Here is a summary of the NWP output for 12z on Wednessday.
Issued 0527z, 18th August 2007

The run up to the weekend will see high pressure dominating the UK, as a
ridge builds from the west. Most areas will see dry and warm weather and
there's no sign of a quick change back to unsettled conditions on the
horizon.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
Low pressure lies to the west, bringing SSE'lies and southerlies over the
UK. The low crosses the UK today and tomorrow, allowing a weak ridge to
cross the UK on Monday. Tuesday sees a ridge to the west and NW'lies for
most.

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 strong jet heading NE'wards across the North
Atlantic, passing between Scotland and Iceland. This has the effect of
allowing a large upper ridge to extend NE'wards over the UK from the Azores.
MetO shows a similar upper ridge over the UK, as does ECM. GEM has a tighter
NNE'ly gradient over the UK, with the ridge further west.
At the surface, GFS brings a strong ridge over the UK with light winds for
most. MetO shows a similar ridge but further south, leading to SW'lies for
Scotland and Northern Ireland. ECM centres the ridge over Scotland and
Northern Ireland, with northerlies elsewhere. GEM is similar to ECM, albeit
with stronger northerlies over England and Wales.

Evolution to T+168
ECM shows the Azores High building and moving slowly NNE'wards to the west
of the UK. On day 6 a ridge persists over Scotland and Northern Ireland, as
is the case on day 7. On both days England and Wales lie under northerlies.
Days 6 and 7 on the GFS show high pressure building to the west of Ireland,
with a NW'ly flow over the UK.

Looking further afield
The ECM shows the high slowly declining and moving SE'wards on days 8 to 10.
A mixture of NW'lies and northerlies covers the UK on days 8 and 9, with
westerlies on day 10.
On days 8 to 10 the GFS brings high pressure slowly eastwards across the UK
and, by day 10, over the nearby Continent. Days 8 and 9 see a mixture of
westerlies and NW'lies, followed by SW'lies and SE'lies on day 10 as the
high recentred over southern Germany.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show a warm, dry spell on the way.