Regardless of what the longer term outlook may bring I am still in awe of the WAA and lava lamp style CAA taking place at the year's end. 

[quote=Gusty;747976]

Regardless of what the longer term outlook may bring I am still in awe of the WAA and lava lamp style CAA taking place at the year's end. 

Wow parts of the med are colder than parts of the Arctic at the 850 level.

I have always thought that the 'battleground' was going to be the other side of the North Sea at best, based on the charts over the last few days.  We've had some runs that have brought the boundary over the country and others that have shown a more mobile pattern winning out.  

I had a look at the UKMO T+144 chart and good as it looks at first glance it really isn't that special except for what it might deliver on day 7 and beyond.  The 500-1,000 thickness value for London on that chart is around 540dam. Air at 528dam sits 400-500 miles east of Scotland. 850hPa values are above freezing.

If the low tracks east and pulls that colder air westwards then it gets more interesting, perhaps.

Yes, impressive isn't it.  It would be even more so if it was 1,000 miles west.

I don't really understand what is being said here. I've often viewed GFS as more progressive, assuming we're talking about a west to east flow across the NA / Europe region. In addition the European 12z takes the Atlantic through pretty conclusively so I'm not sure what Exeter are thinking.

In that case, it is our longitude which is the problem.

☺

Nor do I Brian. I've always considered GFS as being more progressive from an atlantic driven perspective ?

We usually refer to progressive meaning westerly based..perhaps UKMO and ECM refer to it as a European (or more continental driven outcome ?). Being European models the idea does have some credence. 

Possibly a bit of personal mirth making via deliberately obfuscatory language?

Hence Fergusson's comment of Emphasis on "least"!!, with the double exclamation mark, referring to the Met Office labelling of GFS as the least progressive model. Presumably he too found it odd.

I wonder if it's to do with GFS producing a strong MJO phase 7 type signature in the 8-16 day range, having gone for it faster and harder than ECM for example?

There seems to have been a move this evening toward an active Atlantic trough becoming stuck to our west and throwing bands of rain and at times strong winds our way, these becoming slow moving as they come up against the block. Tropical and return-polar maritime airmasses exchange frequently to produce a run of temps varying from just below average to some way above.

It's very November 2009-like if you ask me, and about the worst possible path to be taking as the polar profile undergoes those major changes towards a more blocked regime with the tropospheric vortex becoming fragmented by cross-polar heights. Here's a couple of snapshots from Nov 2009, the first showing those lows stalling out due to the block, and the second showing the block migrating across the Arctic while the Atlantic finally starts to make more inroads across the UK:

There's a lot of charts knocking about from recent NWP output which show variants on both of the above. Notice how the Euro High is capable of making a bit of a comeback even in a precursor to what happened in December 2009 - so no need to worry if that features at some point in a model run for the mid-range. 

Looking at the progression that occurred between late Nov and mid-Dec 2009, I think that offers a reasonable guide as to the sort of things we should look out for in the far reaches of the GFS output at the moment. Essentially we're seeking very amplified ridges in the mid-Atlantic or perhaps through the UK. The first example below is not sufficient but does reflect the increasing potential due to the high-lat blocking developing. The second example shows a ridge through the UK that managed to trigger retrogression of the HP over Russia to become a fully fledged Greenland block a few days later.

The vortex disruption looks to favour the 'trigger ridge' being further west this year which makes a retrogressing high from Russia less likely, but could mean that an independent area of blocking develops over Greenland. A bit like Nov 2010, except that year also had a strong high over Scandinavia which added to the extraordinary developments going forward:

If the Atlantic lows push through the UK during the first week or so of Jan and the jet shifts south in response to the high-latitude blocking developing, something like the above may well be achievable - but that's about as good as it gets so you'd be setting the bar unreasonably high if you made it the target for Jan-Feb 2016!

Just how quickly the polar profile changes in Jan '16 is still open to some question IMO, but extensive high-latitude blocking looks to be an inevitable outcome one way or another. We'll then begin the game of watching for the pieces to fall into the right places for the UK to receive a good spell of cold, snowy weather.

Dutch ecm ensembles.

A late response for me tonight as it's taken me an hour or so to read the latest from Jam Tamara on the other side...a bit of a shocker from the ECM but there is enough doubt in the medium range for some very different outcomes later on and I would expect the deterministic to be at the very mild end of the ensembles from day 8 onwards.

Your not alone Brian, those on NW were a little bemused by it all also

Just been looking at the long range CFS v2 out to October 2016 and it shows a very warm/hot and at times thundery summer.

JFF of course.

FI is at 72 hours. In such circumstances as those forecast for early January, not that surprising.  All output beyond 72 hours needs to be treated with EXTREME caution.  As Sid Waddell used to say "down to the wire"

I don't care how the easterly get's here..just get here if you can. 

https://www.youtube.com/watch?v=Z0WDS-EQoIM

Basically: *Current* GFS has less linkage (=layers) into stratosphere. Hence can be more vulnerable to establishing  faux-blocking/easterlies especially at medium to longer range in it's output (versus eg ECMWF)..Cheers all..

Thanks for the clarification 

A long way off of course, but FWIW that sounds rather like summer 1983, which came on the back of a winter that occurred during a strong El Nino event.

We can but hope when the time comes!

I recon this is a 50:50 situation and it really could go either way but at the end of the day it will go one way or the other. The Atlantic will win or the block will.

Thanks Q.  That's a real help.