I reckon we're just going to have to be patient, a bit like two winters ago. The model output didn't look great for much of the time during December 2012, but we weren't disappointed after the New Year.

Euro models are great tonight

Let the fun and games begin (been too long imo )

EURO4 snow accumulation. I thought this model did very well during the Winter 2012-13 snow.

Quite.  Over analysis at this stage is purely academic but the day 7 and 8 charts for next weekend on that run are of interest for many.  Some evidence of Northern blocking on the deep FI GEM too, worth watching as a potential trend, I'm almost starting to think we could get something of real interest by Christmas, but not quite yet.

I think those confident of a return to an Azores dominated WSW'ly outlook should exercise some caution post 192 hours. 

It was only a few days ago the output was showing a very flat westerly atlantic pattern. Slowly over the recent days the flow has veered more and more NW'ly and now N'ly by the end of the week. Yesterday's 12z's were pivotal in closing the atlantic train for a few more days and hence increasing the longevity of the polar incursion commencing Thursday 11th December.

The trend continues in high res. to slowly rip the Polar Vortex out of Greenland and move it towards Scandinavia.

Observe trends, keep an open mind and bear in mind that once models move towards low res in such a setup the atlantic is normally favoured. 

The outlook is interesting. The longer that mid atlantic ridge prevails, the greater chance of deeper cold the longer it goes on. Who knows a Scandinavia High could even set up if the cold pool is eventually allowed to stagnate ?

Yes the odds are stacked in favour of an eventual atlantic return but for now keep an open mind of the potential. 

I don't think the 552 line is getting enough attention, hence I present to you the 552 parameter. Its still not quite getting to Greenland unfortunately. 

This is about as close as it gets on the GFS 12z, it does even worse on the ECM.

It has been the most satisfying evening of winter model watching for a long time.  Last year I began to fear the next storm and had trees down and structural damage to the house, and it was a punishing experience.

I was kind of expecting the models to back off this evening but the ECM has upped the ante and the day 8 chart though clearly FI shows that a cold pM or modified Arctic flow in December can deliver the goods further south and lower.  Tomorrow's runs will be of interest, and not in the nightmarish way of 2013-14.  Phew!

is it me or to many jds tonight unreal uppers in usa record warmth?

http://www.meteociel.fr/modeles/ecmwf/runs/2014120612/ECH0-168.GIF?06-0

Well said, on all accounts.

Anything would be better than last year! At least all of this makes interesting model watching times.

Today has established two significant developments for the next 10 days.

The first is the potential for a widespread lowland snow event sometime between next Friday and next Monday. It's little more than potential at this stage, but seems plausible given a very unstable air mass over the UK with uppers at least low enough to support now from evaporative cooling situations IF we get a shortwave feature with relatively light winds toward the center - as the ECM 12z op run shows.

The second is the transferal of yet another trough from Canada to the Greenland area and/or the Atlantic, which looks to draw the polar vortex back west by a few thousand miles and perhaps north as well - though I'm highly skeptical of the way ECM evolves as it requires some quite unusual or extreme interactions between the Canadian trough and the subtropical jet.

It means we still have a fair while to wait for the Pacific/Atlantic energy transfer to be blocked off by a ridge across the U.S., which seems the most likely route to higher heights around Greenland in response to the MJO reaching phase 8, shown nicely by the GFS 12z op run late on.

Support for the MJO progressing to the East Pacific i.e. phase 8 is now pretty strong:

Which as far as I understand should start to lend a hand in about 10-14 days time.

Considering this likely movement west of the polar vortex in 6-8 days time, we're lucky to have the potential for some decent snowfall to keep us entertained. Only a few days ago, the Canadian trough was faster and the chance of more than fleeting lowland snow slim to nil.

looks like the MJO wave is stlll forecast to run out of oomph though. shame as decent amplitude in 7/8 would correlate to a greeny ridge.

Since there is quite a lot of interest in the ECM image, I have done my front approximation. These are based for those that are wondering on comparisons between SLP and the met fax charts. Although it is possible to get an approximation of surface fronts, more sophisticated methods are used to derive their exact position on for instance the FAX charts. In particular I find troughs very difficult to place (although I am improving), and I think I have mostly mastered occluded fronts now, which are much harder than warm or cold. Med lows are always sons of bitches though. 

Anyway we have a developing wave to the NW, these are good providers for central and northern britian. At this point of the chart we have the occluded front affecting England. The southern part of the front could give some heavy and persistent snow, the northern part is as annoying as hell, even 12 hours before the event the width of the band or whether its just showers is very difficult to determine. Anyway, without looking at the 850s I can tell this will be all snow just from the pattern.

