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:

20 OCT 2019

Temp/Wind data from:

NOAA Digital Forecast
Sun Mon Tue Wed Thu Fri
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps NW 18 0 NW 5 0 NW 5 0 NW 12 0 NE 10 0 NE 7 0
Mt Diablo N 17 1951 N 21 4348 N 18 4676 N 26 4676 NE 16 4512 NE 9 4676
Ed Levin N 13 2899 N 22 5245 N 16 5731 N 28 5569 NE 8 5731 E 6 5731
Mission Peak NW 12 2732 NE 17 4949 NE 13 5436 NE 22 5274 NE 9 5436 E 6 5598
Potato Hill NW 5 2657 N 7 5000 N 7 5000 N 12 4376 N 12 6453 W 6 6805
Mt Tamalpais NW 15 1079 N 9 3330 NW 7 3935 W 12 3935 NE 12 4901 NE 7 4228
Tollhouse W 8 2727 SW 6 4531 W 6 6003 SW 6 5642 NE 6 5276 SW 6 5276
Elk Mountain NW 9 2216 N 6 6033 NW 7 6646 N 12 6646 NE 10 6033 W 7 5679
Big Sur N 22 0 N 15 1371 NE 9 2641 N 12 2333 NE 7 2641 NE 3 2641
Ft Funston NW 21 0 W 5 0 W 5 0 W 12 0 NE 10 0 NE 7 0
Marina Beach NW 17 340 NW 8 340 NE 7 762 NW 15 562 E 8 1131 W 6 1131
Dunlap SW 7 1318 SE 5 3158 NE 6 4316 NE 6 3647 NE 6 3484 E 6 3484
Weaver Bally W 13 0 N 7 969 N 10 1753 NE 12 969 NE 14 1365 W 8 2513
Timberline NW 10 591 N 9 3867 N 9 4651 N 13 4651 NE 14 3867 W 8 3867
Burn Launch NW 7 112 NE 7 2307 N 6 2697 NE 10 1262 E 9 1434 SW 7 1947
Hat Creek Rim W 6 1295 NE 6 3281 N 8 3448 NE 12 3448 E 9 3448 W 6 4049
St John NW 10 0 N 10 1312 N 12 1817 N 18 1647 N 15 1480 W 8 1647
Noel Springs NW 9 1752 N 12 4721 N 10 5087 N 21 3975 N 16 3975 N 7 4350
Lake McClure NW 16 3833 E 8 5305 W 6 6109 S 6 5788 NE 6 6109 W 6 5948
Sugar Hill W 12 0 W 6 415 W 6 926 NE 8 244 NE 6 0 W 7 585
Goat Mountain N 18 4273 N 13 5747 N 7 7388 N 13 6890 SE 10 7138 E 7 7138
Mt Vaca NW 14 2988 N 21 4980 N 14 5307 N 21 5144 N 21 4653 N 9 4817

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 [email protected]