Mmm... (a lurker here). The December '81 cold spell was a Greenland high. And it didn't initiate from an easterly.

Peter

I think the thing is that Scandi blocks are simply easier to form, while a Greenland block is the ultimate atlantic defense mechanism it is extremely expensive, wheras a Scandi high is a quick and dirty way to get heights to greenland by retrogression and a slicer low. 

Well the ecm this morning was pretty much the warmest run this morning for London. Cold from the 27th onwards if the ensembles have it right.

There was quite a good rebound in the GEFS this morning, which suggests that the 00z operational GFS run was a particularly unfortunate outcome while the 06z is right up at the fortunate end... so from one end of the suite to the other I suppose! 

May have to keep an eye at around the 27th December where it now looks like a low pressure system may slice through the northern half of the UK, deepening in doing so as it try to interact with a jet stream positioned at roughly the same location overhead.



At 180 hours, it is a long way off in forecasting terms but if verified, that would bring its own set of traffic-related disruptions across the UK, not needed at a time when most of us are planning on getting home after the Christmas break. I fancy that this would be the more likely outcome than any fleeting cold snaps.

EDIT: Even GFS's baby brother, GFSP seem to be coming up with the same idea.

I probably missed someone mention it, but anyone know why the GEFS ens aren't out yet? Looks like they're stuck on the 00Z to me?

I concur- it also matches up with what fergie was saying - so probably the METO are seeing this aswell.

If that LP can be enticed more south - it would introduce some very interesting conditions on its northern edge.

As I said earlier there are upstream problems.

Does anyone actually bother reading this thread? 

Brian mentioned that there would be issues with the GFS / GFSP and GEFS today due to upstream data issues, Netweather hasnt updated to 06z yet on the GFS or GFSP, but some people are having luck using Meteociel and others...

So the 06z is out there, just not on my usual radar of sites.

That little feature at t120 needs watching might  have a few surprises

http://www.wetterzentrale.de/pics/Rtavn1203.gif

Dew north 0c

850

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=120&code=0&mode=1

THE GFSP6z is fully available on TWO:

http://www.theweatheroutlook.com/twodata/datmdlout.aspx

The GFS 6z is available to +192 hours.

GEFS currently are still in the starting blocks.

this really needs watching IMO. Could be brutal and not pretty. Expect a further adjustment north? If so we could be in for a battering, perhaps blizzards over Scottish mountains.

Looks like the weather won't be boring over the holiday period. With somewhere maybe getting a big snowfall and also storm!

Very interesting update from Ian Ferguson Netweather

An awful lot of focus here on how pronounced any cold might be.... but arguably, one of the most eye-catching forecast issues amongst ensembles is one of possible explosive cyclogenesis (vast majority of EC-EPS members from 00z suite producing lows from Boxing Day onwards, some very deep indeed, and all considered likely to entrain sub-zero theta-w irrespective of track). So, for us it's a story of potentially bad weather across a fair scope of outcomes (gales/severe gales/heavy rain/snow) rather than a myopic focus solely on snow. Whilst I appreciate some people merely seek the latter to the exclusion of all else, there is a resultant risk of not seeing the woods for the trees in terms of the potential (still highly uncertain) evolutions and how these might provide a very interesting / volatile period meteorologically, irrespective of how cold it proves.

Jacko's looking for the wet rather than white solution

Fergie's update and other rumblings continue to create a lot of interest in the post xmas week.

Could be the kitchen sink given the potential for rapid cyclogenesis

Onboard as in Wet and Wild or Cold?

Thanks - very good

On board in the vaguest possible way. They must employ English language experts to come up with the most ambiguous legal jargon to cover all bases!