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 AUG 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 SW 9 0 SW 9 0 SW 9 0 SW 14 0 W 14 0 W 15 0
Mt Diablo W 16 2637 W 14 3530 W 15 3088 W 20 1442 W 20 965 W 18 965
Ed Levin SW 9 3192 W 8 2607 W 9 3192 W 12 1932 W 12 824 W 12 824
Mission Peak W 10 1739 W 9 1739 W 9 1739 W 12 925 W 13 23 W 13 0
Potato Hill W 10 7404 S 10 7544 SW 7 7544 SW 10 6348 SW 9 5849 W 8 6099
Mt Tamalpais W 9 0 W 9 0 W 10 0 SW 13 0 W 14 0 W 16 0
Tollhouse W 9 3528 W 9 3419 SW 8 4232 SW 8 3419 W 9 3080 W 9 3080
Elk Mountain SW 10 4891 SW 12 5873 SW 9 5873 W 10 4891 W 10 3553 W 10 3553
Big Sur SE 5 0 NW 5 0 N 5 0 W 8 0 W 12 0 NW 10 0
Ft Funston SW 8 0 SW 8 0 SW 8 0 SW 14 0 W 14 0 W 14 0
Marina Beach SW 8 360 W 8 360 W 7 360 W 13 360 W 16 360 NW 17 360
Dunlap W 7 2822 W 6 2562 NE 6 2822 SW 7 2822 SW 6 2300 W 7 1913
Weaver Bally W 9 2768 NE 6 3731 SE 7 3876 SW 9 3025 SW 9 2250 W 9 1588
Timberline SW 10 3533 SW 7 3790 SW 9 4046 SW 12 3044 SW 9 1711 SW 8 2325
Burn Launch SW 14 3641 W 7 4976 SW 10 4976 SW 13 3380 SW 13 2854 SW 13 3118
Hat Creek Rim W 14 5081 W 8 6179 W 8 6179 SW 12 6036 SW 10 4827 SW 9 4827
St John W 9 1070 SW 9 2312 SW 9 2312 SW 14 960 SW 12 460 S 9 460
Noel Springs W 10 4646 SW 9 4901 SW 9 5601 SW 13 4389 SW 12 3900 SW 9 3900
Lake McClure W 8 5670 NW 8 5502 W 7 6782 W 7 5502 W 8 5042 W 9 4785
Sugar Hill W 17 3512 N 6 3512 E 8 4542 SW 9 3949 W 14 3292 SW 12 3292
Goat Mountain W 8 6623 NW 9 6623 NW 7 6907 W 13 6623 NW 12 5923 NW 13 5672
Mt Vaca SW 15 3603 SW 14 4476 SW 15 4233 SW 17 2710 SW 17 1580 SW 15 1580

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