March 24, 2013: This site is running the code developed by Tad Hurst.

This section created with the help of Aaron Colby.
Why not submit your favorite site? I need site name, lat, long, LZ and launch altitudes and the zipcode.

- Alan

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)


24 OCT 2020

Temp/Wind data from:

NOAA Digital Forecast
error getting data for coordinate: 35.850727,-117.972205 error getting data for coordinate: 37.468227,-118.263270
Sat Sun Mon Tue Wed Thu
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Garlock SW 17 1519 N 16 153 NE 23 0 N 10 0 NW 7 1519 N 8 1777
Boomer Ridge W 35 1720 W 22 0 N 21 0 N 13 0 NW 12 543 NW 12 1720
Flynns W 9 4558 N 18 307 NW 13 0 NW 9 701 N 7 3215 SE 7 3805
Paiute SW 9 2847 N 22 0 N 20 0 NW 14 0 N 10 2272 S 12 2847
Chalk Bluffs S 8 3642 N 18 946 N 13 0 N 9 1610 NW 6 3006 SE 6 3006
McGee Creek SW 14 2496 N 17 0 N 17 0 N 13 782 NE 8 2074 NE 9 2910
Bria Dog Ridge W 13 2881 N 21 0 NW 17 0 N 14 0 NE 10 1818 SE 10 2380
Mammoth SW 16 0 SW 18 0 NE 40 0 N 17 0 N 15 566 W 14 566
Walts S 12 1674 N 13 0 N 24 0 N 15 0 N 12 0 N 9 433
Copper Mountain W 15 0 N 16 0 NE 20 0 NE 12 0 W 8 0 N 9 0
Horseshoe S 12 1674 N 13 0 N 24 0 N 15 0 N 12 0 N 9 433
Wolf Peak W 15 53 N 15 0 E 28 0 NE 15 0 N 10 1361 NW 13 1866
Sweetwater W 15 449 N 16 0 E 26 0 N 14 0 N 10 449 NW 12 1216
Lake Isabella Ground Launch Center W 22 773 W 22 0 NE 15 0 SW 13 0 SW 13 1104 SE 12 1487

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  If a front comes through, the sounding is no longer valid.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