Feb 16, 2021
- Problems getting data from National Weather Service began on Feb 11 impacting operation of the Soaring Predictor software.
The service seems to be working again at about 75% as of this morning, Feb 16.

Backup data is being sourced from however, their free service is limited to 3 days. If you see a three day forecast for your favorite site, thank the WeatherAPI folks. The full 5-day forecasts are receiving input data from the National Weather service (thank them too :-).



KTUS (alt)


17 APR 2021

Temp/Wind data from:

NOAA Digital Forecast
Sat Sun Mon Tue Wed Thu
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
South Mountain W 7 13937 WSW 13 14166 NE 7 14166
Oatman Mt WNW 12 14692 N 9 14460 NE 6 15381
Shaw Butte SSE 10 12649 NNE 18 11203 SW 12 13228
The Y NW 16 11306 E 14 11306 W 14 15812
Phoenix Regional NW 13 14078 SW 9 13790 NNW 9 14078
Humbolt SW 12 13529 NNE 21 13529 SW 16 15819
Miller Canyon W 17 17514 ESE 10 16213 NW 15 17329
Box Canyon NNW 15 17063 ESE 13 14772 NW 12 16875
Mustang Mountain WNW 16 11126 ESE 9 10161 NW 15 10886
Whetstone Mountain WNW 16 11151 ESE 9 10187 NW 15 10911
Mt Lemmon WSW 13 18491 E 8 17948 NW 11 18310
A Mountain NW 14 12541 ESE 11 10514 ESE 11 12251
Rainbow Valley W 6 14253 NNE 14 13965 WSW 8 14517
Pinal Peak W 15 12847 ESE 15 8883 W 12 10531
Harquahala WNW 18 15432 N 12 15432 NW 10 17539
El Tiro Gliderport NW 11 12699 WSW 10 12699 NW 13 12699
Mt Ord SW 12 17882 NNE 21 17882 SW 16 18434

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  If a front comes through, the sounding is no longer valid.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 website.  Puddle temperatures can exceed this temperature. 

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

Wind Gust: This estimate is taken from the National Weather Service or 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