Ensemble from multiple sources

[Mandelli Alessandro]

This map
http://www.meteogiornale.it/mappe/mandelli/ensemble/spaghetti500_0.png
is obtained through server side extraction of ensemble data from
http://nomad5.ncep.noaa.gov:9090/dods/ens/archive/

This one though
http://www.meteogiornale.it/mappe/mandelli/ensemble/enspost500_0.png
is obtained from grepping the source grib data 'enspost.t12z.z500' from
ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/mrf/prod (again, thanks to
Sacchetti)

Now: they are not equal, as I would expect; they don't even look alike.
Model is the same, init is the same, resolution is the same: I would
expect the same output.

Any thought anyone?