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:

16 JUL 2019

Temp/Wind data from:

NOAA Digital Forecast
Tue Wed Thu Fri Sat Sun
Site
Name
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Wind Above
Launch
Dumps W 17 0 S 13 0 SW 18 0 S 10 0 S 8 0 SW 8 0
Mt Diablo W 17 2465 W 10 2465 SW 17 1602 SW 17 130 W 15 344 W 15 810
Ed Levin W 12 2875 W 8 2609 SW 10 1985 SW 10 942 SW 9 1083 W 9 1985
Mission Peak W 13 1123 W 9 1123 S 10 926 SW 12 714 SW 10 785 W 10 926
Potato Hill W 10 7100 E 7 7404 S 8 7252 SE 6 6947 S 7 6947 SW 8 7100
Mt Tamalpais NW 21 199 W 9 36 W 7 0 S 10 0 S 9 0 S 9 0
Tollhouse W 10 5589 SW 7 5054 SW 7 4503 SW 7 3933 SW 7 2726 SW 7 5054
Elk Mountain W 15 6576 W 9 6728 SW 8 6576 SW 8 6181 SW 10 6424 SW 10 6424
Big Sur NW 7 0 S 3 0 NE 5 0 W 7 0 SW 6 0 W 6 0
Ft Funston W 23 0 SW 12 0 SW 17 0 S 9 0 S 8 0 SW 8 0
Marina Beach W 12 307 W 10 307 SW 16 307 SW 9 307 SW 10 307 W 8 307
Dunlap W 7 3879 SW 6 3879 SW 6 3879 SW 6 2135 SW 6 1179 SW 6 3879
Weaver Bally W 12 2818 W 12 2818 W 6 3707 E 5 2818 E 5 3347 S 6 3550
Timberline NW 12 4914 W 8 4757 SW 9 4757 S 7 4313 S 8 4313 SW 8 4757
Burn Launch SW 9 4674 SW 13 4805 SW 13 4957 SW 13 4674 SW 10 4805 SW 12 6338
Hat Creek Rim W 12 6015 W 12 6776 W 13 6440 W 9 6319 W 9 6319 W 9 6776
St John NW 9 2724 N 7 2724 S 10 3263 S 9 1592 SE 9 1592 S 9 2724
Noel Springs W 8 5771 N 7 6052 S 10 5927 S 9 5615 SE 9 5615 S 10 5771
Lake McClure W 9 6300 SW 6 6300 SW 6 5751 SW 6 5751 SW 6 4595 SW 6 6830
Sugar Hill W 10 4106 W 15 5556 W 12 6460 W 13 5556 N 7 6460 NE 5 7616
Goat Mountain NW 13 7189 SW 8 6606 SW 10 6452 SW 12 4693 SW 12 4693 SW 10 6452

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