>airsports@usa.com (Mark Griffin)

>First off all the AVN is a model.
>Check out the National Weather Services page of definitions
>under AVN
>http://www.srh.noaa.gov/LUB/safety/glossary.htm
>and look under AVN for its definition.
>

Just b/c it comes from an NWS web site doesn/t mean the people who put it
together know what they are talking about. Take it from someone who spent
almost a decade with the oprganization.

I/ll rummage around and cough up a few links to prove my point that the AVN is
not a model, but it is a forecast run from the Global Spectral Model (GSM) run
at NCEP. The GSM is the same model that produces the MRF, although nowadays,
with the new naming convention, the GSM output is just called the AVN.

>As for your comment on the accuracy of the NGM model being higher than
>the AVN
>model is unfounded. It is common knowledge that the AVN model is more
>accurate
>than the NGM model. No further comments are offered.

There is no argument that the AVN modeled output (geo-potential heights,
temperature, moisture) is better than that from the NGM, but that does not
extrapolate to mean the AVN MOS is better than the NGM MOS. In fact, both
product/s forecast for winds and clouds suck. The inflation factor alone when
the forecast wind speed is above mean wind speed makes it all but useless for
soaring wx and forget about getting reasonably accurate wind direction.

>As for your comments on the accuracy of the Winds Aloft Forecast, let
>me just say that the winds aloft stations are totally different than
>the NGM model stations which means that they are two different sources
>of information. If the Winds Aloft Forecast came from the NGM model
>then there would be a Winds Aloft Forecast for every NGM station.

You are correct that the FD winds and the NGM MOS stations are different but
that doesn/t mean there aren/t other products that derive from NGM output; the
FDUS winds being a case in point. The NGM output is also used to provide wind
and seas forecasts for stations that are not MOS stations, as well. You
comments shows a distinct lack of knowledge about the NWP data your web site
presents and it would behoove you to be better informed.
---
- T Q -

Start every day off with a smile and get it over with.
-- W.C. Fields --

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