The crucial period coming up which will influence the weather to the end of December is over this weekend. GFS 12z and UKMO 12z vary quite a bit at t144 (Monday). The UKMO run builds high pressure from the South whereas GFS is more progressive with the Atlantic LP.

http://www.wetterzentrale.de/en/topkarten.php?map=1&model=ukm&var=1&run=12&time=144&lid=OP&h=0&mv=0&tr=24#mapref

http://www.wetterzentrale.de/en/topkarten.php?map=1&model=gfs&var=1&time=144&run=12&lid=OP&h=0&tr=3&mv=0

If GFS verifies then we could well be looking at a very changeable Atlantic dominated spell of weather out to the end of December. If the UKMO verifies there's hints of another blocked spell into next week.

The Met Office extended outlook today seems to favour the GFS evolution. An interesting few days of runs coming up.

bit off topic, but the best snowfalls have always arrived with a LP clipping england when under the influence of an easterly.  a big fat wedge of moisture.  hours and hours of snowfall.  as the LP approaches the winds increase, blizzards.  And you know from the radar youre a good 200 miles from the other side of the system.

Probably the closest we get to a "noreaster"

Whereas snow shows feeding off a north west wind really are hit and miss, mostly hail and if youre near the coast, more often, rain.

Easterlys almost guarantee you anything that falls from the sky will be snow - even in marginal conditions.  Whereas ive had nailed on conditions from a northerly and its been hail and sleet.  Saying that, the slightest wrong angle and its dry air over the pennines for us in the north west.

It’s basically the opposite of that here - easterlies will almost always deliver rain (even the cold ones), a decent northerly (a rare Beast these days) will almost always give snow here.

On that subject some transient snow still looks possible for inland northern parts especially with elevation at the weekend before things become more unsettled (or not knowing the case of the 12z UKMO). Nothing too notable in terms of temperature one way or the other.

For me its northerlies that are now pretty much useless.  Up til about 2006 these could pack punch.  The October 2008 was one of the last Arctic hurrahs down here.

I think the already known massive warming of the Arctic has meant these airmasses are now rarely capable of delivering much in the way of cold, let alone snow for the south.  Places like Portsmouth struggle to get below 9c in a northerly.

A most distressing reality, as I always used to love a northerly as a kid and teenage weather fanatic.

https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/glob-seas-prob

This below seems quite significant - denotes blocking to our north!? - Jan to March? - as you can see..?

Tally, those are probability anomaly charts.  The pressure one just suggests low pressure won't be as deep as usual to our north and high pressure will be less to our south. It is not forecasting any blocking necessarily.  That's also supported by the temperature charts which don't show the expected negative anomalies.

What leaps out on those charts is the likely dominance of above-normal temperatures  across pretty much the entire planet.

1 more step closer to an undercut with the HP winning out again...

Little lobe of HP into Scandinavia
http://www.wetterzentrale.de/maps/GFSOPEU18_147_1.png

Looking back at the last few days we have migrated from an unsettled LP positioned over the atlantic... running up to the arctic. On this evenings 6z run we have a LP that stalls to the west of scandi.. pressure consistently rising or rather not dropping to the north.

Meanwhile wedges of milder air run up to UK and are defusing in strength on every run.

Its a weight tipping game this ... matter of time. When not if.

Taken on face value the last week of the year looks mild and unsettled at the moment.

Pizza slice over the UK once again for Xmas Day:

YES but if you go back to Jan - March 2018 from December 2017 - the Met Forecast mild and we all know Feb and March turned out blocked and colder after the SSW. tHIS Year we are expecting one in 2 weeks time. SO here's to some cold and blocked weather for January/?

Maybe but don’t get your hopes up just yet.

Anyway, what you’ve said isn’t relevant to your apparent misinterpretation of those charts, which was my point.  You’re not the first person to misread an anomaly chart.

What do you make of this then from the Met Office and their updated ensemble mean anomaly? They have (if anything) strengthened the block since last months update. It's quite a strong signal for northern Blocking.

Southerly tracking lows me thinks and bitterly cold easterly winds at times!?

2-4 months:

https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/ens-mean

3- 5 Months

Now look at the Temperature mean:

2 - 4 Months

3 - 5 Months:

Indeed, I remember someone with a rather large ego doing just the same several years ago - and boy, did they sulk when that was explained to them. Anyway, those charts are just raw GLOSEA output - one of a large pot of charts. The long-range ECM has an interesting pressure anomaly by week 6, which is an unusually strong signal that far out:

http://brunnur.vedur.is/kort/ec-ens/2018/12/06/00/ec-ens_nat_taem_gh500_anom_2018120600_1104.png

To me, that'd suggest lows tracking much further south than normal.

The contingency planners' forecast, which combines GLOSEA, the ECM and others, shows a marked cold signal for December-January-Fenruary. Now that is unusual in that product, which normally shows a milder than average winter period.

https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/public-sector/forecast-temp-djf-v2.pdf

Bit surprised they say that we are in for a moderate El Nino this winter? I thought we were struggling to get a weak one!?

And how often do we get this forecast from the MET OFFICE?

"For December-January-February as a whole, below-average temperatures are more likely than above-average temperatures, with the highest chances of impacts from cold weather later in the period"

http://www.wetterzentrale.de/maps/GFSOPEU06_117_1.png 

"Tis the season for jam tomorrow, tra la la la la la la la la la"