Here is a summary of the NWP output for noon on Sunday.
Issued 0459z, 17/05/11

The start of the new week will see WSW'lies or westerlies across the UK,
with showery conditions for the north and west especially. Low pressure will
then approach from the west, with southerlies in advance and then westerlies
as a trough moves NE'wards. It may be the case that any rain from the trough
fizzles out as it reaches the SE.

Analysis and evolution to T+120 via GFS
SW'lies cover the UK, with a deep low to the NW. Tomorrow a trough moves
eastwards, with westerlies across the UK (albeit light in the south). On
Friday there are SW'lies for most, although the SE third of England lies
under a col. Much the same is true on Saturday.

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 strong westerly flow over the UK with a zonal
flow upstream. At the 500hPa level there's also a strong westerly flow. The
other runs also show the jetstream over the UK, with a strong WSW'ly or
westerly flow at 500hPa.
At the surface the runs all show WSW'lies, with a ridge to the south and a
low to the north.

Evolution to T+168
Days 6 and 7 with ECM show southerlies followed by westerlies as a deep low
moves NE'wards to the north of Scotland.
A trough covers the UK on day 6 with GFS, leading to strong westerlies. On
day 7 there are lighter southerlies ahead of a deepening low to the west.

Looking further afield
A ridge covers the UK on day 8. On day 9 it settles over northern Scotland,
bringing NE'lies for most. Day 10 sees easterlies and ESE'lies as the ridge
becomes a high to the NE.
GFS brings low pressure over the UK on day 8, followed by NW'lies as a ridge
builds from the west on day 9. On day 10 a ridge covers England and Wales,
leading to SW'lies elsewhere.

Ensemble analysis
http://www.meteociel.com/cartes_obs/...&ville=Londres
The GEFS shows temperatures close to or slightly above average.

ECM ensembles
http://www.meteogroup.co.uk/meteo/ep...tt6-london.gif
ECM also shows temperatures a little above average over the coming week.