"Scott W" wrote in message
...
On Wednesday, 16 December 2015 13:55:27 UTC, Dave Cornwell wrote:
"..The GFS model as we know has a tendency to over-develop LP systems
and if it does decrease in intensity in subsequent runs, it may promote
a more rapid pressure build over Norther Scandinavia than currently
projected."
Do we know? Is this feasible?

Often see stuff of this ilk quoted on weather forums but surely the
people at GFS, ECMF etc aren't stupid. If models consistently have a
tendency to predict something incorrectly surely they would just tweak
the algorithms a bit. I thought that was the whole point of a
mathematical model.

Dave

I was quite shocked when Will mentioned a while ago that the models DON'T
consider climatology, for example Lamb Weather Types etc. One of Philip
Eden's articles a while ago mentioned that if you are faced with a 50/50
situation while looking at a model you go with the 'average' of what
happened before. I think that is where the skill of a professional
forecaster comes in.
=======

Yes indeed. And to re-iterate (in a nutshell), NWP models solve
computationally the Navier Stokes equations on an oblique spheroid for the
general dynamics (4D synoptic evolution). Physics and radiation packages are
used to add in detail of vertical profiles of temperature, precipitation,
cloud and humidity at the gridpoints. Post-processing is used to add in
site-specific detail accounting for unresolved features (such as topographic
detail) and for commercial requirements. Ensemble means of synoptic
variables are used to provide a broad overview of expected evolution with
the ensemble members giving an indication of the uncertainty.
Post-processing of ensemble members will give probability of weather at
specific locations. Nowadays, the Met Office has ensembles at 1.5km
resolution covering the UK out to circa 36 hours ahead.

Will
--
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
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