Here is a summary of the NWP output for noon (GMT) on Friday.
Issued 0524z, 4th August 2008

Saturday will see a weak ridge move swiftly across the UK, bringing a
settled day for many away from the far west. Rain associated with a trough
will affect many areas on Sunday and thereafter a generally unsettled regime
will prevail.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
Low pressure lies to the NE, with westerlies for the UK as a result. There's
a col and light winds tomorrow, followed by southerlies and SW'lies on
Wednesday due to a trough over Ireland. Thursday sees a trough over Scotland
and Northern Ireland, with light SSW'lies to the south and moderate
northerlies to the NW.

T+120 synopsis
http://85.214.49.20/pics/Rtavn12014.png /
http://85.214.49.20/pics/Rtavn1201.png
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 to the west and a NW'ly flow over the
UK. At the 500hPa level there's a ridge to the west, while MetO has a weaker
ridge. ECM shows a ridge to the west and a trough over the UK. GEM has an
upper low over the North Sea and NNW'lies aloft.
At the surface GFS has NW'lies for all with a ridge to the west. MetO has a
ridge over the UK with WNW'lies, while ECM shows NW'lies as well. GEM brings
strong cyclonic NW'lies with a low over the North Sea.

Evolution to T+168
Day 6 with ECM brings a ridge over England and Wales, with southerlies
across the UK. SW'lies cover the UK on day 7 as a trough moves swiftly
eastwards.
A ridge covers the UK on day 6 with GFS, with westerlies and SSW'lies as a
result. SSW'lies continue to affect the UK on day 7 due to a trough over
Ireland.

Looking further afield
On day 8 with ECM there's a low to the west and southerlies for all. The low
moves eastwards on day 9, leading to northerlies over Scotland and
westerlies or SW'lies elsewhere. Westerlies and WNW'lies affect the UK on
day 10.
The UK lies under a trough on day 8 with GFS, leading to WSW'lies for most.
On day 9 there are SSW'lies and southerlies as a secondary low approaches
from the SW. The low crosses into the North Sea on day 10, leaving the UK
under a col.

Ensemble analysis
(http://91.121.94.83/modeles/gens/gra...ille=Lond res)
The ensembles show a warm couple of days later this week, followed by a
marked drop in termperatures on Saturday.