afternoon all. Lovely chart that- bank it!

a quick flick through today hints at possible pattern change deep FI but nothing too concrete at the moment. Some milder interlude next week, but nothing lasting too long sadly. 

Some interesting charts showing up much later on

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Not a bad set of options ........................................start of a trend ????

Hi Gooner - Could you send me the link to those set of runs please???? Thanks.

I am getting something totally different: -  http://www.wetterzentrale.de/pics/Rtavn3601.gif

Met Office talk about colder weather towards New Year!??

I wouldn't get too excited about what you read in the papers, an eye catching headline is to make people buy the paper. Though we cannot completely rule everything out. 

They're the GFS ensembles and can be found on the 'charts' section of TWO web pages, under GEFS.

I've been busy today, only just caught up with the model output.

Seems that UK high trend was stamped out this morning as the models decided to throw more energy over the ridge rather than less. 

By contrast, UKMO has thrown out a teaser tonight, with a much stronger ridge in the Atlantic gaining some support from a Canadian High, enough so to keep the shortwave low over Greenland from interacting with the cut-off low on the Eastern Seaboard:

That would probably lead to the Greenland low racing SE to the UK rather than combining with the U.S. low to create a western North Atlantic trough, which is what GFSP and GFS do on their respective 12z op runs.

This UKMO run is the first to really go for such a scenario - though the GFSP 06z op run came mighty close - so it would need support from the ECM 12z op run to even raise an eyebrow. If that happened, it would represent a huge shift in the modelling of that U.S. low by ECM at 6 days range... not the most common of events.

Longer range, the operational GFS 12z was reluctant to wind down the Pacific jet days 10-16 and create that strong W. Pacific ridge that I mentioned yesterday, but many GEFS members are more willing, with some suitably wacky outcomes as that ridge plays havoc with the polar vortex.

The GFSP 12z behaves in the same way, in fact it really goes for it, resulting in a slightly insane looking day 16 chart:

You can really see the extreme amplification of the U.S. flow and subsequent effect on the Atlantic flow.

The all-important change sets in on day 10, as a deep low develops right on the dateline and the major ridge starts to build in the East Pacific. I know, this is well outside the reliable... I'm just using it to illustrate what the weakening Pacific jet could lead to IF it took place.

FWIW the 00z ECM was building that E. Pacific ridge but using a trough digging south on the dateline rather than an intense storm system.

At long last, an ECM run featuring some positive signs!

They owe themselves largely to a shift that has taken place days 6-7. This is perhaps best illustrated by comparing the ECM 00z and 12z op runs as that clearly highlights the nature of the shift:

The 00z, on the left, has the low near Canada interacting with the shortwave by Iceland. On the following output, this resulted in the jet travelling just south of that location, with low pressure development over Iceland the following day, which connects to an Azores High stretching well into Europe.

The 12z, on the right, has far more of a ridge in between the Canada low and the Greenland shortwave. While this chart is for 12 hours sooner, the following chart still has the two lows separate (http://www.meteociel.fr/modeles/ecmwf/runs/2014121312/ECH1-168.GIF?13-0). By the time they interact, the shortwave has tracked SE, which means the jet is directed further south. That disrupts the Greenland polar vortex lobe and helps with the U.S./Atlantic amplification, itself initiated as the Pacific jet weakens.

Of the GEFS 12z suite, only one manages to have such a strong ridge of high pressure separating the U.S./Canada low and the Greenland shortwave low (or trough, where the shortwave is absent), and in that case the angle of the trough is SW-NE which directs the jet NE anyway.

So really the GEFS aren't having any of it, leaving ECM and UKMO out on their own branch of the tree.

The GFSP 06z op run is the closest any American or Canadian model run that I've seen has come to achieving it.

JMA is a bit closer to ECM than GFS but it's not enough to count as support.

European models versus the world's! 

Some signs after the 21st of something more notably colder may develop out east.

http://modeles.meteociel.fr/modeles/gfs/runs/2014121318/gfsnh-0-120.png?18

Can the pub run deliver the winter goodies

Thanks James.

