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:

15 JUL 2019

Temp/Wind data from:

NOAA Digital Forecast
Mon Tue Wed Thu Fri Sat
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps W 13 0 SW 15 0 W 13 0 S 10 0 SW 12 0 W 12 0
Mt Diablo W 18 1601 NW 9 646 W 15 1129 SW 16 646 W 17 0 W 17 0
Ed Levin W 13 728 W 12 438 W 10 519 SW 10 519 W 10 438 W 10 371
Mission Peak W 14 355 W 13 220 W 10 287 SW 12 287 W 12 86 W 12 86
Potato Hill NW 10 7809 NW 7 6650 S 8 8329 S 9 7809 S 9 6650 S 8 7809
Mt Tamalpais NW 21 0 N 13 0 W 14 0 SW 13 0 SW 12 0 W 14 0
Tollhouse W 12 6269 W 9 4738 SW 7 3819 SW 8 2696 SW 7 3819 SW 7 3819
Elk Mountain W 14 6397 W 13 6397 W 9 7476 SW 10 7476 SW 10 4966 W 10 4197
Big Sur NW 6 0 W 6 0 NW 9 0 SW 7 0 SW 7 0 W 7 0
Ft Funston W 17 0 W 15 0 W 13 0 SW 10 0 SW 10 0 W 12 0
Marina Beach W 12 383 W 10 383 W 13 383 SW 12 383 W 12 383 W 12 383
Dunlap W 9 4039 W 7 3300 E 6 2785 SW 6 1468 SW 7 2785 SW 7 2184
Weaver Bally W 13 576 W 12 1279 NW 12 2062 SW 10 2852 W 9 973 S 8 973
Timberline NW 13 3744 NW 10 2901 W 9 4466 SW 10 4466 SW 9 2901 SW 9 1991
Burn Launch SW 15 5733 SW 9 5186 SW 13 5733 SW 13 5733 SW 13 4621 W 12 5733
Hat Creek Rim W 13 7483 W 9 7989 W 12 9009 SW 12 10081 W 10 6962 W 10 6962
St John NW 10 1768 N 7 1003 SW 10 2397 S 12 1768 S 12 0 S 9 0
Noel Springs W 10 6996 N 7 5314 SW 10 6996 S 12 6464 S 10 4592 S 10 4592
Lake McClure W 10 8010 W 8 6056 W 7 4669 SW 6 5277 SW 7 4669 W 7 5277
Sugar Hill W 15 4676 NW 9 4676 W 15 7795 W 14 8081 W 15 8081 W 8 6026
Goat Mountain NW 13 8080 W 12 6486 SW 10 5805 SW 10 5072 W 10 4226 W 10 4226

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