Here is a summary of the NWP output for noon on Sunday.
Issued 0534, 30th Jan 2008

The end of the weekend will see a messy transition back to milder weather,
with a front moving in from the west. Initially it'll fall as rain but as it
meets the cold air further east it's likely to turn to snow, with the
potential for some heavy falls in places. It's likely that later on in the
day it'll turn back to rain, but not before a covering of snow in many
places. Into next week milder air returns, with a standard NW/SE split
likely, most of the rain in the north and west.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
A trough covers SE England, with westerlis and WNW'lies following behind.
Tomorrow sees a deep low to the north with strong to gale force SW'lies over
the UK. A trough moves SE'wards and by Friday the eholw of the UK lies under
a much colder westerly or WNW'ly flow, with gales or severe gales and snow
likely for much of Scotland. By Saturday the low fills and moves ENE'wards,
leaving the UK under notably cold NW'lies.

T+120 synopsis
http://85.214.49.20/pics/Rtavn12015.png /
http://85.214.49.20/pics/Rtavn1201.png
http://85.214.49.20/pics/Rukm1201.gif
http://85.214.49.20/pics/Recm1201.gif /
http://www.meteociel.fr/modeles/nogapse_cartes.php
The jetstream chart shows a zonal flow across the North Atlantic, with the
the core of the jet below 50N. There's a trough over the UK, with the jet
heading northwards over eastern parts of the UK. At the 500hPa level there's
an upper low to the NW and a trough over Ireland, with upper southerlies
over much of the UK. MetO shows a similar setup, with upper southerlies and
SW'lies for the UK, as is the case with ECM. GEM brings upper SSW'lies with
a low to the WNW.
At the surface GFS brings a trough over the UK, with SSE'lies or SE'lies for
Scotland and eastern England and SW'lies elsewhere. MetO has the trough over
northern Scotland instead, with SW'lies for most. ECM brings strong
southerlies for all, with a trough over Northern Ireland, while GEM has a
low to the north and SW'lies for all.

Evolution to T+168
ECM shows strong SSW'lies for all, with a low to the WNW on day 6. The low
moves northwards and fills on day 7, with SW'lies for all.
A deep low lies to the west on day 6 with GFS, leading to strong
southerlies. The low moves NNE'wards on day 7, leaving SW'lies for the UK.

Looking further afield
A low lies to the west on day 8 with ECM, with southerlies over the UK. The
winds become SSW'lies and SW'lies on day 9 as a weak ridge moves NE'wards,
followed by further SW'lies on day 10.
GFS shows a secondary low crossing the UK on day 8, followed by a weak ridge
and westerlies on day 9. By day 10 winds are SSW'lies with high pressure to
the ESE.

Ensemble analysis
(http://91.121.94.83/modeles/gens/gra...ille=Lond res)
The ensembles still show three cold days followed by a return to much milder
conditions.