Ofc it is 192 hours so this isn't all that useful I admit.

Just wanted to share this Met Office seasonal temp (updated) with you:

Doesn't this denote lower pressure over N. Atlantic and Blocking to the North?  -Notice how the whole of Europe is above average in terms of temperatures!?  -Northern Ireland and Scotland may do well with these N'ly and North westerly winds bringing in colder Arctic air and wintry showers. 

On the upgraded charts over on the NW Strat thread, we're seeing output of +15C over the pole by 384. The 18Z shows warming climbing to -20C (the second highest it has shown this winter period I believe), so something certainly seems to be brewing up above. Certainly feels cold enough at the moment. I'm struggling to remember a period with no notable prevailing weather type as we have now. Not Zonal, not blocked, not Barty, the euro block receding and the azores high coming and going. Perhaps I'm seeing it as I wish to rather than as it is, but to me this seems like a fascinating period of model watching, whatever the weather is doing.

Another excuse to take GRADs for a spin! Very close on the 18z, but still not quite.

The wavier the line gets though the better, and it seems more wavy on the 18z. The UK is north of the polar front though so a cold, if not 'beasterly' theme. 

Sorry everyone, I just downloaded a colour script, so I'm getting rather drunk with power. Here is that 10hpa 384hr chart, but this time  height rather than temperature which is somewhat less impressive with a strong vortex over greenland, with the high heights coming in from the pacific.

Sorry about the colorbar, next weekend when I have time, I will install pygrads, with a python interface I will be unstoppable. Mwhahah MWhahaha! 

My apologies, I'm just getting really into it. I downloaded grads several months ago, but never had time to fully explore it; but over the last week or so I finally got time. And its fantastic, I'm working on things like producing my own snow risk maps based on various parameters such as partial thicknesses and dew points. The color.gs script that I recently downloaded (and I'm convinced is the same one weatherbell uses) makes my life so much easier, I don't have to make my own color scales, or use the rainbow default one. My only regret is a lack of mathematical functions and versatility so I want to try and get python working. 

Anyway, apologies for this giddyness! I don't want to get banned from being way off topic. With regards to the strat there is some interesting warming going on towards the end of the run, and you can see the polar votex getting displaced, however I worry its towards greenland. Ideally don't we want strat warming that starts in the atlantic, the so called Achilles heel (this is a really interesting point to read up upon, strat warming at the point on the south of Greenland can be devastatingly effective in ending the polar vortex). 

Its in Kelvin; this scale ranges from -80C to +20C, this is still +384hr and the level is 10hpa in this case. Its more prominant at this level; compared to 10hpa, but its hardly earth shattering. What do people think about the fact that this is coming from Eurasia, this sort of thing happened last year and not much came of it.

keep on boozing Q because they are excellent informative posts! 

:-)

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY DECEMBER 7TH 2014.

NEXT UPDATE MONDAY DECEMBER 8TH 08:00

THE CURRENT GENERAL SITUATION  A cold front will clear SE Britain this morning and a further showery trough crosses SE over England tonight followed by a cold NW flow ahead of a weak ridge of High pressure later tomorrow.

MODELS-2 WEEK HEADLINE Rather cold and windy for most with wintry showers or longer spells of rain or sleet with snow on hills especially in the North later this week. Perhaps milder especially in the South next week. Some night frosts where skies clear.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble forecast shows the flow positioned to the South of the UK with a trough in the flow to the East of the UK gradually lifting out in Week 2 to a flatter West to East pattern just to the South of the UK.

GFS OPERATIONAL The GFS operational this morning shows a lot of rather cold and unsettled weather across the UK as the pattern of Low to the North and occasionally NW and NE and High to the SW persists. There is spells of wet and windy weather shown for all at times followed by spells of colder and clearer weather with wintry showers across the North and West in particular. It is shown to be often windy too. Temperatures may recover towards average or a little above at times across the South for a time mid period.

THE GFS PARALLEL RUN The GFS Parallel run is not available until Monday of next week.

THE GFS CONTROL The GFS control run maintains a similar pattern to the operational with winds from a Westerly point alternating with more NW or even North winds at times as each weather system moves away East. Occasional rain followed by wintry showers will be a repeated process through the run with snow at times over most high ground.

THE GEFS ENSEMBLES  The GEFS Ensembles maintain a period of zonal Westerly winds over the next two weeks circulating around Low pressure to the North and High to the South. As a lot of colder air interjects at times especially across the North there will be wintry showery type weather for many of these areas too with frost and snow at times over even modest high ground on occasion. However, in the South these incursions will be shorter-lived and modified at times.

