I liked Stormchasers Post Yesterday re: looking at the GFS difference vs the ECMWF, The UKMO swiftly is often sided to ECMWF while the GFS spends two days working the 144-168 solution out ahem Kudos Stormchaser's Post of Yesterday.

ECMWF for that period is actually quite similar to Today's 12z UKMO Model but they come to similar outcomes Ridge trough Ridge Pattern woww.

At 18z GFS develops an English Channel Low.

It is common for the Models to behave just like this in advance of Xmas day they have fun at us.

But I really just take notice of situations that are presented to us in the 00z run and 12z run.

I am happy with forecasting the Boring Azores Ridge Sceuro High with Mid NE Central N Atlantic Low tied in to another Low to the SW of it ahem.

I mean the GFS has push the Low not away much from Newfoundland at 120-144 but then it quickly move it to into West and Sw Greenland, While the ECMWF does the Opposite today's'so 12z run Large Greenland and Western to NW Atlantic High.

Well as well they behave different on short time periods but then shortly after reduce the UK chances of suggested outcome for Strong N And NW Atlantic Plus Greenland High to be gifted for a 120 144hr slot.  They all are clambered to Low to Our West and SW or to our West and NW with the Azores High clinching the UK weather situation and not allow any Decent Cold NW or Northerly at all we just wait and then look and the charts throw the towels and mild clouds back to us at 120hrs and beyond The PFJ and Mid Lat Southern Westerly punches in with the Strong West and North Greenland Low.

Lets keep watching as I still am ready to listen in here for any sudden and rare surprises ouch<>.

Watch that Western NW Pacific Low Pressure and the PV Low affecting The Western USA and the Pacific Mid Far East of Mid NE Side, it gives a lot of rain with plenty of Hill Snow, Looked at it and can see the Far Western NW Mid West Pacific PV Low Depression as strong as the other This Pattern of the El Niño is the Real McCoy that is often the Precursur to What Follows in Topsy Turvy Newfoundland West SW Greenland and the SW UK Azores High that is also to now spread East to W Europe.

Some of the Mid West N Atlantic South Side Low Pressure as well as an Iceland NW W UK NE Tracking Low I'd Imagine would at 120to 144hrs to 168 from today clearly match the Up Down Down Up Pattern of Low Pressure Trajectory in both Large Oceans be related to each other.

But there is A Large areas in USA Canada seeing Cold Dry Conditions but some with heavy rains e.g California such as has been occurred a lot already with the heavy rain and Snow.

Winter High Pressure System vs the Oceanic Low Pressure Cyclonic Jetstream it looks like the Weather Systems have more strength than Getting a Sustained Nortwest Atlantic N Atlantic and Greenland High link to survive the Strength of getting pushes from the SE Side and from the West and North in Atlantic N. Of Equator! Discussing the N Pacific & N Atlantic Just mention the EL Nino That is the winner next year may be even warmer than this years 1.6 above normal in the UK, that has my bells and whistles (It is going Strong in November December according to where the heavy rains are bringing relief to drought affected areas I am pleased to see this being collected thank heavens, chuckle that.

How much of an impact do you think the troublesome trough has on the situation? From our point of view a decent shortwave pattern is an essential catalyst to advect cold air to us but what is its impact on the greenland high if any? Anyway what you say about the GFS bias makes sense, it really is standing alone, even the NAVGEM is on the ECMs side. I have found in these situations an ECM-GFS hybrid is perhaps prefered, but if such a solution is contrived then I would dump it and plump for the ECM. 

Interesting to scan through the models at leisure this morning.  No great surprises, though the Met O 144 chart has a nasty storm system  with a deep low pressure with steep gradients sat over the northern UK.

The 00z GFS parallel run also has a rather nasty storm around that time period.

Morning model watchers.

I took a break from model watching last night, had an early night, got 8 hours of sleep and have come back with a fresh pair of eyes.

As it was really, certainly up to the early part of Boxing day with mild air in the south being swept away from the south on Christmas Eve ahead of a bright and chilly couple of days with the risk of a few wintry showers in the north east. Aberdeen looks favoured at the moment for the odd flurry on the big day Doc. 

The rapidly deepening depression on the night of the 26/27th is becoming generally well modelled with the exception of the ECM. The GEFS continue to pick this up well.

In the wake of the depression there is the potential for some cold air, at least temporarily, in its wake with the risk of snow showers for exposed eastern and coastal locations and possibly more generally if the feature develops a wrap around occlusion or the track is further south.

Thereafter high pressure appears to settle close to the UK bringing us into a calm frosty period in a week's time, what happens to the high pressure thereafter is very much FI. The form horse would be for it to slowly ebb into Europe restoring the PV to Greenland restoring the recent pattern, however, there are some weak signals for an attempted ridge to Scandinavia, hence increasing the longevity of the colder spell into New Year.

