[ The following is only of use for those in England (except far SW),
Wales (except far W) & the Southern Uplands of Scotland ]

Not sure if everyone is aware of the higher (output) resolution
representation of various parameters that are now available via the
'Topkarten' site at:-

http://www.wetterzentrale.de/topkarten/

but if you navigate via:-

"GFS" (top-left panel)

"M-Europa" (next panel along: 'middle Europe')

you can choose from various fields with 3 hr time-steps; in particular,
and most useful currently, the field labelled:-

" 3h Niederschlag " will show precipitation amounts in millimetres (I
assume where the phase is snow then it is 'liquid water equivalent',
though I can't see any legend to that effect), and also shown are
contours of the height of the zero degC level (in metres).

This latter shouldn't be taken as the 'snow-level' as such, because of
course snow can descend (depending upon the relative humidity in the
boundary layer & intensity) well below this level, but it is a useful
guide.

If the freezing level is less than ~300 m above your elevation, then it
is reasonable to assume that there is a 50% probability of PPN falling
as snow inland. If it is 100m then there is a =90% probability of
snow. (However, in coastal areas with an onshore wind off a relatively
warmer ocean, then these figures will not apply so well if at all). [
Ref: Boyden Met.Mag 1964 ]

The horizontal resolution of the GFS is approx. 40 km out to 180hr (~80
km beyond that), and the output resolution of these charts, according to
the site information, is 50km, so for this display you are seeing
near-full model resolution, as opposed to the main charts, which are
'thinned' to ~100 km.

The GFS is still a crude model to use for 'local' work though, bearing
in mind that modern mesoscale models are working down to the ~10km or
better level.

Martin.

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