January 24, 2008: This site is running the code developed by Tad Hurst.

Why not submit your favorite site? I need site name, lat, long, LZ and launch altitudes and the zipcode.

- Alan



KOTX (alt)


25 JAN 2021

Temp/Wind data from:

NOAA Digital Forecast
Mon Tue Wed Thu Fri Sat
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Chelan SW 2 0 ENE 7 0 NNE 6 0 N 6 0 SSE 6 0 S 6 0
Jupiter Ridge W 3 1903 SW 7 1181 SE 5 1903 SE 6 1903 S 10 1903 S 13 1903
Saddle Mt WSW 3 570 NE 10 335 N 9 830 NNW 9 960 WNW 8 1413 WNW 9 1413
Blanchard ESE 12 1269 ESE 18 1480 E 6 1058 E 6 1480 SE 10 1269 SE 13 1480
BJ S 8 2304 N 6 2517 E 9 2304 E 8 2660 SE 9 2304 E 10 2517
Fort Ebey SSE 15 1414 SSE 26 1625 ESE 10 1414 ESE 7 1414 SE 14 1414 SE 16 1625
Tiger Mt SW 10 1339 ESE 26 1339 E 7 1642 ESE 7 1903 SSE 10 1642 SSE 10 1903

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  If a front comes through, the sounding is no longer valid.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