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

Station:

KOTX

Date/Time:

17 NOV 2017

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)
4 AM Fri 31 31 SW 6 0 3820 0 Blue 0
5 AM Fri 32 32 SW 6 0 3820 0 Blue 0
6 AM Fri 33 33 SW 7 0 3820 0 Blue 0
7 AM Fri 32 32 W 7 0 3820 0 Blue 0
8 AM Fri 32 32 SW 8 0 3820 0 Blue 0
9 AM Fri 36 36 SW 10 2139 3820 0 White 0
10 AM Fri 40 40 SW 10 2139 3820 0 White 0
11 AM Fri 43 44 W 12 2904 3820 0 White 9
12 Noon Fri 44 45 W 13 3121 3820 0 White 10
1 PM Fri 45 46 W 12 3338 3820 0 White 11
2 PM Fri 45 45 W 12 3121 3820 0 White 10
3 PM Fri 43 43 W 10 2686 3820 0 White 8
4 PM Fri 41 41 W 8 2255 3820 0 White 0
5 PM Fri 38 38 W 8 2139 3820 0 White 0
6 PM Fri 35 35 W 7 2139 3820 0 White 0
7 PM Fri 33 33 W 7 0 3820 0 Blue 0
8 PM Fri 32 32 W 7 0 3820 0 Blue 0
9 PM Fri 31 31 W 7 0 3820 0 Blue 0
10 PM Fri 31 31 W 7 0 3820 0 Blue 0
11 PM Fri 31 31 SW 7 0 3820 0 Blue 0
12 Midnight Sat 31 31 W 6 0 3820 0 Blue 0
1 AM Sat 30 30 W 6 0 3820 0 Blue 0
2 AM Sat 29 29 W 6 0 3820 0 Blue 0
3 AM Sat 29 29 SW 6 0 3820 0 Blue 0
4 AM Sat 29 29 SW 6 0 3820 0 Blue 0
5 AM Sat 28 28 SW 6 0 3820 0 Blue 0
6 AM Sat 28 28 SW 5 0 3820 0 Blue 0
7 AM Sat 28 28 SW 5 0 3820 0 Blue 0
8 AM Sat 30 30 SW 5 0 3820 0 Blue 0
9 AM Sat 32 32 SW 3 0 3820 0 Blue 0
10 AM Sat 34 34 SW 3 2139 3820 0 White 0
11 AM Sat 37 37 S 3 2139 3820 0 White 0
12 Noon Sat 39 39 S 5 2139 3820 0 White 0
1 PM Sat 40 40 S 5 2139 3820 0 White 0
2 PM Sat 40 40 S 5 2139 3820 0 White 0
3 PM Sat 38 38 S 3 2139 3820 0 White 0
4 PM Sat 37 37 SE 3 2139 3820 0 White 0
5 PM Sat 35 35 SE 3 2139 3820 0 White 0
6 PM Sat 33 33 SE 3 0 3820 0 Blue 0
7 PM Sat 32 32 SE 3 0 3820 0 Blue 0
8 PM Sat 31 31 SE 3 0 3820 0 Blue 0
9 PM Sat 31 31 SE 3 0 3820 0 Blue 0
10 PM Sat 31 31 SW 2 0 3820 0 Blue 0
11 PM Sat 30 30 SW 2 0 3820 0 Blue 0
12 Midnight Sun 29 29 SW 2 0 3820 0 Blue 0
1 AM Sun 29 29 W 3 0 3820 0 Blue 0
2 AM Sun 28 28 W 3 0 3820 0 Blue 0
3 AM Sun 28 28 W 3 0 3820 0 Blue 0
4 AM Sun 27 27 SW 3 0 3820 0 Blue 0
5 AM Sun 27 27 SW 3 0 3820 0 Blue 0
6 AM Sun 27 27 SW 3 0 3820 0 Blue 0
7 AM Sun 27 27 S 6 0 3820 0 Blue 0
8 AM Sun 29 29 S 6 0 3820 0 Blue 0
9 AM Sun 30 30 S 6 0 3820 0 Blue 0
10 AM Sun 32 32 S 5 0 3820 0 Blue 0
11 AM Sun 34 34 S 5 2139 3820 0 White 0
12 Noon Sun 35 35 S 5 2139 3820 0 White 0
1 PM Sun 36 36 S 9 2139 3820 0 White 0
2 PM Sun 36 36 S 9 2139 3820 0 White 0
3 PM Sun 36 36 S 9 2139 3820 0 White 0
4 PM Sun 35 35 S 6 2139 3820 0 White 0
5 PM Sun 34 34 S 6 2139 3820 0 White 0
6 PM Sun 32 32 S 6 0 3820 0 Blue 0
7 PM Sun 32 32 S 6 0 3820 0 Blue 0
8 PM Sun 33 33 S 6 0 3820 0 Blue 0
9 PM Sun 34 34 S 6 2139 3820 0 White 0
10 PM Sun 35 35 SW 5 2139 3820 0 White 0
11 PM Sun 34 34 SW 5 2139 3820 0 White 0
12 Midnight Mon 33 33 SW 5 0 3820 0 Blue 0
1 AM Mon 32 32 SW 5 0 3820 0 Blue 0
