Here is a summary of the NWP output for noon on Wednesday.
Issued 0444, New Year's Eve 2011

The outlook remains a zonal one. There's now a stronger sign for mildness
continuing, with the cooler trend of the past few days' output looking
somewhat less likely now.

Analysis and evolution to T+120 via GFS
WSW'lies cover the UK in association with a weak ridge. Tomorrow there are
SW'lies as a trough approaches from the west, followed by colder SW'lies on
Monday. Tuesday sees strong SSW'lies due to a low to the WNW.

T+120 synopsis
http://www.wetterzentrale.de/wz/pics/Rtavn12014.png
http://www.wetterzentrale.de/wz/pics/Rtavn1201.png
http://www.wetterzentrale.de/wz/pics/Rukm1201.gif
http://www.wetterzentrale.de/wz/pics/Recm1201.gif
http://www.wetterzentrale.de/wz/pics/Rjma1201.gif
The jetstream chart shows a marked ridge to the west, with the jet heading
SE'wards over the UK and France. At the 500hPa level there are also NW'lies,
with WNW'lies on the other runs due to a weaker ridge.
At the surface GFS brings strong WNW'lies, with moderate to strong
westerlies on the other runs.

Evolution to day 7
ECM brings NW'lies on day 6 as the result of a ridge to the west. There are
WSW'lies on day 7 as the ridge moves eastwards.
Mild WSW'lies cover the UK on day 6 with GFS as a ridge moves eastwards.
There's little change on day 7.

Looking further afield
Day 8 with ECM shows a trough moving eastwards, followed by WNW'lies on day
9 as a ridge approaches from the west. On day 10 the ridge moves away to the
east, allowing SW'lies to cover the UK.
Days 8 to 10 with GFS show WSW'lies and westerlies, with a strongly zonal
flow.

Ensemble analysis
http://www.meteociel.com/cartes_obs/...&ville=Londres
The GEFS shows zonality continuing, still with a trend for cooler
temperatures but now over a week away.

ECM ensembles
http://www.meteogroup.co.uk/meteo/ep...tt6-london.gif
ECM shows zonality with the majority of members now favouring a continuation
of generally mild conditions.