I think that the instance we're trying to remember was in early February 2009. I don't have an image of the full ensembles, but someone had a snip from them in their sig and I took a copy of it. I don't know how to post an image from my computer, so if someone could give me a tip on how to do it, I'd be grateful. I used to use photobucket to host images but that's not available now.

Actually they are both party of the jigsaw with the op runs being at a higher resolution than the ensemble members. You shouldn’t take any op run in the medium to long term at face value but when there is a large divergence at around the 5th of January I wouldn’t take any one scenario for granted either.

It is a messy and potentially rather wintry picture. We may end up with a brief snap of cold and limited snow or a scenario like the 12z GFS or the 00z GFS op runs, or the 00z ECM, or the 06z AIFS and no amount of psychology (reverse or otherwise) will change that one iota.

All we can say is that there are possibilities for cold and snowy weather, something that wasn’t really evident a week or so ago.

https://postimg.cc  - upload your image, use the direct link code and paste it in here, using the insert image button on the toolbar.

Incidentally the 12z ECM is rolling out, and it currently shows the second low, the wind-bringer, to be both shallower and further south as of T+54. Good, hopefully!

https://wxcharts.com/?panel=default&model=ecmwf,ecmwf,ecmwf,ecmwf®ion=europe&chart=overview,accprecip,wind10mmph,snowdepth&run=12&step=054&plottype=10&lat=51.398&lon=0.922&skewtstep=0 

That is from yesterday I think. Also, it's worth remembering that most of the changes we've seen so far today have taken place from the 06Z updates onwards. Obviously I don't know how they work, but I would be inclined to wait to see if the breaking changes persist for more than a couple of cycles before making significant alterations to the long range forecast wording.

https://wxcharts.com/charts/ecmwf/eng/charts/gustmph_20241229_12_078.jpg?  

https://wxcharts.com/charts/ecmwf/eng/charts/gustmph_20241229_00_090.jpg? 

That's true but the chance of a significant cold spell has reduced compared to yesterday.

At least the trend is for the low to go south and be shallower. Hopefully the GFS pub run will move in this direction

It’s been mentioned in the mid term text for a couple of days, but not like this (in the long term) until today. 

With thanks to Retron for the instructions, the image of the ensembles just before they flipped should be ...

(Well, that's no flipping use as it appears much larger in the preview before posting. Please bear with me while I try to enlarge it.)

[/url]

[url=https://www.wetterzentrale.de/en/topkarten.php?map=20&model=gfs&var=25&time=270&run=12&lid=OP&h=0&mv=0&tr=6]https://www.wetterzentrale.de/en/topkarten.php?map=20&model=gfs&var=25&time=270&run=12&lid=OP&h=0&mv=0&tr=6 

You won't be able to enlarge it as the forum now shrinks images that aren't hosted on TWO's servers (and no, I don't know why - it doesn't save any bandwidth!)

Here's an animated version showing that mother-of-all-flips. I think I did the original one too, but I no longer have it!

https://i.postimg.cc/631QtB77/ani2.gif 

Heartbreaking! That really did highlight the futility of weather forecasting, even with supercomputers.

That’s it!! Thanks both

https://www.wetterzentrale.de/en/topkarten.php?map=1&model=ecm&var=1&run=12&time=120&lid=OP&h=0&mv=0&tr=24#mapref 

The EC mean post 240hr is showing a warmer trend than the 00z,  but still cool until then. 

I still think there's a chance we could get a flip back colder for longer tmrw as it's fine margins.  But if it can go wrong it normally does.

Very apt advice!

In my experience there's usually 2 outcomes when a 'blip' gets modelled in what had looked like a solid colder pattern:-

1)  The strength of the new pattern is overplayed and the models move back towards the original solution but not all the way, usually meaning you end up with a worse solution than originally shown but better than when the 'blip' was first picked up.

2) The models gradually wipe out the colder signal and you end up mild. 

Just a guess but I'd say even if 2 ends up being the route this time, the far North may well end up either colder throughout or cold air remains close enough to be pulled back at times.  It all rather reminds me of a few years back where a Greenie HP was modelled and whilst it happened, in the end it was too far West and Scotland aside the cold air didn't make it. That though turned out to be attempt 1 and attempt 2 did bring nationwide cold for a time (and I think possibly snow IMBY but could be getting confused!).