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

Station:

KOTX

Date/Time:

N/A

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 Fri 21 21 W 19 38 N/A N/A N/A N/A N/A
1 AM Fri 25 25 WSW 17 35 N/A N/A N/A N/A N/A
2 AM Fri 27 27 WSW 6 14 N/A N/A N/A N/A N/A
3 AM Fri 28 28 WSW 13 28 N/A N/A N/A N/A N/A
4 AM Fri 27 27 WSW 12 25 N/A N/A N/A N/A N/A
5 AM Fri 25 25 SW 7 15 N/A N/A N/A N/A N/A
6 AM Fri 27 27 WSW 11 21 N/A N/A N/A N/A N/A
7 AM Fri 27 27 W 11 19 N/A N/A N/A N/A N/A
8 AM Fri 28 28 W 6 10 N/A N/A N/A N/A N/A
9 AM Fri 30 30 W 10 15 N/A N/A N/A N/A N/A
10 AM Fri 33 33 WNW 8 11 N/A N/A N/A N/A N/A
11 AM Fri 34 36 W 4 4 N/A N/A N/A N/A N/A
12 Noon Fri 36 36 WNW 8 9 N/A N/A N/A N/A N/A
1 PM Fri 37 37 W 9 10 N/A N/A N/A N/A N/A
2 PM Fri 39 41 W 7 8 N/A N/A N/A N/A N/A
3 PM Fri 38 38 WSW 9 11 N/A N/A N/A N/A N/A
4 PM Fri 37 37 WSW 9 11 N/A N/A N/A N/A N/A
5 PM Fri 36 36 WSW 11 17 N/A N/A N/A N/A N/A
6 PM Fri 34 34 WSW 9 13 N/A N/A N/A N/A N/A
7 PM Fri 32 32 WSW 8 13 N/A N/A N/A N/A N/A
8 PM Fri 31 31 W 7 13 N/A N/A N/A N/A N/A
9 PM Fri 29 29 W 8 13 N/A N/A N/A N/A N/A
10 PM Fri 28 28 W 7 12 N/A N/A N/A N/A N/A
11 PM Fri 27 27 WNW 5 9 N/A N/A N/A N/A N/A
12 Midnight Sat 27 27 WNW 6 10 N/A N/A N/A N/A N/A
1 AM Sat 27 27 WNW 6 10 N/A N/A N/A N/A N/A
2 AM Sat 27 27 WNW 5 8 N/A N/A N/A N/A N/A
3 AM Sat 26 26 WNW 5 10 N/A N/A N/A N/A N/A
4 AM Sat 25 25 WNW 6 11 N/A N/A N/A N/A N/A
5 AM Sat 25 25 WNW 6 11 N/A N/A N/A N/A N/A
6 AM Sat 24 24 WNW 5 11 N/A N/A N/A N/A N/A
7 AM Sat 25 25 WNW 5 10 N/A N/A N/A N/A N/A
8 AM Sat 24 24 WNW 5 9 N/A N/A N/A N/A N/A
9 AM Sat 28 28 WNW 5 7 N/A N/A N/A N/A N/A
10 AM Sat 30 31 W 4 6 N/A N/A N/A N/A N/A
11 AM Sat 32 34 W 4 4 N/A N/A N/A N/A N/A
12 Noon Sat 34 36 W 4 4 N/A N/A N/A N/A N/A
1 PM Sat 36 38 WSW 3 4 N/A N/A N/A N/A N/A
2 PM Sat 37 39 WSW 3 4 N/A N/A N/A N/A N/A
3 PM Sat 36 37 WSW 3 4 N/A N/A N/A N/A N/A
4 PM Sat 35 35 WSW 3 5 N/A N/A N/A N/A N/A
5 PM Sat 33 33 SW 3 6 N/A N/A N/A N/A N/A
6 PM Sat 31 31 WSW 3 7 N/A N/A N/A N/A N/A
7 PM Sat 29 29 WSW 4 8 N/A N/A N/A N/A N/A
8 PM Sat 27 27 W 4 10 N/A N/A N/A N/A N/A
9 PM Sat 26 26 W 5 10 N/A N/A N/A N/A N/A
10 PM Sat 25 25 W 5 11 N/A N/A N/A N/A N/A
11 PM Sat 26 26 W 5 11 N/A N/A N/A N/A N/A
12 Midnight Sun 24 24 W 5 11 N/A N/A N/A N/A N/A
1 AM Sun 23 23 W 5 11 N/A N/A N/A N/A N/A
2 AM Sun 24 24 WNW 5 11 N/A N/A N/A N/A N/A
3 AM Sun 23 23 WNW 4 9 N/A N/A N/A N/A N/A
4 AM Sun 24 24 WNW 4 8 N/A N/A N/A N/A N/A
5 AM Sun 25 25 WNW 3 6 N/A N/A N/A N/A N/A
6 AM Sun 25 25 WNW 3 6 N/A N/A N/A N/A N/A
7 AM Sun 25 25 NW 2 5 N/A N/A N/A N/A N/A
8 AM Sun 26 26 NNW 1 2 N/A N/A N/A N/A N/A
9 AM Sun 27 27 WSW 2 3 N/A N/A N/A N/A N/A
10 AM Sun 28 29 SSE 2 2 N/A N/A N/A N/A N/A
11 AM Sun 33 35 SE 2 2 N/A N/A N/A N/A N/A
12 Noon Sun 32 33 ESE 2 2 N/A N/A N/A N/A N/A
1 PM Sun 33 34 ESE 2 2 N/A N/A N/A N/A N/A
2 PM Sun 36 37 SSE 2 2 N/A N/A N/A N/A N/A
3 PM Sun 34 34 ESE 2 3 N/A N/A N/A N/A N/A
4 PM Sun 33 33 ESE 2 3 N/A N/A N/A N/A N/A
5 PM Sun 34 34 ESE 2 3 N/A N/A N/A N/A N/A
6 PM Sun 30 30 E 2 3 N/A N/A N/A N/A N/A
7 PM Sun 29 29 ENE 1 3 N/A N/A N/A N/A N/A
8 PM Sun 28 28 ENE 2 4 N/A N/A N/A N/A N/A
9 PM Sun 25 25 NE 2 5 N/A N/A N/A N/A N/A
10 PM Sun 23 23 NE 3 6 N/A N/A N/A N/A N/A
11 PM Sun 19 19 NE 2 4 N/A N/A N/A N/A N/A

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 ac_soaring@yahoo.com