UKMO expect NAO phasing more neutral through the next week or so. First weakly -ve NAO cluster we've seen in recent EC-EPS now appears in back end of today's 12z suite but way out at T+360, needs to be taken with due caution(!). Nonetheless, shift remains in line with ongoing UKMO medium range expectation.     

 

From Fergie ^^^^^^^^^     

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Not much to come out of that then....

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Imagine if he talked like that on his televised forecast...

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I haven't been on here for a while but I had to reply to this post (for my first post in almost 3 years)!

I think you are looking at the "small picture" to be honest. If we only had charts and data just for our little section of the world then I would be thinking that things look pretty poor, but you need to look at the big picture.
Looking down on the N hemisphere for example, there are signs of a change taking place, things (admittedly later in the run) are looking a lot more amplified for a start and have done for a few runs now, also I have been interested in the ridging in the far eastern Pacific, western US and Canada. I know it happens in fi but it keeps popping up in the latest runs, the GFS and its offspring (the parallel that is) have both been showing something of interest. Ok, to get from ridging over the western US to cold for the UK takes a lot of work and if it happened it would be a good couple of weeks down the line maybe (Beg - Mid January) but I have always seen that as a positive sign and at least a step in the right direction.
There are a bunch of other potential positives too but im just talking from a basic model perspective. 

There is some excellent analysis in this thread, but without sounding stuffy it is the 'Model Output Discussion' thread and not the 'Decipher the wording of tweets and extrapolate the potential meaning behind sporadic long-range forecasts from well-known individuals' thread.

Playing devil's advocate I see a number of posters being shot down for simply commenting on what the operational NWP is showing, and not seeing the bigger picture. There is room for all levels in here and if I want to say 'looks like a mild Christmas and into the New Year on most of the models' I should be able to do so without being corrected and criticised because I'm not getting the 'bigger picture'.
I say devil's advocate because as a rule I do get the bigger picture and welcome the excellent analysis here, but as it stands the next few weeks look like a continuation of the last two weeks - mobile, changeable, wet and mild and cool in equal measure. Chances of any appreciable frost or snow anywhere on Christmas Day - no better than 10%.

As for January - there is no model I have access to that goes that far.

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 Good post. The NWP is the most reliable indicator we have for the short to medium term and it's snowless for most of the population. Things remain more interesting for Scotland of course. As I said before even cold UK winters can usually be boiled down to no more than 2 or possibly 3 significant snow events for lowland areas. The exceptions such as 1947 and 63 can't be forecast. 

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HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SATURDAY DECEMBER 13TH 2014.

NEXT UPDATE SUNDAY DECEMBER 14TH 20:00

THE CURRENT GENERAL SITUATION A ridge of High pressure will cross SE across Britain today followed by a milder SW flow ahead of a cold front approaching the North and West of the UK tomorrow.

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 a few 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 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 rises over the South with drier and more settled conditions possible with frost at night while the North maintains a Westerly feed with rain at times and milder periods. Late in the period with High pressure over SE Europe the weather become milder again in a SW flow across the UK.

THE GFS PARALLEL RUN The GFS Parallel run is broadly similar in structure with latter details day to day not mportant at this range but with the jist of it showing higher pressure developing close to the South of the UK near Christmas with bands of rain off the Atlantic principally affecting the North more than the South with frost and fog patches possible under the ridges more likely over the South later before High pressure ridges North over the Atlantic at the end of the run with a cold North flow affecting all then..

THE GFS CONTROL The GFS control run today maintains a basically mobile Westerly flow across the UK over the period leading up to Christmas. There will be spells of milder and rainier conditions alternating with short colder periods with showers especially across the North. Later in the period a more pronounced push of High pressure affects the South at times with colder and less breezy weather more common with frost and fog patches at night between short periods of rain and cold conditions with snow on hills as Low pressure sinks SE across the UK post Christmas.

THE GEFS ENSEMBLES The GEFS Ensembles are indicative that Low pressure to the North of the UK and High to the South and SW will continue to be dominant through much of the period but the trend towards a weaker Jet profile and weaker pressure gradients over the UK opens the door for other solutions including cold ones under Northerly winds to be shown within the ensemble pack.

UKMO UKMO today shows a strong Westerly flow across the UK towards the middle of next week with deep Low pressure to the North. With temperatures close to average it will feel chilly in the wind and all areas will see further spells of rain and showers at times with a some snow on the higher Northern hills in the showery periods between rainbands.

THE FAX CHARTS The Fax Charts show a couple of occluded fronts crossing SE over the UK in the coming days bringing rain at times and showers behind them, wintry over hills in the North. Towards midweek a warm front with a more proniunced warm sector crosses England and Wales with rain at times before the North sees a cold front cross midweek with a return to colder and more showery conditions once more. Generally quite windy at times.

GEM GEM shows little change in conditions to that we have experienced over recent days with spells of rain alternating with colder NW winds with showers, wintry in the North. Later in the run the trend towards pressure rising across the South and later to the West over the Atlantic brings quieter and more settled conditions across the South with some patchy frost and fog at night. As we approach Christmas High pressure is shown ridging North over the Atlantic with a spell of mild westerly wins being replaced by colder northerlies in the days up to the big event with wintry showers developing over the North.

NAVGEM NAVGEM continues to show the pattern to which we have become accustomed of late with deep Low pressure to the North and High pressure to the SW sending spells of milder west winds and rain over the UK alternating with colder, windy and showery NW winds when showers turn to snow over high ground in the North. It too shows hints of pressure rising North over the Atlantic 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. It currently shows a mild and benign looking Christmas over the UK as a whole..

