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

Station:

KOAK

Date/Time UTC:

250217/1200

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 Mon 41 41 W 5 8 2631 4000 0 Blue 0
1 AM Mon 41 41 W 5 8 2631 4000 0 Blue 0
2 AM Mon 40 40 W 5 8 2631 4000 0 Blue 0
3 AM Mon 40 40 W 5 8 2631 4000 0 Blue 0
4 AM Mon 40 40 NW 4 8 2631 4000 0 Blue 0
5 AM Mon 40 40 NW 4 8 2631 4000 0 Blue 0
6 AM Mon 40 40 NW 4 8 2631 4000 0 Blue 0
7 AM Mon 40 40 NNW 4 8 2631 4000 0 Blue 0
8 AM Mon 39 39 NNW 4 8 2631 4000 0 Blue 0
9 AM Mon 42 42 NNW 4 8 2631 4000 0 Blue 0
10 AM Mon 43 43 NW 8 12 2631 4000 0 Blue 0
11 AM Mon 45 45 NW 8 12 3508 4000 0 Blue 0
12 Noon Mon 47 47 NW 8 12 4791 4000 0 Blue 2
1 PM Mon 47 47 WNW 8 13 4791 4000 0 Blue 2
2 PM Mon 48 48 WNW 8 13 4878 4000 0 Blue 3
3 PM Mon 48 48 WNW 8 13 4878 4000 0 Blue 3
4 PM Mon 47 47 NW 6 11 4791 4000 0 Blue 2
5 PM Mon 44 44 NW 6 11 2631 4000 0 Blue 0
6 PM Mon 43 43 NW 6 11 2631 4000 0 Blue 0
7 PM Mon 41 41 NNW 8 12 2631 4000 0 Blue 0
8 PM Mon 41 41 NNW 8 12 2631 4000 0 Blue 0
9 PM Mon 40 40 NNW 8 12 2631 4000 0 Blue 0
10 PM Mon 39 39 N 6 11 2631 4000 0 Blue 0
11 PM Mon 39 39 N 6 11 2631 4000 0 Blue 0
12 Midnight Tue 39 39 N 6 11 2631 4000 0 Blue 0
1 AM Tue 39 39 N 8 12 2631 4000 0 Blue 0
2 AM Tue 39 39 N 8 12 2631 4000 0 Blue 0
3 AM Tue 38 38 N 8 12 2631 4000 0 Blue 0
4 AM Tue 38 38 N 5 9 2631 4000 0 Blue 0
5 AM Tue 38 38 N 5 9 2631 4000 0 Blue 0
6 AM Tue 37 37 N 5 9 2631 4000 0 Blue 0
7 AM Tue 38 38 N 3 4 2631 4000 0 Blue 0
8 AM Tue 40 40 N 3 4 2631 4000 0 Blue 0
9 AM Tue 45 45 N 3 4 3508 4000 0 Blue 0
10 AM Tue 49 50 SW 3 4 5004 4785 785 Blue 5
11 AM Tue 52 54 SW 3 4 5142 5036 1036 Blue 9
12 Noon Tue 54 56 SW 3 4 5211 5105 1105 Blue 11
1 PM Tue 56 58 W 5 10 5296 5174 1174 Blue 13
2 PM Tue 57 58 W 5 10 5296 5174 1174 Blue 13
3 PM Tue 57 58 W 5 10 5296 5174 1174 Blue 13
4 PM Tue 55 55 W 5 9 5177 5070 1070 Blue 10
5 PM Tue 54 54 W 5 9 5142 5036 1036 Blue 9
6 PM Tue 52 52 W 5 9 5073 4949 949 Blue 7
7 PM Tue 50 50 WSW 2 3 5004 4785 785 Blue 5
8 PM Tue 49 49 WSW 2 3 4954 4324 324 Blue 4
9 PM Tue 48 48 WSW 2 3 4878 4000 0 Blue 3
10 PM Tue 47 47 SE 3 4 4791 4000 0 Blue 2
