Here is a summary of the NWP output for 12z on Friday.
Issued 0605z, 5th February 2007.

The "battleground" scenario remains this week, although it's now likely that
it'll be a shortlived affair across much of England and Wales with milder
air by the end of the working week. For Scotland and Northern Ireland things
look like staying colder for longer, and it's here there's the greatest risk
of disruptive snowfall. Areas further south may well see some, but as ever
these things are hard to pin down more than 48 hours or so away! By Sunday
it looks wet and windy everywhere and the theme continues into next week
with low pressure never far away.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
http://85.214.49.20/pics/avnpanel1.gif
Northerlies and NW'lies cover the UK, due to complex low pressure over
Scandinavia and a large high ridging south from Greenland. The ridge
declines and moves SE'wards over Ireland tomorrow, leading to NW'lies for
most. By Wednesday a low to the SW brings SE'lies to western part of the UK,
with light winds over the east due to a low over Denmark. By Thursday a
strengthening ESE'ly heralds the arrival of a low over the Celtic Sea, with
milder air working its way northwards.

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/Rjma1201.gif /
http://85.214.49.20/pics/Rukm1201.gif
http://85.214.49.20/pics/Recm1201.gif /
http://85.214.49.20/pics/Rngp1201.gif
The jetstream chart shows a strong and zonal jet across the North Atlantic,
albeit mainly to the south of the UK. At the 500hPa level there's a trough
from the west affecting the UK, while ECM shows the trough further west.
MetO also shows a trough from the west affecting the UK, with an upper low
west of Ireland. NGP shows the trough further NW, while GEM has much higher
heights to the immediate west.
At the surface GFS has a deep low over East Anglia. Strong easterlies affect
Scotland, Northern Ireland lies under a col and NW'lies and westerlies cover
England and Wales. ECM shows southerlies with a deep low to the west and a
secondary east of Scotland. MetO brings ESE'lies and easterlies over the UK,
with a trough over the Channel and a low to the west. NGP shows southerlies
due to a complex low to the west, while JMA has a low to the south of
Ireland and SE'lies for all.

Evolution to T+168
ECM shows very unsettled conditions developing. On day 6 SW'lies cover the
UK with a low to the NW, with further (near gale force) SW'lies on day 7 as
a new low deepens to the WNW.
GFS brings a deep low across the UK on day 6, with easterlies for Scotland
and strong to gale force SW'lies elsewhere. By day 7 NW'lies affect the UK
in the wake of the low.

Looking further afield
ECM brings strong WSW'lies over the UK on days 8 to 10 as complex low
pressure slowly moves eastwards in the vicinity of Iceland.
GFS also shows complex low pressure, this time to our west. SE'lies and
southerlies cover the UK on day 8 as a secondary low crosses the Celtic Sea,
followed by westerlies as the low moves over Scotland on day 9. By day 10 a
new low lies to the west, with southerlies and SE'lies as a result.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show cold air lingering across Scotland until the weekend,
with a shorter cold spell in the south as milder air moves northwards on
Thursday.