kold weather

Well the ECM at 144hrs explodes the LP just to the west and forces a lot of milder air into the UK and so probably a snow-rain transition for most of the country, with more in the north obviously. Could do with the low not exploding just to our west, like the GFSP. Certainly a better run though, but in the end we end up in the same location.

Well the 12z ECM looking much better at 120hrs. Its basically between the GFS and the GFSP. Interesting though, closer to what we are needing.

Hmmm looks different out to 96hrs from previously, at least with regards to how it phases with the first low that comes along. Chris, no norhern areas should still do well, much more uncertain for the south and I think that's where a lot of the negative comments are coming from.

GFSP has a decent snowfall for this area...also worth noting a lot of the GFS ensembles have at least something coming our way on Tuesday. A couple go very severe. Still way too far in advance than anything other than maybe a cursory look.

Nope not yet. First trace of energy I can find along the frontal boundary is coming off Mexico in to the Gulf on Saturday night, that energy works up the frontal boundary and creates the low pressure cell on Sunday daytime. Until that happens still could have anything happen. Anyway GFS para has very little snow north of B'ham fwiw other than the odd trough feature coming into Scotland. C.S England ends with about 20cms. Tight Isobar, its not even in the womb yet, its still just a gleam in the eye!!

Quite a few of the ensembles are really bringing in significant disruptive snowfall into the south on Tuesday evening. A few ensembles nudging it a little further north as well. Really feel this maybe more of a story than the 2nd low at this rate. Hard to eyeball it, but based on liquid amounts converted to snowfall, several runs show something between 9-12 inches, and the rest are in the 3-6 type range, but as I said that is only a very rough estimate.

The GFSP has been stubborn with this idea, almost as stubborn as the ECM has been with its idea. As long as its holding onto it, I suppose it is still an option, however small the support is from other models. It'd be a worrying sign to see it wrong, especially as its so out of kilter, but every model has to have a win at some point, this would be a grand place to start!

If that happens then I will be very happy indeed. I highly doubt it will, but you can hope I suppose! Anyway ensembles are looking pretty snowy now for Tuesday for the southern half of the country. Ensembles have a little more in the way of transient snow than the 06z suite did as well before the milder air comes in on Tuesday. Not great, but its something.

As I said, this maybe the one to watch, especially as the low this weekend has gradually been getting deeper/further north with time. I'd say around 80% of the ensembles broadly look like the OP run. Not quite full agreement but getting closer in terms of the general evolution being for the low to become larger and more circular and to move somewhere close to the UK whilst drawing up milder WSW air.

Ensembles as Mucka say don't have any real agreement, though far more are still going for the 'fat' LP like the OP has. They ARE however making more and more of that LP that swings across France. It may be worth watching that one because the stronger it gets the more the tendency it will have to rotate tighter to the core of the upper low to our north- which means in translation closer to the south of England. That in fact maybe the low to watch if you want snow, not the 2nd one. Ben- yes ensembles are starting to sniff out something for S.england as well on Tuesday.

Without any more data we go on what we have...and what we have is utterly overwhelmingly going only one direction. I think that's clear to see. However, people will have to keep on learning the hard way I suppose that when you get this sort of agreement, 95% of the time, its going to lock into place, especially with something like this. Looks like the lesson with the easterly hasn't been learnt with some... EDIT- lets hope the GFSP stay cold, if that jumps off it really is game set and match to the ECM.

Whilst true it gives huge confidence to anyone that that solution is right, when you have all the main models with differing datas/algorithm and they all come to more or less an identical solution, then I think to expect anything other than what is shown is probably hopecasting at best, and ignorance at worst. It can change, but the trend is very solid, indeed the ECM looks more or less unchanged now for 2-3 days and the point is the evolution is likely to be correct if all the models are showing the same thing. For us in the south, its time to move on from this, its not happening. Tuesday still has a chance, and who knows after Friday...but that LP isn't happening for jus down here. For the north, there is still enough movement and uncertainty to suggest change. PS- here comes that pressure rise over to our NE/N again...next time on the "chase".

Next slider trying to detach and move towards us. May not be the worst of thing as it may help to introduce a fresh batch of colder air again. Hopefully we can shove the whole lot southwards and get an upper high building in its place. Probably a long way from sustained cold still but won't be mild, plus good for the north.

Low isn't moving as well out the way here which means the cold pool doesn't really come down. Next slider may well slide Into air on the wrong side of marginal. We may even get our friend, the mild easterly at some point. As others have said, solid agreement. Looking like the King Euro nailed this, well done to ICON again for going with it before ukmo and GFS. Third time lucky guys?!

Still more or less as expected on the models. Of course would want it south but this isnow the 2nd suite with very strong agreement between ukmo and GFS.