Lots to watch..especially that potential nasty storm.

Have a good day.  

Yes this one (at 156hrs)

Later it moves in Europe but the UK succeeds in missing out on a bonus 'lee' Noreaster.  Worth watching over the 12z runs.

yes, that caught my eye too. I was wondering the other day when many people were talking about a pattern change if indeed the new pattern was to be a stormy one and not cold as some were hoping? I imagine it's just a one off, but something to keep an eye on non the less.

Snap shot from history. Some similarities in the snapshots with some models.

Today's 0z ECM ensembles. There's a slight downgrade on the post-Christmas cold spell in terms of median temperatures, but only by at most one degree. It now looks likely that Boxing Day will be cold and bright for much of the UK, before milder weather sweeps in from the west. Thereafter, colder than average conditions are still the most likely outcome.

Note as well how the temperature scatter is diminishing, compared to yesterday's output!

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY DECEMBER 21ST 2014.

NEXT UPDATE MONDAY DECEMBER 22ND 08:00

THE CURRENT GENERAL SITUATION A mild SW flow will become established over England and Wales while a cold front slips slowly South over Scotland tomorrow becoming slow moving over Northern England.

MODELS-2 WEEK HEADLINE Remaining changeable with rain at times especially across the North and West. Possibly becoming more generally colder and unsettled post Christmas with some snow and ice in places, at least for a time and chiefly over the North.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Foreecast is for the flow to gradually settle into a familiar pattern of becoming quite flat, crossing West to East in the vicinity of the UK between a large Azores anticyclone and Low pressure to the North and NW.

GFS OPERATIONAL The GFS operational this morning in general reflects the pattern that we have seen throughout the Winter so far and that is that repeated attempts of cold NW winds come down over the UK to be followed by a collapsing ridge of High pressure crossing from the West and being replaced by renewed spells of SW or West winds with rain at times in mild air. The two pronged cold attack both at Christmas and again towards the New Year have been reduced to no more than brief affairs on this run today.

THE GFS PARALLEL RUN The Parallel run is somewhat different in asmuch as the second attac post Christmas is much more potent being driven by an intense depression crossing SE down the North Sea and on into Europe. Cold and wintry weather with snow for some would then slowly be replaced by quiet and calm conditions under a strong Winter High with widespread harsh frosts and freezing fog before milder SW winds and rain at times are shown to take over at the end of the run.

THE GFS CONTROL The GFS control run appears to follow a similar trend to the operational in making less of the storm cell after Christmas and keeping the pattern rather flatter, alternating the periods of mild and damp weather with colder and brighter weather with wintry showers in the North going well into 2015.

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 today maintains the colder push into Christmas quickly followed by a powerful storm system close to Northern Scotland soon after Christmas with severe or even storm force Westerly winds and heavy rain likely by Day 6 across the British Isles.

THE FAX CHARTS The Fax Charts today show a couple of cold fronts straddling the UK as they edge very slowly SE over the next 72 hours. By Christmas they clear the SE making for colder NW flow with scattered wintry showers over the North for Christmas with High pressure building from the SW.

GEM GEM today shows the smae attern as the rest of the output. In regard to the storm post Christmas it develops West of Ireland after which it drifts East over the UK with strong winds and heavy rain being replaced by cold North winds briefly as we approach the New Year with snow showers quite widely. At the end of the run a ridge os collapsing across the UK being the precursor of a pattern reset to milder west winds and rain at times soon after.

NAVGEM NAVGEM's runshows the storm developing to the North and ttansferring to Scandinavia in a weeks time with severe gales and heavy rain being replaced by cold North or NW winds and snow showers particularly over the North.

ECM ECM this morning shows that the mild SW winds after Christmas quickly become replaced by cold weather behind the storm which transfers East quickly to Europe with a strong pressure rise close to the SW by the end of the run. Heavy rain and gales post Christmas would be replaced by snow showers for many before quieter frosty weather slowly takes control by the end of the run in much lighter North or NW'lies.

ECM 10 DAY MEAN The ECM 10 Day Mean Chart reflects a pattern made up of the majority of members showing High pressure down to the SW and lower or Low pressure remaining to the NW, North and possibly East of the UK with the mix of milder and wetter conditions alternating with colder conditions with wintry showers at times in the North.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS Trends this morning show strong support for a cold and potentially stormy interlude post Christmas with the strongest trend being for this to be short-lived to a likely return of milder Atlantic Westerly winds again as we move into 2015.

