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

Station:

KOTX

Date/Time:

18 OCT 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 Fri 41 41 W 9 0 3820 0 Blue 0
6 AM Fri 40 40 W 9 0 3820 0 Blue 0
7 AM Fri 39 39 SW 9 0 3820 0 Blue 0
8 AM Fri 39 39 SW 9 0 3820 0 Blue 0
9 AM Fri 41 41 W 10 0 3820 0 Blue 0
10 AM Fri 44 44 W 10 2750 3820 0 Blue 2
11 AM Fri 47 48 W 13 3271 3820 0 Blue 6
12 Noon Fri 49 50 SW 12 4044 3820 0 Blue 8
1 PM Fri 50 51 SW 13 4492 3820 0 White 9
2 PM Fri 51 52 SW 13 4712 3820 0 White 10
3 PM Fri 51 51 SW 13 4492 3820 0 White 9
4 PM Fri 50 50 SW 12 4044 3820 0 Blue 8
5 PM Fri 49 49 SW 10 3518 3820 0 Blue 7
6 PM Fri 47 47 SW 9 3181 3820 0 Blue 5
7 PM Fri 46 46 SW 9 3090 3820 0 Blue 4
8 PM Fri 45 45 SW 8 2997 3820 0 Blue 3
9 PM Fri 44 44 SW 8 2750 3820 0 Blue 2
10 PM Fri 43 43 SW 7 2568 3820 0 Blue 1
11 PM Fri 42 42 SW 7 0 3820 0 Blue 0
12 Midnight Sat 42 42 S 7 0 3820 0 Blue 0
1 AM Sat 42 42 S 7 0 3820 0 Blue 0
2 AM Sat 41 41 S 7 0 3820 0 Blue 0
3 AM Sat 41 41 S 6 0 3820 0 Blue 0
4 AM Sat 41 41 S 6 0 3820 0 Blue 0
5 AM Sat 40 40 S 5 0 3820 0 Blue 0
6 AM Sat 40 40 S 5 0 3820 0 Blue 0
7 AM Sat 39 39 S 5 0 3820 0 Blue 0
8 AM Sat 39 39 W 3 0 3820 0 Blue 0
9 AM Sat 40 40 W 3 0 3820 0 Blue 0
10 AM Sat 42 42 W 5 0 3820 0 Blue 0
11 AM Sat 44 44 NW 3 2750 3820 0 Blue 2
12 Noon Sat 46 46 W 3 3090 3820 0 Blue 4
1 PM Sat 47 47 W 5 3181 3820 0 Blue 5
2 PM Sat 48 48 W 7 3271 3820 0 Blue 6
3 PM Sat 48 48 W 8 3271 3820 0 Blue 6
4 PM Sat 47 47 W 8 3181 3820 0 Blue 5
5 PM Sat 47 47 W 10 3181 3820 0 Blue 5
6 PM Sat 46 46 W 12 3090 3820 0 Blue 4
7 PM Sat 45 45 W 12 2997 3820 0 Blue 3
8 PM Sat 44 44 W 12 2750 3820 0 Blue 2
9 PM Sat 43 43 W 8 2568 3820 0 Blue 1
10 PM Sat 42 42 W 7 0 3820 0 Blue 0
11 PM Sat 41 41 W 7 0 3820 0 Blue 0
12 Midnight Sun 40 40 W 6 0 3820 0 Blue 0
1 AM Sun 39 39 W 5 0 3820 0 Blue 0
2 AM Sun 38 38 W 5 0 3820 0 Blue 0
3 AM Sun 38 38 W 5 0 3820 0 Blue 0
4 AM Sun 37 37 W 3 0 3820 0 Blue 0
5 AM Sun 36 36 W 3 0 3820 0 Blue 0
6 AM Sun 35 35 W 3 0 3820 0 Blue 0
7 AM Sun 35 35 W 2 0 3820 0 Blue 0
8 AM Sun 36 36 W 2 0 3820 0 Blue 0
9 AM Sun 38 38 W 2 0 3820 0 Blue 0
10 AM Sun 40 40 SW 2 0 3820 0 Blue 0
11 AM Sun 43 43 SW 2 2568 3820 0 Blue 1
12 Noon Sun 45 45 SW 3 2997 3820 0 Blue 3
1 PM Sun 46 46 SW 3 3090 3820 0 Blue 4
2 PM Sun 47 47 SW 5 3181 3820 0 Blue 5
3 PM Sun 48 48 SW 5 3271 3820 0 Blue 6
4 PM Sun 48 48 SW 5 3271 3820 0 Blue 6
5 PM Sun 47 47 SW 3 3181 3820 0 Blue 5
6 PM Sun 46 46 SW 3 3090 3820 0 Blue 4
7 PM Sun 44 44 SW 3 2750 3820 0 Blue 2
8 PM Sun 43 43 SW 3 2568 3820 0 Blue 1
9 PM Sun 43 43 SW 3 2568 3820 0 Blue 1
10 PM Sun 43 43 SW 3 2568 3820 0 Blue 1
11 PM Sun 43 43 SW 3 2568 3820 0 Blue 1
12 Midnight Mon 43 43 SW 3 2568 3820 0 Blue 1
1 AM Mon 41 41 SW 3 0 3820 0 Blue 0
2 AM Mon 41 41 SW 3 0 3820 0 Blue 0
3 AM Mon 41 41 SW 3 0 3820 0 Blue 0
