Detailed Predictions for: Chelan
Launch Lat, Long, Altitude (f): 47.80712500000001, -120.0336861111111, 3820
LZ Altitude (f): 1200
Sounding

Station:

 KOTX

Date/Time:

 11 DEC 2023

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)		 High
Temp
Puddle
Temp
Wind
 (mph)		 Wind
 Gust		 Thermal
Ceiling
(ft)		 Soaring
Ceiling
(ft)		 Above
Launch
(ft)		 Thermal
Type		 Thermal
Index
(F)
12 Midnight Mon 31 31 NE 4 5 0 3820 0 Blue 0
1 AM Mon 31 31 ENE 4 5 0 3820 0 Blue 0
2 AM Mon 30 30 NE 3 5 0 3820 0 Blue 0
3 AM Mon 31 31 NE 4 5 0 3820 0 Blue 0
4 AM Mon 30 30 NE 4 5 0 3820 0 Blue 0
5 AM Mon 30 30 NE 4 6 0 3820 0 Blue 0
6 AM Mon 30 30 NE 4 5 0 3820 0 Blue 0
7 AM Mon 30 30 NE 4 5 0 3820 0 Blue 0
8 AM Mon 30 30 NE 4 6 0 3820 0 Blue 0
9 AM Mon 31 31 NNE 4 5 0 3820 0 Blue 0
10 AM Mon 32 32 NNE 3 5 0 3820 0 Blue 0
11 AM Mon 34 34 NNE 4 5 2135 3820 0 White 0
12 Noon Mon 35 35 NNE 4 5 2213 3820 0 White 0
1 PM Mon 36 36 NNE 4 5 2431 3820 0 White 2
2 PM Mon 35 35 NW 3 5 2213 3820 0 White 0
3 PM Mon 36 36 WNW 3 5 2431 3820 0 White 2
4 PM Mon 35 35 N 3 5 2213 3820 0 White 0
5 PM Mon 34 34 ENE 2 4 2135 3820 0 White 0
6 PM Mon 33 33 NE 3 5 0 3820 0 Blue 0
7 PM Mon 33 33 NE 3 5 0 3820 0 Blue 0
8 PM Mon 32 32 NE 3 5 0 3820 0 Blue 0
9 PM Mon 32 32 NE 3 5 0 3820 0 Blue 0
10 PM Mon 32 32 WNW 2 4 0 3820 0 Blue 0
11 PM Mon 32 32 N 2 4 0 3820 0 Blue 0
12 Midnight Tue 32 32 NNE 2 4 0 3820 0 Blue 0
1 AM Tue 32 32 N 3 4 0 3820 0 Blue 0
2 AM Tue 32 32 NW 3 5 0 3820 0 Blue 0
3 AM Tue 32 32 WNW 3 4 0 3820 0 Blue 0
4 AM Tue 31 31 NNW 2 4 0 3820 0 Blue 0
5 AM Tue 31 31 W 3 4 0 3820 0 Blue 0
6 AM Tue 31 31 N 3 5 0 3820 0 Blue 0
7 AM Tue 30 30 N 2 4 0 3820 0 Blue 0
8 AM Tue 31 31 NNW 3 4 0 3820 0 Blue 0
9 AM Tue 31 31 NNW 3 4 0 3820 0 Blue 0
10 AM Tue 32 32 NNE 2 4 0 3820 0 Blue 0
11 AM Tue 33 33 NNE 2 4 0 3820 0 Blue 0
12 Noon Tue 34 34 NNE 2 4 2135 3820 0 White 0
1 PM Tue 34 34 NE 3 4 2135 3820 0 White 0
2 PM Tue 34 34 NE 3 4 2135 3820 0 White 0
3 PM Tue 33 33 NE 3 4 0 3820 0 Blue 0
4 PM Tue 33 33 NE 3 5 0 3820 0 Blue 0
5 PM Tue 33 33 NE 3 5 0 3820 0 Blue 0
6 PM Tue 34 34 NE 3 5 2135 3820 0 White 0
