Detailed Predictions for: Elk Mountain
Launch Altitude (f): 4000
LZ Altitude (f): 1600
Sounding

Station:

KOAK

Date/Time:

18 SEP 2019

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 Wed 59 59 W 7 4031 4000 0 Blue 4
6 AM Wed 55 55 W 7 3316 4000 0 Blue 0
7 AM Wed 53 53 W 7 2572 4000 0 Blue 0
8 AM Wed 53 53 W 7 2572 4000 0 Blue 0
9 AM Wed 57 57 W 7 3745 4000 0 Blue 2
10 AM Wed 57 58 W 7 3901 4000 0 Blue 3
11 AM Wed 59 61 W 9 4290 4000 0 Blue 6
12 Noon Wed 62 65 W 9 5136 4943 943 Blue 10
1 PM Wed 63 66 W 9 5198 5006 1006 Blue 11
2 PM Wed 65 68 W 12 5422 5131 1131 Blue 13
3 PM Wed 66 68 W 12 5422 5131 1131 Blue 13
4 PM Wed 66 68 W 12 5422 5131 1131 Blue 13
5 PM Wed 64 65 NW 13 5136 4943 943 Blue 10
6 PM Wed 61 61 NW 13 4290 4000 0 Blue 6
7 PM Wed 56 56 NW 13 3564 4000 0 Blue 1
8 PM Wed 50 50 NW 8 2572 4000 0 Blue 0
9 PM Wed 51 51 NW 8 2572 4000 0 Blue 0
10 PM Wed 52 52 NW 8 2572 4000 0 Blue 0
11 PM Wed 53 53 NW 8 2572 4000 0 Blue 0
12 Midnight Thu 52 52 NW 8 2572 4000 0 Blue 0
1 AM Thu 51 51 NW 8 2572 4000 0 Blue 0
2 AM Thu 52 52 N 7 2572 4000 0 Blue 0
3 AM Thu 52 52 N 7 2572 4000 0 Blue 0
4 AM Thu 52 52 N 7 2572 4000 0 Blue 0
5 AM Thu 52 52 N 6 2572 4000 0 Blue 0
6 AM Thu 50 50 N 6 2572 4000 0 Blue 0
7 AM Thu 50 50 N 6 2572 4000 0 Blue 0
8 AM Thu 52 52 NE 5 2572 4000 0 Blue 0
9 AM Thu 60 61 NE 5 4290 4000 0 Blue 6
10 AM Thu 62 64 NE 5 5073 4283 283 Blue 9
11 AM Thu 65 68 N 5 5422 5131 1131 Blue 13
12 Noon Thu 68 72 N 5 6944 5598 1598 Blue 17
1 PM Thu 70 74 N 5 7455 6653 2653 Blue 19
2 PM Thu 72 76 W 7 7950 7163 3163 Blue 21
3 PM Thu 73 77 W 7 8124 7416 3416 Blue 21
4 PM Thu 73 75 W 7 7709 6908 2908 Blue 20
5 PM Thu 71 72 W 9 6944 5598 1598 Blue 17
6 PM Thu 66 66 W 9 5198 5006 1006 Blue 11
7 PM Thu 60 60 W 9 4160 4000 0 Blue 5
8 PM Thu 56 56 NW 5 3564 4000 0 Blue 1
9 PM Thu 56 56 NW 5 3564 4000 0 Blue 1
10 PM Thu 58 58 NW 5 3901 4000 0 Blue 3
11 PM Thu 60 60 N 5 4160 4000 0 Blue 5
12 Midnight Fri 60 60 N 5 4160 4000 0 Blue 5
1 AM Fri 59 59 N 5 4031 4000 0 Blue 4
2 AM Fri 59 59 N 5 4031 4000 0 Blue 4
3 AM Fri 58 58 N 5 3901 4000 0 Blue 3
4 AM Fri 59 59 N 5 4031 4000 0 Blue 4
5 AM Fri 59 59 NE 6 4031 4000 0 Blue 4
6 AM Fri 58 58 NE 6 3901 4000 0 Blue 3
7 AM Fri 58 58 NE 6 3901 4000 0 Blue 3
8 AM Fri 60 60 NE 6 4160 4000 0 Blue 5
9 AM Fri 64 65 NE 6 5136 4943 943 Blue 10
10 AM Fri 69 71 NE 6 6687 5410 1410 Blue 16
11 AM Fri 73 76 W 6 7950 7163 3163 Blue 21
12 Noon Fri 76 81 W 6 9097 8498 4498 White 25
1 PM Fri 78 83 W 6 9523 9503 5503 White 27
2 PM Fri 79 84 W 6 9743 9743 5743 White 28
3 PM Fri 80 84 W 6 9743 9743 5743 White 28
4 PM Fri 80 83 W 6 9523 9503 5503 White 27
5 PM Fri 78 79 NW 7 8674 7918 3918 White 23
6 PM Fri 72 72 NW 7 6944 5598 1598 Blue 17
7 PM Fri 66 66 NW 7 5198 5006 1006 Blue 11
8 PM Fri 62 62 NW 7 4948 4025 25 Blue 7
9 PM Fri 61 61 NW 7 4290 4000 0 Blue 6
10 PM Fri 63 63 NW 7 5011 4154 154 Blue 8
11 PM Fri 65 65 N 6 5136 4943 943 Blue 10
12 Midnight Sat 65 65 N 6 5136 4943 943 Blue 10
1 AM Sat 64 64 N 6 5073 4283 283 Blue 9
2 AM Sat 64 64 N 6 5073 4283 283 Blue 9
3 AM Sat 64 64 N 6 5073 4283 283 Blue 9
4 AM Sat 64 64 N 6 5073 4283 283 Blue 9
