Here is a summary of the NWP output for 12z on Friday.
Issued 0521z, 13th August 2007

The weekend is likely to be showery, with an upper trough near or over the
UK. By the end of Sunday, high pressure will be ridging across Scotland and
it looks likely to affect the whole of the UK during the first half of next
week.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
http://85.214.49.20/pics/avnpanel1.gif
Low pressure is centred over Scotland, with SW'lies for the UK. Tomorrow a
low deepens to the west, with a mixture of SSW'lies and southerlies for the
UK. Wednesday sees the low move over the Celtic Sea, with strong SSW'lies
for England and Wales. Elsewhere winds are northerlies, with today's low
persisting to the east of Scotland. On Thursday the lows merge to the north,
leaving the UK under WNW'lies.

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 large trough over the UK and western Europe. At
the 500hPa level there's a slack trough over the UK, while MetO has a
flatter pattern aloft. ECM also has a weak trough over the UK, while NGP has
a sharper trough instead.
At the surface, GFS brings a shallow trough with WSW'lies for all. MetO also
shows WSW'lies, but of an anticyclonic nature. THe same is true of ECM,
while NGP has a trough and light winds for most.

Evolution to T+168
ECM shows a low to the WSW and a trough over Scotland, with SW'lies for
most. A ridge topples over Scotland on day 7, with NE'lies across the UK.
Day 6 on the GFS shows light winds and a col. Day 7 sees a ridge build over
Scotland and Northern Ireland, with NNE'lies elsewhere.

Looking further afield
The ECM shows a ridge over the UK on day 8, followed by a return of WSW'lies
for Soctland on day 9 as the ridge declines over England and Wales. By day
10 the ridge builds again across the UK.
The GFS on day 8 shows a ridge over the UK, followed by more of the same on
day 9. By day 10 a low lies to the east, bringing a mixture of northerlies
and NE'lies for the UK.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show a cool spell for the latter half of the week, followed by
an abrupt change to warmer conditions in just over a week.