2 AM Mon 32 32 SW 5 0 3820 0 Blue 0
3 AM Mon 32 32 SW 5 0 3820 0 Blue 0
4 AM Mon 32 32 W 3 0 3820 0 Blue 0
5 AM Mon 31 31 W 3 0 3820 0 Blue 0
6 AM Mon 29 29 W 3 0 3820 0 Blue 0
7 AM Mon 29 29 W 3 0 3820 0 Blue 0
8 AM Mon 29 29 W 3 0 3820 0 Blue 0
9 AM Mon 31 31 W 3 0 3820 0 Blue 0
10 AM Mon 32 32 NW 3 0 3820 0 Blue 0
11 AM Mon 34 34 NW 3 2139 3820 0 White 0
12 Noon Mon 35 35 NW 3 2139 3820 0 White 0
1 PM Mon 36 36 NW 3 2139 3820 0 White 0
2 PM Mon 36 36 NW 3 2139 3820 0 White 0
3 PM Mon 35 35 NW 3 2139 3820 0 White 0
4 PM Mon 34 34 W 7 2139 3820 0 White 0
5 PM Mon 33 33 W 7 0 3820 0 Blue 0
6 PM Mon 31 31 W 7 0 3820 0 Blue 0
7 PM Mon 30 30 W 7 0 3820 0 Blue 0
8 PM Mon 29 29 W 7 0 3820 0 Blue 0
9 PM Mon 29 29 W 7 0 3820 0 Blue 0
10 PM Mon 29 29 NW 5 0 3820 0 Blue 0
11 PM Mon 29 29 NW 5 0 3820 0 Blue 0
12 Midnight Tue 28 28 NW 5 0 3820 0 Blue 0
1 AM Tue 28 28 NW 5 0 3820 0 Blue 0
2 AM Tue 28 28 NW 5 0 3820 0 Blue 0
3 AM Tue 28 28 NW 5 0 3820 0 Blue 0
4 AM Tue 28 28 N 3 0 3820 0 Blue 0
5 AM Tue 28 28 N 3 0 3820 0 Blue 0
6 AM Tue 28 28 N 3 0 3820 0 Blue 0
7 AM Tue 28 28 N 3 0 3820 0 Blue 0
8 AM Tue 28 28 N 3 0 3820 0 Blue 0
9 AM Tue 28 28 N 3 0 3820 0 Blue 0
10 AM Tue 28 28 N 3 0 3820 0 Blue 0
11 AM Tue 30 30 N 3 0 3820 0 Blue 0
12 Noon Tue 32 32 N 3 0 3820 0 Blue 0
1 PM Tue 34 34 N 3 2139 3820 0 White 0
2 PM Tue 35 35 N 3 2139 3820 0 White 0
3 PM Tue 35 35 N 3 2139 3820 0 White 0
4 PM Tue 34 34 N 2 2139 3820 0 White 0
5 PM Tue 33 33 N 2 0 3820 0 Blue 0
6 PM Tue 31 31 N 2 0 3820 0 Blue 0
7 PM Tue 30 30 N 2 0 3820 0 Blue 0
8 PM Tue 30 30 N 2 0 3820 0 Blue 0
9 PM Tue 30 30 N 2 0 3820 0 Blue 0
10 PM Tue 30 30 N 2 0 3820 0 Blue 0
11 PM Tue 31 31 N 2 0 3820 0 Blue 0
12 Midnight Wed 31 31 N 2 0 3820 0 Blue 0
1 AM Wed 30 30 N 2 0 3820 0 Blue 0
2 AM Wed 30 30 N 2 0 3820 0 Blue 0
3 AM Wed 30 30 N 2 0 3820 0 Blue 0
4 AM Wed 30 30 S 2 0 3820 0 Blue 0
5 AM Wed 30 30 S 2 0 3820 0 Blue 0
6 AM Wed 31 31 S 2 0 3820 0 Blue 0
7 AM Wed 32 32 S 2 0 3820 0 Blue 0
8 AM Wed 33 33 S 2 0 3820 0 Blue 0
9 AM Wed 34 34 S 2 2139 3820 0 White 0
10 AM Wed 36 36 SE 3 2139 3820 0 White 0
11 AM Wed 37 37 SE 3 2139 3820 0 White 0
12 Noon Wed 38 38 SE 3 2139 3820 0 White 0
1 PM Wed 39 39 SE 3 2139 3820 0 White 0
2 PM Wed 39 39 SE 3 2139 3820 0 White 0
3 PM Wed 39 39 SE 3 2139 3820 0 White 0
4 PM Wed 38 38 SW 6 2139 3820 0 White 0
5 PM Wed 38 38 SW 6 2139 3820 0 White 0
6 PM Wed 37 37 SW 6 2139 3820 0 White 0
7 PM Wed 37 37 SW 6 2139 3820 0 White 0
8 PM Wed 37 37 SW 6 2139 3820 0 White 0
9 PM Wed 37 37 SW 6 2139 3820 0 White 0
10 PM Wed 37 37 SW 8 2139 3820 0 White 0
11 PM Wed 37 37 SW 8 2139 3820 0 White 0
12 Midnight Thu 36 36 SW 8 2139 3820 0 White 0
1 AM Thu 36 36 SW 8 2139 3820 0 White 0
2 AM Thu 36 36 SW 8 2139 3820 0 White 0
3 AM Thu 36 36 SW 8 2139 3820 0 White 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