The idea has been that with tropical forcing moving steadily on from phase 8, the support for a Euro High should be limited, with more of a mid-latitude block favoured with less in the way of low heights to the N of the UK than the 12z output has come together on.

GFS had been going with the MJO dropping out in phase 8 for a number of days and I assumed this was the main reason it was coming up with those Euro highs. Yet today has seen that model move in line with ECM etc. in taking the MJO on through phase 1, but without this changing the outlook away from the Euro high... indeed quite the reverse trend has manifested!

This leaves me looking at possible strat. influences which could overwhelm the tropical forcing. This would be an unfortunate death for the incoming chilly spell, but as I hinted at earlier, the implied greater trop/strat connection could well be a part of the process by which a SSW is achieved late this month.

This would be a satisfyingly straight-forward explanation as it stands... but there's a wildcard in the mix that also affects the balance of play, and that's the subtropical system moving from Bermuda to the Azores and which appears to give the westerlies a bit of a kick between +144 and +168 on the ECM 12z op for example. It's not the controlling factor though - GEM keeps it away from the westerlies yet also throws the jet over the Atlantic ridge with a relegation to Europe taking place.

It doesn't stop there either; the strangest thing about the 12z ECM and GEM op runs at day 10 is how closely they mirror the Dec '15 pattern, despite totally different tropical forcing, and that brings the North Atlantic 'Cold Pool' back into mind, which I believe was among the biggest driving forces behind the extreme pattern we saw last month. It may well be adding to the momentum in the Atlantic as well as the signs of the jet digging south out there as opposed to across Europe.

This is all speculation of course, and only worth studying in detail if the pattern shown by the 12z ECM +192 to +240 (for example) does come into fruition.

If the tropical forcing does get to have a say, then low heights should hang on in Europe with a strong high across the UK and possible easterly flow across the south - just as the few ECM op runs prior to today's 12z were showing. I'd be happy enough with that given the potential for Feb. Fingers crossed 

Excellent post SC  Great to read and understand the possible determining factors behind the current output written so clearly 

(even I can understand it )

agreed. It would be highly surprising if the models all came into consistent alignment with the ECM 12z op, and the actual weather then delivered very close to what we're seeing currently on the ECM up to and including t+240 over the next 10 days! 

Into FI but FWIW GFS is slightly less like the 12 z and slightly more UKMOish.  Here' 120:

If we could get enough momentum going SE from the split in the jet in the western N. Atlantic in 5 days time there's a chance we could turn that Azores low from foe to friend. In that respect the 18z GFS op is a slight improvement.

Edit: may as well analyse this further just in case it turns out to be the start of a trend:

A striking difference in the jet profile to our W and NW with less of a jet cutting through the mid-Atlantic ridge.

The ridge gets a lot further toward Greenland on the 18z. Now what I had envisioned today was GFS adjusting gradually toward an ECM 12z that had moved more in like with UKMO. Yet ECM went berserk with the jet and ruined that vision entirely.

Still some cause for hope that we can get a better jet profile in the western N. Atlantic. Perhaps the 'Cold Pool' isn't going to mess with us and the Azores low can be used to help with getting a negative trough alignment (supporting the ridge) instead of powering the trough east.

The pub run has lived up to it's name in that it has provided a rally for positive thinking. This is why I hesitate to assume anything about the balance of forcing mechanisms at play until I can look back and use the power of hindsight 

That forecast looking woefully poor now: more like 3-6 away from SW coast, some poor judgement evident and naiivity by being all too quick to jump on board.

I will bank that.

Northerlies don't seem to carry the same punch as they did when I was a lad. These days it seems average temps. are the best we can hope for - no good if it's snow you're after.

things i love about this chart

Number 1:

Plenty of LPs to the east heading west

Number 2:

WAA heading north to the west of us

Number 3:

Cold embedding iteself into the UK.  Frost days will be apparant in favoured spots.

Number 4:

Our pressure cell links with arctic one.

Yes Russ, all FI but much to be upbeat about!  Good night!

Substantial upgrade on the 12z.... Beyond 96+.  Fascinating stuff...  

Has anyone seen such a cold UK high before?

-8C in the east, and -6C at the 850hpa level in the west must be exceptional if not near record breaking for a UK high. I do not remember seeing anything quite this extreme, and this must convert to damn cold temperatures at the surface - I assume below 0C everywhere.

9C as far north as Wales on that map, but you can safely place a bet on is in a northerly those temps will certainly end up a few degrees warmer in the south if the sun shines.