kold weather

The development of a LP there is certainly plausible, though obviously we aren't playing with quite the same type of gradients as they do have over there in the states. I think whats more unlikely is the way it tucks in the colder air. To get a snow event from a LP coming up from the SW like that without any cold air already in place requires a very rapidly deepening LP with a very tight northern gradient plus with a very active frontal system. If any of those factors are even slightly out, or the GFS has even modestly overdone the cold air to our north, then we go from a snow to rain set-up very quickly, as we've seen countless times before. I think that still is absolutely the form option as well, though at least we are in with a whiff of something which is better than it was looking 36-48hrs ago. Still it does require close watching.

Interesting set-up potential again from some of the 00z models, though I'm extremely wary of any set-up that requires a rapidly deepening low on the sort of track projected, probably 8/10 they end up weaker or south, and either solution will drastically reduce the snow chances down towards 0 for most. We need a deep LP to help really tuck any marginally cold air into the system enough and help the front be as strong as possible to help with evaporative cooling. Any weaker low will likely be further south AND not tuck the cold air in meaning an end game of cold rain instead. Its a fairly rare set-up for it to happen like the GFS/GEM. The fact both models are known for overdoing LPs also doesn't fuel confidence. However we've not had anything remotely approaching a rare snow set-up since March 2018, so maybe we are overdue a bit of synoptic luck

Can't deny it's going to be very mild this week. The real question is just how high we go and how close to any records we can get. 15-17c seems the probable range at the moment.

Well looks like the chances of snow has just about gone now for all bar maybe high ground in select usual locations. Probably will still feel cold given the rainfall about. Beyond that and strong signal for warming up. May not be quite as extreme as modelled but if it comes up as modelled now we will see the odd 16-17c in usual favoured winter hotshots, more widely 13-15c. I expect it will try and ridge its way northwards and the models again will struggle with it.

Agreed with this, for a brief time it did look interesting but this screams elevated wet snow and rain for most at lower levels. The globals generally overdo snowfall in this setup, whilst the higher resolution models generally aren't keen at all. At least many will share the far south's rain this time round.

Well 12z ecm is good. Good if you like considerable amounts of rain away from high ground in the North...

ECM ensembles are definately cold than the model. They really are lacking with snow over the Boxing day period, only 12 have any snow at all south of bham, and most of those are simply trace amounts. Stronger hints afterwards, but too far out, some do look alot like the GFS op though. I still suspect that the Boxing day fronts won't even make it to the UK and will instead skirt through the channel, maybe just touching the far south for a short time.

Have to say at least for most of England more ensemble members are wet than Snowy out to boxing day night. There definitely are Snowy runs out to that time and maybe more go that way once the first low is cleared buy still no real clear cut agreement.

Well thats quite the wet 12z ECM thats for sure. Quite the difference between it and the other runs though to be fair.

ECM has only hill snow for the north on Boxing day. Another low co0ming up from the SW which may provide some possibilities to wrap in some colder air but not a great run overall out to 144hrs if snow is what your looking for Looks like at least for the south its going to be a wet one on the ECM.

The ECM really is considerably further north with the colder air than just about all other models at the same timeframe. Hard to believe its going to be right!

A heck of a lot of milder air to displace on the 12z ECM at 120hrs, frontal boundary likely to be considerably further north than it was on some of the other runs.

GFS ensembles still a bit of a uncertain mess regarding any possibilities during Boxing day. Typically though the models tend to somewhat overdo the cold air digging in during such situations and there is usually less snow than the globals want to predict. Something to think about. Not to say it will be the case this time! I also wouldn't be the least bit surprised if this ends up staying in the channel as well, seen it time and time again.

