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 AUG 2017

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 SW 15 0 SW 17 0 SW 14 0 W 9 0 W 9 0 SW 9 0
Mt Diablo SW 13 1843 W 13 5070 W 12 5686 W 13 6503 SW 13 6503 SW 9 5924
Ed Levin W 10 1199 S 12 1330 W 9 2770 W 8 5936 SW 8 5720 SW 7 2770
Mission Peak W 13 1139 S 14 1244 W 12 2499 W 9 5496 SW 9 5496 SW 8 2069
Potato Hill SE 7 5356 E 5 7089 S 9 7769 S 6 8298 SW 6 7769 SE 5 6628
Mt Tamalpais W 12 1069 W 12 1181 W 12 1310 W 9 1351 W 9 1351 SW 8 1310
Tollhouse W 9 4180 SW 6 4513 W 6 5524 SW 5 6638 SW 7 7075 SW 7 6857
Elk Mountain S 7 4934 S 6 6210 SW 9 7058 SW 8 8883 W 10 7344 W 9 6210
Big Sur W 6 0 S 5 161 NW 5 777 NW 10 2464 W 6 4177 NW 6 777
Ft Funston S 13 108 S 14 108 S 9 1948 SW 9 2319 SW 9 2319 SW 9 1547
Marina Beach SW 14 248 SW 16 248 SW 14 248 W 8 248 W 8 248 SW 9 248
Dunlap W 8 2530 W 7 3689 W 6 5524 W 3 5524 SW 5 7098 SW 6 6675
Weaver Bally W 7 6071 NE 6 7124 NE 9 8162 W 5 8368 W 5 7541 SW 5 6495
Timberline W 7 4426 N 5 7024 SW 7 7446 SW 6 7863 W 9 7446 S 8 5599
Burn Launch W 10 7058 N 7 7483 W 12 7906 W 12 7694 SW 13 7694 SW 13 7271
Hat Creek Rim W 9 6553 N 7 8262 NW 6 9092 W 8 9502 W 10 8679 W 8 8054
St John SE 6 2841 N 3 4521 S 9 5063 SW 6 6736 SW 10 6316 S 9 4300
Noel Springs SE 6 4908 N 5 7879 S 7 8301 S 5 8719 S 12 8301 S 10 7879
Lake McClure SW 7 5952 W 9 6282 W 7 7584 W 7 7907 W 6 8648 W 6 8276
Sugar Hill W 10 6319 N 7 6950 N 7 7578 W 8 7578 W 8 7369 W 13 7161
Goat Mountain W 9 4847 NW 9 4967 N 12 6700 NW 10 9186 W 9 10329 S 12 7134

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