"Paul Bartlett" wrote in message
...
In message , Darren Prescott
writes
Here is a summary of the latest NWP output for noon on Tuesday. Issued 0544,
20 Jan 06.

ECMWF: http://217.160.75.104/pics/Recm1201.gif
A ridge covers the UK with light winds for all. The ridge moves NE'wards and
builds over the Shetlands at T+144, introducing a light easterly flow over
England and Wales. Elsewhere winds are light SE'lies. By T+168 the high
transfers NE'wards to Scandinavia, with a ridge SW'wards over the UK. Winds
remain light for all, southerlies over Scotland and Northern Ireland with
NE'lies elsewhere.

MetO: http://217.160.75.104/pics/Rukm1201.gif
MetO brings high pressure over the North Sea, resulting in SE'lies and
southerlies for the UK. The high drifts slowly NW'wards at T+144, with
SE'lies and southerlies persisting.

GFS: http://217.160.75.104/pics/Rtavn1201.png
The shows SE'lies over England and Wales with a ridge over the two
countries. Scotland lies under westerlies while Northern Ireland lies under
SSE'lies. A mixture of SE'lies and southerlies persists at T+120 as pressure
builds to the north. The high merges with the Siberian High at T+168 and
starts pulling easterlies over the UK with cold, sub-5C 850 air affecting
eastern areas of the UK.

GEM: http://meteocentre.com/models/glb00_120.html
The Canadian run shows a large ridge to the east, leading to SSE'lies for
all. The ridge builds and moves NE'wards at T+144, leaving the UK under
SSE'lies.

GME/DWD:
http://www.wetter.com/home/img/sat/g...190000_120.gif
The UK is sandwiched between a European high and a low to the west and this
leads to southerlies for all. The low to the west deepens and moves
northwards at T+144, resulting in further southerlies for most.

JMA: http://217.160.75.104/pics/Rjma1201.gif
The Japanese run also shows a southerly flow for the UK, with a ridge over
the North Sea. The ridge builds northwards at T+144, bringing easterlies
across much of England; elsewhere winds are SE'lies or southerlies.

NOGAPS: http://217.160.75.104/pics/ngp10.prp.120.europeg.gif
NOGAPS is similar to most of the runs today, with southerlies again as a
result of a North Sea ridge. The southerlies continue at T+144 as the ridge
develops into a high to the east.

KMA: http://www.kma.go.kr/kma03/gif/g21nh_smsr_120.gif
The Korean run shows a ridge from the east over the UK with a mixture of
southerlies and SE'lies.

In summary, the runs show southerlies for the middle of the week, with a
ridge to our east. In a similar fashion to the Christmas easterly, it looks
like the ridge will build northwards then NE'wards, eventually settling over
Scandinavia. Meanwhile a low over Scandinavia will move away SE'wards,
opening the gates to another easterly spell.

Yesterday's EPS at T+168 suggested an easterly is likely by then and today's
GFS ensembles show 8 of 11 runs bringing an easterly at some stage. The
operational run was a very cold run, bringing widespread snow and ice days
over much of England. It was one of the coldest ensemble members, but three
others show a similar pattern.

To sum up - an easterly is now likely in 7 to 10 days time, but it's still
up in the air as to how cold it will get and where (or if) any snow will
fall. However, the easterly is unlikely to be as severe as today's
operational GFS shows.
Thanks a lot Darren things VT 201200 look pretty cold still. But it
really is a long way off. We shall cop it round here if the forecast by
the 27th are correct. Amazing isn't it when in 2006 we can be half
serious about a weekly forecast, in 1960 when I signed up to the Office
even a 24 hour prog could be seriously wobbly in marginal conditions.
The early 3 level Octagon circa 1967 to T+ 96(?) was a giggle. Then in
the '70s they had to be taken seriously to T+120 on certain things.
i.e. NOT cloud base and visibility but on general evolution. In the
1980's the first global model was up and running for the Falklands war
(1982) which I found a great help at HQSTC - cloud base forecasts relied
on local knowledge as even the high res models were still unreliable in
1991 when I left. 4 and 5 day forecasts from US, DWD and UK were
getting better and better out to 5 days (once you learned their little
idiosyncrasies).
Now we are taking models seriously out to 7 days - as long as there is
fair agreement.
Mind you all because we take them seriously doesn't mean that they are
going to be correct!
Cheers
Paul
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It gets better Paul. Nobody here sees the outputs but there is now an
operational 4Km mesoscale model running in the Met Office and by 2009 a 1.5Km
resolution model may be operational in the UK. In the 2010s I am confident that
pretty accurate cloud base and visibility forecasts on the town scale up to 24
hours ahead will become a reality. Not sure about the longer range as I feel we
may be close to hitting chaos, but probability forecasts will undoubtedly
improve.

Will.
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