But before we get into the shortwave drama and the ‘trending south’ debates there’s another couple of days to go to see if this continues to gain momentum. 

I did take a cheeky look at the P04 option on this mornings GEFS to see what the fuss was about and it’s certainly an impressive thing to see.

Just looking now before it disappears. Very 80s retro chart! Will never happen of course, but thats why we do this. Its the hope that kills you!

But it’s the potential that keeps you interested. 🙂

The best way to minimise the bumps on the rollercoaster is to focus on the ensemble mean beyond about five days: the trend and any clearly signalled short-wave developments.

https://www.theweatheroutlook.com/twodata/mogreps.aspx?run=mr-na&pstype=snow_depth&hour=108 

The 00z ECM postage stamps for New Year’s Day show a bias towards the colder air winning out. A few show a strong push of milder air, driven by quite marked cyclogenesis as LP moves NNE to our west. The spread chart shows the zone of greatest uncertainty sits through the southernmost part of England, through The Channel and into Northern France.

A long way to go, but the signals for a battleground in our vicinity have been evolving for quite a few days now.

I agree there is plenty of interest - the ECM ENS stamps below are for New Year's Day. However, I am in the camp which believes a)  cross model agreement is needed b) model accuracy in the North Atlantic regions can take a dip on 25/12 and 26/12. Hopefully things will be much clearer  by Saturday.

Yup, it's why I'm never too bothered about what the models may show on Christmas and Boxing Day. You usually get at least one eye-popping run, with a predisposition towards a more blocked scenario than normal, along with greater model swings generally, but it soon sorts itself out by the time we get to the 27th.

FWIW, we've lost just under 40% of the global flight data over the past 24-36 hours, and that should return to almost normal by tonight... Boxing Day isn't a thing in the States.

The biggest impact would be on Russian jetstream-level obs, as since the war in Ukraine the data has all but vanished there. While it should have a bigger effect on North America, of course the modelling of the jet here relies on it being modelled accurately on the other side of the Atlantic - so there will be a knock-on effect here.

As an example, here's the data coverage from the 2400 and 2600 cycles. There are far more obs than there used to be when I first mentioned the problems, 10 or so years ago, but we're still losing a similar percentage. Obs at jetstream level are, IMO, very useful in terms of data input, something satellites and surface obs can't reproduce.

https://ukwct.org.uk/weather/2400.png 

https://ukwct.org.uk/weather/2600.png 

Snow spikes appearing in the ENS as well 

Congrats!  I wish the pair of you a long and happy life together 

🎉❤️👩‍❤️‍👨

I thought you were referring to the upper 850s and said you were engaged as in (interested!) In what's going on...etc..

If it lasts beyond tomorrow I'll offer them my congratulations. 😊

I’ve been engaged many times before and only once has it been worth the effort. This applies both in terms of relationships and getting involved in the weather 😂

😄👏

Agreed you can never count your chickens till they hatch when it comes to forecasting cold weather in the UK and especially when model data and accuracy will have been reduced due to a lack of data over the Xmas period.

lol. I was going to say something similar. 

AIFS is a real beauty.  In AI we trust.

Isn't it? Fantastic run - cold moves in quickly and stays around a while.

But GFS again doesn’t want to know. There’s a way to go before calling next week.

Yes, far from clear at this stage.  But I would point out that the GFS 18z Op is in the upper decile, briefly upper quartile, in the ensembles for here from Sunday until New Year’s Day, and 3-4c on NYE.

I’m not suggesting it’s likely that we will see anything wintry but just that the Op served up a milder pattern before dipping sharply on NYD.