11 PM Tue 46 46 SE 3 4 4362 4000 0 Blue 1
12 Midnight Wed 46 46 SE 3 4 4362 4000 0 Blue 1
1 AM Wed 45 45 S 4 8 3508 4000 0 Blue 0
2 AM Wed 44 44 S 4 8 2631 4000 0 Blue 0
3 AM Wed 43 43 S 4 8 2631 4000 0 Blue 0
4 AM Wed 43 43 S 4 8 2631 4000 0 Blue 0
5 AM Wed 43 43 S 4 8 2631 4000 0 Blue 0
6 AM Wed 43 43 S 4 8 2631 4000 0 Blue 0
7 AM Wed 44 44 SW 6 11 2631 4000 0 Blue 0
8 AM Wed 45 45 SW 6 11 3508 4000 0 Blue 0
9 AM Wed 45 45 SW 6 11 3508 4000 0 Blue 0
10 AM Wed 46 46 WSW 10 17 4362 4000 0 Blue 1
11 AM Wed 47 47 WSW 10 17 4791 4000 0 Blue 2
12 Noon Wed 49 49 WSW 10 17 4954 4324 324 Blue 4
1 PM Wed 49 49 W 12 19 4954 4324 324 Blue 4
2 PM Wed 49 49 W 12 19 4954 4324 324 Blue 4
3 PM Wed 49 49 W 12 19 4954 4324 324 Blue 4
4 PM Wed 48 48 WNW 10 16 4878 4000 0 Blue 3
5 PM Wed 47 47 WNW 10 16 4791 4000 0 Blue 2
6 PM Wed 46 46 WNW 10 16 4362 4000 0 Blue 1
7 PM Wed 45 45 WNW 12 20 3508 4000 0 Blue 0
8 PM Wed 44 44 WNW 12 20 2631 4000 0 Blue 0
9 PM Wed 44 44 WNW 12 20 2631 4000 0 Blue 0
10 PM Wed 43 43 NW 10 16 2631 4000 0 Blue 0
11 PM Wed 42 42 NW 10 16 2631 4000 0 Blue 0
12 Midnight Thu 42 42 NW 10 16 2631 4000 0 Blue 0
1 AM Thu 41 41 NW 10 16 2631 4000 0 Blue 0
2 AM Thu 40 40 NW 10 16 2631 4000 0 Blue 0
3 AM Thu 39 39 NW 10 16 2631 4000 0 Blue 0
4 AM Thu 38 38 N 8 13 2631 4000 0 Blue 0
5 AM Thu 37 37 N 8 13 2631 4000 0 Blue 0
6 AM Thu 36 36 N 8 13 2631 4000 0 Blue 0
7 AM Thu 37 37 N 8 13 2631 4000 0 Blue 0
8 AM Thu 40 40 N 8 13 2631 4000 0 Blue 0
9 AM Thu 44 44 N 8 13 2631 4000 0 Blue 0
10 AM Thu 49 51 NNW 6 11 5038 4872 872 Blue 6
11 AM Thu 53 56 NNW 6 11 5211 5105 1105 Blue 11
12 Noon Thu 56 59 NNW 6 11 5386 5208 1208 Blue 14
1 PM Thu 59 62 NNW 6 11 6528 5367 1367 Blue 17
2 PM Thu 60 62 NNW 6 11 6528 5367 1367 Blue 17
3 PM Thu 60 61 NNW 6 11 5867 5290 1290 Blue 16
4 PM Thu 59 59 NNW 8 11 5386 5208 1208 Blue 14
5 PM Thu 57 57 NNW 8 11 5246 5139 1139 Blue 12
6 PM Thu 54 54 NNW 8 11 5142 5036 1036 Blue 9
7 PM Thu 52 52 NNW 8 11 5073 4949 949 Blue 7
8 PM Thu 49 49 NNW 8 11 4954 4324 324 Blue 4
9 PM Thu 48 48 NNW 8 11 4878 4000 0 Blue 3
10 PM Thu 46 46 NNE 8 13 4362 4000 0 Blue 1
11 PM Thu 45 45 NNE 8 13 3508 4000 0 Blue 0
