DrJack sez:
Welcome to the expanded BLIPMAP predictions,
now providing two different model forecasts!
This page is primarily for new users, since regular users will create
bookmarks to lead them directly to the forecast region and model of
interest to them. Here you choose between the two model forecast
types available, NAM or RAP - clicking on the top link in each column will lead
you that model's regional
coverage areas.
NAM and RAP are two different models run by NOAA's NCEP (National Center
for Environmental Prediction) and intended for slightly different purposes.
BLIPMAPs post-process the output from each to forecast parameters which are
more useful to gliding pilots than the standard meteorological parameters.
The principal differences between the models are given below, the most
salient being that if you are looking for a forecast for other than
the "current day" then you must choose the NAM model. Although
the models use the same basic methodology there are differences,
notably in the simplifications used when processes are too complex to
be treated exactly, so differences between the NAM and RAP forecasts
do occur. This is acerbated by the sensitivity of such models to
uncertainties in our knowledge of the full 3D state of the atmosphere
at any time.
NAM |
RAP |
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Click here for NAM forecasts |
Click here for RAP forecasts |
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Model Features: Forecasts out to 84 hours Available only for two hours each day Updated at 6 hr intervals For same forecast period, NAM available ~1hr later 12 km horizontal resolution Poorer vertical BL resolution |
Model Features: Forecasts out to 12 hours Available for five hours through day Updated at 3 hr intervals For same forecast period, RAP available ~1hr earlier 20 km horizontal resolution Better vertical BL resolution |
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Numerous model differences of detail, such as their parameterization of clouds, may lead to one model providing better forecasts
of certain soaring parameters for your location, but that can only be determined through actual flight experience.
A more detailed description of differences between the two models is provided in the NAM vs RAP Model Comparison webpage Usage information is available on the BLIPMAP information webpage |
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