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:

28 APR 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
Dumps NW 25 0 NW 14 0 NW 15 0 NW 17 0 W 13 0 W 8 0
Mt Diablo N 30 5975 N 23 6965 W 8 7143 N 21 8183 N 22 8607 N 14 8183
Ed Levin N 25 5359 N 23 7204 W 10 7204 N 16 7680 N 15 8218 N 6 7839
Mission Peak N 22 5380 NE 18 7230 W 10 7071 N 17 7388 N 15 8063 N 7 7705
Potato Hill N 15 4302 N 10 6018 W 5 6662 NW 13 7609 N 16 8035 N 14 8980
Mt Tamalpais N 22 4382 N 23 6973 N 14 5601 NW 22 6973 NW 14 7605 N 7 6534
Tollhouse N 16 4936 E 9 5962 W 14 7210 NW 8 6770 N 6 7210 NE 5 7641
Elk Mountain N 9 5026 NE 7 6562 NW 8 6792 NW 14 8057 N 13 8483 N 12 9318
Big Sur N 22 2338 N 22 4877 NW 7 6104 N 17 6265 N 14 6426 S 6 6104
Ft Funston NW 17 1332 W 17 1777 W 10 1510 W 14 2024 W 8 3142 W 7 2024
Marina Beach NW 29 367 NW 22 367 W 13 367 NW 16 367 NW 14 367 SW 6 367
Dunlap W 9 3250 E 6 4961 W 8 6000 W 7 5801 SW 5 5801 NE 3 5602
Weaver Bally N 9 4079 NW 7 6154 NW 9 5502 NW 9 6585 N 8 6370 NE 5 7365
Timberline N 13 3667 NE 8 5009 NW 8 5891 NW 14 6722 N 14 6938 NE 13 7794
Burn Launch NE 16 2188 N 15 4381 W 10 7032 N 12 6153 NE 12 6374 NE 10 6813
Hat Creek Rim NE 13 4009 E 6 6753 NW 8 7543 NW 12 7543 N 12 7972 NE 9 9599
St John N 15 1723 N 12 4012 N 6 4904 N 14 5741 N 17 6387 N 16 6387
Noel Springs N 21 4524 N 14 6743 N 8 7362 N 18 8010 N 18 8438 N 16 8438
Lake McClure NW 22 7242 NE 8 7729 NW 13 8432 NW 12 8043 NW 7 8237 N 3 8627
Sugar Hill N 12 340 W 7 4039 W 12 3349 NW 14 4894 N 9 4039 E 8 5989

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