4 AM Mon 41 41 SW 3 0 3820 0 Blue 0
5 AM Mon 41 41 W 2 0 3820 0 Blue 0
6 AM Mon 40 40 W 2 0 3820 0 Blue 0
7 AM Mon 39 39 W 2 0 3820 0 Blue 0
8 AM Mon 39 39 W 2 0 3820 0 Blue 0
9 AM Mon 42 42 W 2 0 3820 0 Blue 0
10 AM Mon 45 45 W 2 2997 3820 0 Blue 3
11 AM Mon 48 48 SW 3 3271 3820 0 Blue 6
12 Noon Mon 49 49 SW 3 3518 3820 0 Blue 7
1 PM Mon 50 50 SW 3 4044 3820 0 Blue 8
2 PM Mon 51 51 SW 3 4492 3820 0 White 9
3 PM Mon 51 51 SW 3 4492 3820 0 White 9
4 PM Mon 51 51 SW 3 4492 3820 0 White 9
5 PM Mon 51 51 S 2 4492 3820 0 White 9
6 PM Mon 50 50 S 2 4044 3820 0 Blue 8
7 PM Mon 48 48 S 2 3271 3820 0 Blue 6
8 PM Mon 47 47 S 2 3181 3820 0 Blue 5
9 PM Mon 46 46 S 2 3090 3820 0 Blue 4
10 PM Mon 46 46 S 2 3090 3820 0 Blue 4
11 PM Mon 46 46 W 2 3090 3820 0 Blue 4
12 Midnight Tue 46 46 W 2 3090 3820 0 Blue 4
1 AM Tue 46 46 W 2 3090 3820 0 Blue 4
2 AM Tue 46 46 W 2 3090 3820 0 Blue 4
3 AM Tue 45 45 W 2 2997 3820 0 Blue 3
4 AM Tue 44 44 W 2 2750 3820 0 Blue 2
5 AM Tue 43 43 W 2 2568 3820 0 Blue 1
6 AM Tue 43 43 W 2 2568 3820 0 Blue 1
7 AM Tue 43 43 W 2 2568 3820 0 Blue 1
8 AM Tue 45 45 W 2 2997 3820 0 Blue 3
9 AM Tue 46 46 W 2 3090 3820 0 Blue 4
10 AM Tue 49 49 W 2 3518 3820 0 Blue 7
11 AM Tue 51 51 W 6 4492 3820 0 White 9
12 Noon Tue 53 54 W 6 5143 4732 912 White 12
1 PM Tue 54 55 W 6 5359 5359 1539 White 13
2 PM Tue 55 56 W 6 5573 5573 1753 White 14
3 PM Tue 55 55 W 6 5359 5359 1539 White 13
4 PM Tue 54 54 W 6 5143 4732 912 White 12
5 PM Tue 53 53 W 6 4928 4011 191 White 11
6 PM Tue 51 51 W 6 4492 3820 0 White 9
7 PM Tue 49 49 W 6 3518 3820 0 Blue 7
8 PM Tue 47 47 W 6 3181 3820 0 Blue 5
9 PM Tue 45 45 W 6 2997 3820 0 Blue 3
10 PM Tue 43 43 W 6 2568 3820 0 Blue 1
11 PM Tue 42 42 W 6 0 3820 0 Blue 0
12 Midnight Wed 41 41 W 6 0 3820 0 Blue 0
1 AM Wed 41 41 W 6 0 3820 0 Blue 0
2 AM Wed 41 41 W 6 0 3820 0 Blue 0
3 AM Wed 40 40 W 6 0 3820 0 Blue 0
4 AM Wed 40 40 W 6 0 3820 0 Blue 0
5 AM Wed 39 39 W 7 0 3820 0 Blue 0
6 AM Wed 38 38 W 7 0 3820 0 Blue 0
7 AM Wed 38 38 W 7 0 3820 0 Blue 0
8 AM Wed 39 39 W 7 0 3820 0 Blue 0
9 AM Wed 40 40 W 7 0 3820 0 Blue 0
10 AM Wed 43 43 W 7 2568 3820 0 Blue 1
11 AM Wed 46 47 W 13 3181 3820 0 Blue 5
12 Noon Wed 48 50 W 13 4044 3820 0 Blue 8
1 PM Wed 49 51 W 13 4492 3820 0 White 9
2 PM Wed 51 52 W 13 4712 3820 0 White 10
3 PM Wed 51 52 W 13 4712 3820 0 White 10
4 PM Wed 51 51 W 13 4492 3820 0 White 9
5 PM Wed 49 49 W 5 3518 3820 0 Blue 7
6 PM Wed 47 47 W 5 3181 3820 0 Blue 5
7 PM Wed 45 45 W 5 2997 3820 0 Blue 3
8 PM Wed 42 42 W 5 0 3820 0 Blue 0
9 PM Wed 41 41 W 5 0 3820 0 Blue 0
10 PM Wed 40 40 W 5 0 3820 0 Blue 0
11 PM Wed 39 39 W 3 0 3820 0 Blue 0
12 Midnight Thu 38 38 W 3 0 3820 0 Blue 0
1 AM Thu 38 38 W 3 0 3820 0 Blue 0
2 AM Thu 37 37 W 3 0 3820 0 Blue 0
3 AM Thu 37 37 W 3 0 3820 0 Blue 0
4 AM Thu 37 37 W 3 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