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

Station:

KOTX

Date/Time:

25 APR 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 Thu 40 40 N 6 2399 3820 0 Blue 1
6 AM Thu 40 40 N 6 2399 3820 0 Blue 1
7 AM Thu 42 42 N 6 2414 3820 0 Blue 3
8 AM Thu 44 44 N 6 2435 3820 0 Blue 5
9 AM Thu 47 48 N 6 2531 3820 0 Blue 9
10 AM Thu 51 53 N 6 3052 3820 0 Blue 14
11 AM Thu 55 56 NE 5 3702 3820 0 Blue 17
12 Noon Thu 57 58 NE 5 6101 3820 0 Blue 19
1 PM Thu 59 61 NE 5 9080 5929 2109 Blue 22
2 PM Thu 61 62 SE 5 9812 7130 3310 Blue 23
3 PM Thu 62 63 SE 5 9937 8111 4291 Blue 24
4 PM Thu 63 63 SE 5 9937 8111 4291 Blue 24
5 PM Thu 63 63 S 5 9937 8111 4291 Blue 24
6 PM Thu 62 62 S 5 9812 7130 3310 Blue 23
7 PM Thu 60 60 S 5 8281 4679 859 Blue 21
8 PM Thu 58 58 E 5 6101 3820 0 Blue 19
9 PM Thu 55 55 E 5 3476 3820 0 Blue 16
10 PM Thu 53 53 E 5 3052 3820 0 Blue 14
11 PM Thu 51 51 W 5 2715 3820 0 Blue 12
12 Midnight Fri 50 50 W 5 2637 3820 0 Blue 11
1 AM Fri 49 49 W 5 2561 3820 0 Blue 10
2 AM Fri 48 48 W 7 2531 3820 0 Blue 9
3 AM Fri 47 47 W 7 2502 3820 0 Blue 8
4 AM Fri 47 47 W 7 2502 3820 0 Blue 8
5 AM Fri 46 46 W 9 2472 3820 0 Blue 7
6 AM Fri 46 46 W 9 2472 3820 0 Blue 7
7 AM Fri 47 47 W 9 2502 3820 0 Blue 8
8 AM Fri 48 48 W 10 2531 3820 0 Blue 9
9 AM Fri 51 52 W 10 2840 3820 0 Blue 13
10 AM Fri 54 56 W 10 3702 3820 0 Blue 17
11 AM Fri 57 62 W 14 9812 7130 3310 Blue 23
12 Noon Fri 59 65 W 14 10192 9636 5816 Blue 26
1 PM Fri 61 67 W 14 10776 10028 6208 Blue 28
2 PM Fri 62 67 W 15 10776 10028 6208 Blue 28
3 PM Fri 62 66 W 15 10326 9904 6084 Blue 27
4 PM Fri 62 65 W 15 10192 9636 5816 Blue 26
5 PM Fri 61 62 W 16 9812 7130 3310 Blue 23
6 PM Fri 59 59 W 16 7319 3820 0 Blue 20
7 PM Fri 56 56 W 16 3702 3820 0 Blue 17
8 PM Fri 54 54 W 12 3265 3820 0 Blue 15
9 PM Fri 51 51 W 12 2715 3820 0 Blue 12
10 PM Fri 49 49 W 12 2561 3820 0 Blue 10
11 PM Fri 47 47 W 9 2502 3820 0 Blue 8
12 Midnight Sat 46 46 W 9 2472 3820 0 Blue 7
1 AM Sat 45 45 W 9 2446 3820 0 Blue 6
2 AM Sat 44 44 W 10 2435 3820 0 Blue 5
3 AM Sat 43 43 W 10 2424 3820 0 Blue 4
4 AM Sat 42 42 W 10 2414 3820 0 Blue 3
5 AM Sat 41 41 W 10 2406 3820 0 Blue 2
6 AM Sat 42 42 W 10 2414 3820 0 Blue 3
7 AM Sat 43 43 W 10 2424 3820 0 Blue 4
8 AM Sat 46 47 W 12 2502 3820 0 Blue 8
9 AM Sat 48 50 W 13 2637 3820 0 Blue 11
10 AM Sat 51 54 W 15 3265 3820 0 Blue 15
11 AM Sat 52 56 W 17 3702 3820 0 Blue 17
12 Noon Sat 53 58 W 17 6101 3820 0 Blue 19
1 PM Sat 54 59 W 18 7319 3820 0 Blue 20
2 PM Sat 54 59 NW 18 7319 3820 0 Blue 20
3 PM Sat 54 58 NW 17 6101 3820 0 Blue 19
4 PM Sat 54 56 NW 17 3702 3820 0 Blue 17
5 PM Sat 53 54 NW 17 3265 3820 0 Blue 15
6 PM Sat 51 51 NW 15 2715 3820 0 Blue 12
7 PM Sat 48 48 NW 13 2531 3820 0 Blue 9
8 PM Sat 46 46 NW 12 2472 3820 0 Blue 7
9 PM Sat 44 44 W 10 2435 3820 0 Blue 5
10 PM Sat 42 42 W 9 2414 3820 0 Blue 3
11 PM Sat 41 41 W 9 2406 3820 0 Blue 2
12 Midnight Sun 39 39 W 9 2391 3820 0 Blue 0
1 AM Sun 38 38 NW 9 0 3820 0 Blue 0
2 AM Sun 36 36 NW 9 0 3820 0 Blue 0
