weather eater

They must use the same sources but it’s the software that does the calculations that counts, the ECM model simply does it better, more often.

Work called so it’s taken a while to get back to you, in regards GloSea5, IF will have to answer that because I don’t know the answer. What I would say is this, while it may appear to be only common sense for the models to take past patterns into account, in reality there are good reason why they don’t. Among them would be that the climate is interconnected, so even today, if we had a synoptic pattern across the Atlantic, UK and Europe that looked exactly the same as let’s say Jan the 6th 1947, that pattern today would not go on and develop in exactly the same way as it did in 1947. For it to have even a remote chance of doing so, the synoptic pattern and all the other factors that drive climate would have to be an exact match worldwide, to those that existed on that day in 1947, even then it would still be highly unlikely that the pattern would evolve in exactly the same way past a couple of days if that, given that there are so many factors that are influencing the climate all of the time, some of which we simple don’t have the ability to measure. My own opinion is that while a model that referenced past patterns might be useful for short range and local forecasting, long range I feel it would make matters worse, by potentially making the wrong kind of corrections to projected forecasts on a frequent basis, not only that but the computing power would have to be far greater than it already is.

Just to add my two pence worth it’s pretty obvious that the ECM outscores the GFS, the stats don’t lie, however, one of the problems with that truth is that people seem to then go on and draw the conclusion that. 1. The ECM trumps the GFS every run, when it does not and. 2. If the ECM says cold synoptics are coming our way, then it’s almost a dead cert, also not true.

Again this morning I see nothing that has changed my prognosis of (sounding like an old drum) Atlantic running out of steam, MLB and then back to zonal, seems to me the only thing the models have yet to work out is exactly how that MLB will set up and how long it will last for. One thing the operational’s do agree on is that there no sign of any major cold outbreak coming our way for the time being.

For me the 18z is just keeping broadly in step with earlier runs, zonal slowing down then an element of MLB for a while before going back to zonal, it’s not very palatable but it is a clear trend as far as I can see, the ECM much keener on blocking, classic standoff situation which means more forum drama tomorrow, it’s like watching a courtroom drama, who will crack first and confess all. It was me milord I couldn’t help it, I’m addicted to zonal

While mindful of IFs post regarding GloSea5, the other models GFS, ECM, etc do not use previous weather patterns as such, by that I mean that they don’t hold records of what happened on such and such a date, make comparisons and recalculate future synoptics based on what happened in the past, they are a pure mathematical model, they simulate the climate, in simple terms the latest data goes in and a result comes out, obviously they are constantly monitored in regards their performance and updated usually every few years.

Look at it this way at least the forums rolling a bit now, with something to talk about that’s almost in touching distance and something other than wind and rain.

Not bad from the ECM, C+ must work harder, I have to say though, neither it nor the flat looking GFS has changed my mind, zonal running out of steam, MLB still looking the most likely outcome at the moment, HP close to or over the UK.

Re the GEM not bad but when was it ever close at that range, what the ECM does is of far more interest.

Arguably a little better in fact, slightly quicker evolution as well. dam Ice day you beat me to it

One thing for certain if the GFS is wrong it’s going to have to get dragged kicking and screaming to give up zonal let alone model HLB. It’s going to be an interesting ECM this evening, one thing for certain, no winter is compete until we have a major Mexican standoff between the GFS and the ECM.

Ha not if we don't get off this subject I will get shot by the mods 5-10 years more like 5-10 mins.

I was talking about overall ice extent not specific areas, and I did say I could be wrong but I'd be willing to put a fair bit on the fact that we won’t see that kind of 47 63 spell in the rest of my life time, unless we see changes in the arctic, mainly because I think changes in sea ice cover are altering synoptic patterns over this side of the Atlantic, I could go on but it’s not the place, you obviously think differently fair enough. I did find these, I trust that they are correct, and of as now.

I have looked and yes the winters are chalk and cheese but for the reasons I gave and the fact that i was not just talking about this winter I stand by what i said, if we see no winter sea ice recovery back to the levels they were in the 40s 50s 60s we are far less likely to see another 47 or 63 spell. now I may be wrong and boy would I be happy to be so but that's my opinion. On a model note I confess to being pleased with the prognosis from IF my optimism for a cold spell has just gone up a notch.

Yes Europe already cold and that’s another thing not in our favour, although the continent can cool quickly and warmer sea temps could help with a snow fest.

Indeed Shed and had this forum been around then there would have been much despondency, strong PV, big euro high I won’t use the B word, just goes to show what can happen. However things right across the NH were different then, arctic ice extent for one thing, back then sea ice coverage in August was as great as it is now at its greatest winter extent, so the winter ice pack back then must have been vast, I’m sure someone can find some data on that. My own theory and I stress that. Is that there is a correlation between winter sea ice cover and the prevalence of HLB across Greenland and Scandinavia and I seriously doubt if we could get another 47 or 63 unless that changes, leastwise our odds against it are substantially greater now. That of course doesn’t mean we can’t get HLB at all as recent years have shown, just that it’s less likely, certainly less likely to be of that extreme nature. The 06z is out now but it’s done nothing to change my mind, although post mid range it looks substantially different from the 00z, the central theme remains, zonal, MLB, back to zonal, although there are again some hints at HLB it never really gets off the ground and only has a minimal impact on us.

