There have been two such events in relatively recent times. One was last year when "that ECM" (as they call it on NetWeather) showed deep cold as close as 96 hours out, it then flipped and the other models also flipped.

Then there was the one back in 2008 or so when the models similarly flipped around 96 hours out.

Both cases involved a potential easterly and in both cases the entire ensemble suites flipped along with the operationals.

For the latter one, if memory serves me correctly, one or two ensemble members on the GFS were, as we'd normally put it, 'outliers' well and truely, and at quite a close time scale. Then, all of a sudden, the whole lot flipped with them. I think a current/previous member had a screen shot of it as their profile picture sometime ago. Can't think who though

The outlier thing happened in both cases - the screenshot you're thinking of was from the older event rather than last year's one.

And the Lone Ranger prize for rank outlier this morning goes to:

http://modeles.meteociel.fr/modeles/gens/run/gens-3-1-348.png?0

GFS 00Z ENS Pert #3 (The White Christmas Run)

Blink and you'll miss it LOL.

http://modeles.meteociel.fr/modeles/gens/run/gensnh-20-1-300.png?0

Brief NEly just before Xmas

crumbs of no comfort

Good morning. Here is the report on the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday December 9th 2013.

All models show a mild Southerly flow over the UK between High pressure over Southeast Europe and Low pressure over the mid Atlantic. The mildest conditions are shown towards the NW where Southerly breezes will be at their strongest with a little rain at times. In the SE drier continental air may filter across over the next 24-48 hurs bringing slightly less mild air and a greater risk of mist and fog overnight for a time. However, by the end of the week and into the weekend troughs make more progress across the UK bringing at least a short spell of rain and stronger winds for all before things dry up and settled down somewhat again over the second half of the weekend as High pressure is shown to build back North to some degree from the South.

GFS then shows a very mobile pattern next week and on until Christmas with the details irrelevant. With a train of Low pressure crossing quickly over or just to the North all areas can expect wind and rain and there will be quite a lot at times on Western upslopes. Winds will often be strong but always from a mild SW'ly direction continuing the no risk of wintry weather going for all areas.

UKMO today shows a return to this weeks synoptics early next week with High pressure refusing to move away from NW Europe with Low pressure out to the NW with a broad and very mild SW flow carrying rain at times to Northern and Western areas while the South and East maintain a lot of dry weather.

GEM today continues it's trend from yesterday with mild SW winds blowing strongly across all areas next week. Troughs and smal depressions in the flow will move rapidly NE over the North at times with some fast moving spells for all with the heaviest rain as usual towards the north and West with some drier interludes more likely towards the SE.

NAVGEM this morning holds the main thrust of Low pressure further to the NW and as a result High pressure remains close to the South and SE and although a few weak troughs deliver a little rain in the South at times the main share of Atlantic rain will be across the NW with mild conditions persisting everywhere.

ECM shows the weather becoming more deeply unsettled and often wet through the middle and end of next week with Low pressure troughs digging South across the UK delivering spells of rain and showers in blustery and mild SW winds. Things are shown to feel less mild later as winds switch more towards the West or even a little north of West at times when showery interludes could include a little wintriness over Northern hills.

The GFS Ensembles today show a few more dry days before things steadily turn more unsettled and often wet in the North and West but less so in the SE. This pattern is very indicative of a normal winter pattern of deep Low pressure to the NW and High to the SE with troughs crossing NE over all areas at times, most active towards the NW. Upper temperatures will fall off from current levels to nearer average ones later but at the surface some very mild days could be enjoyed in the SE Especially and to the lee of high ground in the NE. There looks absolutely no sign of anything remotely wintry from any ensemble member other than the odd one or two this morning.

The Jet Stream maintains it's trend to sink SE over the next few days to be running still in a NE direction across the Atlantic but this time over the UK allowing Atlantic lows and fronts to make deeper inroads into the UK. The trajectory though remains totally unbeneficial for getting any sort of cold anywhere near the UK due to persistent High pressure over SE Europe.

In Summary the trend towards more unsettled but still very mild weather is gathering some pace this morning. However, it looks unlikely that the SE will see too much in the way of rain but the North and West could become quite wet at times. Winds will also become more of a feature for all areas, blowing from the SW strongly at times with gales or severe gales in places and maintaining temperatures average or above for all. As we move inexorably towards Christmas, day by day the chances of anything Wintry over the UK on the big day look distinctly remote from today's trend and synopses endorsed further by the latest 10 day ECM Ensemble chart.

ECM 10 Day Mean Chart

Look like UK will miss any cold action hile severe cold take hold in N America and very cold weather for E Med regions this coming week which I will be watching very closely. 

Have looked at the GEFS 0h ensembles.Now Xmas is in range (360H) albeit in FI thought it worth tracking the types of  Xmas day circulation types thrown up by the 20 ensembles.So starting today the  spilit is Zonal W/SW 13(65%),Anticyclonic NE/E/SE 7(35%).

The Anticyclonic ens are 2,3,8,10,11,16,20.

I saved a copy of the screen extract used as a profile picture, and I'll try to work out how to post it.  In case I can't post it, the date was Mon 9 Feb 2009, the 18Z run.  The ensemble mean 850 temps weren't shown as dropping as far as -15, but at T+12 dropped to between -5 and -10 and then were shown staying there for a couple of weeks.  Then in the real world it didn't happen.

Angus

Edit: try this

Why?