3 AM Sun 36 36 NW 9 0 3820 0 Blue 0
4 AM Sun 35 35 NW 9 0 3820 0 Blue 0
5 AM Sun 35 35 NW 10 0 3820 0 Blue 0
6 AM Sun 36 36 NW 10 0 3820 0 Blue 0
7 AM Sun 38 38 N 10 0 3820 0 Blue 0
8 AM Sun 40 40 N 10 2399 3820 0 Blue 1
9 AM Sun 44 45 N 9 2446 3820 0 Blue 6
10 AM Sun 47 49 NE 9 2561 3820 0 Blue 10
11 AM Sun 50 53 NE 9 3052 3820 0 Blue 14
12 Noon Sun 52 55 NE 9 3476 3820 0 Blue 16
1 PM Sun 54 57 E 8 4763 3820 0 Blue 18
2 PM Sun 55 57 E 8 4763 3820 0 Blue 18
3 PM Sun 56 58 E 8 6101 3820 0 Blue 19
4 PM Sun 57 58 E 7 6101 3820 0 Blue 19
5 PM Sun 57 58 E 7 6101 3820 0 Blue 19
6 PM Sun 55 55 E 7 3476 3820 0 Blue 16
7 PM Sun 52 52 E 7 2840 3820 0 Blue 13
8 PM Sun 49 49 SE 5 2561 3820 0 Blue 10
9 PM Sun 46 46 SE 5 2472 3820 0 Blue 7
10 PM Sun 44 44 SE 5 2435 3820 0 Blue 5
11 PM Sun 42 42 N 6 2414 3820 0 Blue 3
12 Midnight Mon 41 41 N 6 2406 3820 0 Blue 2
1 AM Mon 40 40 N 6 2399 3820 0 Blue 1
2 AM Mon 39 39 N 6 2391 3820 0 Blue 0
3 AM Mon 38 38 N 6 0 3820 0 Blue 0
4 AM Mon 37 37 N 6 0 3820 0 Blue 0
5 AM Mon 36 36 N 7 0 3820 0 Blue 0
6 AM Mon 37 37 N 7 0 3820 0 Blue 0
7 AM Mon 38 38 N 7 0 3820 0 Blue 0
8 AM Mon 40 40 N 7 2399 3820 0 Blue 1
9 AM Mon 43 44 N 7 2435 3820 0 Blue 5
10 AM Mon 46 48 N 7 2531 3820 0 Blue 9
11 AM Mon 49 52 NE 8 2840 3820 0 Blue 13
12 Noon Mon 52 55 NE 8 3476 3820 0 Blue 16
1 PM Mon 53 56 NE 8 3702 3820 0 Blue 17
2 PM Mon 55 58 NE 8 6101 3820 0 Blue 19
3 PM Mon 56 59 NE 8 7319 3820 0 Blue 20
4 PM Mon 56 58 NE 8 6101 3820 0 Blue 19
5 PM Mon 56 56 N 7 3702 3820 0 Blue 17
6 PM Mon 55 55 N 7 3476 3820 0 Blue 16
7 PM Mon 53 53 N 7 3052 3820 0 Blue 14
8 PM Mon 51 51 N 7 2715 3820 0 Blue 12
9 PM Mon 49 49 N 7 2561 3820 0 Blue 10
10 PM Mon 47 47 N 7 2502 3820 0 Blue 8
11 PM Mon 45 45 N 8 2446 3820 0 Blue 6
12 Midnight Tue 43 43 N 8 2424 3820 0 Blue 4
1 AM Tue 42 42 N 8 2414 3820 0 Blue 3
2 AM Tue 40 40 N 8 2399 3820 0 Blue 1
3 AM Tue 39 39 N 8 2391 3820 0 Blue 0
4 AM Tue 38 38 N 8 0 3820 0 Blue 0
5 AM Tue 38 38 N 8 0 3820 0 Blue 0
6 AM Tue 39 39 N 8 2391 3820 0 Blue 0
7 AM Tue 41 41 N 8 2406 3820 0 Blue 2
8 AM Tue 43 43 N 8 2424 3820 0 Blue 4
9 AM Tue 46 47 N 8 2502 3820 0 Blue 8
10 AM Tue 49 51 N 8 2715 3820 0 Blue 12
11 AM Tue 52 54 N 10 3265 3820 0 Blue 15
12 Noon Tue 53 56 N 10 3702 3820 0 Blue 17
1 PM Tue 55 58 N 10 6101 3820 0 Blue 19
2 PM Tue 56 59 N 10 7319 3820 0 Blue 20
3 PM Tue 57 59 N 10 7319 3820 0 Blue 20
4 PM Tue 58 59 N 10 7319 3820 0 Blue 20
5 PM Tue 58 58 NW 9 6101 3820 0 Blue 19
6 PM Tue 57 57 NW 9 4763 3820 0 Blue 18
7 PM Tue 54 54 NW 9 3265 3820 0 Blue 15
8 PM Tue 52 52 NW 9 2840 3820 0 Blue 13
9 PM Tue 49 49 NW 9 2561 3820 0 Blue 10
10 PM Tue 47 47 NW 9 2502 3820 0 Blue 8
11 PM Tue 46 46 NW 7 2472 3820 0 Blue 7
12 Midnight Wed 44 44 NW 7 2435 3820 0 Blue 5
1 AM Wed 42 42 NW 7 2414 3820 0 Blue 3
2 AM Wed 41 41 NW 7 2406 3820 0 Blue 2
3 AM Wed 39 39 NW 7 2391 3820 0 Blue 0
4 AM Wed 38 38 NW 7 0 3820 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 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