Seasonality

Inter run variation. Note ecm gives a mid way solution to what you posted there and the op was definitely on the milder side for central Europe. Plenty of much colder options.

12z 384h vs 18z para 384h. Just for fun. But I think the 12z block could end up in a favourable position.

More spread out by day 16 though.

But cold at the surface is exactly what Matt is referring to, hence why theta-e's are relevant. No barrel scraping, just telling it like it is. Not sure why you think it is 'lmao'

Raging? The run ends with an arctic high spreading the vortex out nicely.

I believe it is an Omega block in fact, just not positioned in the way most here would hope it would be. But just look at the cold air flooding around either side, certainly good for me considering where I will be Xmas week! But it is 384h after all

And look whats coming for Christmas. More UK HP.

Come on Steve, GP works very hard to make his forecasts and his knowledge is incredible. If I knew a tenth of what he did about forecasting I'd be a happy man. There is no need to insult him.

No, not at all. It means the possible outcomes are split into two groups. Put simply, there are two groups of outcomes, one saying cold and one saying mild. So expressed as a mean they then get 'cancel each other out' as average.

Yes Ali, looks like cooling nicely. I'm surprised there isn't more excitement this morning. GP hinted at this turnaround yesterday and the other pros have been sticking to their guns. Colder blocked second half of December looking to be on track.

Morning @northwestsnow I made a gif so everyone could see the critical timeframe. I think you've hit the nail on the head.

You mean this one? Not out of the realms of possibility Gavin, as I said in earlier post this isn't the first output to show such an outcome.

The interest begins less than one week away, plenty of time for things to change but no longer in the far ranges of deepest FI. By the 12th the re-amplification is already apparent. Here at 162h.

GFS and ECM comparable at 192h. No flat euro slug!

Morning weather fans. Something is brewing in the East. Much clearer drop and tighter clustering of lower temps in Central Europe than in recent runs and a clear cool down London too. And look where we end up on the 21st. Posted jokingly yesterday from CMA output but a solution reached for the same date by yesterday's 06z parallel. Euro slug has had salt poured on him and amplification is back. Well supported run by ensembles. Perhaps the model output change hinted at by GP is happening.

Don't laugh folks. The 06z paralell gfs reached a similar outcome to the cma, albeit a few days delayed. A solution as possible as any.

But Matt is a pro and Mulzy is just one of us forum members. No offence Mulzy, that includes rank amateurs like me too.

Hi Ali, which perturbation and what time frame please?

The parallel run is producing rather different outcomes. A frigid Christmas week on the cards according to the 06z parallel.

Hello GP. Where do you get this information from? Do you have access to a broad overview of the data gathered? Not asking for you to post anything business sensitive, just curious as to broadly where this comes from.

We may be in a position where the ensembles are leading the way. Op run on 18z again at the mildest end in the second half of the run. This isn't only for the UK but for Central Europe too. I've included the Warsaw ensembles as you can clearly see the split of the chillier cluster heading lower around 12 December. UK will trend the same I suspect so the prediction of a colder turn of the weather mid-month may be a good prediction. I certainly would be pleased if it was as it would be a victory for the experts in the face of unfair criticism from some quarters.

Big old high centred over Scotland on the 06z parallel run. Looks like this could be what the meto are predicting!

But most people, and the CET for that matter base their feeling/record of cold on how it was measured/felt at the surface...as I'm sure you're well aware.

I'm pleased to report Warsaw's first 'proper' snow fall of the season. After a dusting earlier in November and a few snow showers here and there the first day of meteorological winter delivered in style with a good 5-10cm of snow settling from falls from 1 December into this morning with more forecast this afternoon and tonight. Pleased to report airports working perfectly and no travel disruption and everybody going about their daily business (contrast with the chaos this would bring to London for example, but noted that Warsaw is much more used to this and has infrastructure like snow ploughs etc in place). Webcam view across the River Vistula to the National Stadium on the left bank.

No very true. Must be frustrating for peple like Tamara and Gav who put so much effort and knowledge into their passion for weather to have to see the utter nonsense that often gets posted here.