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Old August 25th 03, 07:14 AM posted to uk.sci.weather
Darren Prescott Darren Prescott is offline
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First recorded activity by Weather-Banter: Jul 2003
Posts: 874
Default Today's model interpretation (25/08/03)

Here is a summary of the latest NWP output, for noon (GMT) on Friday. Issued
0613z, 25/08/03.

ECMWF: http://www.wetterzentrale.de/pics/Recm1201.html
A deep (975hPa) low lies over the North Sea, bringing strong to gale force
northerlies and NNW'lies over the UK. The strongest winds are over NE
England, severe gale force. The low fills as it moves over Denmark at T+144,
leaving the UK under moderate NW'lies. The winds become moderate westerlies
for most at T+168, as a secondary low moves over southern Norway.

MetO: http://www.wetterzentrale.de/pics/Rukm1201.html
The UK lies under moderate northerlies, with a trough over Scandinavia and
high pressure to the WNW. The high sinks southwards at T+144, bringing
NW'lies to northern Scotland and northerlies elsewhere.

GFS: http://www.wetterzentrale.de/pics/Rtavn1081.gif
The GFS run shows a moderate northerly flow over the UK, with lows over
France and the Czech Republic. The lows merge and move away to the NE at
T+120, leaving the UK under slightly lighter northerlies. 850hPa
temperatures range from -1C over NE Scotland to +5C over SE England. The
winds become NNW'lies and NW'lies at T+144, due to a trough to the ENE of
Scotland. Lighter northerlies and NNW'lies move over the UK by T+168, as
high pressure drifts eastwards slowly towards the UK. By day 8 the
(declining) high covers the UK, with light winds for all. The high builds
over the UK on day 9, but by day 10 it moves eastwards, bringing light winds
over the SE half of England, with moderate SSW'lies elsewhere.

GEM: http://meteocentre.com/models/glb00_120_e.html
High pressue lies well to the west of the UK, with low pressure over
Scandinavia. This leads to moderate north or NNW'lies over the UK. The low
fills at T+144, although moderate northerlies and NW'lies continue to affect
the UK. The winds become slightly lighter northerlies and NNW'lies at T+168
as the low fills over southern Scandinavia. The same is true on days 8 and
9; by day 10 a trough brings light winds over England and Wales, with a
ridge and northerlies over Scotland. Northern Ireland lies under NE'lies.

JMA: http://www.wetterzentrale.de/pics/Rjma1201.html
In a similar setup to the other runs, northerlies and NW'lies cover the UK,
with low pressure over the Baltic and a high to the SW of Iceland. 850hPa
temperatures range from +1C over NW Scotland to +4C over southern England.

Model overlay charts (GEM/GFS/JMA):
http://expert.weatheronline.co.uk/da.../ens/pslv.html
The T+108 chart shows low pressure over Scandinavia and high pressure to the
west, with northerlies or NW'lies over the UK.

In summary, the runs today show a cool spell of weather approaching, with
northerlies or NW'lies affecting all of the UK at some stage next weekend.
There are large differences with regards to the track and intensity of the
lows again, so as ever more runs are needed.