LINKS TO THE LATEST BLIPSPOT FORECASTS
BLIPSPOTs give thermal soaring parameters
at a single geographic location for different times.
BLIPSPOT™ = Boundary Layer Information Prediction SPOT
Created by Dr. John W. (Jack) Glendening
November 15, 2008:
For Iphone users:
Iphones seem to have the quirk of wrapping long lines in a text file -
if you wish to avoid that behavior, so that each line will remain a
single line maintaining their column alignment, use a bookmark having
the "txt" filename tail replaced by "html".
March 28, 2005:
New BLIPSPOTs again available:
After taking a hiatus of nearly 2 years, I've decided to again start
producing new BLIPSPOTs for those who want them. For information
on requesting creation of a BLIPSPOT for your location, see the
"BLIPSPOT Creation webpage" link just below.
For information about sponsoring a new BLIPSPOT,
BLIPSPOT Creation webpage
For information about renewing an existing or expired BLIPSPOT,
BLIPSPOT Renewal webpage
20km RAP RESULTS
Updated continuously between 07Z to 23Z
BLIPSPOTs predict thermal soaring conditions resulting
from boundary layer heating by post-processing numerical weather predictions
to provide parameters suited to the needs of soaring pilots.
BLIPSPOTs are processed as soon as forecast files are available
and thus provide the "latest" predictions for a given location.
One intent of the BLIPSPOT is to help determine when conditions at a location
removed from the launch site are worth taking a long tow to investigate.
A BLIPSPOT emphasizes temporal changes whereas a BLIPMAP depicts spatial
variations but their parameters are essentially identical and
are described on the BLIPMAP
The most important parameter is either "Hcrit" for flat terrain or
for non-flat terrain, which
estimates the maximum thermalling height under cloudless
Relative differences are expected to be more
reliable indicators of soaring variations than are the precise numerical
The BLIPSPOT parameters are averages over 20km grid
squares forecast by NOAA's Forecast Systems Laboratory RAP
BLIPSPOTs do not predict thermal lift created by small-scale
terrain features which are not resolved by the model topography, which
often give localized updrafts significantly stronger than those over the
surrounding smoother terrain. The BLIPSPOT thus indicates conditions over an
area surrounding the specific feature used for naming purposes rather than
immediately above the feature itself.
Since the smoothed model topography differs from the actual
topography, the surface height and temperature used for the BLIPSPOT
are sometimes altered from those used by the model as an approximate
adjustment for such differences or in an attempt to better predict
conditions over a small-scale feature not included in the model
topography. The first elevation following the BLIPSPOT name is
the surface elevation assumed by the BLIPSPOT and following that is
the actual model grid point data, including its longitude, latitude,
and surface elevation. Any surface temperature adjustment used
is noted in the header information - this is an ad hoc adjustment and
may be altered if thermalling height/strength is consistently
over/under that predicted by the BLIPSPOT.
Maps with location identifiers (BLIPSPOTs are
magenta colored) and additional topography information are
available at the
Regional Grid Orientation webpage.
Also provided on this webpage are links to the FSL interactive
soundings located at the model grid point lat/long used for the
BLIPSPOT (so its lat/long may therefore differ from airport or city
lat/longs) - however, the FSL soundings are only available for a
40km-spaced subsample of the full 20km-resolution grid, so there a 75%
probability that the profile viewed is not at the exact
location used by the BLIPSPOT (the line immediately above the plot
will then read "Xnm ... from ..." where X is not
0), and the values are also smoothed by averaging over the neighboring
40km-subsample points. Another pitfall of use of this sounding
data is that the lowest-height temperature displayed is that of the model's
first grid level, not the "surface" temperature - since the former
will alwyas be cooler than the latter on convective days, use of these
sounding will somewhat underpredict the BL top. Some information
on interpreting such soundings is available at the Convective Boundary Layer
and Sounding Analysis webpage.
Other RUC forecast variables are available at the FSL RUC
forecast products webpage and RUC soundings are available at the interactive
(Java) FSL RUC sounding webpage.. Ideally 6hr forecasts are available
every hour while 3hr,6hr,...18hr forecasts are available at 00Z,03Z,...21Z
initialization/analysis times - however, the 20km FSL RUC forecasts are
only semi-operational so results can be missing for various forecast
to the BLIPMAP regional forecasts
Go to pilot flight experiences using BLIPMAPs and BLIPSPOTs.
Go to BLIPMAP Help webpage.
to DrJack's home page