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

Station:

KOTX

Date/Time:

14 DEC 2018

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 35 35 N 3 0 3820 0 Blue 0
5 AM Fri 33 33 N 3 0 3820 0 Blue 0
6 AM Fri 32 32 S 2 0 3820 0 Blue 0
7 AM Fri 31 31 SE 2 0 3820 0 Blue 0
8 AM Fri 31 31 E 3 0 3820 0 Blue 0
9 AM Fri 31 31 N 6 0 3820 0 Blue 0
10 AM Fri 31 31 N 6 0 3820 0 Blue 0
11 AM Fri 32 32 N 6 0 3820 0 Blue 0
12 Noon Fri 32 32 N 6 0 3820 0 Blue 0
1 PM Fri 34 34 NE 3 0 3820 0 Blue 0
2 PM Fri 34 34 E 3 0 3820 0 Blue 0
3 PM Fri 34 34 S 2 0 3820 0 Blue 0
4 PM Fri 35 35 S 5 0 3820 0 Blue 0
5 PM Fri 35 35 S 6 0 3820 0 Blue 0
6 PM Fri 35 35 S 7 0 3820 0 Blue 0
7 PM Fri 33 33 SW 6 0 3820 0 Blue 0
8 PM Fri 33 33 SW 8 0 3820 0 Blue 0
9 PM Fri 35 35 SW 10 0 3820 0 Blue 0
10 PM Fri 35 35 SW 12 0 3820 0 Blue 0
11 PM Fri 33 33 SW 13 0 3820 0 Blue 0
12 Midnight Sat 33 33 SW 13 0 3820 0 Blue 0
1 AM Sat 33 33 SW 12 0 3820 0 Blue 0
2 AM Sat 33 33 SW 10 0 3820 0 Blue 0
3 AM Sat 32 32 SW 9 0 3820 0 Blue 0
4 AM Sat 32 32 SW 8 0 3820 0 Blue 0
5 AM Sat 30 30 SW 8 0 3820 0 Blue 0
6 AM Sat 28 28 SW 7 0 3820 0 Blue 0
7 AM Sat 28 28 SW 7 0 3820 0 Blue 0
8 AM Sat 29 29 SW 6 0 3820 0 Blue 0
9 AM Sat 30 30 SW 5 0 3820 0 Blue 0
10 AM Sat 31 31 SW 3 0 3820 0 Blue 0
11 AM Sat 32 32 SW 2 0 3820 0 Blue 0
12 Noon Sat 34 34 S 2 0 3820 0 Blue 0
1 PM Sat 34 34 E 2 0 3820 0 Blue 0
2 PM Sat 35 35 E 2 0 3820 0 Blue 0
3 PM Sat 34 34 E 2 0 3820 0 Blue 0
4 PM Sat 32 32 E 2 0 3820 0 Blue 0
5 PM Sat 31 31 E 2 0 3820 0 Blue 0
6 PM Sat 30 30 NE 2 0 3820 0 Blue 0
7 PM Sat 29 29 NE 2 0 3820 0 Blue 0
8 PM Sat 29 29 NE 2 0 3820 0 Blue 0
9 PM Sat 29 29 NE 2 0 3820 0 Blue 0
10 PM Sat 29 29 NE 2 0 3820 0 Blue 0
11 PM Sat 30 30 NE 2 0 3820 0 Blue 0
12 Midnight Sun 30 30 N 2 0 3820 0 Blue 0
1 AM Sun 31 31 N 2 0 3820 0 Blue 0
2 AM Sun 31 31 N 2 0 3820 0 Blue 0
3 AM Sun 32 32 N 2 0 3820 0 Blue 0
4 AM Sun 32 32 N 2 0 3820 0 Blue 0
5 AM Sun 32 32 N 2 0 3820 0 Blue 0
6 AM Sun 31 31 N 2 0 3820 0 Blue 0
7 AM Sun 31 31 N 2 0 3820 0 Blue 0
8 AM Sun 31 31 N 2 0 3820 0 Blue 0
9 AM Sun 31 31 NE 2 0 3820 0 Blue 0
10 AM Sun 32 32 NE 2 0 3820 0 Blue 0
11 AM Sun 32 32 NE 2 0 3820 0 Blue 0
12 Noon Sun 32 32 NE 3 0 3820 0 Blue 0
1 PM Sun 33 33 NE 3 0 3820 0 Blue 0
2 PM Sun 33 33 NE 3 0 3820 0 Blue 0
3 PM Sun 34 34 NE 3 0 3820 0 Blue 0
4 PM Sun 34 34 NE 3 0 3820 0 Blue 0
5 PM Sun 35 35 NE 3 0 3820 0 Blue 0
6 PM Sun 36 36 N 2 0 3820 0 Blue 0
7 PM Sun 36 36 N 2 0 3820 0 Blue 0
8 PM Sun 36 36 N 2 0 3820 0 Blue 0
9 PM Sun 36 36 NE 2 0 3820 0 Blue 0
10 PM Sun 36 36 NE 2 0 3820 0 Blue 0
11 PM Sun 36 36 NE 2 0 3820 0 Blue 0
12 Midnight Mon 36 36 E 1 0 3820 0 Blue 0
1 AM Mon 36 36 E 1 0 3820 0 Blue 0
