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

Station:

KOTX

Date/Time:

16 FEB 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)
4 AM Sat 21 21 N 1 0 3820 0 Blue 0
5 AM Sat 20 20 NW 2 0 3820 0 Blue 0
6 AM Sat 18 18 NW 2 0 3820 0 Blue 0
7 AM Sat 18 18 NW 2 0 3820 0 Blue 0
8 AM Sat 19 19 NW 2 0 3820 0 Blue 0
9 AM Sat 21 21 N 2 0 3820 0 Blue 0
10 AM Sat 23 23 N 2 0 3820 0 Blue 0
11 AM Sat 25 25 NE 2 0 3820 0 Blue 0
12 Noon Sat 26 27 NE 2 0 3820 0 Blue 0
1 PM Sat 27 28 SE 2 2622 3820 0 White 1
2 PM Sat 28 28 SE 2 2622 3820 0 White 1
3 PM Sat 28 28 SE 2 2622 3820 0 White 1
4 PM Sat 27 27 SE 2 0 3820 0 Blue 0
5 PM Sat 26 26 SE 2 0 3820 0 Blue 0
6 PM Sat 24 24 E 2 0 3820 0 Blue 0
7 PM Sat 23 23 S 2 0 3820 0 Blue 0
8 PM Sat 22 22 S 2 0 3820 0 Blue 0
9 PM Sat 21 21 W 1 0 3820 0 Blue 0
10 PM Sat 20 20 NW 1 0 3820 0 Blue 0
11 PM Sat 20 20 NW 2 0 3820 0 Blue 0
12 Midnight Sun 19 19 NW 2 0 3820 0 Blue 0
1 AM Sun 19 19 NW 2 0 3820 0 Blue 0
2 AM Sun 19 19 NW 2 0 3820 0 Blue 0
3 AM Sun 19 19 NW 2 0 3820 0 Blue 0
4 AM Sun 19 19 S 2 0 3820 0 Blue 0
5 AM Sun 19 19 S 2 0 3820 0 Blue 0
6 AM Sun 18 18 SE 2 0 3820 0 Blue 0
7 AM Sun 18 18 SE 3 0 3820 0 Blue 0
8 AM Sun 19 19 SE 6 0 3820 0 Blue 0
9 AM Sun 21 21 E 8 0 3820 0 Blue 0
10 AM Sun 23 23 NE 9 0 3820 0 Blue 0
11 AM Sun 25 25 E 8 0 3820 0 Blue 0
12 Noon Sun 26 26 E 6 0 3820 0 Blue 0
1 PM Sun 27 27 E 5 0 3820 0 Blue 0
2 PM Sun 28 28 E 6 2622 3820 0 White 1
3 PM Sun 28 28 NE 9 2622 3820 0 White 1
4 PM Sun 27 27 N 13 0 3820 0 Blue 0
5 PM Sun 25 25 N 13 0 3820 0 Blue 0
6 PM Sun 23 23 N 13 0 3820 0 Blue 0
7 PM Sun 21 21 N 13 0 3820 0 Blue 0
8 PM Sun 19 19 N 14 0 3820 0 Blue 0
9 PM Sun 18 18 N 13 0 3820 0 Blue 0
10 PM Sun 16 16 N 12 0 3820 0 Blue 0
11 PM Sun 16 16 N 10 0 3820 0 Blue 0
12 Midnight Mon 15 15 N 9 0 3820 0 Blue 0
1 AM Mon 14 14 N 8 0 3820 0 Blue 0
2 AM Mon 14 14 N 6 0 3820 0 Blue 0
3 AM Mon 13 13 N 5 0 3820 0 Blue 0
4 AM Mon 12 12 N 2 0 3820 0 Blue 0
5 AM Mon 11 11 N 2 0 3820 0 Blue 0
6 AM Mon 11 11 N 2 0 3820 0 Blue 0
7 AM Mon 11 11 N 2 0 3820 0 Blue 0
8 AM Mon 12 12 N 2 0 3820 0 Blue 0
9 AM Mon 13 13 N 2 0 3820 0 Blue 0
10 AM Mon 15 16 N 2 0 3820 0 Blue 0
11 AM Mon 17 18 NE 2 0 3820 0 Blue 0
12 Noon Mon 19 20 E 3 0 3820 0 Blue 0
1 PM Mon 20 21 SE 3 0 3820 0 Blue 0
2 PM Mon 22 23 SE 3 0 3820 0 Blue 0
3 PM Mon 22 22 SE 3 0 3820 0 Blue 0
4 PM Mon 21 21 SE 3 0 3820 0 Blue 0
5 PM Mon 19 19 SE 3 0 3820 0 Blue 0
6 PM Mon 16 16 SE 3 0 3820 0 Blue 0
7 PM Mon 14 14 SE 3 0 3820 0 Blue 0
8 PM Mon 12 12 SE 3 0 3820 0 Blue 0
9 PM Mon 10 10 S 2 0 3820 0 Blue 0
10 PM Mon 10 10 S 2 0 3820 0 Blue 0
11 PM Mon 9 9 S 2 0 3820 0 Blue 0
12 Midnight Tue 9 9 S 2 0 3820 0 Blue 0
1 AM Tue 8 8 S 2 0 3820 0 Blue 0
