Here is a summary of the latest NWP output for noon on Saturday. Issued
0647z, 20/01/04.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.html
A deep low lies to the NW of Iceland, with a secondary low south of Ireland.
This leads to westerlies for all. A high is developing to the NNW of the
Azores and by T+144 is builds strongly to the south of Iceland, leading to
northerlies and NNW'lies over the UK. The northerlies continue at T+168 as
the high moves northwards and builds. The 10-day chart from Meteocentre
shows an Omega block over Iceland, with an upper NE'ly flow over the UK.

MetO: http://www.wetterzentrale.de/pics/Rukm1201.html
The Met Office run shows a NW'ly flow over the UK, with high pressure
extending from Greenland SSE'wards to east of the Azores. The high to the
west of the UK builds at T+144, leading to northerlies for most.

GFS: http://expert.weatheronline.co.uk/
As with the ECM run, westerlies cover the UK due to a deep low to the north
and a secondary low south of Ireland. By T+120 the winds become NW'lies as
the secondary low deepens over northern France and high pressure builds to
the west. 850hPa temperatures range from -5C over NW Scotland and Northern
Ireland to freezing over SE England. Strong northerlies cover the UK at
T+144 as high pressure builds to the south of Iceland; there's little change
at T+168 as the high continues to build. Northerlies persist on day 8, but
by day 9 the Icelandic high declines, leading to NW'lies and northerlies for
the UK. By day 10 a new low forms to the SW of Ireland, bringing SW'lies
across England and Wales.

GEM: http://www.meteocentre.com/models/glb00_120.html
The Canadian run also shows westerlies, but the synoptic setup is slightly
different. Instead of a ridge to the WSW, the Greenland High ridges south to
the west of Iceland, with low pressure to the WSW of the UK. 850hPa
temperatures range from -3C over NW Scotland to freezing over SW England. By
T+144 the low deepens and moves ENE'wards to lie over the English Channel,
with northerlies and NE'lies over the UK.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
Westerlies cover much of the UK, with a similar setup to the ECM and GFS
runs. A deep low is located to the ENE of Iceland, while high pressure lies
to the WSW of the UK. 850hPa temperatures vary from -4C over NW Scotland to
+1C over SE England. The winds become northerlies at T+144 as high pressure
builds to the west of the UK, followed by NNE'lies and northerlies at T+168
as the high recentres to the SE of Iceland. By day 10 a trough severs the
ridge between the Azores and Icelandic highs, leading to NE'lies over the
UK.

In summary, the models show yet another change today; gone is the link
between the Scandinavian and Icelandic highs, instead it looks like another
northerly blast is on the cards. As ever, more runs are needed.

"Darren Prescott" wrote in message ...
Here is a summary of the latest NWP output for noon on Saturday. Issued
0647z, 20/01/04.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.html
A deep low lies to the NW of Iceland, with a secondary low south of Ireland.
This leads to westerlies for all. A high is developing to the NNW of the
Azores and by T+144 is builds strongly to the south of Iceland, leading to
northerlies and NNW'lies over the UK. The northerlies continue at T+168 as
the high moves northwards and builds. The 10-day chart from Meteocentre
shows an Omega block over Iceland, with an upper NE'ly flow over the UK.

MetO: http://www.wetterzentrale.de/pics/Rukm1201.html
The Met Office run shows a NW'ly flow over the UK, with high pressure
extending from Greenland SSE'wards to east of the Azores. The high to the
west of the UK builds at T+144, leading to northerlies for most.

GFS: http://expert.weatheronline.co.uk/
As with the ECM run, westerlies cover the UK due to a deep low to the north
and a secondary low south of Ireland. By T+120 the winds become NW'lies as
the secondary low deepens over northern France and high pressure builds to
the west. 850hPa temperatures range from -5C over NW Scotland and Northern
Ireland to freezing over SE England. Strong northerlies cover the UK at
T+144 as high pressure builds to the south of Iceland; there's little change
at T+168 as the high continues to build. Northerlies persist on day 8, but
by day 9 the Icelandic high declines, leading to NW'lies and northerlies for
the UK. By day 10 a new low forms to the SW of Ireland, bringing SW'lies
across England and Wales.

GEM: http://www.meteocentre.com/models/glb00_120.html
The Canadian run also shows westerlies, but the synoptic setup is slightly
different. Instead of a ridge to the WSW, the Greenland High ridges south to
the west of Iceland, with low pressure to the WSW of the UK. 850hPa
temperatures range from -3C over NW Scotland to freezing over SW England. By
T+144 the low deepens and moves ENE'wards to lie over the English Channel,
with northerlies and NE'lies over the UK.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
Westerlies cover much of the UK, with a similar setup to the ECM and GFS
runs. A deep low is located to the ENE of Iceland, while high pressure lies
to the WSW of the UK. 850hPa temperatures vary from -4C over NW Scotland to
+1C over SE England. The winds become northerlies at T+144 as high pressure
builds to the west of the UK, followed by NNE'lies and northerlies at T+168
as the high recentres to the SE of Iceland. By day 10 a trough severs the
ridge between the Azores and Icelandic highs, leading to NE'lies over the
UK.

In summary, the models show yet another change today; gone is the link
between the Scandinavian and Icelandic highs, instead it looks like another
northerly blast is on the cards. As ever, more runs are needed.

This is potentially looking extremely cold with sub 510 air down as
far as the north Devon! When was the last time this happened?