MY THOUGHTS The models remain all over the place with regard to the development and positioning of a Post Christmas Storm which is shown in some shape or form by all models this morning. As a result of this the evolutions following this point in time could be thrown into turmoil by models not being able to nail down the intensity, movement and engagement of cold air around it. The general theme remains for a deep Low to develop near Northern Britain before it quickly moves off into Northern Europe. There looks a good chance that all areas will see a good blow from this with potential for severe gales and heavy rain. There is also of course potential for snow, probably unproblematic for many Southern areas but as the cold polar flow behind the Low gets pulled strongly South blizzards in shower form is expected to affect the Northern hills and mountains. The weather thereafter as hinted at earlier will be driven by the final resting place of this storm in relation to what remains of High pressure over the Atlantic by that point. The most favoured and less desirable option appears to be for any High pressure in the Atlantic at the end of the year will likely drift SE in the form of a ridge with a period of cold and frosty weather before mild Atlantic winds take hold again with rain at times. The pattern though is very fluid and any changes in model thoughts on the behaviour in the development of the post Christmas storm event could continue to throw very different evolutions into the mix over model runs of the coming days. However, to bring a sustained cold weather event we need to somehow hold higher pressure up to the NW and less power to the Azores High and in neither instance within the ensembles does that look likely currently so my best stab goes with a short and sharp cold snap post Christmas before a mobile Atlantic feed takes back over control as we move into 2015.

All model output now more or less singing from the same hymn sheet - a rapidly deepening low affecting us around the 27th, with a brief surge of cold air following behind with wintry/snow showers for some before the pattern clears E and we are back into a westerly dominated flow. The possibly deep RACY low around 27th is the main interest IMO, severe gales, heavy rain with local flooding and a possible storm surge down the E coast possible.

GFSP

The picture for coldies looking further ahead doesn't look great with a flat pattern looking likely to develop with a strong PV towards Greenland and probably a continuing strong Azores high. Temps probably average to above and unsettled especially to the N.

ECM day 10

NAEFS and GEM ensembles show a flat pattern and the vortex to the NW strengthening out to +384.

Wow. How long did it take you to find that! And what happened afterwards?

The collapse in heights over Greenland is now complete on all the models. Kudos to GFS once again. ECM now follows with its tail between its legs.

As we all feared this is turning into a boring average winter with the odd burst of winter every now and again. Standard British Weather.

Next week's "bomb" could be very interesting though and will keep me model watching  for a while longer

Back to square one. Depressing but at least its Christmas

Think it's a bit early to be saying that, Beast. That has been the way of it so far for sure, but we're only at Dec 21st and aren't even a third of the way through it right now. Still a long, long way to go after today.

I get the feeling that any pattern change that does occur may not be spotted by the models until relatively short notice; I've seen this happen numerous time in past winters, two years ago was a fairly good case in point. The model runs during Xmas 2012 didn't look that great for coldies but by the time we were into the early days of 2013, things were looking rather different.

The 18z CFS (1 month) run from last night shows how the collapse in heights over Greenland does not have to result in a mild Atlantic flow swiftly following to the UK. High pressure to the west of the UK gradually drifts east into central Europe rather than drifting south keeping the UK under cold 850 temperatures and Europe even colder.

At T432 the UK is under a cold easterly flow. It takes until 12 Jan for the Atlantic lows to finally push through to the UK.

31 Dec http://modeles.meteociel.fr/modeles/cfs/runs/2014122018/run1m/cfs-0-252.png?18

4 Jan http://modeles.meteociel.fr/modeles/cfs/runs/2014122018/run1m/cfs-0-354.png?18

7 Jan http://modeles.meteociel.fr/modeles/cfs/runs/2014122018/run1m/cfs-0-432.png?18
http://modeles.meteociel.fr/modeles/cfs/runs/2014122018/run1m/cfs-2-432.png?18

12 Jan http://modeles.meteociel.fr/modeles/cfs/runs/2014122018/run1m/cfs-0-540.png?18

This is very different to most other models are showing but just highlights that at this point the pattern beyond the storm predicted for 27/28 Dec is pure speculation. Anything is possible.

http://www.wetterzentrale.de/pics/Rtavn1261.gif

Here comes the bomb

Same refrain as last year - winter isn't over yet! But it never came.Time to give up on model watching, get a life and do something useful instead - another winter will come and the law of statistics says we will get another 1947 or 1963 sometime, because we know it is possible. 

Much better ridge north on this run

http://modeles.meteociel.fr/modeles/gfs/runs/2014122106/gfs-0-150.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014122106/gfs-2-156.png?6

perhaps a little back edge snow

The problems that low pressure and what happens afterwards is causing the models is quite unbelievable, LOL.

http://modeles.meteociel.fr/modeles/gfs/runs/2014122106/gfs-0-162.png?6

We need some height rises over Scandi to save the day

http://modeles.meteociel.fr/modeles/gfs/runs/2014122106/gfs-0-168.png?6

pressure is rising but it wont be quick enough. A better run anyway