2 AM Tue 9 9 S 2 0 3820 0 Blue 0
3 AM Tue 9 9 SW 1 0 3820 0 Blue 0
4 AM Tue 8 8 SW 1 0 3820 0 Blue 0
5 AM Tue 8 8 W 1 0 3820 0 Blue 0
6 AM Tue 7 7 NW 2 0 3820 0 Blue 0
7 AM Tue 7 7 NW 2 0 3820 0 Blue 0
8 AM Tue 9 9 N 2 0 3820 0 Blue 0
9 AM Tue 11 11 NE 2 0 3820 0 Blue 0
10 AM Tue 13 13 E 2 0 3820 0 Blue 0
11 AM Tue 16 16 E 3 0 3820 0 Blue 0
12 Noon Tue 17 17 E 3 0 3820 0 Blue 0
1 PM Tue 18 18 E 5 0 3820 0 Blue 0
2 PM Tue 19 19 E 5 0 3820 0 Blue 0
3 PM Tue 19 19 SE 5 0 3820 0 Blue 0
4 PM Tue 18 18 SE 3 0 3820 0 Blue 0
5 PM Tue 18 18 SE 3 0 3820 0 Blue 0
6 PM Tue 17 17 SE 3 0 3820 0 Blue 0
7 PM Tue 16 16 SE 3 0 3820 0 Blue 0
8 PM Tue 15 15 SE 3 0 3820 0 Blue 0
9 PM Tue 15 15 SE 3 0 3820 0 Blue 0
10 PM Tue 15 15 NW 2 0 3820 0 Blue 0
11 PM Tue 14 14 NW 2 0 3820 0 Blue 0
12 Midnight Wed 14 14 NW 2 0 3820 0 Blue 0
1 AM Wed 13 13 NW 2 0 3820 0 Blue 0
2 AM Wed 13 13 NW 2 0 3820 0 Blue 0
3 AM Wed 12 12 NW 2 0 3820 0 Blue 0
4 AM Wed 12 12 NW 2 0 3820 0 Blue 0
5 AM Wed 12 12 NW 2 0 3820 0 Blue 0
6 AM Wed 12 12 NW 2 0 3820 0 Blue 0
7 AM Wed 13 13 NW 2 0 3820 0 Blue 0
8 AM Wed 15 15 NW 2 0 3820 0 Blue 0
9 AM Wed 17 17 NW 2 0 3820 0 Blue 0
10 AM Wed 19 19 NE 3 0 3820 0 Blue 0
11 AM Wed 21 21 NE 3 0 3820 0 Blue 0
12 Noon Wed 22 22 NE 3 0 3820 0 Blue 0
1 PM Wed 23 23 NE 3 0 3820 0 Blue 0
2 PM Wed 23 23 NE 3 0 3820 0 Blue 0
3 PM Wed 24 24 NE 3 0 3820 0 Blue 0
4 PM Wed 24 24 N 2 0 3820 0 Blue 0
5 PM Wed 22 22 N 2 0 3820 0 Blue 0
6 PM Wed 21 21 N 2 0 3820 0 Blue 0
7 PM Wed 19 19 N 2 0 3820 0 Blue 0
8 PM Wed 18 18 N 2 0 3820 0 Blue 0
9 PM Wed 18 18 N 2 0 3820 0 Blue 0
10 PM Wed 18 18 N 5 0 3820 0 Blue 0
11 PM Wed 17 17 N 5 0 3820 0 Blue 0
12 Midnight Thu 16 16 N 5 0 3820 0 Blue 0
1 AM Thu 15 15 N 5 0 3820 0 Blue 0
2 AM Thu 15 15 N 5 0 3820 0 Blue 0
3 AM Thu 15 15 N 5 0 3820 0 Blue 0
4 AM Thu 15 15 N 6 0 3820 0 Blue 0
5 AM Thu 15 15 N 6 0 3820 0 Blue 0
6 AM Thu 15 15 N 6 0 3820 0 Blue 0
7 AM Thu 15 15 N 6 0 3820 0 Blue 0
8 AM Thu 16 16 N 6 0 3820 0 Blue 0
9 AM Thu 18 18 N 6 0 3820 0 Blue 0
10 AM Thu 20 20 N 6 0 3820 0 Blue 0
11 AM Thu 23 24 N 6 0 3820 0 Blue 0
12 Noon Thu 25 26 N 6 0 3820 0 Blue 0
1 PM Thu 26 27 N 6 0 3820 0 Blue 0
2 PM Thu 27 28 N 6 2622 3820 0 White 1
3 PM Thu 27 27 N 6 0 3820 0 Blue 0
4 PM Thu 25 25 N 3 0 3820 0 Blue 0
5 PM Thu 23 23 N 3 0 3820 0 Blue 0
6 PM Thu 20 20 N 3 0 3820 0 Blue 0
7 PM Thu 18 18 N 3 0 3820 0 Blue 0
8 PM Thu 16 16 N 3 0 3820 0 Blue 0
9 PM Thu 15 15 N 3 0 3820 0 Blue 0
10 PM Thu 14 14 N 3 0 3820 0 Blue 0
11 PM Thu 14 14 N 3 0 3820 0 Blue 0
12 Midnight Fri 13 13 N 3 0 3820 0 Blue 0
1 AM Fri 13 13 N 3 0 3820 0 Blue 0
2 AM Fri 13 13 N 3 0 3820 0 Blue 0
3 AM Fri 13 13 N 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