Detailed Predictions for: Chelan
Launch Altitude (f): 3820
LZ Altitude (f): 1200
Sounding

Station:

KOTX

Date/Time:

24 AUG 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 Sat 61 61 SW 5 2610 3820 0 Blue 3
6 AM Sat 60 60 W 7 2548 3820 0 Blue 2
7 AM Sat 61 61 W 7 2610 3820 0 Blue 3
8 AM Sat 62 62 W 5 2671 3820 0 Blue 4
9 AM Sat 65 66 W 2 2917 3820 0 Blue 8
10 AM Sat 68 70 W 2 3163 3820 0 Blue 12
11 AM Sat 71 73 NW 12 3348 3820 0 Blue 15
12 Noon Sat 74 77 NW 10 4598 3820 0 Blue 19
1 PM Sat 76 79 W 10 6261 4369 549 Blue 21
2 PM Sat 77 81 W 13 7261 4793 973 Blue 23
3 PM Sat 78 81 W 15 7261 4793 973 Blue 23
4 PM Sat 79 81 W 17 7261 4793 973 Blue 23
5 PM Sat 78 80 W 20 6670 4582 762 Blue 22
6 PM Sat 76 77 W 18 4598 3820 0 Blue 19
7 PM Sat 73 73 W 18 3348 3820 0 Blue 15
8 PM Sat 69 69 W 17 3101 3820 0 Blue 11
9 PM Sat 67 67 W 8 2978 3820 0 Blue 9
10 PM Sat 65 65 W 8 2855 3820 0 Blue 7
11 PM Sat 64 64 SW 9 2794 3820 0 Blue 6
12 Midnight Sun 62 62 W 10 2671 3820 0 Blue 4
1 AM Sun 61 61 W 10 2610 3820 0 Blue 3
2 AM Sun 59 59 SW 10 2487 3820 0 Blue 1
3 AM Sun 58 58 W 7 2425 3820 0 Blue 0
4 AM Sun 57 57 W 7 0 3820 0 Blue 0
5 AM Sun 56 56 W 7 0 3820 0 Blue 0
6 AM Sun 56 56 W 9 0 3820 0 Blue 0
7 AM Sun 58 58 W 7 2425 3820 0 Blue 0
8 AM Sun 60 60 W 9 2548 3820 0 Blue 2
9 AM Sun 63 64 W 9 2794 3820 0 Blue 6
10 AM Sun 67 70 NW 9 3163 3820 0 Blue 12
11 AM Sun 70 74 NW 7 3441 3820 0 Blue 16
12 Noon Sun 73 78 W 7 4809 3955 135 Blue 20
1 PM Sun 75 81 W 7 7261 4793 973 Blue 23
2 PM Sun 77 82 W 7 7930 6143 2323 Blue 24
3 PM Sun 78 82 W 8 7930 6143 2323 Blue 24
4 PM Sun 79 82 W 9 7930 6143 2323 Blue 24
5 PM Sun 78 80 W 9 6670 4582 762 Blue 22
6 PM Sun 76 77 W 9 4598 3820 0 Blue 19
7 PM Sun 73 73 W 9 3348 3820 0 Blue 15
8 PM Sun 70 70 W 8 3163 3820 0 Blue 12
9 PM Sun 67 67 W 8 2978 3820 0 Blue 9
10 PM Sun 65 65 W 7 2855 3820 0 Blue 7
11 PM Sun 63 63 W 7 2732 3820 0 Blue 5
12 Midnight Mon 61 61 W 6 2610 3820 0 Blue 3
1 AM Mon 59 59 W 6 2487 3820 0 Blue 1
2 AM Mon 58 58 W 5 2425 3820 0 Blue 0
3 AM Mon 56 56 W 5 0 3820 0 Blue 0
4 AM Mon 55 55 NW 3 0 3820 0 Blue 0
5 AM Mon 54 54 NW 3 0 3820 0 Blue 0
6 AM Mon 54 54 NW 3 0 3820 0 Blue 0
7 AM Mon 56 56 NW 3 0 3820 0 Blue 0
8 AM Mon 58 58 N 0 2425 3820 0 Blue 0
9 AM Mon 62 63 N 0 2732 3820 0 Blue 5
10 AM Mon 66 69 N 0 3101 3820 0 Blue 11
11 AM Mon 70 74 N 0 3441 3820 0 Blue 16
12 Noon Mon 74 79 N 0 6261 4369 549 Blue 21
1 PM Mon 76 82 N 0 7930 6143 2323 Blue 24
2 PM Mon 78 83 N 0 8568 6612 2792 Blue 25
3 PM Mon 79 84 N 0 9177 7151 3331 Blue 26
4 PM Mon 80 83 N 0 8568 6612 2792 Blue 25
5 PM Mon 80 82 N 0 7930 6143 2323 Blue 24
6 PM Mon 78 79 N 0 6261 4369 549 Blue 21
7 PM Mon 76 76 N 0 4384 3820 0 Blue 18
8 PM Mon 73 73 N 0 3348 3820 0 Blue 15
9 PM Mon 70 70 N 0 3163 3820 0 Blue 12
10 PM Mon 68 68 N 0 3040 3820 0 Blue 10
11 PM Mon 66 66 N 0 2917 3820 0 Blue 8
12 Midnight Tue 64 64 N 0 2794 3820 0 Blue 6
1 AM Tue 63 63 N 0 2732 3820 0 Blue 5
2 AM Tue 62 62 N 0 2671 3820 0 Blue 4
3 AM Tue 60 60 N 0 2548 3820 0 Blue 2
