NEWS:

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

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


Sounding

Station:

KVBG (alt)

Date/Time:

17 NOV 2017

Temp/Wind data from:

NOAA Digital Forecast
Fri Sat Sun Mon Tue Wed
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Garlock W 21 2677 E 6 2241 N 5 3109 W 12 3325 NW 6 4613 W 9 5040
Boomer Ridge W 36 2976 N 10 2536 W 7 3631 W 9 3849 W 6 4497 W 9 5131
9-Mile W 38 3168 N 8 2731 NW 8 3168 W 22 3821 S 8 4683 N 8 5315
Flynns N 24 2085 NE 5 2863 NE 6 3666 N 12 4105 E 10 4754 E 7 5392
Gunter W 20 298 E 6 0 NE 6 1587 S 7 2651 NW 9 3298 NE 5 3298
Paiute SW 25 1317 SE 6 2972 SE 7 4943 SW 9 5379 NW 12 6460 SW 6 6030
Chalk Bluffs NW 17 2785 SE 3 3362 W 2 4234 NE 6 4667 SE 7 5315 E 3 5743
McGee Creek SW 26 43 S 7 3693 SW 9 4571 SW 14 4353 SW 10 5441 SW 8 5441
Bria Dog Ridge SW 24 1256 S 5 3932 SW 7 4372 SW 12 4589 S 10 5668 SW 7 5239
Mammoth SW 60 0 SW 12 753 SW 16 2601 SW 28 2347 SW 30 3756 S 21 3537
Walts W 55 2773 NW 8 2991 W 10 3425 W 16 3857 W 10 4498 W 9 5134
Copper Mountain SW 26 0 SW 8 2909 SW 12 3413 SW 17 3413 S 14 4477 SW 12 4477
Horseshoe W 55 2773 NW 8 2991 W 10 3425 W 16 3857 W 10 4498 W 9 5134
Wolf Peak SW 29 0 SW 9 2013 SW 14 2529 SW 18 2013 S 16 4127 S 15 3686
Sweetwater SW 39 0 SW 12 2422 SW 18 3402 SW 31 3402 SW 33 4563 SW 25 4563
Lake Isabella Ground Launch Center W 23 0 E 7 1156 W 6 1589 W 8 1156 W 6 2664 W 7 3515

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  If a front comes through, the sounding is no longer valid.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 ac_soaring@yahoo.com