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Old July 16th 07, 09:31 AM posted to uk.sci.weather
Dave Cornwell Dave Cornwell is offline
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First recorded activity by Weather-Banter: Jan 2007
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Default Today's model interpretation (16/07/07)


"Darren Prescott" wrote in message
...
Here is a summary of the NWP output for 12z on Friday.
Issued 0547z, 16th July 2007.

The models are split regarding the weekend. ECM shows a generally settled
picture, but MetO and GFS show less settled conditions (especially on
Sunday). Givem the GFS ensembles it looks like the ECM is on its own this
time, meaning the weekend is likely to be unsettled.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
http://85.214.49.20/pics/avnpanel1.gif
A weak trough covers England and Wales, with ENE'lies elsewhere. Tomorrow
a low lies to the west of Scotland, with SW'lies across the UK. A trough
remains over Scotland on Wednesday, with SW'lies persisting elsewhere. On
Thursday a ridge lies to the west, with light northerlies over the UK as a
result.

T+120 synopsis
http://85.214.49.20/pics/Rtavn12015.png /
http://85.214.49.20/pics/Rtavn1201.png
http://85.214.49.20/pics/Rjma1201.gif /
http://85.214.49.20/pics/Rukm1201.gif
http://85.214.49.20/pics/Recm1201.gif /
http://www.meteociel.fr/modeles/nogapse_cartes.php
The jetstream chart shows a strong jet across the North Atlantic and a
trough over the UK. At the 500hPa level there's a low over the North Sea
and a ridge to the west. MetO shows an upper ridge to the north and an
upper low over England and Wales, while ECM brings an upper trough over
the UK. NGP has upper SW'lies for the UK and GEM shows an upper trough
over England.
At the surface GFS brings northerlies and NW'lies, with a shallow trough
over SE England. MetO has a low over the North Sea and a mixture of
northerlies and NW'lies for the UK. ECM also brings a mixture of
northerlies and NW'lies, while NGP has SW'lies for England and Wales and a
col over Scotland. GEM brings a ridge to the west and WNW'lies for all.

Evolution to T+168
ECM brings a ridge from the west by Sunday. On day 6 a col covers the UK
and on day 7 a ridge "topples" over the UK, leading to light westerlies
and WNW'lies.
GFS has a different outlook, with a large upper trough moving close to the
UK. On day 6 a deep low lies to the WNW, with a weak ridge over the UK in
advance. SW'lies and WSW'lies are the result, followed by strong SW'lies
as the low deepens and moves ESE'wards to the west of Scotland.

Looking further afield
Beyond day 7, the ECM shows SW'lies on day 8 with a low to the NW,
followed by further SW'lies on day 9. By day 10 a ridge builds over
Biscay, leading to SSW'lies.
GFS shows the upper trough moving slowly eastwards. On day 8 winds are
SW'lies for all with a low over northern Scotland. Day 9 sees a trough
linger over Scotland with SW'lies elsewhere. By day 10 the trough moves
away to the east, leaving the UK under a mixture of NW'lies and WSW'lies.

Ensemble analysis
(http://expert.weatheronline.co.uk/da...ia/ensdia.html -
last night's 18z)
The ensembles continue to show temperatures aloft below average for the
forseeable future.

----------------------

Hi Darren, predicting summer seems as difficult as predicting snow this
year! After this weekend turned out so nice I think I'll wait nearer the
time for next weekend. Thanks, as usual.
Dave, S.Essex.
P.S - I expect you caught some of last night's rain? 1mm here for whole of
weekend!