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

Station:

KOTX

Date/Time:

19 JUN 2018

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 Tue 60 60 N 3 2926 3820 0 Blue 7
6 AM Tue 62 62 N 3 3075 3820 0 Blue 9
7 AM Tue 66 66 N 3 3374 3820 0 Blue 13
8 AM Tue 70 71 E 3 6731 4464 644 White 18
9 AM Tue 73 75 E 5 7576 7576 3756 White 22
10 AM Tue 75 79 E 3 8416 8416 4596 White 26
11 AM Tue 78 83 E 5 9251 9251 5431 White 30
12 Noon Tue 80 85 E 6 9675 9675 5855 White 32
1 PM Tue 82 87 SE 6 10103 10103 6283 White 34
2 PM Tue 83 87 SE 6 10103 10103 6283 White 34
3 PM Tue 84 88 SE 6 10311 10311 6491 White 35
4 PM Tue 84 86 SE 5 9889 9889 6069 White 33
5 PM Tue 84 85 SE 5 9675 9675 5855 White 32
6 PM Tue 84 85 SE 5 9675 9675 5855 White 32
7 PM Tue 83 83 E 5 9251 9251 5431 White 30
8 PM Tue 81 81 SE 5 8835 8835 5015 White 28
9 PM Tue 77 77 SE 5 7996 7996 4176 White 24
10 PM Tue 74 74 S 3 7364 7364 3544 White 21
11 PM Tue 70 70 SW 3 6519 3820 0 White 17
12 Midnight Wed 69 69 SW 3 6304 3820 0 White 16
1 AM Wed 68 68 NW 3 4534 3820 0 Blue 15
2 AM Wed 67 67 NW 3 3539 3820 0 Blue 14
3 AM Wed 66 66 NW 3 3374 3820 0 Blue 13
4 AM Wed 64 64 NW 3 3224 3820 0 Blue 11
5 AM Wed 64 64 N 3 3224 3820 0 Blue 11
6 AM Wed 66 66 N 3 3374 3820 0 Blue 13
7 AM Wed 70 70 N 3 6519 3820 0 White 17
8 AM Wed 73 74 N 3 7364 7364 3544 White 21
9 AM Wed 76 78 NE 3 8206 8206 4386 White 25
10 AM Wed 77 80 E 3 8626 8626 4806 White 27
11 AM Wed 79 82 SE 3 9043 9043 5223 White 29
12 Noon Wed 81 85 SE 5 9675 9675 5855 White 32
1 PM Wed 83 87 S 5 10103 10103 6283 White 34
2 PM Wed 85 88 S 6 10311 10311 6491 White 35
3 PM Wed 86 89 S 6 10514 10514 6694 White 36
4 PM Wed 86 88 S 6 10311 10311 6491 White 35
5 PM Wed 86 87 S 6 10103 10103 6283 White 34
6 PM Wed 85 85 SW 6 9675 9675 5855 White 32
7 PM Wed 84 84 SW 5 9460 9460 5640 White 31
8 PM Wed 82 82 W 5 9043 9043 5223 White 29
9 PM Wed 78 78 W 5 8206 8206 4386 White 25
10 PM Wed 75 75 W 5 7576 7576 3756 White 22
11 PM Wed 71 71 NW 5 6731 4464 644 White 18
12 Midnight Thu 69 69 NW 5 6304 3820 0 White 16
1 AM Thu 67 67 NW 6 3539 3820 0 Blue 14
2 AM Thu 66 66 NW 6 3374 3820 0 Blue 13
3 AM Thu 64 64 NW 6 3224 3820 0 Blue 11
4 AM Thu 63 63 NW 5 3150 3820 0 Blue 10
5 AM Thu 63 63 NW 5 3150 3820 0 Blue 10
6 AM Thu 65 65 NW 5 3299 3820 0 Blue 12
7 AM Thu 68 68 NW 5 4534 3820 0 Blue 15
8 AM Thu 71 72 NW 5 6942 5892 2072 White 19
9 AM Thu 74 76 W 5 7787 7787 3967 White 23
10 AM Thu 77 79 W 5 8416 8416 4596 White 26
11 AM Thu 80 83 W 5 9251 9251 5431 White 30
12 Noon Thu 82 86 W 6 9889 9889 6069 White 33
1 PM Thu 84 88 W 7 10311 10311 6491 White 35
2 PM Thu 85 89 W 9 10514 10514 6694 White 36
3 PM Thu 85 88 W 10 10311 10311 6491 White 35
4 PM Thu 85 87 W 10 10103 10103 6283 White 34
5 PM Thu 84 85 W 12 9675 9675 5855 White 32
6 PM Thu 83 84 W 13 9460 9460 5640 White 31
7 PM Thu 81 81 W 14 8835 8835 5015 White 28
8 PM Thu 78 78 W 15 8206 8206 4386 White 25
9 PM Thu 74 74 W 13 7364 7364 3544 White 21
10 PM Thu 69 69 W 10 6304 3820 0 White 16
11 PM Thu 65 65 W 8 3299 3820 0 Blue 12
12 Midnight Fri 62 62 W 8 3075 3820 0 Blue 9
1 AM Fri 60 60 W 9 2926 3820 0 Blue 7
