kold weather

Ig the ECM ensembles are anything like the GFS ensembles, that mean means very very little indeed, just too many conflicting ideas. I'll have to wait to see what the individual members show, with the caveat that the OP very often does lead the way, especially given its now had this set-up broadly for the last 3 runs.

I'd say the 12z ECM is poor for a lot of the country later on and compared to what could happen, that 12z ECM is nearly as bad as it gets from the position qwe find ourselves in at 144hrs. I think that's the problem, combined with the fact that we seem like we are trending back away from where we need to be synoptically again, especially on the best model of them all, the ECM...and the ensembles are a total dogs dinner in terms of agreement, which gives me concern as well. Still plenty to play for though and could just be a couple of bad runs from the ECM. GEM and GFS are still good, the GFS para is good but slightly strange in its evolution. Even the 12z ECM which is poor later does have a few things worth watching earlier on.

It has been a trend to be fair on the GFS today, especially the 12z ensemble suite which had a marked upswing. Of course the thing that really kills us is that large PV lobe coming back again and forcing the jet back on a westerly motion, forcing any blocking to the east as a quick rate.

Yeah its a classic cleaver, aka a type of set-up where the front straddles the country and doesn't progress. It is literally the most teasing set-up there is as you could literally walk faster than the cold is coming down. It will eventually make it into the south even, but it will last 12hrs and then get blasted away by westerlies, that's the typical evolution of that pattern. Its a horrible set-up for those further south, you guys up there should be ok for a little while regardless of the evolution, so maybe share the cold and snow with us down here who may not have been lucky enough to get snow today

Oh no it looked ok at 168hrs, its rather gone down hill since that time thanks to the re-emergence of that PV lobe over Canada. 12z GDS IS miles betters for sure!

I think that's the balance Nick, we could get a brief easterly from a stronger Scandi high, but it makes evolving into a cold spell down the line more difficult. The GEM manages to do it regardless. Here comes that PV lobe again at 240hrs, window rapidly shutting on that 12z ECM with only hsalf the country in the cold and a PAINFULLY slow evolution.

That is ok, a little slow in getting the cold air in and obviously the vortex is going for it agsian over the states so our window to get a solid block in may not be that long...but longer than the failed easterly!

Yeah it is a very slow evolution, also 192hrs is good but at slight risk of going wrong if the atlantic low becomes too dominant in the broader circulation as that could turn the winds more SW. Luckily both the UK low and Atlantic low are weakening at the same time. Karlos, that's certainly a risk though I think there is still too much pressure from the PV lobe for that to happen.

168hrs that low should be the one that helps to trigger at least some sort of colder shot. Arctic pattern looks good for an Azores ridge around 216hrs to get going, but of course I'm sure it'll find a way to mess that up!

Well the ECM continues the trend to edge an easterly into the far east of the country. Interesting trend. Hopefully we will see the ECM still develop a decent attempt at some form of northerly blocking, but we shall see! Catacol, IF the band ever snaps?!

Yep, we are going to hold off getting to excited over the operational runs because there is so much variability. Same goes for any bad runs that come out. Of course I think all are assuming this must mean things are going to go badly, but it is equally possible for things to go explosively well...in truth there is just no way to really know at the moment. The only thing I would say is this is the 2nd time the models have drawn back from a Euro trough idea (the failed easterly being the first).

I missed that by about 10 miles! Ah well. GFS seems to be more keen on some good settling snows for East Anglia tonight, seems like this has one has over-performed compared to what the models were expecting even yesterday.

Yeah, the EURIO4 did show an area of snowfall in that sort of region, so that was a good call from that model.

A few GFS ensembles are showing that solution right now, a few more sill have a stonking northerly if the high doesn't get far enough west. Anyway GEM looks great on the 12z, whilst it never gets too established, the cold air nearby ensures when the next low drops down we remain cold. GFS ensembles by the way are an utter mess, so many different solutions present. Still favoured is the NW-Se tracking low and some sort of heights to our north...but there are at least a few runs keeping heights low to our north and restregnthening the PV...so we will see! Model confidence must be on the floor right now, not because of what happened previously, but because there are so many different runs even st 120hrs out. Knowing our luck this year, we will default back into the Azores high!!