7 PM Tue 34 34 NNE 4 5 2135 3820 0 White 0
8 PM Tue 34 34 NNE 4 5 2135 3820 0 White 0
9 PM Tue 34 34 NNE 4 5 2135 3820 0 White 0
10 PM Tue 34 34 N 3 5 2135 3820 0 White 0
11 PM Tue 34 34 N 3 5 2135 3820 0 White 0
12 Midnight Wed 34 34 N 3 5 2135 3820 0 White 0
1 AM Wed 34 34 N 3 5 2135 3820 0 White 0
2 AM Wed 34 34 N 3 5 2135 3820 0 White 0
3 AM Wed 34 34 N 3 5 2135 3820 0 White 0
4 AM Wed 34 34 NE 3 5 2135 3820 0 White 0
5 AM Wed 34 34 NE 3 5 2135 3820 0 White 0
6 AM Wed 33 33 NE 3 5 0 3820 0 Blue 0
7 AM Wed 33 33 ENE 3 5 0 3820 0 Blue 0
8 AM Wed 33 33 ENE 3 5 0 3820 0 Blue 0
9 AM Wed 32 32 ENE 3 5 0 3820 0 Blue 0
10 AM Wed 32 32 E 4 5 0 3820 0 Blue 0
11 AM Wed 33 33 E 4 5 0 3820 0 Blue 0
12 Noon Wed 33 33 E 4 5 0 3820 0 Blue 0
1 PM Wed 34 34 ESE 4 5 2135 3820 0 White 0
2 PM Wed 34 34 ESE 4 5 2135 3820 0 White 0
3 PM Wed 33 33 ESE 4 5 0 3820 0 Blue 0
4 PM Wed 33 33 E 5 8 0 3820 0 Blue 0
5 PM Wed 33 33 E 5 8 0 3820 0 Blue 0
6 PM Wed 34 34 E 5 8 2135 3820 0 White 0
7 PM Wed 34 34 ENE 4 6 2135 3820 0 White 0
8 PM Wed 34 34 ENE 4 6 2135 3820 0 White 0
9 PM Wed 34 34 ENE 4 6 2135 3820 0 White 0
10 PM Wed 34 34 NNE 4 5 2135 3820 0 White 0
11 PM Wed 33 33 NNE 4 5 0 3820 0 Blue 0
12 Midnight Thu 33 33 NNE 4 5 0 3820 0 Blue 0
1 AM Thu 32 32 NNE 3 5 0 3820 0 Blue 0
2 AM Thu 32 32 NNE 3 5 0 3820 0 Blue 0
3 AM Thu 32 32 NNE 3 5 0 3820 0 Blue 0
4 AM Thu 32 32 NNE 3 5 0 3820 0 Blue 0
5 AM Thu 32 32 NNE 3 5 0 3820 0 Blue 0
6 AM Thu 31 31 NNE 3 5 0 3820 0 Blue 0
7 AM Thu 31 31 N 3 5 0 3820 0 Blue 0
8 AM Thu 31 31 N 3 5 0 3820 0 Blue 0
9 AM Thu 32 32 N 3 5 0 3820 0 Blue 0
10 AM Thu 33 33 N 4 5 0 3820 0 Blue 0
11 AM Thu 33 33 N 4 5 0 3820 0 Blue 0
12 Noon Thu 34 34 N 4 5 2135 3820 0 White 0
1 PM Thu 34 34 NE 5 8 2135 3820 0 White 0
2 PM Thu 34 34 NE 5 8 2135 3820 0 White 0
3 PM Thu 34 34 NE 5 8 2135 3820 0 White 0
4 PM Thu 34 34 NNE 5 6 2135 3820 0 White 0
5 PM Thu 33 33 NNE 5 6 0 3820 0 Blue 0
6 PM Thu 33 33 NNE 5 6 0 3820 0 Blue 0
7 PM Thu 32 32 N 5 8 0 3820 0 Blue 0
8 PM Thu 32 32 N 5 8 0 3820 0 Blue 0
9 PM Thu 32 32 N 5 8 0 3820 0 Blue 0
