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:

17 FEB 2019

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 NW 33 0 NW 20 0 W 13 0 NW 20 0 NW 17 0 N 10 0
Mt Diablo W 23 889 N 24 3190 N 22 2762 W 22 2548 N 21 1638 N 15 2762
Ed Levin NW 24 529 N 23 3544 N 20 3544 NW 15 3333 NW 15 2631 NW 9 3755
Mission Peak NW 23 936 NE 16 3573 NE 18 3573 W 16 3362 NW 16 2400 N 9 3573
Potato Hill N 8 312 N 13 3535 N 9 3745 NW 9 2689 N 14 312 N 10 2689
Mt Tamalpais NW 25 744 N 23 3455 NE 20 2403 NW 23 2040 NW 20 2040 N 14 2763
Tollhouse SE 7 0 W 6 536 NE 5 2304 SW 6 2304 SW 7 536 E 6 2087
Elk Mountain NW 12 0 N 9 2600 NE 6 2600 NW 14 1536 N 13 1536 N 8 2810
Big Sur W 33 0 N 17 0 W 10 0 NW 17 0 NW 20 0 N 14 0
Ft Funston NW 35 0 NW 20 0 NE 12 0 NW 20 0 NW 16 0 N 10 0
Marina Beach NW 31 199 NW 22 199 NW 20 199 NW 18 199 NW 17 199 N 10 199
Dunlap S 8 0 SW 6 0 NE 6 0 SW 6 0 SW 7 0 NE 6 0
Weaver Bally NW 7 0 N 6 1432 NW 9 1793 W 13 0 NW 9 0 N 8 1432
Timberline NW 12 0 N 12 2658 NE 8 3299 NW 17 1291 N 14 987 NW 10 2873
Burn Launch N 9 0 NE 7 830 NE 8 1139 W 9 485 NE 15 0 NE 8 0
Hat Creek Rim N 8 0 SE 6 32 SE 7 1890 W 6 32 N 12 0 E 7 1215
St John NW 12 0 N 16 1094 N 14 1394 W 18 0 NW 18 0 NW 15 1094
Noel Springs N 15 78 N 20 3939 N 15 4152 W 17 2448 N 18 1842 NW 14 3939
Lake McClure SE 7 0 W 6 1221 NE 6 1896 SE 6 2625 W 7 1896 E 6 2625
Sugar Hill N 8 0 NW 6 0 W 7 0 W 13 0 N 10 0 NE 5 0
Goat Mountain N 18 695 N 17 2805 N 12 2805 NW 12 2805 NW 14 1948 N 12 3017

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  If a front comes through, the sounding is no longer valid.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