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)


26 JUN 2017

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
Garlock W 30 10531 W 23 9845 W 23 9496 W 15 9845 SW 14 10190 SW 17 9142
Boomer Ridge W 37 9442 W 31 9095 W 22 8743 NW 12 9442 SW 13 9442 SW 16 9095
9-Mile W 32 11168 W 23 10508 W 20 10508 W 13 10508 W 13 10508 W 17 10508
Flynns W 10 12791 SW 9 11897 NW 7 11433 SW 5 12349 SW 6 12349 W 7 11433
Gunter W 15 12914 NW 7 11330 N 7 10404 S 8 13615 S 12 14271 S 8 13615
Paiute W 17 15319 NW 9 15319 N 8 14603 SW 9 15319 S 13 15319 S 10 14603
Chalk Bluffs W 13 14175 W 9 12390 NW 9 12056 W 3 12853 W 3 12853 NW 3 12056
McGee Creek SW 20 10553 SW 12 10553 W 7 10553 W 6 13272 SW 9 14014 W 5 14014
Bria Dog Ridge W 21 13271 W 13 13271 NW 7 11455 SW 6 14047 SW 10 14765 W 5 14765
Mammoth SW 22 6903 SW 14 7383 SW 10 6903 W 7 6903 SW 10 5902 W 7 6903
Walts W 23 9690 NW 13 10130 W 12 9690 E 9 8778 N 8 8778 SE 9 8778
Copper Mountain SW 21 9910 SW 13 9450 W 7 9910 W 7 13487 SW 12 13487 W 7 13487
Lake Isabella Ground Launch Center W 26 7270 W 21 6040 W 20 5114 W 10 7270 W 10 7270 W 13 6040

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  If a front comes through, the sounding is no longer valid.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