Today's model interpretation (19/11/12)

[Darren Prescott]

Here is a summary of the NWP output for noon on Friday.
Issued 0452, 19/11/12

Most of the models show a generally unsettled end to the week with low
pressure near to the UK. Changeable conditions are likely to persist into
the weekend with low pressure remaining close to the UK. Into next week
there are signs of high pressure building to the NW with colder NE'lies over
the UK.

Analysis and evolution to T+120 via GFS
Southerlies cover the UK, ahead of a low to the west. Tomorrow there are
further southerlies, as is the case on Wednesday. Thursday sees more of the
same, with southerlies continuing.

T+120 synopsis
http://www.wetterzentrale.de/wz/pics/Rtavn12014.png
http://www.wetterzentrale.de/wz/pics/Rtavn1201.png
http://www.wetterzentrale.de/wz/pics/Rukm1201.gif
http://www.wetterzentrale.de/wz/pics/Recm1201.gif
http://www.wetterzentrale.de/wz/pics/Rjma1201.gif
The jetstream chart shows a trough over and to the west of the UK. At the
500hPa level there are SW'lies, as is the case with ECM. MetO has westerlies
aloft with a more zonal flow over and to the west of the UK, while GEM has a
low to the west and southerlies aloft. JMA has SSW'lies with a weak upper
trough to the west.
At the surface GFS brings a shallow low to the SE of the UK, leading to
northerlies for England and Wales and SW'lies elsewhere. MetO shows WSW'lies
for all with a low to the north, while ECM has a col for most (and SW'lies
for the far NW of Scotland). GEM brings a trough over southern areas with
SE'lies from the Midlands north, while JMA has WSW@lies for all from a low
to the NW.

Evolution to T+168
ECM brings a ridge on day 6, followed by moderate WSW'lies as low pressure
moves eastwards towards Scotland on day 7. Southerlies cover the UK on day 6
with GFS, due to a low to the west. On day 7 the low moves SE'wards,
introducing ENE'lies for the UK.

Looking further afield
Days 8 to 10 with ECM show WNW'lies followed by northerlies and NE'lies as
high pressure builds to the NW. GFS has NE'lies and NNE'lies over the UK on
days 8 to 10 as high pressure builds to the NW.

Ensemble analysis
http://www.meteociel.com/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres
The ensembles continue to show colder conditions from the 24th.

ECM ensembles
http://www.meteogroup.co.uk/meteo/eps/ensemble-tt6-london.gif
ECM shows temperatures slowly falling from the 27th.