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

Station:

 KOTX

Date/Time:

 4 FEB 2012

Temp/Wind data from:

NOAA Digital Forecast

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 NW 5 0 3820 0 Blue 0
5 AM Sat 20 20 NW 5 0 3820 0 Blue 0
6 AM Sat 20 20 NW 5 0 3820 0 Blue 0
7 AM Sat 20 20 NW 5 0 3820 0 Blue 0
8 AM Sat 23 23 NW 5 0 3820 0 Blue 0
9 AM Sat 27 27 NW 5 0 3820 0 Blue 0
10 AM Sat 30 30 N 2 2488 3820 0 Blue 2
11 AM Sat 33 34 N 2 2790 3820 0 Blue 6
12 Noon Sat 34 35 N 2 2904 3820 0 Blue 7
1 PM Sat 34 35 N 2 2904 3820 0 Blue 7
2 PM Sat 35 36 N 2 3060 3820 0 Blue 8
3 PM Sat 34 34 N 2 2790 3820 0 Blue 6
4 PM Sat 33 33 N 3 2680 3820 0 Blue 5
5 PM Sat 31 31 N 3 2533 3820 0 Blue 3
6 PM Sat 29 29 N 3 2443 3820 0 Blue 1
7 PM Sat 27 27 NW 3 0 3820 0 Blue 0
8 PM Sat 26 26 NW 3 0 3820 0 Blue 0
9 PM Sat 25 25 NW 3 0 3820 0 Blue 0
10 PM Sat 24 24 NW 3 0 3820 0 Blue 0
11 PM Sat 23 23 NW 3 0 3820 0 Blue 0
12 Midnight Sun 22 22 NW 3 0 3820 0 Blue 0
1 AM Sun 21 21 NW 3 0 3820 0 Blue 0
2 AM Sun 20 20 NW 3 0 3820 0 Blue 0
3 AM Sun 20 20 NW 3 0 3820 0 Blue 0
4 AM Sun 20 20 NW 5 0 3820 0 Blue 0
5 AM Sun 20 20 NW 5 0 3820 0 Blue 0
6 AM Sun 21 21 NW 5 0 3820 0 Blue 0
7 AM Sun 22 22 NW 5 0 3820 0 Blue 0
8 AM Sun 25 25 NW 5 0 3820 0 Blue 0
9 AM Sun 29 29 NW 5 2443 3820 0 Blue 1
10 AM Sun 32 32 N 2 2577 3820 0 Blue 4
11 AM Sun 34 34 N 2 2790 3820 0 Blue 6
12 Noon Sun 35 35 N 2 2904 3820 0 Blue 7
1 PM Sun 36 36 N 2 3060 3820 0 Blue 8
2 PM Sun 37 37 N 2 3217 3820 0 Blue 9
3 PM Sun 37 37 N 2 3217 3820 0 Blue 9
4 PM Sun 36 36 N 2 3060 3820 0 Blue 8
5 PM Sun 35 35 N 2 2904 3820 0 Blue 7
6 PM Sun 33 33 N 2 2680 3820 0 Blue 5
7 PM Sun 31 31 N 2 2533 3820 0 Blue 3
8 PM Sun 30 30 N 2 2488 3820 0 Blue 2
9 PM Sun 28 28 N 2 2398 3820 0 Blue 0
10 PM Sun 27 27 NW 6 0 3820 0 Blue 0
11 PM Sun 26 26 NW 6 0 3820 0 Blue 0
12 Midnight Mon 25 25 NW 6 0 3820 0 Blue 0
1 AM Mon 24 24 NW 6 0 3820 0 Blue 0
2 AM Mon 23 23 NW 6 0 3820 0 Blue 0
3 AM Mon 24 24 NW 6 0 3820 0 Blue 0
4 AM Mon 24 24 NW 6 0 3820 0 Blue 0
5 AM Mon 23 23 NW 6 0 3820 0 Blue 0
6 AM Mon 23 23 NW 6 0 3820 0 Blue 0
7 AM Mon 24 24 NW 6 0 3820 0 Blue 0
8 AM Mon 26 26 NW 6 0 3820 0 Blue 0
9 AM Mon 29 29 NW 6 2443 3820 0 Blue 1
10 AM Mon 32 32 N 3 2577 3820 0 Blue 4
11 AM Mon 34 34 N 3 2790 3820 0 Blue 6
12 Noon Mon 35 35 N 3 2904 3820 0 Blue 7
1 PM Mon 35 35 N 3 2904 3820 0 Blue 7
2 PM Mon 36 36 N 3 3060 3820 0 Blue 8
3 PM Mon 36 36 N 3 3060 3820 0 Blue 8
4 PM Mon 35 35 N 3 2904 3820 0 Blue 7
5 PM Mon 32 32 N 3 2577 3820 0 Blue 4
6 PM Mon 29 29 N 3 2443 3820 0 Blue 1
7 PM Mon 27 27 N 3 0 3820 0 Blue 0
8 PM Mon 25 25 N 3 0 3820 0 Blue 0
9 PM Mon 25 25 N 3 0 3820 0 Blue 0
10 PM Mon 25 25 N 5 0 3820 0 Blue 0
11 PM Mon 25 25 N 5 0 3820 0 Blue 0
12 Midnight Tue 25 25 N 5 0 3820 0 Blue 0
1 AM Tue 25 25 N 5 0 3820 0 Blue 0
