Here is a summary of the NWP output for 12z on Tuesday.
Issued 0520z, 22nd June 2007.

The models are split today. ECM keeps an upper trough over the UK, ensuring
a cool, breezy and showery working week. GFS instead progresses things
aloft, allowing (briefly) warmer SW'lies to affect the UK. Either way it's
unlikely to be a warm week and all areas will see some rain.

Analysis and evolution to T+120 via GFS
http://expert.weatheronline.co.uk/pslv_frame.htm
Low pressure covers the Celtic Sea, leading to light SE'lies for much of the
UK. Tomorrow the low moves away to the NE, leaving behind NW'lies and
westerlies. An upper trough extends southwards on Sunday and low pressure
deepens over the North Sea, leading to cooler NW'lies and westerlies. By
Monday the low covers East Anglia and northerlies set in across 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 east and a NW'ly flow over the
UK. At the 500hPa level there's a large and complex upper low to the east
and NE. MetO paints a similar picture, with the deepest low over the North
Sea. ECM has shallower lows, with a trough over Scotland. GEM keeps the
upper lows further east, with a northerly gradient over the UK.
At the surface GFS shows NW'lies, with a ridge to the west and a deep low
east of Denmark. MetO has a low east of Shetland and stronger NW'lies as a
result. ECM also shows NW'lies, whis time with a low over the Baltic. GEM
brings NW'lies too, as the result of a ridge to the west and a German low.

Evolution to T+168
ECM shows the upper trough retrogressing over the UK. On day 6 a surface
trough moves southwards, with NW'lies in advance and northerlies behind. On
day 7 a trough covers the North Sea, leading to NNW'lies for most.
GFS shows a completely different outlook, with the upper ridge to the west
progressing eastwards. Day 6 sees WSW'lies and a weak ridge, followed by
warmer SW'lies on day 7 as a low deepens to the west.

Looking further afield
NW'lies cover the UK on day 8 of ECM, followed by a col on day 9. By day 10
SW'lies and southerlies affect the UK ahead of a low to the west.
GFS brings SW'lies on days 8 and 9 as low pressure becomes slow moving over
Scotland and Northern Ireland. By day 10 it moves away to the east, leaving
the UK under strong NW'lies and westerlies.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show a notable cold spell on the way, with 850s generally
staying below average until the end of the run.