UKMO UKMO today shows deep Low pressure to the North and later NE of the UK with a progressively cold West then NNW flow for a time at the end of the run bringing plenty of rain showers in the South turning wintry over the hills next weekend while the North sees cold and windy conditions throughout with much more in the way of sleet and snow showers, appreciably over the hills.

THE FAX CHARTS The Fax Charts show a cold NW flow tomorrow give way to a strong Westerly flow across the UK from Tuesday. A front will bring milder winds for a time before cold air sinks slowly South  from midweek with snow and sleet showers in the North from midweek. A more organised band of rain crosses Southern Britain on Thursday before all areas experience cold and strong NW winds by the weekend with wintry showers.

GEM  GEM this morning also follows the pattern of strong Westerly winds and wintry showers developing later this week. these will be restricted to Northern areas in the frst half of the week with longer periods of rain crossing all areas on Tuesday and the South on Thursday before all areas become affected by a short injection of cold NNW winds and snow showers everywhere for a time. Late in the run winds back West and mild air sweeps East across all areas with some rain and a thaw in the North and West.

NAVGEM NAVGEM this morning could be written from the GEM textbook as it mirrors the sequence of events up to 18-hrs with a cold and changeable week giving way to milder conditions as we start next week.

ECM  ECM this morning shows a very changeable week to 10 days to come but shows less penetration of cold air into the South late this week that some of the other output shows. As a result quite a wintry week in the North with strong winds and snow showers look like lasting for three to four days while the South sees more moderate if rather cold conditions at times with rain on Tuesday and again on Thursday before showery weather occurs thereafter with a little wintriness only over the higher hills of the West. Then all areas see a backing of the flow towards the West resulting in all areas becoming milder and windy with rain at times but still with some incursion of colder and more showery weather across the far North at times.

ECM ENSEMBLES This morning's Ensemble data maintains the pattern of Low tpressure to the North and High near the Azores maintaining the changeable pattern of rain or showers at times across the UK with occasional shots of colder polar maritime air across the North of the UK sufficiently chilly enough to promote some wintry showers here while some frost is possible in quieter periods between fronts, again more common across the North.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The main theme is for chilly Westerly winds to predominate across the UK veering to a colder still NW blow for a time later this week before flattening to a milder Westerly pattern next week.

MY THOUGHTS Some parts of Northern Britain are going to see quite a bit of wintry weather this week with plenty of snowfall mounting up on all the higher ground giving rise to some disruption with height. However, height asl is the key here as many lower lying areas will see only limited snowfall and little if any settling of the snow. In the South the pattern will be a lot less exciting with sunshine and showers giving way to more prolonged rainfall and for a time in mild air on Tuesday with more prolonged rainfall on Thursday too. It looks like the period of Friday to Sunday sees a window of opportunity for the South too to see some wintry showers while the North continue to see more troublesome snowfall over the hills. Thereafter the trend looks like the weather will become milder everywhere as the dig of cold into Europe is thwarted by rising pressure there forcing the Jet stream further North over Europe and tilting winds across the UK to a milder WSW orientation. Ther could still be some incursions of colder air into the North and West in particular at times with some wintry showers on the hills while the South will just see rain. Some frosts through this week are likely under clearing skies but there should be way to much wind for fog in a widespread form with frost too becoming more restrictive in week 2. In my opinion we continue to look to the North for the chance of a cold outbreak to occur between now and the New Year and although the shift in emphasis is looking towards less cold synoptics next week I think there will be further incursions of cold air coming down across the UK from the North or NW on various occasions between now and the New Year with little if any chance of anything cold arriving over the UK from mainland Europe within this period.

Got to watch the risk of warm front snow Saturday, the same rules apply as usual; stronger = better. Unfortunately it looks rather weak here, although the atmosphere is pretty cold so that compensates I guess, typically for a strong warm front -2C at the 850hpa level is fine. Its about -5C here, but the front is weak so its very tenuous at this stage, as ofc it will be so far in advance.

Also apologies for not setting the map color to something other than white!

I said the charts would be of interest this morning - and they are - the wintriness has been toned down away from the NW for areas without much  altitude and the output again looks standard westerly mobile with alternating incursions of Pm and Tm airmasses.  A flatter pattern shown as we head towards Christmas BUT I would not completely rule out a more potent plunge from any point between NW and NE before Christmas.  The models are worth keeping a "weather eye" upon, that's for sure.  And at least its not 2013-14

WI

Yes there's no getting away from the fact that any wintriness has been downgraded this morning,it remains a very volatile upper air pattern and I think we'll see the pendulum swing back and forth a few more time yet.