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:

26 MAR 2019

Temp/Wind data from:

NOAA Digital Forecast
Tue Wed Thu Fri Sat Sun
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps SW 12 0 SW 24 0 SW 14 0 W 14 0 W 14 0 W 10 0
Mt Diablo SW 14 119 SW 29 0 W 16 0 NW 9 1408 N 13 3009 N 9 5053
Ed Levin S 10 2841 S 21 1438 S 14 1438 NW 12 4602 NW 10 5232 W 9 5852
Mission Peak S 10 2174 S 23 1215 S 14 1215 NW 10 4436 NW 10 4856 W 9 5274
Potato Hill S 12 1278 SW 17 1278 W 13 0 NW 6 4437 N 7 5473 N 5 5224
Mt Tamalpais S 8 218 S 23 218 W 15 218 W 13 1240 W 13 3256 W 9 2547
Tollhouse S 6 4475 S 12 1833 W 7 1833 W 8 4293 W 6 4707 SW 5 5485
Elk Mountain S 12 464 SW 15 0 W 12 0 W 7 3990 N 6 4402 W 6 4402
Big Sur S 8 0 SW 22 0 W 9 0 NW 14 0 NW 12 623 NW 12 623
Ft Funston SW 10 0 S 23 0 SW 14 0 W 14 0 W 14 0 W 10 0
Marina Beach SW 15 281 S 24 281 W 13 281 NW 15 281 W 15 281 W 13 281
Dunlap E 5 3823 S 12 0 W 7 248 W 7 3615 NE 6 3896 E 5 4163
Weaver Bally SE 9 0 S 15 0 S 12 0 SE 7 1366 E 8 1692 E 7 1507
Timberline S 12 0 SW 16 0 SW 13 0 SW 8 2413 N 8 2756 N 6 2664
Burn Launch SW 15 0 SW 21 0 S 15 0 SW 7 1992 NE 8 2272 SW 6 2366
Hat Creek Rim SW 9 3576 SW 12 2310 SW 12 1452 N 6 3678 E 7 4193 SW 7 4972
St John S 12 0 S 23 0 SW 15 0 SW 10 0 N 12 1875 N 8 1909
Noel Springs S 12 0 S 22 104 SW 15 0 W 10 3238 N 10 3614 N 7 3523
Lake McClure S 6 3653 SE 10 2392 W 6 2392 NW 10 4072 NE 6 4906 NE 6 5525
Sugar Hill SW 13 1048 SW 21 1014 SW 13 54 SW 6 1014 E 6 1733 SW 9 2266
Goat Mountain S 15 4504 S 23 4203 NW 9 4304 N 15 4414 N 13 5047 N 12 5814

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  If a front comes through, the sounding is no longer valid.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