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)


12 MAY 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 14 10406 SW 16 10738 W 21 11227 WSW 21 7557 W 18 2737 W 19 8833
Boomer Ridge W 19 10203 W 21 12202 W 26 10718 WSW 25 7167 W 19 2233 W 23 8661
9-Mile SW 17 11245 W 18 13133 WSW 21 13133 WSW 20 8104 W 14 3161 SSW 13 8104
Flynns SSE 5 8176 W 6 8176 WSW 8 8176
Gunter SSW 12 8925 SW 11 9714 WSW 14 9714 WSW 14 3359 NW 12 91 W 12 4916
Paiute SW 12 11293 SW 12 11293 WSW 16 11891 WSW 14 4669 N 13 2033 W 12 7145
Chalk Bluffs SE 11 10954 W 12 10954 WSW 17 11418 W 16 5297 N 12 4166 WSW 12 9303
McGee Creek WSW 13 11259 W 13 11259 WSW 17 11259 WSW 13 2338 WNW 11 1369 WSW 12 7304
Bria Dog Ridge W 14 11348 W 12 11348 WSW 17 12026 W 13 3352 NW 11 772 W 12 6304
Mammoth WSW 14 8182 WSW 13 8691 WSW 18 8182 WSW 17 0 WNW 14 0 WSW 13 3266
Walts SSE 16 8490 SSE 16 8490 SSE 17 10029 SSW 14 4619 NW 10 20 WNW 11 5246
Copper Mountain W 13 17439 W 14 17627 W 14 17627
Horseshoe SSE 16 8490 SSE 16 8490 SSE 17 10029 SSW 14 4619 NW 10 20 WNW 11 5246
Wolf Peak WSW 13 9240 W 13 9889 WSW 18 9240 NNE 10 0 NNE 10 3212 WSW 12 7183
Sweetwater WSW 14 14756 WSW 13 18543 WSW 15 18543
Lake Isabella Ground Launch Center W 21 10581 W 23 10248 W 27 9586 W 24 3625 W 23 134 W 23 6849

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