Here is a summary of the NWP output for 12z on Monday.
Issued 0540z, 23/11/06

The outlook remains very unsettled and mild in the short term, with signs of
relatively cooler (but still unsettled) conditions for the latter 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
SW'lies cover much of the UK with a deep low near Northern Ireland. The low
moves away to the NE tomorrow, leading to SW'lies for all. A new low fills
to the south of Ireland on Saturday with strong SSE'lies and SE'lies as a
result, followed by westerlies and SW'lies on Sunday as the low deepens to
the NE.

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.jpg /
http://85.214.49.20/pics/Rukm1201.jpg
http://85.214.49.20/pics/Recm1201.jpg /
http://85.214.49.20/pics/Rngp1201.jpg
The jetstream chart shows a trough to the west and a ridge over England,
Scotland and much of western Europe. At the 500hPa level there's a high over
eastern Europe and a low SW of Iceland, with a trough west of the UK. ECM
has the upper low closer to the UK, just to the west of Ireland, while
yesterday's 12z MetO has it further west. JMA is very similar to MetO, while
NGP is closer to ECM with the low closer to the UK. Finally the Canadian run
keeps the upper low much further west.
At the surface GFS shows a very deep low to the SW of Iceland and a high
over Poland. A trough covers the UK, bringing a mixture of southerlies and
SSW'lies. ECM shows southerlies for all with a deep low to the west, with
MetO showing a very similar setup. JMA has SSE'lies instead of southerlies,
while NGP shows southerly and SE'ly gales, with the low close to Ireland.
The Canadian run keeps the low further west with strong SE'lies over the UK.

Evolution to T+168
ECM shows the upper low to the west moving NE'wards on days 5 to 7, with the
associated upper trough moving slowly eastwards over the UK. Strong SSW'lies
cover the UK on day 6 as the surface low fills and moves northwards,
followed by a mixture of westerlies and SW'lies on day 7 as a trough crosses
the UK.
The GFS shows an upper high developing to the NW of Scandinavia and an upper
ridge moving over the UK on days 5 to 7. Day 6 sees a surface trough cross
the UK, leading to southerlies for Scotland and much of England. Elsewhere
winds are SW'lies, followed by SW'lies for most on day 7 due to a secondary
low to the west of the UK.

Looking further afield
ECM out to 10 days brings a weak ridge over Ireland on day 8 with WNW'lies
for the UK. On day 9 a trough approaches from the west with SSW'lies and
SW'lies as a result. By day 10 the trough moves over the North Sea, leading
to WSW'lies for all.
GFS shows the upper high near Scandinavia declining over days 8 to 10, with
an upper low developing to the north of the UK and a strong zonal jet
developing. Winds are SW'lies for all on day 8 with complex low pressure to
the NW, followed by strong to gale force westerlies on day 9 as the lows
move slowly eastwards. By day 10 a trough crosses the UK with westerlies for
all.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles continue to show a "sine wave" effect for the next week or so,
reflecting the passage of lows near the UK. 850hPa temperatures are above
average for at least a week, thereafter there's a good signal for a cooler
spell albeit with scatter suggesting considerable differences in track and
positioning of lows.