Stunning run , can't complain at all 

Expect some more downgrades though... plenty more fun to come

Nice upgrade on the 06z run - however the operational run goes from being one of the mildest option on the 25th to one of the coldest option on 26th! So I am keen to see where this GFS 06z Operational sits in amongst it's 850's ENS members. Let's hope this 06z OP GFS isn't a cold outlier or if it is then let's hope other models will follow this trend. This run is totally in line with the Met Office and other long range models like CFS, JMA as well as EC 46 day were showing.

Laughably good , 78/79 esque.

One day , just one day 

A run for the Hampshire crew.

https://www.wetterzentrale.de/en/topkarten.php?map=20&model=gfs&var=25&run=6&time=384&lid=OP&h=0&mv=0&tr=6#mapref

Although too far for details . If a run now shows cold air over the UK on Christmas Day then it’s got more clout than it did 2-3 days ago

And if, as it shows here, double figures for most of the day then that has even more clout!

(6z GFS forecast for here for Christmas Day).

The ensembles show good support for a milder blip now over Christmas down here and that goes for ECM too - it's beyond that now where the interesting stuff lies.

Still, a week is a long way away in weather terms and I suspect there will be plenty of adjustments still to come. At least some parts of the UK look like seeing snow, a change from the usual mild mush everywhere!

Whats your location?

The boundary line is at the moment Birmingham effectively which is an improvement on the 00z

Another 50 miles and the M4 is in play

Northern UK very good here for a cold and white Christmas based on 06z

I think the 6Z illustrates my point about not being caught too much in the details. That's the coldest and snowiest run I've seen so far this winter and if it comes off (spoiler: it won't) it would be a historic cold spell.

That's only if the run materialises. Remember a couple days ago we were looking at a classic or even historical Christmas with the -10c isotherm and easterlies brining in snow showers and now we are back to mild and wet stuff so what's to stop the weather which the model (which shows a very cold and wintry pattern post Christmas) to back track!? 

Indeed

i fully expect the line to move up and down many times. It could be all the UK by the 12z or just Scotland by the 12z

In fact quite frankly the 6Z is a dangerous cold spell that we probably don't want during COVID.

It is extreme on a 2010 type scale.

The 0Z has a fairly medicore cold snap. It just shows how small differences at even a range of 120h can make such a huge difference.

I was saying the other day, global Synoptics will never be as good for the UK to experience a cold spell. Practically everything you want for a cold scenario is set up across the globe

It doesn’t surprise me to see these sort of charts based on the above 

Obviously chances of things becoming severe are small but definitely cold is a good bet 

I do think the chances of a severe cold spell are unusually good though (though perhaps a 06Z type scenario only has a 10% chance) because such cold air has set up/is setting up over Europe. It seems that one big problem, especially at this time of year is that even if you get good synoptics you don't have deep cold to tap into.

That will not be a problem here. So given the right synoptics we could plausibly get a direct route to Siberia via Scandanavia or the Atlantic arctic which would result in that 06Z scenario with half a metre of snow for many parts of the UK and near double digit maxima during the day as we saw in 2010.

But the synoptics to get that to happen, as you say, require alot of things to happen at the same time so I'd still rate it as unlikely.

The most likely scenario at the moment is an average cold spell around xmas and especially after xmas with some snow but probably fairly forgettable.

I agree with all of it 

Looking at all the models each day for the last few weeks , ive not seen Scandi as cold as this for a while. 

If the LPs on the 12z and beyond continue to dig S then it will continue to prolong cold prospects and avoid westerly influences 

One other point I want to quickly make.

The 6Z being so extreme is not immediately obvious from 850hpa line graphs. The 850hpa temp is often around or slightly above -10 which is cold but not insane (say compared to 2018 where we saw <-15C). Also goes to show the 850hpa temp is not the be all and end all when it comes to cold spell severity.

Check out perturbation 10… snow for the a swathe across the country from north of the M4 up to the Midlands throughout Xmas Day, moving slowly south during the day and fading away by Boxing Day morning.

Edit: then another 24 hours of snow on 29/30th…..

Good point.

Both Op and Control are colder runs it's fair enough to say looking at the ENS when the ENS members are not all that cold by seeing the mean, but when the 12z comes out we could get one or both control and Op run flipping back to mild whilst it's ENS members go cold.  

😂 P10 is definitely a snowy one 

Probably.

Will the -2C 850 be around Southern England.

Probably not but may well be in doubt well into next week.

But may be nofrom this snow on the 25th is not off of the table for anybody.

Just a simple summary of the way I see things. Hope the excitement continues!

Think that was 79 Gavin- but 78 had a good February. Schools closed due to oil shortage & cold.

The models. Snow depth at end of op 50cm + over S Wiltshire & NE Dorset. Would be legendary with big drifts in the combes.