10 PM Thu 32 32 NNW 5 8 0 3820 0 Blue 0
11 PM Thu 32 32 NNW 5 8 0 3820 0 Blue 0
12 Midnight Fri 31 31 NNW 5 8 0 3820 0 Blue 0
1 AM Fri 31 31 NNW 4 8 0 3820 0 Blue 0
2 AM Fri 31 31 NNW 4 8 0 3820 0 Blue 0
3 AM Fri 31 31 NNW 4 8 0 3820 0 Blue 0
4 AM Fri 31 31 NNW 5 6 0 3820 0 Blue 0
5 AM Fri 31 31 NNW 5 6 0 3820 0 Blue 0
6 AM Fri 30 30 NNW 5 6 0 3820 0 Blue 0
7 AM Fri 30 30 NNW 4 8 0 3820 0 Blue 0
8 AM Fri 30 30 NNW 4 8 0 3820 0 Blue 0
9 AM Fri 31 31 NNW 4 8 0 3820 0 Blue 0
10 AM Fri 32 32 NNW 5 8 0 3820 0 Blue 0
11 AM Fri 33 33 NNW 5 8 0 3820 0 Blue 0
12 Noon Fri 34 34 NNW 5 8 2135 3820 0 White 0
1 PM Fri 34 34 N 4 8 2135 3820 0 White 0
2 PM Fri 34 34 N 4 8 2135 3820 0 White 0
3 PM Fri 34 34 N 4 8 2135 3820 0 White 0
4 PM Fri 33 33 NW 5 8 0 3820 0 Blue 0
5 PM Fri 32 32 NW 5 8 0 3820 0 Blue 0
6 PM Fri 32 32 NW 5 8 0 3820 0 Blue 0
7 PM Fri 31 31 WNW 5 8 0 3820 0 Blue 0
8 PM Fri 31 31 WNW 5 8 0 3820 0 Blue 0
9 PM Fri 31 31 WNW 5 8 0 3820 0 Blue 0
10 PM Fri 31 31 WNW 5 8 0 3820 0 Blue 0
11 PM Fri 31 31 WNW 5 8 0 3820 0 Blue 0
12 Midnight Sat 31 31 WNW 5 8 0 3820 0 Blue 0
1 AM Sat 31 31 NW 4 8 0 3820 0 Blue 0
2 AM Sat 31 31 NW 4 8 0 3820 0 Blue 0
3 AM Sat 30 30 NW 4 8 0 3820 0 Blue 0
4 AM Sat 30 30 NNW 4 8 0 3820 0 Blue 0
5 AM Sat 29 29 NNW 4 8 0 3820 0 Blue 0
6 AM Sat 29 29 NNW 4 8 0 3820 0 Blue 0
7 AM Sat 29 29 N 4 8 0 3820 0 Blue 0
8 AM Sat 30 30 N 4 8 0 3820 0 Blue 0
9 AM Sat 31 31 N 4 8 0 3820 0 Blue 0
10 AM Sat 32 32 NNE 6 10 0 3820 0 Blue 0
11 AM Sat 33 33 NNE 6 10 0 3820 0 Blue 0
12 Noon Sat 34 34 NNE 6 10 2135 3820 0 White 0
1 PM Sat 34 34 N 6 9 2135 3820 0 White 0
2 PM Sat 34 34 N 6 9 2135 3820 0 White 0
3 PM Sat 33 33 N 6 9 0 3820 0 Blue 0
4 PM Sat 32 32 NE 5 9 0 3820 0 Blue 0
5 PM Sat 32 32 NE 5 9 0 3820 0 Blue 0
6 PM Sat 31 31 NE 5 9 0 3820 0 Blue 0
7 PM Sat 31 31 N 5 8 0 3820 0 Blue 0
8 PM Sat 31 31 N 5 8 0 3820 0 Blue 0
9 PM Sat 31 31 N 5 8 0 3820 0 Blue 0
10 PM Sat 31 31 N 5 8 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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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 [email protected]