12 Midnight Fri 45 45 NNE 8 13 3508 4000 0 Blue 0
1 AM Fri 45 45 NNE 8 13 3508 4000 0 Blue 0
2 AM Fri 44 44 NNE 8 13 2631 4000 0 Blue 0
3 AM Fri 44 44 NNE 8 13 2631 4000 0 Blue 0
4 AM Fri 44 44 NNE 6 10 2631 4000 0 Blue 0
5 AM Fri 42 42 NNE 6 10 2631 4000 0 Blue 0
6 AM Fri 41 41 NNE 6 10 2631 4000 0 Blue 0
7 AM Fri 41 41 NNE 6 10 2631 4000 0 Blue 0
8 AM Fri 45 45 NNE 6 10 3508 4000 0 Blue 0
9 AM Fri 50 50 NNE 6 10 5004 4785 785 Blue 5
10 AM Fri 55 56 NW 1 2 5211 5105 1105 Blue 11
11 AM Fri 58 60 NW 1 2 5599 5243 1243 Blue 15
12 Noon Fri 61 63 NW 1 2 7327 5578 1578 Blue 18
1 PM Fri 62 64 NW 1 2 8091 5796 1796 Blue 19
2 PM Fri 63 65 NW 1 2 8675 6449 2449 Blue 20
3 PM Fri 63 64 NW 1 2 8091 5796 1796 Blue 19
4 PM Fri 62 62 WNW 4 6 6528 5367 1367 Blue 17
5 PM Fri 60 60 WNW 4 6 5599 5243 1243 Blue 15
6 PM Fri 57 57 WNW 4 6 5246 5139 1139 Blue 12
7 PM Fri 54 54 WNW 4 6 5142 5036 1036 Blue 9
8 PM Fri 52 52 WNW 4 6 5073 4949 949 Blue 7
9 PM Fri 50 50 WNW 4 6 5004 4785 785 Blue 5
10 PM Fri 49 49 N 4 8 4954 4324 324 Blue 4
11 PM Fri 49 49 N 4 8 4954 4324 324 Blue 4
12 Midnight Sat 49 49 N 4 8 4954 4324 324 Blue 4
1 AM Sat 49 49 N 4 8 4954 4324 324 Blue 4
2 AM Sat 48 48 N 4 8 4878 4000 0 Blue 3
3 AM Sat 47 47 N 4 8 4791 4000 0 Blue 2
4 AM Sat 46 46 NNE 3 6 4362 4000 0 Blue 1
5 AM Sat 46 46 NNE 3 6 4362 4000 0 Blue 1
6 AM Sat 46 46 NNE 3 6 4362 4000 0 Blue 1
7 AM Sat 47 47 NNE 3 6 4791 4000 0 Blue 2
8 AM Sat 49 49 NNE 3 6 4954 4324 324 Blue 4
9 AM Sat 53 53 NNE 3 6 5108 5001 1001 Blue 8
10 AM Sat 56 57 W 3 4 5246 5139 1139 Blue 12
11 AM Sat 59 61 W 3 4 5867 5290 1290 Blue 16
12 Noon Sat 61 63 W 3 4 7327 5578 1578 Blue 18
1 PM Sat 63 65 W 3 4 8675 6449 2449 Blue 20
2 PM Sat 64 66 W 3 4 8985 7193 3193 Blue 21
3 PM Sat 64 65 W 3 4 8675 6449 2449 Blue 20
4 PM Sat 63 63 W 4 8 7327 5578 1578 Blue 18
5 PM Sat 61 61 W 4 8 5867 5290 1290 Blue 16
6 PM Sat 58 58 W 4 8 5296 5174 1174 Blue 13
7 PM Sat 55 55 W 4 8 5177 5070 1070 Blue 10
8 PM Sat 53 53 W 4 8 5108 5001 1001 Blue 8
9 PM Sat 52 52 W 4 8 5073 4949 949 Blue 7
10 PM Sat 51 51 N 4 6 5038 4872 872 Blue 6

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]