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)


15 AUG 2017

Temp/Wind data from:

NOAA Digital Forecast
Tue Wed Thu Fri Sat Sun
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Wind Above
Garlock SW 13 5225 SW 12 5225 E 6 6342 SW 7 7468 SW 10 7468 SW 14 7744
Boomer Ridge W 23 5257 E 8 5257 E 8 6120 SE 6 6686 SW 9 6993 W 10 6404
9-Mile W 22 7057 W 14 7503 SE 10 9453 N 9 9910 SW 12 9910 W 14 8985
Flynns SE 7 8783 SE 9 7790 S 7 9259 W 7 10177 SW 9 9259 SW 13 8783
Gunter NE 7 7277 S 9 7277 SW 7 7277 SW 8 8616 SW 9 8154 S 9 7277
Paiute NE 10 7868 S 10 7868 SW 7 8915 SW 8 8915 SW 10 8915 S 12 8336
Chalk Bluffs NW 5 10218 NW 6 9743 NW 7 10218 W 5 11205 SW 5 10218 S 10 10680
McGee Creek E 7 8526 NE 9 8089 E 5 8089 E 5 7544 W 9 8089 S 9 8089
Bria Dog Ridge NE 8 9267 E 9 8805 S 3 9267 W 5 7835 W 9 8290 S 9 7835
Mammoth N 9 5661 N 10 5191 NE 8 6210 NE 9 4709 SW 10 5191 SW 10 5191
Walts NW 16 5634 E 12 5134 SE 9 8049 NW 9 7057 W 9 6120 W 10 6120
Copper Mountain NW 7 7277 N 9 7277 NE 6 7277 W 8 5819 W 9 6803 W 8 6318
Lake Isabella Ground Launch Center W 20 4120 W 13 4860 SE 6 6224 W 5 6783 W 8 7334 W 8 6783

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  If a front comes through, the sounding is no longer valid.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