Here is a summary of the NWP output for 12z on Tuesday.
Issued 0531z, 15th June 2007.

The latter half of next week will see low pressure moving up from the SW and
it'll cross the UK. To the south of the low it's likely to remain on the
warm side but elsewhere temperatures will be close to if not below average.
Longer term the suggestion is for temperatures to fall below average widely,
but that's been at the "week away" stage for over a week now.

Analysis and evolution to T+120 via GFS
http://expert.weatheronline.co.uk/pslv_frame.htm
Low pressure is centred to the SW, with a trough over England and Wales. To
the north winds are easterlies or ENE'lies. Tomorrow the low moves over
England and Wales, with SW'lies for SE England and NE'lies for Scotland and
Northern Ireland. Light winds cover the UK on Sunday as the low moves away
over the North Sea. On Monday a new low lies to the SW, leading to SE'lies
for much of the UK.

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 jet stream chart shows a trough to the SW and the jet heads northwards
over the western half of the UK. At the 500hPa level there's a low to the SW
and a ridge over the North Sea, whereas MetO brings the low over Ireland
instead. ECM is closer to GFS, with low pressure to the SW. GEM places the
upper low further to the SW with a weak ridge over the UK. NGP centres the
upper low over SW Scotland.
At the surface GFS brings SE'lies and a deep low to the SW. MetO's low isn't
as deep and it's centred over Ireland. Southerlies cover most of the UK as a
result. ECM shows a low to the SW and a weak ridge over England and Wales.
Scotland and Northern Ireland lie under variable winds, with southerlies
elsewhere. GEM has a col over the eastern half of the UK, with SE'lies
elsewhere from a low to the NE of the Azores. SW'lies cover England and
Wales with NGP due to a low over northern parts of the UK.

Evolution to T+168
ECM shows the upper and surface lows moving NE'wards over the UK. On day 6
they're centred over SW England, with a trough and southerlies for England
and Wales. Elsewhere winds are ENE'lies. By day 7 the lows move over the
North Sea, leading to northerlies for Scotland and Northern Ireland with
WSW'lies elsewhere.
GFS brings a similar but slower evolution. A low covers the Celtic Sea on
day 6, bringing southerlies and SE'lies for the UK. The low moves slowly
NE'wards on day 7, with further southerlies for most.

Looking further afield
Day 8 on the ECM shows NW'lies and a low over the North Sea. NW'lies persist
on day 9 and by day 10 they're still going, with high pressure building to
the west.
GFS shows SW'lies for most on days 8 to 10 as the low moves very slowly
NE'wards, filling over northern Scotland by day 10.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show temperatures around average for another week, followed by
a cool spell.