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:

25 MAR 2017

Temp/Wind data from:

NOAA Digital Forecast
Sat Sun Mon Tue Wed Thu
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps NW 16 0 S 24 0 NW 25 0 NW 16 0 W 12 0 NW 23 0
Mt Diablo W 12 3663 SW 20 2103 NW 18 3663 N 20 5760 N 16 6173 W 21 4931
Ed Levin NW 15 3522 S 12 1502 NW 16 2741 NW 15 5750 NW 9 6568 W 14 4918
Mission Peak W 15 4022 S 13 2177 NW 16 3282 NW 15 5815 NW 9 6428 W 15 5193
Potato Hill NW 3 2734 S 10 0 W 9 2956 N 12 4438 N 8 4438 N 13 3807
Mt Tamalpais W 17 3458 S 22 2581 NW 18 3668 NW 18 5328 W 12 5122 NW 25 4917
Tollhouse W 10 3069 E 7 2579 W 8 3069 NW 10 4348 N 8 6043 W 12 5398
Elk Mountain SW 7 2251 SW 12 11 NW 8 2464 NW 12 4356 N 8 4356 NW 13 3733
Big Sur NW 9 1156 W 12 693 N 13 693 N 17 4073 N 12 5741 N 17 4495
Ft Funston W 17 377 S 20 377 NW 21 377 NW 10 554 W 9 554 NW 20 377
Marina Beach NW 18 42 SW 12 42 NW 28 42 NW 15 42 NW 14 42 NW 18 42
Dunlap W 7 1943 SE 5 1943 W 9 1943 NW 6 3208 N 5 4448 NW 8 4036
Weaver Bally SW 6 1839 SE 16 0 NW 9 1622 NW 8 3572 W 8 4627 NW 13 3151
Timberline W 6 2376 SW 14 0 NW 12 2079 NW 12 4081 N 8 4730 N 13 3658
Burn Launch SW 9 921 SW 16 1516 NW 10 921 NE 9 4621 E 8 5894 W 21 4407
Hat Creek Rim W 9 2712 SW 14 2407 N 6 2407 NE 6 4836 E 6 5045 N 14 3781
St John NW 5 573 S 14 0 NW 14 854 N 14 2633 N 12 3268 N 13 2422
Noel Springs SW 6 3444 SW 22 832 NW 13 3229 N 15 4935 N 13 5375 NW 12 4725
Lake McClure NW 10 4109 E 6 3080 NW 13 4318 NW 8 5354 NW 8 6576 NW 13 5970
Sugar Hill S 7 2258 S 15 1824 NW 14 1824 W 7 2925 S 5 3988 NW 21 2041

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