 WNW 2 5 3022 4000 0 Blue 0
10 PM Sun 64 64 N 2 5 3022 4000 0 Blue 0
11 PM Sun 62 62 NNE 2 5 3022 4000 0 Blue 0
12 Midnight Mon 61 61 NE 1 3 3022 4000 0 Blue 0
1 AM Mon 60 60 NE 1 3 3022 4000 0 Blue 0
2 AM Mon 59 59 ENE 1 3 3022 4000 0 Blue 0
3 AM Mon 59 59 ENE 1 3 3022 4000 0 Blue 0
4 AM Mon 58 58 NE 1 3 3022 4000 0 Blue 0
5 AM Mon 58 58 NE 1 3 3022 4000 0 Blue 0
6 AM Mon 60 60 ENE 1 3 3022 4000 0 Blue 0
7 AM Mon 68 68 ENE 1 2 3022 4000 0 Blue 0
8 AM Mon 75 76 SW 1 1 3022 4000 0 Blue 0
9 AM Mon 82 84 SW 2 3 3022 4000 0 Blue 0
10 AM Mon 88 92 SW 3 4 5097 4000 0 Blue 5
11 AM Mon 93 99 SW 4 5 17173 12452 8452 White 12
12 Noon Mon 96 104 SW 5 6 18173 18173 14173 White 17
1 PM Mon 98 106 SW 7 8 18565 18565 14565 White 19
2 PM Mon 98 106 SW 8 10 18565 18565 14565 White 19
3 PM Mon 96 103 WSW 9 10 17974 17974 13974 White 16
4 PM Mon 93 99 WSW 9 11 17173 12452 8452 White 12
5 PM Mon 89 93 WSW 7 8 6148 4230 230 Blue 6
6 PM Mon 85 87 W 6 7 3739 4000 0 Blue 0
7 PM Mon 77 77 W 5 6 3022 4000 0 Blue 0
8 PM Mon 68 68 W 3 8 3022 4000 0 Blue 0
9 PM Mon 62 62 WNW 2 4 3022 4000 0 Blue 0
10 PM Mon 59 59 N 1 2 3022 4000 0 Blue 0
11 PM Mon 57 57 ENE 1 2 3022 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]