NEWS:

Feb 16, 2021
- Problems getting data from National Weather Service began on Feb 11 impacting operation of the Soaring Predictor software.
The service seems to be working again at about 75% as of this morning, Feb 16.


Backup data is being sourced from WeatherAPI.com however, their free service is limited to 3 days. If you see a three day forecast for your favorite site, thank the WeatherAPI folks. The full 5-day forecasts are receiving input data from the National Weather service (thank them too :-).

Sounding

Station:

KOAK (alt)

Date/Time:

20 MAY 2022

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 N 17 0 W 12 0 WNW 14 0 WNW 17 0 W 17 0 WSW 14 0
Mt Diablo N 32 2814 WNW 16 3803 W 12 3989 NW 16 4416 WSW 12 5523 W 13 5304
Ed Levin NW 13 6149 WNW 10 7249 WNW 9 7632
Mission Peak NW 13 5587 WNW 10 6690 WNW 9 7126
Potato Hill NNE 23 2518 NNE 13 4339 N 12 4788 WNW 10 5677 NNE 10 6319 WSW 10 7036
Mt Tamalpais N 28 4192 NW 18 4501 NW 16 3688 N 18 4192 WNW 11 4796 SW 11 3880
Tollhouse WSW 8 4588 WSW 8 4813 W 8 5842
Elk Mountain N 17 2980 WNW 9 4075 WNW 9 4743 WNW 8 4964 WNW 8 5786 SW 8 6282
Big Sur NW 9 3743 W 8 3881 NW 9 4552
Ft Funston WNW 17 0 W 12 0 WNW 17 0 WNW 17 0 W 17 0 WSW 14 0
Marina Beach WNW 23 0 W 13 0 W 11 0 WNW 13 0 WNW 13 0 W 11 0
Dunlap WSW 7 4651 W 7 5744 W 7 6046
Weaver Bally NE 20 0 W 13 542 NW 14 1474 W 12 2620 NW 12 2969 W 11 3587
Timberline NNE 29 1152 NNE 16 2715 NW 11 3624 N 10 4003 NW 9 4856 SW 9 5423
Burn Launch ENE 20 347 ENE 10 1853 N 11 2787 NE 9 4200 N 9 4805 SW 11 5782
Hat Creek Rim ENE 18 2402 N 11 3306 N 11 3762 N 8 5109 N 8 5249 W 9 7346
St John N 35 0 N 17 1031 NW 14 1723 NNW 12 3085 NW 10 3309 W 11 4004
Noel Springs N 35 1817 NNW 14 3341 NNW 14 4253 NNW 11 5001 NW 10 5709 WSW 11 7312
Lake McClure NNW 13 5724 SSW 9 6388 NW 12 7045 NW 10 7694 WNW 8 8943 WSW 6 9825
Sugar Hill ENE 11 0 ENE 10 0 N 10 557 NW 10 1715 NNE 6 2720 WSW 8 5330
Goat Mountain N 17 4438 N 11 5330 NNW 13 6192 N 12 7065 NNW 9 8363 WSW 9 8667
Mt Vaca NNW 18 2796 N 17 3998 NNE 13 4182 NNW 18 5060 NNW 8 5713 WSW 9 5713

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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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