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:

18 SEP 2018

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 13 0 NW 16 0 SW 8 0 NW 13 0 NW 13 0 W 13 0
Mt Diablo NW 10 708 N 13 4070 N 21 4701 W 14 4701 W 13 3397 W 14 1778
Ed Levin W 10 1230 NW 14 3634 N 14 4958 W 9 3970 W 9 2077 W 10 1619
Mission Peak W 14 1168 W 13 3238 N 12 5035 W 9 3748 W 9 2142 W 9 1678
Potato Hill N 6 3534 NE 6 4675 N 7 6193 SW 8 5821 SW 7 4031 SW 7 3196
Mt Tamalpais W 15 1223 N 14 1386 W 13 2163 W 16 1386 W 15 1316 W 16 1270
Tollhouse SW 8 3891 W 8 3891 NE 6 5775 SW 7 6146 W 7 5017 W 8 4631
Elk Mountain W 8 3527 NW 8 4653 W 6 6446 W 10 6446 W 9 3910 W 9 2431
Big Sur W 6 52 N 15 310 N 9 2829 W 9 310 NW 9 251 NW 9 251
Ft Funston W 14 0 NW 16 0 SW 9 0 NW 13 0 NW 13 0 W 13 0
Marina Beach W 12 347 NW 12 347 NW 9 347 W 12 347 W 13 347 NW 13 347
Dunlap SW 7 2971 W 7 2780 SW 5 4374 NE 5 4374 W 6 3994 W 6 3352
Weaver Bally W 7 834 N 7 1430 N 7 3361 W 8 2614 W 5 834 NW 7 193
Timberline NE 8 2080 NW 7 3989 N 6 5821 W 9 4677 W 9 2431 SW 12 1686
Burn Launch SW 9 1962 NW 7 2773 S 7 4271 SW 14 5854 SW 15 2773 SW 16 1453
Hat Creek Rim W 8 3761 E 6 3761 NW 7 5656 W 12 7245 W 10 4540 NW 9 3761
St John N 6 960 N 6 1904 N 9 2690 SW 9 3074 NW 12 960 NW 13 10
Noel Springs N 6 3683 N 7 4462 N 10 5532 SW 8 5532 NW 9 3285 SE 10 2543
Lake McClure W 9 4563 NW 10 5399 W 5 6362 W 6 6736 W 8 5774 W 8 5399
Sugar Hill W 6 2519 W 12 2519 NE 5 4268 W 15 4815 SW 16 2902 W 15 1336
Goat Mountain NW 12 3763 N 16 5885 N 12 7785 W 9 6544 W 7 6241 NW 8 5885

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