Here is a summary of the latest NWP output, for noon (GMT) on Friday. Issued
0547z, 29/09/03.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.gif
A ridge covers England, Ireland and Wales, bringing light winds there.
Scotland lies under westerlies from a low to the west of Norway. Further
west, the Atlantic high had merged with the Greenland High and by T+144 it
builds to over 1045hPa and moves NE'wards towards Iceland. A trough covers
Denmark, leading to northerlies over the UK. The Atlantic high sinks
southwards and builds further at T+168, leaving the UK under a run of strong
northerlies.

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

GFS: http://www.wetterzentrale.de/pics/Rtavn1081.gif
The UK lies under NW'lies and WNW'lies, as the result of a trough over the
North Sea. The winds become NNW'lies for all at T+120, as the Atlantic high
builds and ridges towards Greenland. 850hPa temperatures range from -2C over
NW Scotland to +5C over southern England. By T+144 the UK lies under strong
northerlies, as the Atlantic high continues to build. The northerlies
continue at T+168, with sub 528dam air covering the eastern side of England
and Scotland. By day 8 the winds become lighter NNW'lies as the remnants of
the ridge connecting the Atlantic and Greenland highs topples over the UK.
Day 9 sees westerlies and WSW'lies as a deep low moves over Iceland; the
westerlies continue on day 10.

GEM: http://www.wetterzentrale.de/pics/Rgem1201.gif
High pressure lies to the NNW of the Azores, with a ridge towards Greenland.
NW'lies and westerlies cover the UK, due to a trough over the North Sea. The
winds become NNW'lies for all at T+120, with 850hPa temperatures ranging
from -3C over northern Scotland to +4C over southern England. T+144 also
sees NNW'lies over the UK, with a weak ridge to the west of Scotland.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
The Japanese run shows a trough covering the UK, bringing SW'lies over much
of England and Wales. Scotland and Northern Ireland lie under NW'lies and,
like the other runs, high pressure to the west is ridging towards Greenland.
850hPa temperatures range from +1C over NW Scotland to +9C over SE England.
Low pressure deepens and moves SE'wards over southern Norway at T+144,
bringing moderate northerlies and NW'lies over the UK. The winds become
stronger northerlies at T+168 as the ridge connecting the Greenland and
Atlantic highs topples SE'wards towards Scotland.

Model overlay charts (GEM/GFS/JMA):
http://expert.weatheronline.co.uk/da.../ens/pslv.html
The chart shows high pressure to the east of Newfoundland, with a trough
over or to the east of the UK.

In summary, today's runs show a cold spell on the way, with the Atlantic
high ridging towards Greenland. In conjunction with a low over Scandinavia,
a northerly blast looks inevitable - although the runs also agree on it
being a shortlived spell, with the ridge toppling over the UK after a couple
of days.

In uk.sci.weather on Mon, 29 Sep 2003 at 06:47:17, Darren Prescott wrote
:
In summary, today's runs show a cold spell on the way, with the Atlantic
high ridging towards Greenland. In conjunction with a low over Scandinavia,
a northerly blast looks inevitable - although the runs also agree on it
being a shortlived spell, with the ridge toppling over the UK after a couple
of days.

Another chance for an early first air frost in the S of England? (Those
that haven't already had one, obviously).
--
Paul Hyett, Cheltenham, England