2 AM Fri 59 59 W 9 2851 3820 0 Blue 6
3 AM Fri 57 57 W 9 2702 3820 0 Blue 4
4 AM Fri 56 56 W 8 2628 3820 0 Blue 3
5 AM Fri 56 56 W 8 2628 3820 0 Blue 3
6 AM Fri 58 58 W 7 2777 3820 0 Blue 5
7 AM Fri 61 61 W 7 3000 3820 0 Blue 8
8 AM Fri 65 66 W 6 3374 3820 0 Blue 13
9 AM Fri 69 71 W 6 6731 4464 644 White 18
10 AM Fri 72 76 W 6 7787 7787 3967 White 23
11 AM Fri 75 80 W 6 8626 8626 4806 White 27
12 Noon Fri 78 84 W 7 9460 9460 5640 White 31
1 PM Fri 79 85 W 8 9675 9675 5855 White 32
2 PM Fri 81 87 W 10 10103 10103 6283 White 34
3 PM Fri 81 86 W 12 9889 9889 6069 White 33
4 PM Fri 81 85 W 14 9675 9675 5855 White 32
5 PM Fri 79 81 W 15 8835 8835 5015 White 28
6 PM Fri 77 78 W 15 8206 8206 4386 White 25
7 PM Fri 74 74 W 15 7364 7364 3544 White 21
8 PM Fri 70 70 W 15 6519 3820 0 White 17
9 PM Fri 66 66 W 15 3374 3820 0 Blue 13
10 PM Fri 63 63 W 15 3150 3820 0 Blue 10
11 PM Fri 60 60 W 8 2926 3820 0 Blue 7
12 Midnight Sat 58 58 W 8 2777 3820 0 Blue 5
1 AM Sat 57 57 W 8 2702 3820 0 Blue 4
2 AM Sat 56 56 W 8 2628 3820 0 Blue 3
3 AM Sat 55 55 W 8 2553 3820 0 Blue 2
4 AM Sat 54 54 W 8 2479 3820 0 Blue 1
5 AM Sat 54 54 W 8 2479 3820 0 Blue 1
6 AM Sat 56 56 NW 6 2628 3820 0 Blue 3
7 AM Sat 58 58 NW 6 2777 3820 0 Blue 5
8 AM Sat 62 63 NW 6 3150 3820 0 Blue 10
9 AM Sat 65 67 NW 6 3539 3820 0 Blue 14
10 AM Sat 68 72 NW 6 6942 5892 2072 White 19
11 AM Sat 71 76 NW 6 7787 7787 3967 White 23
12 Noon Sat 74 80 W 8 8626 8626 4806 White 27
1 PM Sat 76 82 W 8 9043 9043 5223 White 29
2 PM Sat 78 84 W 8 9460 9460 5640 White 31
3 PM Sat 79 84 W 8 9460 9460 5640 White 31
4 PM Sat 80 84 W 8 9460 9460 5640 White 31
5 PM Sat 80 82 W 8 9043 9043 5223 White 29
6 PM Sat 79 80 W 6 8626 8626 4806 White 27
7 PM Sat 78 78 W 6 8206 8206 4386 White 25
8 PM Sat 75 75 W 6 7576 7576 3756 White 22
9 PM Sat 71 71 W 6 6731 4464 644 White 18
10 PM Sat 67 67 W 6 3539 3820 0 Blue 14
11 PM Sat 64 64 W 6 3224 3820 0 Blue 11
12 Midnight Sun 61 61 W 5 3000 3820 0 Blue 8
1 AM Sun 60 60 W 5 2926 3820 0 Blue 7
2 AM Sun 58 58 W 5 2777 3820 0 Blue 5
3 AM Sun 56 56 W 5 2628 3820 0 Blue 3
4 AM Sun 54 54 W 5 2479 3820 0 Blue 1
5 AM Sun 54 54 W 5 2479 3820 0 Blue 1
6 AM Sun 56 56 S 6 2628 3820 0 Blue 3
7 AM Sun 60 60 S 6 2926 3820 0 Blue 7
8 AM Sun 64 65 S 6 3299 3820 0 Blue 12
9 AM Sun 68 71 S 6 6731 4464 644 White 18
10 AM Sun 71 76 S 6 7787 7787 3967 White 23
11 AM Sun 74 80 S 6 8626 8626 4806 White 27
12 Noon Sun 76 83 S 9 9251 9251 5431 White 30
1 PM Sun 79 86 S 9 9889 9889 6069 White 33
2 PM Sun 81 88 S 9 10311 10311 6491 White 35
3 PM Sun 82 88 S 9 10311 10311 6491 White 35
4 PM Sun 82 86 S 9 9889 9889 6069 White 33
5 PM Sun 82 85 S 9 9675 9675 5855 White 32
6 PM Sun 81 82 W 5 9043 9043 5223 White 29
7 PM Sun 79 79 W 5 8416 8416 4596 White 26
8 PM Sun 76 76 W 5 7787 7787 3967 White 23
9 PM Sun 72 72 W 5 6942 5892 2072 White 19
10 PM Sun 68 68 W 5 4534 3820 0 Blue 15
11 PM Sun 64 64 W 5 3224 3820 0 Blue 11
12 Midnight Mon 61 61 W 6 3000 3820 0 Blue 8
1 AM Mon 60 60 W 6 2926 3820 0 Blue 7
2 AM Mon 58 58 W 6 2777 3820 0 Blue 5
3 AM Mon 57 57 W 6 2702 3820 0 Blue 4
4 AM Mon 55 55 W 6 2553 3820 0 Blue 2

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