Here is a summary of the NWP output for noon on Saturday.
Issued 0517, 23rd March 2010

The weekend will see low pressure crossing the UK with wind and rain for
all. Into next week it'll stay unsettled and on the cool side.

Analysis and evolution to T+120 via GFS
SW'lies cover the UK, with a low to the north. The winds become SSE'lies
tomorrow as a trough moves up from the SW, followed by further SSE'lies on
Thursday. Friday sees a trough move northwards over the UK, with easterlies
in advance and further SSE'lies following behind.

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 weak westerly flow over the UK. At the 500hPa
level there's a zonal westerly flow, while ECM has an upper low over the UK
instead. MetO brings upper NW'lies with a trough to the east, as do GEM and
JMA.
At the surface, GFS brings a col, with light winds. ECM has a slack trough
over the UK, again with light winds for most. MetO has a col over Northern
Ireland, Wales and SW England, with strong WSW'lies elsewhere. GEM has
NW'lies for all with a trough over Kent and JMA has lighter NW'lies and a
low over France.

Evolution to T+168
ECM brings a trough over Scotland on day 6. To the north, northerlies; to
the south, westerlies. On day 7 the trough remains over Scotland with
SW'lies elsewhere.
GFS shows a low to the east and NNW'lies for all on day 6. Day 7 sees
westerlies as a ridge moves eastwards.

Looking further afield
ECM shows SW'lies on days 8 to 10 with low pressure to the WNW.
GFS brings SW'lies on days 8 and 9 as a low moves eastwards. On day 10 the
low brings WNW'lies across the UK as it fills and moves eastwards.

Ensemble analysis
(http://91.121.94.83/modeles/gens/gra...ille=Lond res)
The GEFS shows temperatures not far from average from Friday onwards, albeit
with a marked dip in a week's time.

ECM ensembles
http://www.meteogroup.co.uk/meteo/ep...tt6-london.gif
The ECM ensembles show temperatures just below average from the end of the
week onwards.