Broadly snow to the north, snow-rain to the south. But that line is kinda just a line in the sand, kind of a best guesstimate based on where things are right at the moment and there is plenty of scope still for large changes.

I'm sure we will all be off them again and back on the Prozac by 8pm tonight! I notice some Met office employees are talking about possible event for the south on Tuesday, may not be a big area but all models are showing at least something from this, even the more southerly GFS op has something for Kent...however these features are horribly hard to predict, I've seen them bust even at 24hrs before.

Not impossible that you maybe too far north up there, but that's the trade off for having 85-90% confidence of remaining in the cold throughout I suppose. Typically the models do shift south with these systems, though I note the LP on Sunday has actually become progressively more north and stronger....and it first appeared about 120hrs before hand...so for that LP over France/channel, that maybe something to think about...

That is sounding very much like a Scandinavian high they are forecasting, especially with regards to maybe occasional milder air coming into the south as you get battleground set-ups. Great update!

I think I will need to bust out my tropical tracking models to see exactly what the models are forecasting down in that neck of the woods and see how realistic it looks, I've had quite a bit of experience in the summer looking how lows form within frontal boundaries down there. Still enough uncertainty with the low and its behaviour to rule out anything for Wed-Thurs bigger low that comes down from Canada, the models are pretty keen on phasing it and strengthening at some point before it reaches the UK. I'd not say its a certainty, although the angle of approach probably means the south is going to have a hard time with anything other than maybe the briefest of transitionary snow unless the LP really does change its presentation. Further north I think is where the games really are and I think personally the snow line is really a moveable feast to some extent. The double barrel nature of this low is going to cause the models all manner of problems and therefore away from the far south, I'd say its best to keep options open. Right now northern England and Scotland are on more firm ground for a snow event, but shifts of 100-200 miles at this range are pretty likely and that could make the world of practical difference. After that, a good sign at least from the GEFS is the low moving eastwards, if it does get strong enough or remains strong enough it may help to drag back down colder air again which would basically reset us back to square one. Beyond even that, and more than a few hints from the models of pressure rising to our north/north-east (right in time for my 5-10th Feb call) though it remains to be seen whether its actually going to be of any practical use for us.

Unfortunately too many people have blindly been ramping to kingdom come when really the synoptics were really never there in the first place for it. I think that is why we now have this general feeling of apathy. There are still some that I'd describe as hopecasting (I think Nick F also picked up that point) but we can all live in hope. Too much hope however can blind reality. I remember getting butchered this time last week for being over critical/negative about the easterly, but it was just I didn't have the blinders on and could see it wasn't going to work out. Bluearmy was there a few days earlier than even I was. Its only really been since mid January as others have said that the pieces have been vaguely in our favour. IDO - Yes there is certainly some interesting signs. The ECM ensembles are real mixed as well. There are a couple of fruitcake runs (my favourite ends Thursday with 19 inches near Bath and 12z inches across a huge swathe of the south )

I'm guessing you haven't lived through that many bad winters? As much as this winter has been a little meh here so far, not every winter is going to have a gangbusters event such as Feb 18, etc. So far its been a fairly standard milder than average winter. I wouldn't say its been terrible, there have been some decnt frosty periods, and some bad 0/10 type winters didn't even manage that. (I think December 97 or maybe 98 didn't have a single ground frost all month!) Bluearmy, I've drawn my line from broadly Leeds across for the pure snow line. Not a bad idea to have a point from which to move around. PS - developing El ninos usually are back loaded, they typically don't have great Decembers because the jet normally runs a little too hard in that time, Feb tends to be the best month in El Nino winters. (though technically, this has been neutral).

Yep, broadly about 5-10cms from that. Anyway this is IMO quite a large test for the Para, its really being quite stubborn with its outlook whilst the other models have to most extents fallen inline with the ECM. Lets hope for once its right, not been all that impressed with it thus far. PS, ensembles are becoming more and more aggressive on northern blocking, especially in the Scandinavian region post 300hrs, mean MAY turn easterly at some point in the near future if that trend continues, its not that far away even on the 06z.

Accumulations are widely above 4 inches, most is in S.wales around 10-12 inches, central S. England also gets about 8-10 inches, However that is IMO very much on the extreme end of what is likely, most ensembles don't go anywhere near that high! Frosty, where are those ensembles for?

Yeah more of them are kicking the LP away to the east quicker which allows us to pull back in colder air thanks to the circulation still being strong enough at the time. Its a good step forward for sure. Still got some ensembles showing some heavy snow for the south for Tuesday as well...aka ECM 00z. As for Wednesday, I'd say just 20-30% are cold enough for snow in the south (even for front edge snow odds aren't much better), those odds rise rapidly once north of the Midlands, to something around 90% for Scotland.