Weather Banter - Today's model interpretation (17/02/05)

Here is a summary of the latest NWP output for noon on Monday. Issued 0604z,
17/02/05.

The models show a notable cold spell across the UK, starting this weekend
and lasting at least 4 to 5 days, possibly a fair bit longer. The GFS
ensembles show precipitation at Manchester, Aberdeen and London as well as
cold temperatures, suggesting snow will be widespread. The specifics will be
refined over the coming few days, but it's safe to say it looks like a cold
and snowy spell is probable.

ECMWF: http://64.246.48.81/pics/Recm1201.gif
A large high lies to the south of Iceland, bringing strong NE'lies across
the UK. The high builds at T+144, with NE'lies persisting for most. Milder
northerlies cover northern Scotland though and by T+168 these spread to all
of Scotland and Northern Ireland. Further south winds are still NE'lies as a
ridge topples over England and Wales.

MetO: http://www.wetterzentrale.de/pics/Rukm1201.html
The MetO run also also shows a high to the south of Iceland with a ridge
from a Russian High over Scandinavia. Low pressure is centred over the
western Mediterranean, with a trough over Biscay and France. This leads to
strong ENE'lies across much of the UK, although winds are lighter over
Scotland. A trough moves westwards over England and Wales at T+144, bringing
northerlies for Scotland and Northern Ireland, with NE'lies or NNE'lies
elsewhere.

GFS: http://expert.weatheronline.co.uk/pslv_frame.htm
High pressure is centred over NW Russia, with a ridge extending SW'wards to
the east of Iceland, then southwards to the Azores. NE'lies are the result
for the UK, with 850hPa temperatures from -9C over East Anglia to -7C over
eastern Scotland, Kent and SW England. A shallow trough moves over England
and Wales at T+144, bringing easterlies and northerlies for the UK. By T+168
the trough sinks SW'wards while pressure rises over Iceland; this brings
easterlies across the UK. The easterlies strengthen on day 8 as the
Icelandic high builds and moves NE'wards. Day 9 sees little change, with
ENE'lies for all and an upper cold pool over Belgium. The remnants of the
cold pool get dragged over southern England on day 10. By then the chart
shows a large high over Iceland and Greenland, with lows over Iberia, the
Azores and another further west - the UK lies under moderate easterlies and
ENE'lies.
The GFS ensembles show good agreement of a cold spell from Saturday until
next Friday. Beyond that four of the twelve runs become much milder for
London, with the remaining eight showing a prolonged cold spell. The
operational run was a cold outlier at the beginning of March with its -14C
850hPa temperatures for London.

GEM: http://www.meteocentre.com/models/glb00_120.html
Strong ENE'lies cover the UK, with high pressure over Scandinavia. 850hPa
temperatures vary from -9C over NE Scotland to -6C over Cornwall. The high
retrogresses slowly at T+144 and T+168, with the UK maintained under a cold
ENE'ly or NE'ly flow.

GME/DWD:
http://www.wetter.com/home/img/sat/g...170000_120.gif
The German run shows complex low pressure over the Mediterranean and
southern Europe, with high pressure over Iceland and a ridge from the
Siberian high over Scandinavia. ENE'lies cover the UK, followed by NE'lies
at T+144 as a trough moves westwards. Day 7 sees lows to the west and east
of the UK, with a mixture of easterlies, NE'lies and northerlies for the UK.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
The Japanese run shows NE'lies for all, with the Azores High displaced to
the west of the UK. The high moves northwards at T+144, with NE'lies
persisting for the UK. Day 7 sees high pressure build to the north of
Iceland and this, along with a low over Biscay, brings easterlies across the
UK. The easterlies persist on day 8 as high pressure builds over northern
Scandinavia.

NOGAPS: http://wetterzentrale.com/pics/Rngp1201.gif
A NNE'ly flow covers the UK, again with high pressure to the west. The winds
become NE'lies at T+144 as low pressure forms to the WSW and high pressure
builds to the SW of Iceland.

GM CPTEC: http://www.cptec.inpe.br/prevnum/Global126_sx6_Gl.shtml
High pressure lies to the west of the UK, with a deep low to the west of
Norway. Strong northerlies cover the UK as a result.

KMA: http://www.kma.go.kr/kma03/gif/g21nh_smsr_120.gif
NE'lies cover the UK as the result of a low over northern Italy and a high
to the NW of the UK.