Here is a summary of the latest NWP output, for noon (GMT) on Tuesday.
Issued 0603z, 19/09/03.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.gif
High pressure covers Ireland, bringing westerlies to Scotland and
northerlies or NE'lies over England and Wales. The high builds and drifts
eastwards at T+144, leaving Scotland and Northern Ireland under westerlies.
England and Wales lie under very light winds. Light southerlies cover the UK
at T+168, with a ridge over the UK.

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

GFS: http://www.wetterzentrale.de/pics/Rtavn1081.gif
Unavailable at time of issue.

GEM: http://www.wetterzentrale.de/pics/Rgem1201.gif
The UK lies under NW'lies, with high pressure to the WSW and lows to the NW
and NE. The high moves over western France at T+120, with moderate
westerlies over Scotland and Northern Ireland; England and Wales lie under
much lighter westerlies. 850hPa temperatures range from -1C over southern
Scotland and northern England to +1C over southern England and western
Scotland. Strong WSW'lies cover much of the UK at T+144 as the high moves
over eastern Europe.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
The Japanese run shows a deep low to the west of Norway, with highs to the
west and south of the UK. This leads to a NW'ly flow over the UK and sub
528dam air over northern Scotland (in fact, down to 522dam in the far
north). 850hPa temperatures range from -7C over northern Scotland to +1C
over southern England.

Model overlay charts (GEM/GFS/JMA):
http://expert.weatheronline.co.uk/da.../ens/pslv.html
The T+108 chart shows two of the three runs with a NW'ly flow over the UK,
with lows over or to the west of Scandinavia.

In summary, today's runs show a good chance of a NW'ly flow over the UK for
Tuesday. Beyond that, westerlies or WSW'lies look likely as high pressure
moves eastwards over the southern UK.