NEWS:

January 30, 2008: This site is running the code developed by Tad Hurst.

Why not submit your favorite site? I need site name, lat, long, LZ and launch altitudes and the zipcode.

- Alan

Also check out the Northern California Regional Atmospheric Soaring Prediction BLIPMAP Forecast - produced by Dmitry Chichkov

Sounding

Station:

KOAK (alt)

Date/Time:

19 AUG 2018

Temp/Wind data from:

NOAA Digital Forecast
Sun Mon Tue Wed Thu Fri
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps SW 13 0 SW 16 0 S 16 0 SW 9 0 W 9 0 W 12 0
Mt Diablo W 16 2430 SW 17 581 SW 20 0 W 14 0 W 14 0 W 14 0
Ed Levin W 10 1261 SW 10 205 SW 10 0 W 9 92 W 9 92 W 9 92
Mission Peak W 12 763 S 12 0 S 12 0 S 9 0 W 9 0 W 9 0
Potato Hill SE 10 5212 E 12 3786 SE 14 1783 S 6 3207 N 6 3207 SW 6 3207
Mt Tamalpais NW 13 0 W 14 0 W 13 0 W 12 0 W 12 0 W 12 0
Tollhouse W 10 4741 S 7 4271 SW 7 2880 SW 6 3296 SW 6 3296 W 6 3296
Elk Mountain W 12 5294 S 10 4387 SW 9 2498 SW 8 2498 SW 8 2498 W 8 2498
Big Sur NW 7 0 W 6 0 W 6 0 W 8 0 NW 9 0 NW 14 0
Ft Funston SW 12 0 SW 14 0 S 16 0 SW 9 0 W 10 0 W 12 0
Marina Beach W 10 367 W 13 367 SW 13 367 W 9 367 W 10 367 W 10 367
Dunlap SW 9 3217 SW 9 2733 SW 7 1927 SW 7 2153 W 6 1927 W 8 2153
Weaver Bally W 12 3824 S 7 3332 E 7 479 S 5 1474 SW 7 1474 SW 5 479
Timberline W 9 5300 SE 8 4292 SE 7 3386 SW 8 3386 W 7 3386 W 8 2919
Burn Launch SW 15 5973 SW 13 3401 SW 14 1456 SW 14 2451 SW 14 1959 SW 13 939
Hat Creek Rim W 12 6648 W 9 5626 W 13 5626 W 9 5185 W 9 4276 W 9 4276
St John SE 10 2395 E 10 937 SE 13 61 S 9 61 SW 7 61 SW 7 61
Noel Springs S 8 4696 S 9 3771 S 12 1906 S 9 2302 S 8 2302 SW 7 1906
Lake McClure W 10 5684 S 8 4629 SW 6 3296 W 6 3296 W 7 3901 W 8 3296
Sugar Hill W 10 7450 NW 8 3830 SW 7 3270 W 10 2822 W 12 4915 W 10 3830
Goat Mountain W 12 7249 W 13 5801 SW 12 3966 W 9 3482 NW 9 4440 NW 12 3966

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  If a front comes through, the sounding is no longer valid.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