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

Station:

KOTX

Date/Time:

5 DEC 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 Thu 29 29 NE 3 0 3820 0 Blue 0
5 AM Thu 29 29 NE 3 0 3820 0 Blue 0
6 AM Thu 29 29 NE 3 0 3820 0 Blue 0
7 AM Thu 29 29 NE 3 0 3820 0 Blue 0
8 AM Thu 30 30 N 3 0 3820 0 Blue 0
9 AM Thu 33 33 N 2 0 3820 0 Blue 0
10 AM Thu 35 35 N 2 0 3820 0 Blue 0
11 AM Thu 37 37 NE 2 0 3820 0 Blue 0
12 Noon Thu 38 38 NE 2 2402 3820 0 Blue 0
1 PM Thu 38 38 E 2 2402 3820 0 Blue 0
2 PM Thu 38 38 E 3 2402 3820 0 Blue 0
3 PM Thu 37 37 SE 3 0 3820 0 Blue 0
4 PM Thu 36 36 SE 3 0 3820 0 Blue 0
5 PM Thu 35 35 SE 2 0 3820 0 Blue 0
6 PM Thu 34 34 S 2 0 3820 0 Blue 0
7 PM Thu 34 34 SW 2 0 3820 0 Blue 0
8 PM Thu 33 33 SW 2 0 3820 0 Blue 0
9 PM Thu 33 33 SW 1 0 3820 0 Blue 0
10 PM Thu 34 34 S 1 0 3820 0 Blue 0
11 PM Thu 34 34 SE 1 0 3820 0 Blue 0
12 Midnight Fri 34 34 E 1 0 3820 0 Blue 0
1 AM Fri 34 34 E 1 0 3820 0 Blue 0
2 AM Fri 33 33 E 1 0 3820 0 Blue 0
3 AM Fri 32 32 NE 2 0 3820 0 Blue 0
4 AM Fri 31 31 NE 2 0 3820 0 Blue 0
5 AM Fri 31 31 NE 2 0 3820 0 Blue 0
6 AM Fri 31 31 E 2 0 3820 0 Blue 0
7 AM Fri 31 31 E 2 0 3820 0 Blue 0
8 AM Fri 32 32 E 2 0 3820 0 Blue 0
9 AM Fri 33 33 E 1 0 3820 0 Blue 0
10 AM Fri 33 33 E 1 0 3820 0 Blue 0
11 AM Fri 34 34 E 1 0 3820 0 Blue 0
12 Noon Fri 35 35 E 2 0 3820 0 Blue 0
1 PM Fri 35 35 E 2 0 3820 0 Blue 0
2 PM Fri 36 36 NE 2 0 3820 0 Blue 0
3 PM Fri 36 36 NE 2 0 3820 0 Blue 0
4 PM Fri 36 36 NE 2 0 3820 0 Blue 0
5 PM Fri 35 35 NE 2 0 3820 0 Blue 0
6 PM Fri 34 34 N 2 0 3820 0 Blue 0
7 PM Fri 33 33 N 2 0 3820 0 Blue 0
8 PM Fri 32 32 N 2 0 3820 0 Blue 0
9 PM Fri 32 32 N 2 0 3820 0 Blue 0
10 PM Fri 33 33 N 2 0 3820 0 Blue 0
11 PM Fri 33 33 N 2 0 3820 0 Blue 0
12 Midnight Sat 34 34 NE 2 0 3820 0 Blue 0
1 AM Sat 34 34 NE 3 0 3820 0 Blue 0
2 AM Sat 34 34 NE 3 0 3820 0 Blue 0
3 AM Sat 33 33 NE 2 0 3820 0 Blue 0
4 AM Sat 33 33 N 1 0 3820 0 Blue 0
5 AM Sat 32 32 NE 1 0 3820 0 Blue 0
6 AM Sat 31 31 SE 1 0 3820 0 Blue 0
7 AM Sat 31 31 S 1 0 3820 0 Blue 0
8 AM Sat 31 31 S 1 0 3820 0 Blue 0
9 AM Sat 32 32 S 1 0 3820 0 Blue 0
10 AM Sat 33 33 SE 1 0 3820 0 Blue 0
11 AM Sat 34 34 SE 1 0 3820 0 Blue 0
12 Noon Sat 35 35 E 1 0 3820 0 Blue 0
1 PM Sat 35 35 NE 1 0 3820 0 Blue 0
2 PM Sat 35 35 NE 1 0 3820 0 Blue 0
3 PM Sat 35 35 NE 1 0 3820 0 Blue 0
4 PM Sat 35 35 NE 1 0 3820 0 Blue 0
5 PM Sat 35 35 NE 1 0 3820 0 Blue 0
6 PM Sat 36 36 N 1 0 3820 0 Blue 0
7 PM Sat 37 37 N 1 0 3820 0 Blue 0
8 PM Sat 37 37 N 1 0 3820 0 Blue 0
9 PM Sat 38 38 NW 1 2402 3820 0 Blue 0
10 PM Sat 38 38 NW 1 2402 3820 0 Blue 0
11 PM Sat 38 38 NW 1 2402 3820 0 Blue 0
12 Midnight Sun 37 37 NW 1 0 3820 0 Blue 0
1 AM Sun 37 37 NW 1 0 3820 0 Blue 0