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 A slow trend for more members within model groups that a trend towards High pressure ridging North into Southern Britain at tmes or North over the Atlantic later in the period towards Christmas is indicated this morning but progress and extent is very sketchy and limited currently.

MY THOUGHTS In these thoughts of mine this morning I am not going to dwell on the fact that the models continue to show variations on a well worn track that Westerly winds between Low pressure to the North and High pressure to the SW continue to be the overriding factor within the models again this morning. However, reading between the lines there are a few small and some would say minute but subtle differences in the pattern that show up towards Christmas and more likely thereafter. It looks increasingly likely that High pressure will gradually exert more influence of primarily Southern britain in the run up to Christmas. This will of course mean mild Westerly winds over the North with further rain at times and perhaps less interventions of colder polar maritime air for a time. In addition behind each cold front comes another surge of High pressure eventually from the West which shows more inclination in trend to push north over the Atlantic with time and although in the time frame of this morning's output this is not achieved to any great extent it could spell the first signs of a pattern change as High pressure becomes more dominant to the West of the UK and later NW as the Jet flow pattern continues to show signs of weakening in response to other factors within the atmosphere towards the New Year. I continue to maintain that our best chance of cold weather this year will be from the North and not East and although there is little concrete evidence to support this in a huge way this morning the first baby steps are there but it is a long way to go before a change in pattern will achieve a common theme within extended outputs but I believe the first steps of change are beginning to become apparent within the longer term outlooks this morning and if the info supplied from the Met who have access to much more than we can see is to be right then we could begin to realise what they say about conditions by early January could begin to bear fruit soon within the models. Watch this space.

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The GFS 00z really is a horror show for coldies this morning with the Azores High migrating to Euro land as the run progresses. If the High sets up anchor there it will be very difficult to shift.

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Some will hate it, but for those of us that don't like going outside and being cold, the GFS op is superb toward Xmas. ECM similar. Still a long way out, but I can already hear many of the LRFs for this month being screwed up and binned. Most seemed to be going for a month that got colder toward the end. Looks more like the opposite, although as I say, still way too far out to call yet. 

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Thanks Martin, let's hope you are right with your thoughts at the end of your post.

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yep your absolutely right Matty,  tho its looking like a mild or mild-ish outlook,  but as for end of the month like you say to far out to call anything ,

I wondered if anyone had ever contacted the Met Office and see if they would provide a response to the model output thread ? to see if we are on the right tracks or not. Perhaps one of the moderators could ask them ?  even better if they supplied " A Chief Forecasters View" once a week - good for their publicity I would have thought. They even share some of their charts that are not visible to the public.

 

December so far for me is below average on temps   mean of -0.5c compared with average

Five air frosts compared with none last Winter at all, and we have had a couple of days with falling snow

I fear the second half of December will not be as cold, but enough to keep me interested for a while

 

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Off topic

This 2 weeks into winter is so far so good!

Usual mix of frosts, clear blue skys, wind rain so far.

If it snows this side of winter it is a bonus.

 

 

 

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The GEFS stamps and spreads show little variation from the current overall pattern up to Christmas Day, except with the high a little further east.

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=276

But by the end of the run there are hints that the HP might be on the move, but as ever, not always favourably to bring wintriness to the UK.

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=384

 

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Great stuff Gibby as always. Hope the Meto are onto something. If they are then I think it would be the first cold spell picked up before we see it on any ensembles since December 2010. 

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Interesting 06z. Possible white Christmas for some in the North West and signs of a pressure rise over Greenland at the end of the month

 

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Well - its nice that the theres only certainty up until 18th Dec, after that its a new scenario on each run. Theres a pattern change in the air, how it will pan out no body knows.

At least each run is interesting rather than boring zonality.

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One run etc... we need to see this trend maintained over a few runs if it is to be noteworthy.  I don't think the Christmas Day weather will be clear til next weekend and the  New year by Christmas Day.

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 Which 6z?

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Yes, the GFSP run is a horror show for Christmas - hard to imagine a worse outlook than that! At least it is still FI.

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Update below seems to suggest the initial pattern change will bring milder weather to begin with. Think we can rule out a white Christmas at least for the south.

 

Ian Ferguson Netweather

Referring only to next 10-15 days, UKMO continues to see pattern change to -ve NAO albeit with GloSea doing so via stronger Azores high and northerly-displaced jet. Thus, prospect of dry, settled weather at least for S'rn UK. As of 12 output yesterday (I've yet to check 00z), upward trend in temperature well signalled in EC ENS post d10, with majority continuing thus to d15. As earlier noted in my post last night, caution required in assuming -ve NAO = deep cold, at least in 15d period.

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Time for my daily NAO watch:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

all members still appear to be levelling off and taking a dip towards month end... Rather sharply too, with one dipping obviously negative.
The dip looks more aggressive than it has the last couple of days.

 

maybe this index will show signs of a change before other output?

As bad as last year's? And we all remember how awful that was with a 927 mb low just off Scotland on Christmas Eve. Mind you, it had turned out decent enough on the day itself and I think Scotland did get some snow out of it as we fell into a break between two very active deep depression systems. But other than that, it was a rubbish festive period overall where I had to wait until the first bit of calm weather in January for my brother in law to be able to get onto the roof to repair the roof flashing. 

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temps from the GFS 6z

5c , 7c , 5c , 5c , 11c , 12c , 9c , 5c , 5c , 11c , 11c , 6c , 6c , 3c , 3c , 10c

Quite a mixed bag I'd say with no weather on top mild or cold.

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Nice end to the GFS Control. 

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=360&mode=0&carte=1

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