No concensus yet on the track and intensity of the weekend low. Until that feature is resolved, all variations post +126 are possible, including the GFSP which throws an early Christmas present into the suite this morning.

As ever . . . (you know the rest LOL)

"the models are struggling"

Yesterday the GFS 06z threw up the possibility of a scandi ridge sinking a bit. That seems to be the new consensus  post Saturday's "bomb". But a few more tweaks and we could be in a good position

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY MONDAY DECEMBER 22ND 2014.

NEXT UPDATE TUESDAY DECEMBER 23RD 08:00

THE CURRENT GENERAL SITUATION A mild SW flow will continue to affect England and Wales with a slow moving trough near to the borders between England and Scotland slow moving. A colder westerly flow will affect the far North of Britain.

MODELS-2 WEEK HEADLINE Changeable weather with rain at times and wintry showers at others. It will be cold and windy at times with some overnight frosts.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Foreecast is for the flow to continue it's undulating pattern over the next week or so with the longer term trend still indicative of a relatively flat pattern across the UK between High pressure near the Azores and Low pressure to the NW and North.

GFS OPERATIONAL The GFS operational this morning maintains it's prediction of rapid deepening of a storm system post Christmas as it winds it's way from the North of the UK to Europe. After a quiet and chilly Christmas with frost a period of strong winds and gales become replaced by cold North winds and snow or wintry showers  on the western flank of the Low. As this moves away winds decrease under rising pressure with bright days and sharp frosts and perhaps a little sleet or snow in the SW for a time as a small disturbance bumps into High pressure over the UK. Then as we move into the New Year the default pattern of High to the SW and Low to the NW with mild and strong Westerly winds prevail.

THE GFS PARALLEL RUN The Parallel run makes much less of the storm system with regard to the UK post Christmas but still potent enough to bring strong winds and cold weather under Northerly winds with wintry showers in the North and East. The cold winds then die away as pressure becomes High over the UK with cold and frosty weather prevailing over and into the New Year. Pressure then transfers East to become High over Northern Europe and brings a blast of cold East winds across the Uk towards the end of the run with snow showers in places as a result.

THE GFS CONTROL The GFS control run appears to be fairly similar in storm development to the North of the UK post Christmas with rain and strong winds for all before cold Northerly winds and eventual High pressure take over with frosty night and wintry showers in places for a time. Then the UK High cell drifts South later to set a regular pattern of strong and milder west winds and rain at times late in the run.

THE GEFS ENSEMBLES The GFS Ensembles do show the temporary chance of cold weather from quite a few members post Christmas with the overlying trend thereafter for the cold to lift out in preference to milder Westerly winds between High to the South and Low to the North into the New Year.

UKMO UKMO's development of the storm is more muted with it being just a standard deep Winter depression held well up to the North of Scotland bringing the strongest winds and rain to the North and NE with all areas seeing some rain before chilly NW winds and wintry showers take over by the end of next weekend.

THE FAX CHARTS The Fax Charts today show slow progress SE oof troughs across NW Britain replacing the mild and windy weather with quieter High pressure weather over Christmas with frost and night and light winds. Further fronts and increasing SW winds reach the NW by Day 5.

GEM GEM today shows the UK coming under a very mobile westerly pattern following Christmas with rain and strong winds alternating with colder and brighter periods with some wintry showers in places. The storm system after Christmas looks not at all threatening now blending instead with the overall pattern under strong Westerly winds and average temperatures.

NAVGEM NAVGEM's does show a more direct hit from the storm after Christmas as it drifts down the North sea enhancing a cold north flow for a time with sleet and snow showers quite widesly in the North and East following the rain and gales of previous days. High pressure then feed across Britain with fine and frosty weather developing as we move towards the end of 2014.

ECM ECM this morning shows probably the most direct hit from the storm after christmas this morning sending it SE down across the UK and on into the Meditteranean by the end of the run. This would bring rain and gales followed by cold North or NE winds and wintry showers post Christmas and then a shift of emphasis towards fine and cold, frosty weather develops for many with pressure holding High across Germany to the UK on Day 10.

ECM 10 DAY MEAN The ECM 10 Day Mean Chart is made up of a varity of options but with a bias towards the default pattern of Low near Greenland and High south of the Azores with changeable weather with rain at times under average temperatures the most likely poitn the UK wll find itself in at day 10.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS While the trend towards the severest risk of a marked storm post Christmas has receded for now the new trend appears to focus on the greater persistence of High pressure close to the UK thereafter slowing the breakdown from the West which still holds the greatest trend longer term.