Just a few hints on some of the model/ensembles that we could if everything goes right almost head towards a holy grail snow event type situation where someone really lucks out. Basically if we can get a strong enough low to our SW move up with the perfect timing to sync with the cold pool shooting down from the NE, it will wrap around the low on its northern flank and be enough to effectively halt the eastward progress of the low and hold it in place in what would become a kind of dual circulation. Wherever is on the northern flank when that happens would be in a very heavy frontal band of snow. Its not too dissimilar to what you see in North-easters in NE USA and can give some crazy falls. It is a very low risk set-up, but this is one of the few synoptic evolutions where I feel it is at least plausible.

Thats quite the snow spell on the 18z GFS for the Midlands, and to be honest a pretty good rain-snow event further south as well. I'd tentatively say bank on that run!! Odds are at this stage the risk will sink a little further south over time, though of course thats not a hard rule.

Wonderful 06z GFS, the ensembles are decent as well, but obviously with the huge caveat that it wouldn't take much of a shift in either placement or orientation to turn a possibly snowy pattern into a flooding pattern.

I don't mind if the cold doesn't quite get down into much of England on the first attempt as long as the LP orientates enough N-S it will put us into a really solid position afterwards should the atlantic chain carry on, which is what happens in the 18z run.

Really solid looking 168hrs from the UKMO, there is alot that can be worked with there and the angle of the next low looks decent to me as well even further south.

Yes this set-up feels like its starting to run away from us in terms of a good outcome. Could still shift back and you can never rule out we get super lucky and hit the jackpot like late December 78, but quite a few models are starting to run with a similar looking theme, even if the details are still be ironed out. Still time though! As per usual, the north has a lot of leeway for things to go wrong, the south obviously has nearly 0 at this point.

Well thats a rough 12z GFS. As singularity said its rare to get such an elongated area of lower pressure stretching out like what is seen around Xmas day. Should it come off as GFS suggests, its not snow, but flooding we'd need to keep a close eye on. Lets hope not!

Back to a frosty Xmas day on this run with the LP's being forced further south across most of the country. Awful lot of uncertainty as to how this evolve, the GFS really is shifting left and right with how to handle the atlantic pattern.

I think how you view these runs is going to be highly dependent on where you live at the moment. Those in the south should rightfully not be best pleased with the trend, we've replaced a cold possibly frosty Xmas with the chance of a washout. Further north you obviously have a much greater chance of something happening providing there are no more shifts of that low northwards. The ensembles do look colder than before, but thats purely a function of more of them bringing in a fairly luke 'cool' flow thats being recycled around the LP bringing -5/6/7c type air thats heavily moderated at the surface. Its a classic hill snow type pattern with occasional snow to lower levels on alot of them away from the far north. I'd still take that at this time of year, but its a far cry from the true potential of the set-up. Still plenty of time to go with this evolution and the differences from a wet washout to a snowy wonderful are very minimal right now, so no need to overly panic nor get overly excited just yet. I'd say the risk of a snowy spell is far higher than usual at this time of year BUT it might be a fine line between that and a very miserable and wet few days.

There are some pretty interesting ensemble options on the table on the 18z. Xmas day blizzard on p9 for example. With that being said very long way to go, we've been here so many times before only to have the rug pulled out.

If there is one thing the GFS absolutely sucks at, its disrupting troughing. I can't tell you the number the of times I've seen the GFS try to throw a straight westerly with a large blobby LP complex to flatten the whole lot out, when in truth over time the LP's get weaker and increasingly stretched until it resembles the other models with a much more elongated look.

How you view this trend will depend on where you are. For the south unless we have some cold in place already this type of evolution rarely ends up going well and leads to lots of rain on stalled fronts, if we are lucky some back edge stuff if the cold wins out. For the north, far more leeway, especially if we can get some proper upper cold in before hand. Can bring very snowy conditions for a time. Odds are the initial thrust will be enough to displace any cold eventually and induce a milder S/SW flow, though the surface may well hold colder for longer. If we get lucky and set-up will shunt SE and evolve somewhat like the GFS op, which is no doubts a stunner. I hope for the best, but I've got a sneaky feeling we are going to end up with any LP train too far north for most other than maybe Scotland and the far north of England to get much benefit from.