Here is a summary of the latest NWP output, for noon (GMT) on Thursday.
Issued 0608z, 21/09/03.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.gif
SW'lies cover the UK, from a low to the north of Scotland. The winds ar
light over southern England, however, due to a ridge over France. The low
fills over Scandinavia at T+144, bringing moderate northerlies across the
UK. The winds become lighter NNW'lies at T+168, even though the low deepens
over Denmark.

MetO: http://www.wetterzentrale.de/pics/Rukm1201.html
Unavailable at time of issue.

GFS: http://www.wetterzentrale.de/pics/Rtavn1081.gif
High pressure lies over Poland, with southerlies and SSW'lies over the UK. A
small trough from a low to the west of Norway covers northern and western
Scotland at T+120, with southerlies and SSW'lies persisting over the UK.
850hPa temperatures range from +2C over southern Scotland to +7C over
southern England. By T+144 a northerly flow covers much of the UK, with a
low to the east of Scotland and another over East Anglia. A weak ridge then
topples over the UK at T+168, with NNE'lies over England and Wales; Scotland
and Northern Ireland lie under westerlies. Charts for day 8 and beyond are
unavailable at the time of writing.

GEM: http://www.wetterzentrale.de/pics/Rgem1201.gif
Unavailable at time of issue.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
(Note: This output is labelled as 21/12z, although I'm assuming it's
actually the 20/12z output instead).
The Japanese run shows a northerly flow for much of the UK, with a low over
southern Norway and a high to the west of Scotland. 850hPa temperatures
range from -3C over the Western Isles to +5C over southern England. The
winds become NNW'lies for all at T+144 as the high builds and sinks SE'wards
to the west of Ireland. The high declines and sinks southwards slowly at
T+168, bringing NW'lies to northern Scotland and NNW'lies elsewhere.

Model overlay charts (GEM/GFS/JMA):
http://expert.weatheronline.co.uk/da.../ens/pslv.html
The T+108 chart shows westerlies or SW'lies over the UK.

In summary, today's runs show signs of a northerly spell of weather for
Friday into Saturday, although as ever there are differences between the
runs, mainly regarding the positioning of the high to the west. As ever,
more runs are needed.