2 AM Sun 36 36 NW 1 0 3820 0 Blue 0
3 AM Sun 35 35 NW 2 0 3820 0 Blue 0
4 AM Sun 34 34 NW 2 0 3820 0 Blue 0
5 AM Sun 33 33 NW 2 0 3820 0 Blue 0
6 AM Sun 32 32 NW 2 0 3820 0 Blue 0
7 AM Sun 31 31 NW 2 0 3820 0 Blue 0
8 AM Sun 31 31 NW 2 0 3820 0 Blue 0
9 AM Sun 32 32 NW 2 0 3820 0 Blue 0
10 AM Sun 34 34 NW 2 0 3820 0 Blue 0
11 AM Sun 36 36 N 2 0 3820 0 Blue 0
12 Noon Sun 38 39 E 2 2447 3820 0 Blue 1
1 PM Sun 39 40 E 2 2555 3820 0 Blue 2
2 PM Sun 39 39 E 2 2447 3820 0 Blue 1
3 PM Sun 38 38 SE 2 2402 3820 0 Blue 0
4 PM Sun 37 37 SE 2 0 3820 0 Blue 0
5 PM Sun 36 36 SE 2 0 3820 0 Blue 0
6 PM Sun 34 34 SE 2 0 3820 0 Blue 0
7 PM Sun 34 34 SE 2 0 3820 0 Blue 0
8 PM Sun 33 33 SE 2 0 3820 0 Blue 0
9 PM Sun 32 32 SE 2 0 3820 0 Blue 0
10 PM Sun 31 31 W 1 0 3820 0 Blue 0
11 PM Sun 31 31 W 1 0 3820 0 Blue 0
12 Midnight Mon 31 31 W 1 0 3820 0 Blue 0
1 AM Mon 30 30 W 1 0 3820 0 Blue 0
2 AM Mon 30 30 W 1 0 3820 0 Blue 0
3 AM Mon 30 30 W 1 0 3820 0 Blue 0
4 AM Mon 29 29 N 1 0 3820 0 Blue 0
5 AM Mon 29 29 N 1 0 3820 0 Blue 0
6 AM Mon 28 28 N 1 0 3820 0 Blue 0
7 AM Mon 28 28 N 1 0 3820 0 Blue 0
8 AM Mon 28 28 N 1 0 3820 0 Blue 0
9 AM Mon 29 29 N 1 0 3820 0 Blue 0
10 AM Mon 31 31 E 2 0 3820 0 Blue 0
11 AM Mon 32 32 E 2 0 3820 0 Blue 0
12 Noon Mon 34 35 E 2 0 3820 0 Blue 0
1 PM Mon 35 35 E 2 0 3820 0 Blue 0
2 PM Mon 35 35 E 2 0 3820 0 Blue 0
3 PM Mon 35 35 E 2 0 3820 0 Blue 0
4 PM Mon 34 34 E 1 0 3820 0 Blue 0
5 PM Mon 33 33 E 1 0 3820 0 Blue 0
6 PM Mon 31 31 E 1 0 3820 0 Blue 0
7 PM Mon 30 30 E 1 0 3820 0 Blue 0
8 PM Mon 30 30 E 1 0 3820 0 Blue 0
9 PM Mon 30 30 E 1 0 3820 0 Blue 0
10 PM Mon 29 29 NE 1 0 3820 0 Blue 0
11 PM Mon 29 29 NE 1 0 3820 0 Blue 0
12 Midnight Tue 28 28 NE 1 0 3820 0 Blue 0
1 AM Tue 28 28 NE 1 0 3820 0 Blue 0
2 AM Tue 28 28 NE 1 0 3820 0 Blue 0
3 AM Tue 28 28 NE 1 0 3820 0 Blue 0
4 AM Tue 28 28 E 1 0 3820 0 Blue 0
5 AM Tue 28 28 E 1 0 3820 0 Blue 0
6 AM Tue 27 27 E 1 0 3820 0 Blue 0
7 AM Tue 27 27 E 1 0 3820 0 Blue 0
8 AM Tue 28 28 E 1 0 3820 0 Blue 0
9 AM Tue 29 29 E 1 0 3820 0 Blue 0
10 AM Tue 30 30 E 2 0 3820 0 Blue 0
11 AM Tue 31 31 E 2 0 3820 0 Blue 0
12 Noon Tue 32 32 E 2 0 3820 0 Blue 0
1 PM Tue 32 32 E 2 0 3820 0 Blue 0
2 PM Tue 32 32 E 2 0 3820 0 Blue 0
3 PM Tue 32 32 E 2 0 3820 0 Blue 0
4 PM Tue 31 31 E 2 0 3820 0 Blue 0
5 PM Tue 30 30 E 2 0 3820 0 Blue 0
6 PM Tue 29 29 E 2 0 3820 0 Blue 0
7 PM Tue 29 29 E 2 0 3820 0 Blue 0
8 PM Tue 29 29 E 2 0 3820 0 Blue 0
9 PM Tue 29 29 E 2 0 3820 0 Blue 0
10 PM Tue 29 29 E 0 0 3820 0 Blue 0
11 PM Tue 29 29 E 0 0 3820 0 Blue 0
12 Midnight Wed 28 28 E 0 0 3820 0 Blue 0
1 AM Wed 28 28 E 0 0 3820 0 Blue 0
2 AM Wed 28 28 E 0 0 3820 0 Blue 0
3 AM Wed 28 28 E 0 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