Not much to add this morning as the operational’s ECM, GFS and UKMO pretty much support the post I made last night, Atlantic slowly putting the brakes on, MLB for a while followed by a possible return of the Atlantic, although to be fair only the GFS goes that far out so confidence must remain low on that for the time being, my confidence for sustainable HLB that would really get the forum buzzing is also low, some hints of it in the ECM run and a little in the GFS but I have little faith in it amounting too much. Even if we don’t see the return of the Atlantic, MLB seems more likely to me, frankly any drying up of the pattern would suit me.

I'm sure Nick will say something when he's available, but I'm sure the answer will be yes, especially if it went as far out as the GFS, wisely the programmers restricted it to 240hrs and that’s still stretching it IMO.

Leaving aside the ensembles, I think I’ve said what I wanted about them and leaving aside the GFS as a model in isolation, the clear trend as it appears to me at the moment, derived at from viewing the operational runs of the models over the last few days, that’s across the main three models (ECM, GFS, UKMO) or main two post 144hrs is, zonal though less vigorous than of late for a few days yet, then possible MLB of some sort, certainly some kind of break from all out zonal for a short while, then the Atlantic will come back in. There have been of course other ideas floated by various platforms not to mention other people, but that looks to me the most likely evolution at this point of time.

is that dot com or dot co.uk, ltd or PLC

An informal grouping of cold weather fans, more of a badge than anything else

Thanks for the reply C, however, my experience on NW is that not many if any, have that experience, it is relatively easy to spot a trend but unfortunately the trends tend to come and go for the reasons I gave and on NW rather a lot of people call a trend when it is no such thing, frequently or more likely usually there may’ be more than one, how often do we see a few cold perturbations in an ensemble set called a trend while ignoring the bulk that are not, no wonder people get confused. In simple terms, if the deterministic runs start to trend so will the ensembles for pretty obvious mathematical reasons, good run to run continuity in the starting data, of course they may well produce different synoptics and its often at this point that people start to pick up on a perceived trend in the ensembles, you get situations where the deterministic runs are trending zonal for example and the ensembles may show a clear trend for blocked, frequently there is a trend for both in the ensembles, although on NW the zonal will be ignored in favour of the blocked (if it’s a cold one) every time, However, If the deterministic runs start to fluctuate then so will the ensembles, they must do because they are tweaks based on the same initial data, we often see this, when the threshold of FI is short and the deterministic runs start to produce big variations at short range the ensembles follow suit and you start to get a large scatter very early, it happens all the time. Now that’s not happening at the moment we actually have fairly good continuity out to 144hrs or there about, although it hasn’t stopped it being suggested that the models are fluctuating a lot at the moment, that often happens in winter when signs of a cold spell are not really appearing.

A bit underwhelming but it’s good to see the ECM still going for some sort of block, If it sticks with it then it could well upgrade the cold potential in the coming days.

I have to say C with all respect, people have been following the Ens since late autumn and they have offered no more in the way of guidance than simply following the operational’s and using a little knowledge and some common sense, they chop, change and trend this way and that in much the same way, which is not surprising as they come from the same data, just tweaked. If over the years I had a tenner for every time this thread had been advised that the Ens would cast some light on the way ahead, only for the Ens to show nothing of the sort, I'd have accumulated a large pile of cash by now. The main problem for all modelling, is that the starting data is constantly changing, the Ens are supposed to help with that fact, but what you end up with is Bertie Bots every flavour of jelly bean, with little idea of which one isn’t poisoned, thus people on this thread just go with whatever most suits their preference, usually cold in winter because that’s what most of us are looking for. In terms of the tweaking there must be a set criteria for the way each perturbation is set, so with every new run with its change in data a corresponding pre-set change must be made to each ensemble run, therefore an ensemble spread can only be of real use when analysing the run that they were derived from, trying to put them in the context of several runs over several days in an attempt to look for trends is fraught with even more problems than attempting to find a trend in just the operational’s, this is because the greater number of perturbations the greater spread of possible outcomes, in other words spotting the correct trend can become like looking for a needle in a haystack, especially given that the chaotic nature of climate means that even when something looks to have wide support it still has a massive chance of not being the correct trend, in other words you may have a good cluster of members supporting a similar evolution but a single member with no support could conceivably be the correct call. I hope this make sense it does to me at least LOL

As you were for most of this run with the Atlantic running out of puff and then in low res the GFS gives everyone a little tease of HLB before changing its mind and reverting to the zonal train which at least is more PM than recently.