MY THOUGHTS While the overall trend in the short to mid term remains as before the focus on the main storm event post Christmas have taken a more relaxed view on it's positioning and severity in the way it affects the UK. It is still shown though to give all areas a good blow with rain followed by colder conditions with wintry showers as the wind swings Northerly on the exiting East of the depression. The new theme appears to be a greater reluctance to bring the Atlantic back in as quickly with a strong surge of High pressure over the UK towards the New Year. What's more interesting is that this High pressure extends into Europe and with lower pressure held over the Med it is shown far enough North by a few models to allow a cold East flow across the South of the UK in particular with some further wintry or snow showers in the East and more importantly keeping things cold and the Atlantic at bay for a time. This is specifically shown by the GFS Parallel run but is hinted at by ECM too at the Day 10 point with cold frosty weather maintainedover the UK should it verify. However, having said all that there is also a lot of support for a flattening of the pattern into a mobile Westerly flow between Low pressure near Iceland and Greenland and High pressure over the Azores with strong winds across the UK delivering rain at times under mild conditions overall. In my opinion the period post Christmas remains a very fluid situation and the behaviour of the deep Low expected at that time could have major repercussions on the emphasis of pattern resulting thereafter. If it's final resting place lies to the SE or over the Meditteranean then High pressure could hold cold and frosty weather in situ over the UK ala GFS(p) or ECM or if it floats away further East over mainland Europe the pattern will quickly flatten to one of zonal West winds and rain at times and temperatures close to average if not a little above in the South. All should be revealed over the coming days as we near the event and the models hopefully get a more conclusive handle on the timing, depth and positioning of the Low.

The spread on the 0z ECM ENS Go check it out: "Del Shannon Entropy" call it what you will.  Chances of a 12z re-run runaway  of the Op .... slim....

Really will be hats off to GFSP if we end up with an Easterly, it was looking at this last week.

Early days of course

http://expert-images.weatheronline.co.uk/daten/proficharts/en/2014/12/22/basis00/ukuk/rart/14122800_2_2200.gif

Frost Hollow

Get your camera ready , more winter wonderland stuff for you

Ok 6z is off and at 6h it is totally different to the 0z..................all joking aside hopefully by the 12z's we will see a bit more consistency!

Could be a game changer if it comes to pass. i think it was major changes in the stratosphere that were largely responsible for altering the course of the winter two years ago.

Seems like it is more of a glancing blow on the 27/28th on this run by the op;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=0&carte=1

With less ridging towards Greenland

With the GFSP totally different setting up a West based NAO

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=&runpara=1&carte=1&runpara=1

ECM (left) has really made a fool of itself lately... this morning's op run is a dramatic departure from previous op runs in terms of how that low behaves, and now has the most amplified solution with the feature dropping due south days 5-6. Oddly enough, this happens in combination with the most rapid push of low heights through Greenland, the other models (GFSP, right, as an example) being less progressive with that, particularly GFS and UKMO.

So the confusing output continues unabated... but at least one thing is becoming clearer now - this UK storm will mark the end of an era over Scandinavia, because as it digs south, it promotes an increase in pressure over western Russia and leads to the demise of the persistent low pressure that has been extending from Scandinavia to Siberia for quite some time now.

So there is a pattern change on the way, but just how the different features position and align themselves is a total guessing game at the moment.

Despite this, the broad-scale outcome seems to be fairly well agreed upon now, this being expansive high pressure extending from the UK all the way to the heart of the Asian continent.

The operational runs suggest this will be far north enough to keep much of the UK under settled conditions, perhaps turning quite cold across the SE in particular as the flow becomes very anticyclonic with a flow from the continent also possible.

The ensembles are more chaotic, with a wide spread of outcomes, the least pleasant being ones which don't shut the door on a train of low pressure moving across from the Azores - these solutions suppress the rise in pressure from the west and basically bring unsettled westerlies.

At the other end of the scale are runs which either sink the LP so far south than a ridge builds west from Russia to bring a cold easterly, or go the way of the GFSP 00z op run, developing a UK high and then getting Atlantic low pressure to undercut, allowing the UK high to push north, amplifying the flow, forcing the remains of the UK's storm of 27th south and setting up a decent easterly via an elongated high, which I may as well post in large form as this is the season of good cheer after all:

I think the most important feature here is the low heights extending from Canada to Siberia, yet so far north that the westerlies don't start until you reach Iceland. It almost seems like the PV is being influenced by the very low heights on the other side of the pole from us.

Just for fun at this stage but you know what, ECM is also set up for that path come day 10 so it's okay to entertain the idea - just don't go expecting results... even if we see cross-model agreement for something like the above in 10 days time, I will remain as skeptical as ever 

By the way, there is an unofficial term for the elongated high extending through Scandinavia as shown above, coined by Steve Murr... the 'Murr Sausage'. I know, not the most cautious of names 

http://www.wetterzentrale.de/pics/Rtavn3001.gif

No block to the East from GFS