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 :-).

RASP and Windgrams should not be impacted

See the southern California RASP Model The detail grid covers the San Diego sites, but the 4km grid covers most of southern California.

Instructional video on reading the RASP Model

Check out the WINDGRAMS Windgrams are available for some Eastern Sierra sites from the more accurate RASP data



KVBG (alt)


23 JUN 2021

Temp/Wind data from:

NOAA Digital Forecast
Wed Thu Fri Sat Sun Mon
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Garlock SSW 21 7671 W 23 9297 WSW 12 10297 E 12 15087 N 12 15839 SSE 13 15839
Boomer Ridge SSW 21 8771 WSW 17 9655 W 16 10966 W 17 14839 NW 16 15793 SW 16 15604
9-Mile S 20 10046 WSW 20 10046 WSW 18 13771 SW 17 17485 NW 16 18427 S 17 18803
Flynns SSE 11 6782 SW 7 7918 ESE 7 8977
Gunter SE 19 6324 SSW 14 5567 ESE 12 7543 ENE 12 9199 ESE 11 9997 SSE 13 9997
Paiute SSE 19 7880 S 13 7494 ESE 13 9375 ENE 14 15088 E 13 15882 SSE 16 16081
Chalk Bluffs SSE 11 4763 SW 7 5519 ESE 7 6286
McGee Creek SSW 25 13004 WSW 11 6266 NNE 10 12111 NE 11 14407 ENE 9 15203 SSE 10 15203
Bria Dog Ridge SSW 23 8639 SE 10 6071 ENE 11 7394 NNE 12 12832 NE 10 13426 SSE 10 13820
Mammoth SW 24 9158 WSW 13 2153 NNW 19 4751 NNW 13 13960 N 13 14728 WSW 13 14728
Walts S 20 6660 SSE 16 6660 ESE 14 8311 NE 16 9559 ENE 14 9972 SE 14 10759
Copper Mountain SW 19 14466 WSW 13 13466 ENE 12 14466
Horseshoe S 20 6660 SSE 16 6660 ESE 14 8311 NE 16 9559 ENE 14 9972 SE 14 10759
Wolf Peak SSW 23 12087 E 9 3997 NNE 10 6061 N 10 12896 E 8 14100 SW 9 14300
Sweetwater SSW 24 11059 SSW 13 2636 N 13 5571 NNE 12 13174 N 12 14381 WSW 13 14381
Lake Isabella Ground Launch Center W 21 7617 W 14 8684 W 20 9192 W 17 11609 ESE 16 12194 SSE 17 12390

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 [email protected]