Here is a summary of the NWP output for noon on Wednesday.
Issued 0539, 9th January 2010.

It looks as though the cold spell will ease somewhat in the south by the
middle of the week. It'll still be colder than average, but precipitation is
more likely to be rain rather than snow by Wednesday. There's likely to be a
fair bit of it too, as a trough or low approaches from the southwest. The
ensembles show the milder air failing to make it as far north as Manchester
next week, suggesting a battleground scenario over the UK and the chance of
further snow in the north.

Analysis and evolution to T+120 via GFS
Strong NE'lies cover England and Wales, with high pressure over southern
Norway and a ridge over Scotland and Northern Ireland. Tomorrow the high
builds to the NE, with strong and biting NE'ly or NNE'ly winds over the UK.
The winds become ENE'lies on Monday, with slightly less-cold air being
pulled in from the east. Tuesday sees SE'lies as pressure falls to the SW.

T+120 synopsis
http://91.121.93.17/pics/Rtavn12015.png /
http://91.121.93.17/pics/Rtavn1201.png
http://91.121.93.17/pics/Rukm1201.gif
http://91.121.93.17/pics/Recm1201.gif /
http://www.meteociel.fr/modeles/nogapse_cartes.php
The jetstream chart shows a broad, strong and zonal jet far to the south,
crossing the Azores and heading into Iberia. The northern branch of the jet
is weak and displaced far tp the north, up near Svalbard. The 500hPa chart
shows an upper high over Scandinavia and a shallow trough over the UK. ECM
has a sharper trough over the UK, with a weaker upper high to the NE. MetO
shows a trough over the UK as well, while GEM has a stronger high to the NE
and an upper low over northern France; this leads to upper easterlies. JMA
has an upper col.
At the surface, GFS brings SE'lies across the UK, with a deep low to the SW.
ECM is more progressive with a low over the North Sea leading to milder
conditions in the south. For much of Scotland, northern England and Northern
Ireland winds remain easterly. MetO shows SE'lies and ESE'lies, with a
shallow low to the south. GEM has stronger (and colder) easterlies, this
time with complex low pressure to the SW. JMA brings SE'lies and ESE'lies,
with a high to the NE.

Evolution to T+168
ECM shows a low over Ireland on day 6, with southerlies for England and
SE'lies or ESE'lies elsewhere. The low fills over the English Channel on day
7, leaving much of the UK under a col.
GFS brings a weak NE'ly flow on day 6 due to a weak high over Ireland. On
day 7 a ridge covers Scotland with a shallow trough over western France.
Light easterlies are the result.

Looking further afield
ECM shows a SE'ly flow on day 8 with a trough to the SW. The trough crosses
the Midlands on day 9, bringing SW'lies to the south and SE'lies elsewhere.
The trogh disrupts on day 10, leaving the UK under a col.
GFS has SE'lies and a trough to the SW on day 8. Day 9 sees a weak trough
over the UK, followed by a ridge over the UK on day 10. This leads to light
winds for England and Wales with southerlies elsewhere.

Ensemble analysis
(http://91.121.94.83/modeles/gens/gra...ille=Lond res)
The GFS ensembles show a marked warming aloft after today, although it'll
take another 5 days or so before the warming makes it to the surface.
Although it won't be mild for some time, London at least is more likely to
see rain rather than snow by Wednesday.

ECM ensembles
http://www.meteogroup.co.uk/uk/home/..._forecast.html
ECM shows daytime high just above zero until Wednesday, followed by a
warming trend.