Here is a summary of the NWP output for 12z on Saturday.
Issued 0516z, 21/11/06

The outlook remains unsettled with low pressure close by. Temperatures will
be above average in the 3 to 8 day range but beyond that they look like
returning close to average.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
http://85.214.49.20/pics/avnpanel1.gif
WSW'lies and westerlies cover the UK with a deep low to the north. The low
moves eastwards tomorrow, allowing westerlies and WSW'lies to affect the UK.
On Thursday a new low moves over Ireland, introducing southerlies to all. On
Friday the low deepens and moves NE'wards, allowing strong SW'lies to affect
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.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 strong jet across the North Atlantic and western
Europe, with the UK under a marked trough. At the 500hPa level there's also
a large trough to the west of the UK and an upper low to the SW. The other
runs also show a trough to the west, but they differ quite widely regarding
the location of the lowest heights.
At the surface, GFS shows a deep low to the west and strong to gale force
southerlies over the UK. MetO has a deep low to the north with WSW'lies and
SW'lies, while GEM brings a secondary low to the SW with southerlies for
all. JMA shows southerlies with a trough to the west, while southerlies are
also forecast with NGP. ECM has a deep low west of Scotland and a mixture of
WSW'lies and SW'lies for the UK.

Evolution to T+168
ECM shows a deep low forming to the WSW at T+144 with southerlies for the
UK. The low moves northwards on day 7 with further southerlies for the UK.
The GFS shows the upper trough filling and moving eastwards. At T+144 a low
is centred to the north of Northern Ireland with gale or severe gale force
southerlies and SE'lies over the UK. By day 7 low pressure fills to the west
of Scotland with lighter southerlies for all.

Looking further afield
ECM out to 10 days shows low pressure moving slowly northwards on day 8 with
SSW'lies for the UK. The low fills to the north on day 9 with SW'lies for
Northern Ireland and Scotland; elsewhere winds are light due to a col. Day
10 sees a ridge over Scotland and Northern Ireland with NE'lies elsewhere.
GFS shows westerlies and WNW'lies on day 8, with low pressure filling to the
north. On day 9 a ridge covers the English Channel and SW'lies cover the UK.
By day 10 a low lies to the west with strong SW'lies for all.


Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html - last
night's 18z)
The ensembles show a spell of above average temperatures for the latter half
of the week and into the weekend, followed by a gradual cooling.