NEWS:
Feb 16, 2021
- Problems getting data from National Weather Service began on Feb 11 impacting operation of the Soaring Predictor software.
The service seems to be working again at about 75% as of this morning, Feb 16.
Backup data is being sourced from WeatherAPI.com however, their free service is limited to 3 days. If you see a three day forecast for your favorite site, thank the WeatherAPI folks. The full 5-day forecasts are receiving input data from the National Weather service (thank them too :-).
Hourly wind gust has been added to the detail page.
RASP and Windgrams should not be impacted
See the southern California RASP Model 
The detail grid covers the San Diego sites, but the 4km grid covers most of southern California.
Instructional video on reading the RASP Model
Check out the WINDGRAMS
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 If a front comes through, the sounding is no
longer valid.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 or WeatherAPI.com website. Puddle temperatures can exceed
this temperature.
Puddle Temp: This estimate is
based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.
Wind Gust: This estimate is
taken from the National Weather Service or WeatherAPI.com 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
i
n 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