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:

25 SEP 2017

Temp/Wind data from:

NOAA Digital Forecast
error getting data for coordinate: 37.67264,-122.49
Mt Diablo N 14 5871 N 12 6982 S 5 7441 W 10 7737 W 10 6982 W 5 7238
Ed Levin N 13 6113 N 9 6506 NW 8 7060 W 9 7060 W 9 6506 W 7 6506
Mission Peak N 12 5359 N 10 6312 W 8 6867 W 9 6867 W 9 6120 W 7 6120
Potato Hill NE 10 5640 NE 12 5919 N 8 6746 S 7 6472 SW 6 6472 NE 7 6746
Mt Tamalpais W 9 4918 NE 5 5760 SW 6 6218 W 8 5085 W 10 4557 NW 9 5001
Tollhouse NE 8 4216 NE 10 5414 NE 7 5695 NE 7 5974 NE 6 5974 NE 6 5974
Elk Mountain N 7 6011 NE 12 6461 NE 8 8126 SW 9 6461 W 7 6259 N 5 6461
Big Sur NE 7 0 NE 5 3716 E 7 3972 NW 8 4409 NW 12 4409 NW 10 4058
Ft Funston W 14 171 N 10 171 NE 9 171 W 8 171 W 9 171 SW 7 171
Marina Beach W 12 311 W 8 311 W 7 311 W 9 311 W 10 311 W 9 311
Dunlap E 8 3842 NE 10 4573 NE 7 5126 NE 6 5126 NE 5 5400 NE 5 5400
Weaver Bally NE 9 3420 E 13 5402 E 16 5402 SE 5 6058 SW 6 4975 NW 5 5764
Timberline NE 9 5007 NE 15 5783 NE 8 6711 SW 9 5007 W 7 5007 W 3 5007
Burn Launch E 12 2626 NE 15 4060 NE 10 5464 E 6 6379 SW 7 6725 W 6 6379
Hat Creek Rim NE 9 4334 E 10 5184 E 7 6394 W 7 6394 W 7 7636 N 6 6394
St John N 12 3074 NE 15 3358 NE 10 4105 S 10 3898 SW 9 3639 N 7 3639
Noel Springs N 13 5294 NE 16 5502 N 12 7204 S 9 5854 N 13 5854 E 12 5854
Lake McClure NE 7 6049 NE 7 6781 NE 6 7599 W 7 7599 NW 8 7328 NW 7 7599
Sugar Hill N 8 1889 NE 8 3029 E 9 5322 SE 8 6037 W 7 5864 NW 10 5684
Goat Mountain N 12 5505 E 3 6502 SE 5 8214 N 5 8905 N 9 8214 N 8 8214

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  If a front comes through, the sounding is no longer valid.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