Good luck trying to pick a pattern out of the GFS 12z ensembles, all over the shop! Some develop strong northern blocking, some are redeveloping quite a potent looking PV. Some have a cracking southerly jet (indeed maybe abut too much even for us) whilst some create some impressive ridging into Europe. Even from 120hrs there is considerable volatility, with everything from a Azores ridge, a weak easterly, a COL, powerful northerly or gentle NW showing. Generally I'd say a lot more of the Azores ridge on this suite of the 12z GFS ensemble, quite noticeable at times, though most runs do scoop it up eventually still (only for some to spit it back out again!)

GFS para still not great out to 240hrs, compared to what we could be seeing! 216hrs looks a lot like the ECM with the circular LP sitting over the UK and keeping the cold air to our north. Also new LP's forming to our west will slow down the cold air even more. Right ole mess frankly! EDIT- 288hrs and it finally lands us into the colder air, but the whole set-up aloft is a heck of a mess with the PV desperately trying to pull itself together again!

Just to note, there are a couple of runs now starting to go for a easterly airflow as soon as the start of next week. Far from the form horse but just worth keeping an eye on. 12z control ONLY just about makes it and the 12z GFS para is not looking the best at 192hrs either, though should also just make it down the line...so plenty to keep grounded about still. Truth is, this is a highly volatile situation and could go both better or worse. Form horse would say worse but each situation is different!

Ha you might be right! Its a solid run though, I won't deny that and I'd still take it for sure compared to what we have had this winter. I just think as Catacol has already said, we may see a few really big runs some point soon. Anyway the GFS para should be a shot across the bowels of those getting a little carried away again, still cold, and I think it will still get there vby 240hrs, but that's far from solid.

Worth noting though both the control and para GFS have got a rather different pattern come 192hrs with our friend the Azores high ridging into Europe as the upper low doesn't really dig down but moves more ESE. Both could still evolve cold but that would put abit of a spanner in the works, and we know how reluctant the Azores high has been to move at all so far this winter...

Good 12z GFS, indeed its kind a mixture between the two different camps that there present in the GFS ensembles. Indeed, I feel that maybe quite a good compromise solution and doesn't require much of stretch from what we are already seeing, plus it pretty much fits the MJO situation as well. Not quite at boom status, but a good effort.

Sleety rain just moved through here on the western edge of the region, looks like sleet is the main order of these showers, but further east the extra 1-2hrs of cooling may just make the difference. Here, precip just never got heavy enough to drag the snow level down, like it has with some of the areas that have had snow.

For most it still looks too marginal, but its a lot closer than it was on the 06z ICON for sure and I wouldn't rule out some very backedge stuff based on the parameters, especially for those on high ground.

I'm not sure I totally agree. Sure they have highlighted the possible change to cold but having looked through alot of the summaries this winter, they were nearly always said with a large caveat of the possibility of it remaining milder. I think some people are seeing the METO use the phrase 'cold' and assume that means northern blocking, and powerful easterlies/northerlies. Truth is this week for example would likely be classified as 'cold' by the Met office, therefore making that statement factually correct. They did however make a boo-boo with the easterly...but then again there weren't many that didn't get suckered into that one, especially given background teleconnections as well.

I'd watch the mass from Oxford to Reading. Quite strong and as it heads eastwards into hopefully cooling daytime temperatures I wouldn't be surprised to see some snow reports coming in from this area as it heads towards the London area.

Yeah Surrey its certainly something worth watching, could be a quick fire 2-4cms IF that little low does develop like a few models are suggesting. I'd keep an eye on the surface wind reports, any signs of an earlier development and the far SE could be in for a surprise fall of snow tonight. Also this trough does look like its strengthening thanks to peak temperatures, some fairly impressive radar returns showing up now and the stronger they get the better the chances of pulling down the snow level. Trough looks sharpest further south looking at the surface wind reports, I'd expect that's the location to key into rather than the further north location but still worth watching.