Here is a summary of the NWP output for noon on Sunday.
Issued 0514, 17th March 2010

The new week will start with low pressure near the UK but there's no
agreement as to where the low will be. ECM shows it affecting the south
while GFS has the low staying away to the NW, with the weather being the
opposite to ECM (ie rain in the north, dry in the south). MetO agrees with
GFS, so for the time being ECM is out on its own.

Analysis and evolution to T+120 via GFS
Southerlies cover the UK, with a ridge to the east. There are further
southerlies tomorrow but by Friday a trough moves eastwards and WSW'lies
cover the UK. SE'lies affect the UK on Saturday with a low to the WSW.

T+120 synopsis
http://91.121.93.17/pics/Rtavn12014.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 westerly flow over the Atlantic, with the jet
further south than normal. At the 500hPa level there's a SW'ly flow with a
low to the west. ECM has a weak upper ridge over the UK, while MetO has an
upper low over the UK. GEM shows a SW'ly flow aloft as per GFS and JMA
brings SW'lies aloft too.
At the surface, GFS brings SSW'lies and a low to the west. ECM has
easterlies and ESE'lies with a low to the south, whilst MetO has a low over
the North Sea and northerlies for Scotland. Elsewhere, south of a trough,
winds are SW'lies. GEM brings a weak ridge over Ireland and a mixture of
northerlies and NW'lies for the UK, while JMA has a trough over Scotland and
WSW'lies elsewhere.

Evolution to T+168
ECM shows a trough over the far south on day 6, leading to easterlies for
most. On day 7 NE'lies move across Scotland, northern England and Northern
Ireland, with a trough over the Midlands and Wales bringing westerlies for
the far south.
GFS brings SSW'lies on day 6 due to a secondary low over Scotland. On day 7
there's a col and light winds.

Looking further afield
ECM shows easterlies backing NE'ly on days 8 to 10 as high pressure
retrogresses and some deep cold air approaches the UK.
GFS has SE'lies and easterlies on day 8 due to a low to the WSW. Day 9 has
light winds due to a col, followed by strong SW'lies spreading northwards
due to a low to the west.

Ensemble analysis
(http://91.121.94.83/modeles/gens/gra...ille=Lond res)
The GEFS shows a warm few days ahead, followed by a slight cooling.

ECM ensembles
http://www.meteogroup.co.uk/meteo/ep...tt6-london.gif
The ECM ensembles also show a marked cooling next week, with the operational
being one of the coldest runs.