4 AM Tue 59 59 N 0 2487 3820 0 Blue 1
5 AM Tue 58 58 N 0 2425 3820 0 Blue 0
6 AM Tue 57 57 N 0 0 3820 0 Blue 0
7 AM Tue 57 57 N 0 0 3820 0 Blue 0
8 AM Tue 59 59 N 0 2487 3820 0 Blue 1
9 AM Tue 63 64 N 0 2794 3820 0 Blue 6
10 AM Tue 68 71 N 0 3224 3820 0 Blue 13
11 AM Tue 72 76 N 0 4384 3820 0 Blue 18
12 Noon Tue 75 80 N 0 6670 4582 762 Blue 22
1 PM Tue 78 84 N 0 9177 7151 3331 Blue 26
2 PM Tue 80 85 N 0 9538 7811 3991 Blue 27
3 PM Tue 82 87 N 0 9777 9043 5223 Blue 29
4 PM Tue 83 86 N 0 9675 8441 4621 Blue 28
5 PM Tue 83 85 N 0 9538 7811 3991 Blue 27
6 PM Tue 81 82 N 0 7930 6143 2323 Blue 24
7 PM Tue 77 77 N 0 4598 3820 0 Blue 19
8 PM Tue 74 74 N 0 3441 3820 0 Blue 16
9 PM Tue 71 71 N 0 3224 3820 0 Blue 13
10 PM Tue 69 69 N 0 3101 3820 0 Blue 11
11 PM Tue 67 67 N 0 2978 3820 0 Blue 9
12 Midnight Wed 66 66 N 0 2917 3820 0 Blue 8
1 AM Wed 65 65 N 0 2855 3820 0 Blue 7
2 AM Wed 63 63 N 0 2732 3820 0 Blue 5
3 AM Wed 62 62 N 0 2671 3820 0 Blue 4
4 AM Wed 61 61 N 0 2610 3820 0 Blue 3
5 AM Wed 60 60 N 0 2548 3820 0 Blue 2
6 AM Wed 60 60 N 0 2548 3820 0 Blue 2
7 AM Wed 60 60 N 0 2548 3820 0 Blue 2
8 AM Wed 62 62 N 0 2671 3820 0 Blue 4
9 AM Wed 66 67 N 0 2978 3820 0 Blue 9
10 AM Wed 71 74 N 0 3441 3820 0 Blue 16
11 AM Wed 75 79 N 0 6261 4369 549 Blue 21
12 Noon Wed 79 84 N 0 9177 7151 3331 Blue 26
1 PM Wed 82 87 N 0 9777 9043 5223 Blue 29
2 PM Wed 84 89 N 0 10940 9651 5831 Blue 31
3 PM Wed 86 90 N 0 11267 9752 5932 Blue 32
4 PM Wed 87 90 N 0 11267 9752 5932 Blue 32
5 PM Wed 87 89 N 0 10940 9651 5831 Blue 31
6 PM Wed 85 86 N 0 9675 8441 4621 Blue 28
7 PM Wed 81 81 N 0 7261 4793 973 Blue 23
8 PM Wed 78 78 N 0 4809 3955 135 Blue 20
9 PM Wed 75 75 N 0 3985 3820 0 Blue 17
10 PM Wed 73 73 N 0 3348 3820 0 Blue 15
11 PM Wed 71 71 N 0 3224 3820 0 Blue 13
12 Midnight Thu 69 69 N 0 3101 3820 0 Blue 11
1 AM Thu 67 67 N 0 2978 3820 0 Blue 9
2 AM Thu 66 66 N 0 2917 3820 0 Blue 8
3 AM Thu 64 64 N 0 2794 3820 0 Blue 6
4 AM Thu 63 63 N 0 2732 3820 0 Blue 5
5 AM Thu 63 63 N 0 2732 3820 0 Blue 5
6 AM Thu 62 62 N 0 2671 3820 0 Blue 4
7 AM Thu 62 62 N 0 2671 3820 0 Blue 4
8 AM Thu 64 64 N 0 2794 3820 0 Blue 6
9 AM Thu 67 68 N 0 3040 3820 0 Blue 10
10 AM Thu 72 74 N 0 3441 3820 0 Blue 16
11 AM Thu 76 79 N 0 6261 4369 549 Blue 21
12 Noon Thu 80 84 N 0 9177 7151 3331 Blue 26
1 PM Thu 83 88 N 0 10517 9479 5659 Blue 30
2 PM Thu 85 89 N 0 10940 9651 5831 Blue 31
3 PM Thu 87 91 N 0 11565 10342 6522 Blue 33
4 PM Thu 88 91 N 0 11565 10342 6522 Blue 33
5 PM Thu 88 89 N 0 10940 9651 5831 Blue 31
6 PM Thu 85 85 N 0 9538 7811 3991 Blue 27
7 PM Thu 82 82 N 0 7930 6143 2323 Blue 24
8 PM Thu 79 79 N 0 6261 4369 549 Blue 21
9 PM Thu 76 76 N 0 4384 3820 0 Blue 18
10 PM Thu 73 73 N 0 3348 3820 0 Blue 15
11 PM Thu 71 71 N 0 3224 3820 0 Blue 13
12 Midnight Fri 70 70 N 0 3163 3820 0 Blue 12
1 AM Fri 68 68 N 0 3040 3820 0 Blue 10
2 AM Fri 67 67 N 0 2978 3820 0 Blue 9
3 AM Fri 66 66 N 0 2917 3820 0 Blue 8
4 AM Fri 65 65 N 0 2855 3820 0 Blue 7

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