2 AM Mon 36 36 SE 1 0 3820 0 Blue 0
3 AM Mon 36 36 S 1 0 3820 0 Blue 0
4 AM Mon 36 36 SW 1 0 3820 0 Blue 0
5 AM Mon 35 35 SW 1 0 3820 0 Blue 0
6 AM Mon 33 33 SW 2 0 3820 0 Blue 0
7 AM Mon 32 32 SW 2 0 3820 0 Blue 0
8 AM Mon 32 32 SW 2 0 3820 0 Blue 0
9 AM Mon 33 33 SW 2 0 3820 0 Blue 0
10 AM Mon 35 35 SW 2 0 3820 0 Blue 0
11 AM Mon 36 36 SW 2 0 3820 0 Blue 0
12 Noon Mon 37 37 SW 2 0 3820 0 Blue 0
1 PM Mon 37 37 S 2 0 3820 0 Blue 0
2 PM Mon 37 37 S 2 0 3820 0 Blue 0
3 PM Mon 36 36 S 2 0 3820 0 Blue 0
4 PM Mon 36 36 S 2 0 3820 0 Blue 0
5 PM Mon 35 35 S 2 0 3820 0 Blue 0
6 PM Mon 35 35 S 2 0 3820 0 Blue 0
7 PM Mon 34 34 S 2 0 3820 0 Blue 0
8 PM Mon 34 34 S 2 0 3820 0 Blue 0
9 PM Mon 34 34 S 2 0 3820 0 Blue 0
10 PM Mon 34 34 SE 2 0 3820 0 Blue 0
11 PM Mon 34 34 SE 2 0 3820 0 Blue 0
12 Midnight Tue 34 34 SE 2 0 3820 0 Blue 0
1 AM Tue 34 34 SE 2 0 3820 0 Blue 0
2 AM Tue 35 35 SE 2 0 3820 0 Blue 0
3 AM Tue 36 36 SE 2 0 3820 0 Blue 0
4 AM Tue 36 36 S 3 0 3820 0 Blue 0
5 AM Tue 35 35 S 3 0 3820 0 Blue 0
6 AM Tue 34 34 S 3 0 3820 0 Blue 0
7 AM Tue 33 33 S 3 0 3820 0 Blue 0
8 AM Tue 33 33 S 3 0 3820 0 Blue 0
9 AM Tue 33 33 S 3 0 3820 0 Blue 0
10 AM Tue 34 34 S 5 0 3820 0 Blue 0
11 AM Tue 35 35 S 5 0 3820 0 Blue 0
12 Noon Tue 36 36 S 5 0 3820 0 Blue 0
1 PM Tue 37 37 S 5 0 3820 0 Blue 0
2 PM Tue 37 37 S 5 0 3820 0 Blue 0
3 PM Tue 38 38 S 5 0 3820 0 Blue 0
4 PM Tue 38 38 SW 6 0 3820 0 Blue 0
5 PM Tue 38 38 SW 6 0 3820 0 Blue 0
6 PM Tue 38 38 SW 6 0 3820 0 Blue 0
7 PM Tue 38 38 SW 6 0 3820 0 Blue 0
8 PM Tue 38 38 SW 6 0 3820 0 Blue 0
9 PM Tue 38 38 SW 6 0 3820 0 Blue 0
10 PM Tue 38 38 SW 5 0 3820 0 Blue 0
11 PM Tue 38 38 SW 5 0 3820 0 Blue 0
12 Midnight Wed 37 37 SW 5 0 3820 0 Blue 0
1 AM Wed 37 37 SW 5 0 3820 0 Blue 0
2 AM Wed 37 37 SW 5 0 3820 0 Blue 0
3 AM Wed 37 37 SW 5 0 3820 0 Blue 0
4 AM Wed 37 37 W 5 0 3820 0 Blue 0
5 AM Wed 36 36 W 5 0 3820 0 Blue 0
6 AM Wed 35 35 W 5 0 3820 0 Blue 0
7 AM Wed 34 34 W 5 0 3820 0 Blue 0
8 AM Wed 34 34 W 5 0 3820 0 Blue 0
9 AM Wed 35 35 W 5 0 3820 0 Blue 0
10 AM Wed 36 36 S 3 0 3820 0 Blue 0
11 AM Wed 37 37 S 3 0 3820 0 Blue 0
12 Noon Wed 38 38 S 3 0 3820 0 Blue 0
1 PM Wed 39 39 S 3 0 3820 0 Blue 0
2 PM Wed 39 39 S 3 0 3820 0 Blue 0
3 PM Wed 38 38 S 3 0 3820 0 Blue 0
4 PM Wed 38 38 S 2 0 3820 0 Blue 0
5 PM Wed 37 37 S 2 0 3820 0 Blue 0
6 PM Wed 37 37 S 2 0 3820 0 Blue 0
7 PM Wed 37 37 S 2 0 3820 0 Blue 0
8 PM Wed 37 37 S 2 0 3820 0 Blue 0
9 PM Wed 38 38 S 2 0 3820 0 Blue 0
10 PM Wed 38 38 S 2 0 3820 0 Blue 0
11 PM Wed 37 37 S 2 0 3820 0 Blue 0
12 Midnight Thu 37 37 S 2 0 3820 0 Blue 0
1 AM Thu 37 37 S 2 0 3820 0 Blue 0
2 AM Thu 37 37 S 2 0 3820 0 Blue 0
3 AM Thu 38 38 S 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