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:

16 SEP 2021

Temp/Wind data from:

NOAA Digital Forecast
Thu Fri Sat Sun Mon Tue
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps SW 14 0 SW 16 0 WSW 13 0 WNW 14 0 WNW 18 0 W 11 0
Mt Diablo SW 11 0 SSW 13 191 SW 19 0 WSW 16 0 N 16 317 NNW 11 776
Ed Levin S 9 602 S 10 836 S 9 427 WNW 9 250 NNW 14 718 WNW 8 1334
Mission Peak WNW 8 3450 WNW 7 6462 WNW 10 1846
Potato Hill E 11 1979 S 13 5872 WSW 11 0 WSW 11 0 N 13 819 NNW 10 5247
Mt Tamalpais W 5 180 SW 6 247 WNW 10 234 WNW 12 260 WNW 13 450 W 8 535
Tollhouse WSW 8 7391 SW 7 6903 SW 8 5061
Elk Mountain SW 8 4680 WSW 9 4771 W 12 0 W 12 0 N 6 759 SW 6 4105
Big Sur W 4 0 SSW 5 0 S 4 0 WNW 6 0 N 9 0 NNE 5 0
Ft Funston SW 12 0 SW 13 0 WSW 12 0 WNW 14 0 WNW 18 0 W 11 0
Marina Beach W 9 0 W 7 0 WNW 9 0
Dunlap WSW 9 0 SW 6 0 WSW 9 0 W 10 0 WSW 9 0 W 8 0
Weaver Bally SSW 5 1776 W 8 1869 WSW 13 0 WSW 13 0 ENE 6 0 NE 4 0
Timberline NNE 12 3039 S 12 2935 SW 12 0 WNW 13 0 NNW 10 0 W 8 0
Burn Launch WSW 9 3138 SW 12 3763 SW 16 0 SW 18 0 ENE 8 0 E 8 0
Hat Creek Rim W 9 5762 WSW 12 5762 WSW 16 0 W 12 0 NE 11 0 E 9 879
St John N 8 15264 SE 9 16041 WSW 12 12431
Noel Springs N 9 4482 S 13 5521 SW 11 430 WSW 11 0 N 13 0 WNW 12 854
Lake McClure NNW 8 1970 W 8 2236 WSW 6 1538 WNW 12 838 WNW 8 1044 SW 5 2236
Sugar Hill ESE 9 1520 WSW 19 3240 SW 26 0 SW 17 0 NE 6 0 ESE 6 0
Goat Mountain S 9 5070 SSW 10 5070 SSW 9 4692 WNW 11 1501 N 12 1501 E 10 6360
Mt Vaca SW 5 93 SSW 5 470 SW 9 0 SW 9 0 NNW 13 470 N 9 1170

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