2 AM Tue 24 24 N 5 0 3820 0 Blue 0
3 AM Tue 24 24 N 5 0 3820 0 Blue 0
4 AM Tue 23 23 N 3 0 3820 0 Blue 0
5 AM Tue 22 22 N 3 0 3820 0 Blue 0
6 AM Tue 21 21 N 3 0 3820 0 Blue 0
7 AM Tue 22 22 N 3 0 3820 0 Blue 0
8 AM Tue 25 25 N 3 0 3820 0 Blue 0
9 AM Tue 29 29 N 3 2443 3820 0 Blue 1
10 AM Tue 33 33 N 2 2680 3820 0 Blue 5
11 AM Tue 34 34 N 2 2790 3820 0 Blue 6
12 Noon Tue 34 34 N 2 2790 3820 0 Blue 6
1 PM Tue 34 34 N 2 2790 3820 0 Blue 6
2 PM Tue 34 34 N 2 2790 3820 0 Blue 6
3 PM Tue 33 33 N 2 2680 3820 0 Blue 5
4 PM Tue 32 32 N 1 2577 3820 0 Blue 4
5 PM Tue 31 31 N 1 2533 3820 0 Blue 3
6 PM Tue 29 29 N 1 2443 3820 0 Blue 1
7 PM Tue 28 28 N 1 2398 3820 0 Blue 0
8 PM Tue 27 27 N 1 0 3820 0 Blue 0
9 PM Tue 25 25 N 1 0 3820 0 Blue 0
10 PM Tue 24 24 NW 2 0 3820 0 Blue 0
11 PM Tue 24 24 NW 2 0 3820 0 Blue 0
12 Midnight Wed 23 23 NW 2 0 3820 0 Blue 0
1 AM Wed 23 23 NW 2 0 3820 0 Blue 0
2 AM Wed 23 23 NW 2 0 3820 0 Blue 0
3 AM Wed 23 23 NW 2 0 3820 0 Blue 0
4 AM Wed 24 24 N 1 0 3820 0 Blue 0
5 AM Wed 25 25 N 1 0 3820 0 Blue 0
6 AM Wed 27 27 N 1 0 3820 0 Blue 0
7 AM Wed 29 29 N 1 2443 3820 0 Blue 1
8 AM Wed 31 31 N 1 2533 3820 0 Blue 3
9 AM Wed 33 33 N 1 2680 3820 0 Blue 5
10 AM Wed 35 35 NE 1 2904 3820 0 Blue 7
11 AM Wed 36 36 NE 1 3060 3820 0 Blue 8
12 Noon Wed 37 38 NE 1 3331 3820 0 Blue 10
1 PM Wed 37 37 NE 1 3217 3820 0 Blue 9
2 PM Wed 37 37 NE 1 3217 3820 0 Blue 9
3 PM Wed 36 36 NE 1 3060 3820 0 Blue 8
4 PM Wed 35 35 E 1 2904 3820 0 Blue 7
5 PM Wed 34 34 E 1 2790 3820 0 Blue 6
6 PM Wed 32 32 E 1 2577 3820 0 Blue 4
7 PM Wed 31 31 E 1 2533 3820 0 Blue 3
8 PM Wed 29 29 E 1 2443 3820 0 Blue 1
9 PM Wed 27 27 E 1 0 3820 0 Blue 0
10 PM Wed 26 26 NW 1 0 3820 0 Blue 0
11 PM Wed 26 26 NW 1 0 3820 0 Blue 0
12 Midnight Thu 25 25 NW 1 0 3820 0 Blue 0
1 AM Thu 26 26 NW 1 0 3820 0 Blue 0
2 AM Thu 26 26 NW 1 0 3820 0 Blue 0
3 AM Thu 27 27 NW 1 0 3820 0 Blue 0
4 AM Thu 27 27 N 2 0 3820 0 Blue 0
5 AM Thu 28 28 N 2 2398 3820 0 Blue 0
6 AM Thu 30 30 N 2 2488 3820 0 Blue 2
7 AM Thu 31 31 N 2 2533 3820 0 Blue 3
8 AM Thu 32 32 N 2 2577 3820 0 Blue 4
9 AM Thu 34 34 N 2 2790 3820 0 Blue 6
10 AM Thu 35 35 N 1 2904 3820 0 Blue 7
11 AM Thu 35 35 N 1 2904 3820 0 Blue 7
12 Noon Thu 36 36 N 1 3060 3820 0 Blue 8
1 PM Thu 36 36 N 1 3060 3820 0 Blue 8
2 PM Thu 36 36 N 1 3060 3820 0 Blue 8
3 PM Thu 36 36 N 1 3060 3820 0 Blue 8
4 PM Thu 36 36 NE 2 3060 3820 0 Blue 8
5 PM Thu 35 35 NE 2 2904 3820 0 Blue 7
6 PM Thu 33 33 NE 2 2680 3820 0 Blue 5
7 PM Thu 32 32 NE 2 2577 3820 0 Blue 4
8 PM Thu 30 30 NE 2 2488 3820 0 Blue 2
9 PM Thu 29 29 NE 2 2443 3820 0 Blue 1
10 PM Thu 28 28 N 2 2398 3820 0 Blue 0
11 PM Thu 27 27 N 2 0 3820 0 Blue 0
12 Midnight Fri 26 26 N 2 0 3820 0 Blue 0
1 AM Fri 25 25 N 2 0 3820 0 Blue 0
2 AM Fri 24 24 N 2 0 3820 0 Blue 0
3 AM Fri 24 24 N 2 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