In article
,
Lawrence13 writes:
The GFS isn't fit for purpose. Really, what is its value when it can
do a 180 degree turn before its even started. It's a waste of the USA
governments money and our time.

It depends on what you think its purpose is. It almost always provides
useful guidance out to 5 days, usually to 7 or 8, and occasionally to 10
or more, especially from the ensemble as a whole. If you focus only on
the operational run, and expect reliable guidance towards the further
end of the 16 day period, then you are doomed to disappointment. But if
you think that the model is a waste of your time, then why spend time on
it? The remedy is in your own hands.

It's significant that the ECM doesn't release anything beyond 10 days,
and most of the other models restrict themselves to even shorter periods
than that. I'm sure that those responsible for the GFS regard the output
for beyond 10 days as a research tool rather than as suitable for making
a forecast, but being Americans they have an admirable attitude of
keeping nothing back from the general public. As to the cost to the
American government, I imagine that the extra expense of running the
model out to 16 days rather than 10 is minimal.

Whatever you think of Dawlish's attitude towards some other posters, his
requirement for consistency from four successive model runs before
taking what is shown seriously is a sensible one.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw