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:

21 JUL 2018

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 SW 15 0 W 12 0 W 13 0 W 12 0 W 13 0 W 12 0
Mt Diablo W 20 1004 W 16 2426 W 18 2426 W 16 6700 W 17 5434 NW 16 4438
Ed Levin W 12 1453 W 10 1453 W 10 1453 W 10 2059 W 12 2309 W 12 1756
Mission Peak W 14 1476 W 14 1628 W 13 1628 W 10 2930 W 12 2930 W 12 1779
Potato Hill S 10 3805 SE 9 4386 SW 7 9636 SW 8 9313 SW 9 10760 W 9 9881
Mt Tamalpais W 14 121 W 16 233 NW 17 362 NW 15 882 W 15 804 NW 17 233
Tollhouse SW 7 5645 W 8 7045 W 5 8288 W 6 9122 W 7 9329 N 6 8706
Elk Mountain S 9 3505 SW 10 4074 W 9 8913 W 10 8913 W 10 11208 W 12 9401
Big Sur SW 6 0 S 6 0 W 6 941 NW 13 2200 NW 16 2200 N 21 1959
Ft Funston SW 14 0 W 12 0 W 13 0 W 12 0 W 13 0 W 12 0
Marina Beach SW 18 344 W 12 344 W 12 344 W 10 344 W 13 344 W 12 344
Dunlap W 7 2767 SW 7 1319 W 5 2767 W 5 6823 W 6 6823 NE 3 6823
Weaver Bally W 6 4800 SE 5 1148 S 7 6098 SW 7 6939 W 8 6939 W 9 6351
Timberline S 8 5234 SW 8 2573 W 7 7612 W 10 8342 W 9 8136 W 12 8342
Burn Launch SW 14 6052 SW 10 6974 SW 9 10119 SW 12 10536 W 14 10327 SW 13 10743
Hat Creek Rim W 12 8358 W 8 8358 W 10 9386 W 10 9590 W 10 9590 W 9 9792
St John S 9 1615 SE 8 2063 SW 7 6578 SW 10 7079 SW 8 7079 W 9 6578
Noel Springs S 10 4618 SE 8 5663 SW 7 9199 SW 10 9199 SW 8 9608 W 8 9199
Lake McClure NW 10 5169 W 9 5169 W 7 6237 NW 9 9681 NW 9 10950 W 9 10950
Sugar Hill W 9 8640 W 8 8018 W 8 8847 W 9 8640 W 10 8433 W 10 8433
Goat Mountain W 14 6079 W 12 7873 N 15 7873 NW 13 9320 NW 15 9116 W 15 8704

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