5 AM Sat 64 64 N 6 5073 4283 283 Blue 9
6 AM Sat 63 63 N 6 5011 4154 154 Blue 8
7 AM Sat 62 62 N 6 4948 4025 25 Blue 7
8 AM Sat 64 64 N 6 5073 4283 283 Blue 9
9 AM Sat 67 68 N 6 5422 5131 1131 Blue 13
10 AM Sat 72 74 N 6 7455 6653 2653 Blue 19
11 AM Sat 77 81 W 6 9097 8498 4498 White 25
12 Noon Sat 80 85 W 6 9962 9962 5962 White 29
1 PM Sat 81 87 W 6 10388 10388 6388 White 31
2 PM Sat 82 87 W 6 10388 10388 6388 White 31
3 PM Sat 83 87 W 6 10388 10388 6388 White 31
4 PM Sat 83 86 W 6 10182 10182 6182 White 30
5 PM Sat 80 81 W 8 9097 8498 4498 White 25
6 PM Sat 74 74 W 8 7455 6653 2653 Blue 19
7 PM Sat 67 67 W 8 5283 5068 1068 Blue 12
8 PM Sat 63 63 W 8 5011 4154 154 Blue 8
9 PM Sat 62 62 W 8 4948 4025 25 Blue 7
10 PM Sat 64 64 W 8 5073 4283 283 Blue 9
11 PM Sat 66 66 NW 5 5198 5006 1006 Blue 11
12 Midnight Sun 67 67 NW 5 5283 5068 1068 Blue 12
1 AM Sun 66 66 NW 5 5198 5006 1006 Blue 11
2 AM Sun 65 65 NW 5 5136 4943 943 Blue 10
3 AM Sun 65 65 NW 5 5136 4943 943 Blue 10
4 AM Sun 64 64 NW 5 5073 4283 283 Blue 9
5 AM Sun 64 64 NW 6 5073 4283 283 Blue 9
6 AM Sun 63 63 NW 6 5011 4154 154 Blue 8
7 AM Sun 63 63 NW 6 5011 4154 154 Blue 8
8 AM Sun 64 64 NW 6 5073 4283 283 Blue 9
9 AM Sun 68 69 NW 6 5619 5193 1193 Blue 14
10 AM Sun 72 74 NW 6 7455 6653 2653 Blue 19
11 AM Sun 77 80 W 10 8885 8093 4093 White 24
12 Noon Sun 79 82 W 10 9309 9018 5018 White 26
1 PM Sun 79 83 W 10 9523 9503 5503 White 27
2 PM Sun 79 83 W 10 9523 9503 5503 White 27
3 PM Sun 79 82 W 10 9309 9018 5018 White 26
4 PM Sun 78 80 W 10 8885 8093 4093 White 24
5 PM Sun 76 77 W 13 8124 7416 3416 Blue 21
6 PM Sun 70 70 W 13 6036 5271 1271 Blue 15
7 PM Sun 64 64 W 13 5073 4283 283 Blue 9
8 PM Sun 60 60 W 13 4160 4000 0 Blue 5
9 PM Sun 59 59 W 13 4031 4000 0 Blue 4
10 PM Sun 60 60 W 13 4160 4000 0 Blue 5
11 PM Sun 62 62 NW 9 4948 4025 25 Blue 7
12 Midnight Mon 62 62 NW 9 4948 4025 25 Blue 7
1 AM Mon 61 61 NW 9 4290 4000 0 Blue 6
2 AM Mon 61 61 NW 9 4290 4000 0 Blue 6
3 AM Mon 61 61 NW 9 4290 4000 0 Blue 6
4 AM Mon 61 61 NW 9 4290 4000 0 Blue 6
5 AM Mon 61 61 N 9 4290 4000 0 Blue 6
6 AM Mon 60 60 N 9 4160 4000 0 Blue 5
7 AM Mon 60 60 N 9 4160 4000 0 Blue 5
8 AM Mon 62 62 N 9 4948 4025 25 Blue 7
9 AM Mon 65 66 N 9 5198 5006 1006 Blue 11
10 AM Mon 70 72 N 9 6944 5598 1598 Blue 17
11 AM Mon 74 77 N 8 8124 7416 3416 Blue 21
12 Noon Mon 77 81 N 8 9097 8498 4498 White 25
1 PM Mon 78 83 N 8 9523 9503 5503 White 27
2 PM Mon 80 85 N 8 9962 9962 5962 White 29
3 PM Mon 81 85 N 8 9962 9962 5962 White 29
4 PM Mon 81 84 N 8 9743 9743 5743 White 28
5 PM Mon 79 80 N 10 8885 8093 4093 White 24
6 PM Mon 73 73 N 10 7200 5955 1955 Blue 18
7 PM Mon 67 67 N 10 5283 5068 1068 Blue 12
8 PM Mon 62 62 N 10 4948 4025 25 Blue 7
9 PM Mon 62 62 N 10 4948 4025 25 Blue 7
10 PM Mon 64 64 N 10 5073 4283 283 Blue 9
11 PM Mon 66 66 N 9 5198 5006 1006 Blue 11
12 Midnight Tue 67 67 N 9 5283 5068 1068 Blue 12
1 AM Tue 66 66 N 9 5198 5006 1006 Blue 11
2 AM Tue 64 64 N 9 5073 4283 283 Blue 9
3 AM Tue 64 64 N 9 5073 4283 283 Blue 9
4 AM Tue 64 64 N 9 5073 4283 283 Blue 9

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