Here is a summary of the latest NWP output, for noon (GMT) on Wednesday.
Issued 0603z, 20/09/03.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.gif
High pressure lies to the south of the UK, bringing westerlies to most areas
across the UK. A smalls econdary low lies to the east of NE Scotland, but by
T+144 it is absorbed by a low to the north of Scotland, with more westerlies
across the UK. The winds become NW'lies for all at T+168, as the low moves
over Shetland and deepens.

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

GFS: http://www.wetterzentrale.de/pics/Rtavn1081.gif
WSW'lies cover much of the UK, with high pressure over the Netherlands,
southern North Sea and southern parts of the UK. The far south of England
lies under easterlies, as is the case at T+120 as the high moves eastwards,
leaving a ridge over England and Wales. 850hPa temperatures range from +1C
over Northern Ireland to +3C over SE England. Charts for T+144 and beyond
were unavailable from Wetterzentral at the time of writing.

GEM: http://www.wetterzentrale.de/pics/Rgem1201.gif
As with the other runs, high pressure is located to the south, this time
with westerlies for all. The westerlies continue at T+120 as the high drifts
eastwards, with 850hPa temperatures ranging from +1C over northern Scotland
to +3C over southern England. By T+144 a SSW'ly flow covers the UK, with a
slack low to the west of the British Isles.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
The Japanese run shows a weam sector over the UK, from a low to the west of
southern Norway. High pressure lies to the south of the UK, leading to
westerlies for England, Northern Ireland and Wales. Much of Scotland lies
under NW'lies, behind the cold front. 850hPa temperatures range from -3C
over northern Scotland to +3C over central England.

Model overlay charts (GEM/GFS/JMA):
http://expert.weatheronline.co.uk/da.../ens/pslv.html
The T+108 chart shows westerlies over much of the UK.

In summary, today's runs show westerlies for much of the UK on Wednesday,
although there is a chance of easterlies in the far south if the high is as
far north as the GFS suggests. By Friday, the GFS shows NW'lies while the
GEM shows SSW'lies - so as ever, more runs are needed.