schreef:
Wat een vraag. Ja, het begon me begin oktober op te vallen en de hele maand is me steeds meer gaan verontrusten.
Nee, het is niet structureel, het gaat om patronen die ik voor 't eerst gezien heb.
Zoals er ook geen orkanen bekend zijn die practisch dwars op de kust van New Jersey inland gaan. Geen. Nul.
Ja, het kon weleens structureel voor de najaarsmaanden gaan worden, omdat ik vermoedens heb over verband met het Arctisch zeeijs.
Vandaar dat ik dit allemaal met Argusogen schouw.
Als het arctische zeeijs blijft krimpen in de zomer in de mate zoals nu gebeurd, dan lijkt me dat toch wel structureel?
Bron: Matt Hugo
Sterke hogedruk in het oosten van Europa. Lange termijn blijft staan hogedruk in het noorden, lagedruk in het zuiden.
The latest ECM 32 day model is similar to the previous runs which keeps low pressure dominant across the UK or to the NW for the foreseeable future. The primary difference is it is signalling a more pronounced area of higher pressure across E Europe which as a result allows for the potential development of milder S or SW'lies at times with temperatures around the middle of the month potentially slightly above average.
However and importantly, the final block which now takes us into the opening week of December maintains a trend for pressure to become lower to the south of the UK, whilst pressure becomes higher to the north, essentially creating a -NAO pattern and a signal for temperatures to become below average into early December. That is the reason why if you read the 15 to 30 day update on the UKMO site, they highlight potentially colder conditions long term and it is just to that signal within the ECM 32 day which has been there now consistently, so it'll be interesting to see what happens.
No suprise to see the longer range ECM signalling a rise in pressure to the North and lowering pressure to the south. This is not related to the stratosphere but the lead up to this around mid month (troposperically) will likely have a significant on the stratosphere during the first week December.
Stewarts reactie:
A strong build of pressure over Eastern Europe and Western Russia has a teleconnective influence on Wave 2 activity and I'd be very suprised if we didn't see strong wave 2 response in the stratosphere during early December (wave 2 being more responsible for vortex splits). That places us around late December for a stratospheric influenced pattern.
MetOffice
UK Outlook for Wednesday 21 Nov 2012 to Wednesday 5 Dec 2012:
As is usual, there are uncertainties in the forecast for this period, but there are signs that the changeable conditions will continue through the start of this forecast period. Rainfall amounts are more likely to be above the seasonal average rather than below, especially across England and Wales. There is also a signal for temperatures to be close to or just below the seasonal average. Towards the latter part of the period, there are some suggestions that conditions will turn drier with more in the way of sunshine, but also colder, with temperatures well below the seasonal average. This will give a greater risk of overnight frosts.
Updated: 1134 on Tue 6 Nov 2012
