Here is a summary of the NWP output for 12z on Monday.
Issued 0541z, 19th April 2007.

The middle of next week is likely to be somewhat cloudy, with a good chance
of rain moving in from the west in association with a trough or low.
Temperatures will continue to be at or above average for most and by next
weekend high pressure looks like returning.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
http://85.214.49.20/pics/avnpanel1.gif
High pressure covers England and Wales with westerlies elsewhere. Tomorrow
the whole of the UK lies under a high, with light winds for all. The high
moves eastwards on Saturday, leading to southerlies for all areas except
England, which lies under light winds. There's little change on Sunday.

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://www.meteociel.fr/modeles/nogapse_cartes.php
The jetstream chart shows a split jet over the North Atlantic, with the UK
under a large ridge. At the 500hPa level there's a ridge to the east with
GFS, while ECM has the ridge slightly further west. MetO has a ridge over
the North Sea, while GEM places the ridge further east, over Germany and
Poland.
At the surface GFS brings southerlies across the UK, with a weak ridge to
the east and a trough to the west. ECM is broadly similar, with the
strongest winds over western areas. MetO shows moderate to strong SW'lies
for all, with a deep low to the NW, as is the case with GEM.

Evolution to T+168
A weak trough crosses England and Wales with the ECM on day 6. The trough
then fills on day 7, leaving the UK under a col.
GFS brings a low over the Celtic Sea on day 6, with southerlies for most as
a result. The low moves slowly NNE'wards on day 7, crossing Scotland.
Northerly gales cover western Scotland, with moderate to strong WSW'lies
elsewhere.

Looking further afield
ECM shows a col on day 8, followed by a ridge building from the SW on day 9.
By day 10 the ridge declines again, leaving England and Wales under NW'lies
with SW'lies elsewhere.
GFS brings a ridge over England and Wales on day 8, with more of the same on
day 9. By day 10 the whole of the UK lies under high pressure.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show a brief cold snap for northernmost areas, followed by a
period of above average temperatures. Further south the temperatures stay
above average throughout the 16 day run.