At least there does seem to be some chance of a change of pattern perhaps a few weeks from now. OK, not the holy grail type winter charts that we were seeing at this time in both 2009 and 2010, but certainly no worse that what we were being faced with a year ago. We'd be incredibly unlucky to have a repeat of last winter anytime soon in my opinion.

Surely that is going to have the effect of dragging down sea surface temperatures around our shores?

Another GFSP op run shatters the polar vortex as the strong western-U.S. ridge reaches right up to the Pole and wreaks havoc, and at long last a GFS op run that does the same.

A real shame that they keep on driving energy NE regardless of the major changes unfolding - particularly in the case of GFSP.

The problem is the same as being faced in the 6-7 day period in terms of having enough of a mid-Atlantic ridge between lows in the far-western N. Atlantic and lows south of Greenland. The 18z GFS op wasn't far away though!

Speaking of that 6-7 day issue, the 18z GFS has shifted slightly toward ECM but that's only managed to bring it in line with the GFSP 18z which is pretty much the same as the GFSP 12z as far as the separating ridge in the Atlantic goes.

So the standoff continues.

I am encouraged by the longer-term GFS output because I saw it behave in a similar fashion prior to the blocking to our NW in December 2010. A massive overcooking of the subtropical jet was the main source of error.

As for the GFSP output... it's just so reluctant to clear the low heights away from Greenland, taking until day 15. While ECM is similar in that regard, it has much stronger mid-Atlantic ridging to compensate.

I get the impression that the GFS 18z op run is jumping the gun with such a notable Greenland High in the 10-14 day range, but at the same time the GFSP 18z op seems pessimistic.

Best just wait and see what happens with the day 6-7 business while those seeking cold conditions in the final week of December can take some comfort from the persistent signal for a far more amplified U.S. pattern giving the polar vortex a very hard time.

I think ****THINK**** something could be brewing for the Post Xmas period.

already dropping here

would prefer if we just got a Northernly. An Easterly really is very concentrated in its area of influence in the UK.

Morning.  Huge scatter in the ensembles, something stirring in deepest FI?  I will leave the in depth analysis to others.

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY DECEMBER 14TH 2014.

NEXT UPDATE MONDAY DECEMBER 15TH 20:00

THE CURRENT GENERAL SITUATION Troughs of Low pressure will cross the UK through the day becoming slow moving close to Southern England as small distubances run East along it.

MODELS-2 WEEK HEADLINE Remaining changeable with rain at times especially across the North and West. Temperatures generally close to or a little above average but colder periods over the North when showers could turn wintry.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble forecast continues to show signs of maintaining a West to East flow in the vicinity of the UK over the next few weeks. However, the speed of the flow is looking like weakening with time as the Jet flow filters first further North over the UK by this time next week and later back South to lie South of the UK post Christmas.

GFS OPERATIONAL The GFS operational this morning shows a continuation of the Westerly flow through the next 5- 7 days with rain at times and further wintry showery incursions across the North. In the days that run up to Christmas pressure is High over SW Europe with a mild SW flow across the UK with rain at times. Colder air is shown to move across the UK over the Christmas period with wintry showers especially over the North and post Christmas sees pressure rise through mid Atlantic and Greenland with Low pressure entrenched near the NW of the UK with rain and strong winds for many with average temperatures.

THE GFS PARALLEL RUN The GFS Parallel run is broadly similar in structure through the period up to christmas with the festive time itself looking green for most with rain at times especially over SW areas as Low pressure gets hung up in these parts. At the same time pressure rises near northern Scotland and in the following days this makes it's way to Scandinavia before sinking South at the end of the run. much of the UK wuld become cold and breezy under a fresh SE flow with rain or sleet at times with hill snow principally towards the West and North.

THE GFS CONTROL The GFS control run today maintains avery mobile Westerly flow throughout the period running up to Christmas, Christmas itself and beyond with alternating periods of milder and wetter conditions and spells of colder and windy weather with showers wintry over the hills especially over Northern Britain.

