Today's model interpretation (30/10/07)



Here is a summary of the NWP output for noon on Saturday.
Issued 0543, 30th October 2007

The models show a strong jet over the Atlantic, but it's so far north that high pressure will never be far from the UK. GFS shows a generally settled end to the weekend and start to next week, with a chance of rain affecting northern and eastern Scotland for a time on Monday. ECM pushes a trough quickly eastwards across the UK on Sunday into Monday, before pressure builds once again afterwards.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
A trough lies to the east, leading to a westerly flow over the UK. The winds back SW'ly tomorrow as a ridge crosses southern England and there are further SW'lies on Thursday. Friday sees a ridge over all areas except Scotland, which lies under a trough with SW'lies.

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 zonal jet from Newfoundland across to southern Greenland, Iceland and southern Scandinavia. The UK lies under a ridge, while the 500hPa level chart shows a relatively flat westerly gradient. ECM shows a ridge over Ireland and upper WNW'lies for the UK, while MetO has an upper high over Ireland and NNW'lies over the UK. Upper WSW'lies cover the UK with NGP, while GEM has a ridge over England and Wales.
At the surface GFS brings WNW'lies and a weak ridge, while ECM has a high over Ireland and NNW'lies for much of the UK. MetO shows a high to the NW, leading to northerlies and NNE'lies. NGP has strong SW'lies with a trough to the west and GEM brings high pressure and light winds over the UK.

Evolution to T+168
ECM shows high pressure over England and Wales on day 6, with SW'lies elsewhere. On day 7 westerlies affect the UK as a high builds to the west.
NW'lies cover the UK on day 6 with GFS, due to a ridge over Wales. Another ridge covers Ireland on day 7, leading to NW'lies across the UK.

Looking further afield
The ECM shows NW'lies on day 8 with high pressure to the west. On day 9 the high moves over Ireland, bringing light winds to all areas except Scotland (which lies under SW'lies). On day 10 westerlies cover the UK, with high pressure to the south.
GFS on day 8 brings WSW'lies for all, with high pressure to the SW and a ridge over southern England. Day 9 sees westerlies as the high retrogresses, followed by NW'lies on day 10.

Ensemble analysis (http://expert.weatheronline.co.uk/daten/profi/en/ensdia/ensdia.html - last night's 18z)
The ensembles for London continue to show some warm days ahead, followed by a great deal of scatter (and generally cooler temperatures) after the weekend.


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