THE GEFS ENSEMBLES The GEFS Ensembles members show a variety of options this morning with the main long term feature being the weakening of the Jet flow later and the positioning of it heading South somewhat introducing at least the threat of colder options post Christmas. At this stage the bias is still held for a preference towards a basically Westerly flow with Low pressure to the North and High to the South and SW and perhaps West later.

UKMO UKMO today shows a changeable and breezy week to come with Low pressure areas crossing East to the North of Scotland. The familiar mix of milder and cloudy weather with some rain alternating with brighter, colder and windy weather with showers, wintry in the North continues through to next weekend when it will feel cold everywhere

THE FAX CHARTS The Fax Charts show fronts crossing the UK at times over the next 24 hours or so with weak showery troughs following the cold front out of Southern Britain tonight. Thereafter a quieter period is shown before warm fronts cross East towards midweek introducing a strong and warm sector across the South with a cold front in the East Atlantic waiting to chase this mild sector out of Southern Britain towards the end of the week..

GEM GEM shows little change in pattern this morning with Low pressure crossing East to the North and High to the South maintaining the changeable pattern aforementioned across the UK.

NAVGEM NAVGEM differs in as much as it brings a strong ridge up close to Southern England a week from now diverting Atlantic depressions further to the North to affect only those areas while the South sees the risk of frost and fog patches and generally dry conditions with some bright skies late in the run..

ECM ECM this morning shows a mobile Westerly type pattern maintained through it's duration this morning with all of the UK weather through the period generated over the Atlantic. As of late there will be spells of rain alternating with colder and windy periods with showers, wintry in the North. High pressure does show signs of becoming somewhat more influential in the South later by a reduction in the amounts of rainfall and in the North by bringing strong but milder Westerly winds for longer periods than currently. Christmas itself on current thinking looks like being rather cold and showery under polar maritime air under low pressure to the North

ECM ENSEMBLES Due to work commitments I am unable to report on these this morning as of time of release of this report they had not been issued.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS Trends remain slow this morning with the trend for a longer milder sector across the UK towards Christmas being pushed away by the holiday itself by another shot of colder polar maritime conditions with showers, wintry in the North

MY THOUGHTS Not much change within the model output with the majority showing a continuation of an Atlantic driven pattern between High pressure to the South or SW and low to the North and NE. There looks likely to be a period of mild SW winds in a warm sector in the days running up to Christmas before the Christmas period itself could coincide with polar maritime conditions lying across the UK which could give Northern areas in particular a fairly festive feel to things as wintry showers look likely. Snow at Christmas looks less likely across the South at that time though. Then we need to look between the lines of this pattern to see where we might be heading late in the year and the start of 2015. There is some members this morning within ensemble packs and a few operational runs who do show a desire at least to break us out of this pattern. For example the GFS operational does half heartedly rise pressure through the Atlantic and towards the Greenland area late in its run but in this occasion doesn't benefit the UK other than to drive a deep Low into NW Britain with wind and rain while the Parallel run takes High pressure over to Scandinavia later which would change the pattern to a colder and possibly more blocked pattern. However, progress and extent of these options remain slow and few with the overriding scenario remaining one of a similar pattern to that of now with sturbborn High pressure still a thorn in the side to any required move out of the current pattern. Nevertheless, there are some signs that GFS at least is trying it's best to offer something a little more seasonal longer term and lets hope these are the first baby steps I hinted at yesterday and they are the precursor to more of the output leaning this way in subsequent rns over the next few days. We shall see.

Some interest remains for the Xmas period. Still cant rule out a White Xmas which normally we can do at this range

agree with gavin - period post xmas and pre new year offers our first chance of a snow event this winter. (not that gav went that far!)

Output once again indicates a continuation of the pattern from the last two weeks, with if anything a few more days of more Atlantic W flow with resulting fairly mild days midweek.
After that hints of a subtle change with more robust high pressure to the W or NW over the Christmas week.
What it does show is that the MetO medium range forecasts have been very good, and hints at a colder pattern early New Year should be heeded. It also shows up the fiction spouted from the likes of Madden and He Who Cant Be Named in recent weeks for the total pigswill it really is.