That's absolutely right: the models consist of mathematical equations that attempt to describe the workings of the atmosphere.  The issues are that (1) the data with which they are initialised includes estimates, because actual data isn't available for every grid point, and (2) they can only ever be approximations because the planet isn't made up of neat grids.

Frankly I am amazed at the progress that has been made with the computer models: the ability to predict several days ahead is, when you accept the complexities, remarkable.  But there's a world of difference between a model getting the general pattern right and getting the specific detail at a local level right - as evidenced by the events of the last couple of days.

Then of course there are the longer range models, which use other techniques to try to anticipate general patterns. These are still in their infancy and I doubt, given the complexities, that they will ever be better than broad indicators - again as evidenced by the predictions for this winter.

FLooding next week in parts of the west?

ahaha I hear you Doc.

Though do you care to draw up what the December and January conclusions were ?

ok I will get my coat .....🤪

Conclusions are generally based on evidence otherwise they are guesswork or prediction.

@240z if this came about! - Looks like the whole of Europe will be above freezing during the day except some parts of Scandinavia woah! serious avalanche risk for alps too!

Martin

12z ensembles chart for London: - Some really mild ensembles for February i mean really!! Crazy to think the coldest is like -6 @850hpa - so something is definitely brewing here as Brian said earlier.

GEFS12z 850s probably the mildest we've seen all winter. In fact some would be in the "warm" category at any time in the year.

Trendsetter. 

With exception of 20 at t=0..... just 6 snow rows!  

Make the most of what's left of this cold snap it's not going to last much longer

An early spring potentially for some parts of Europe

I suppose as we enter the last phase of this winter we can ponder on the model performances and the long range forecasts. The most generous I can be is that I suppose the long term prediction of a back loaded winter was vaguely accurate as it certainly wasn't front loaded. The last two weeks of January have been the coldest so far with probably just below average temperatures and some decent snowfall for some. But in the scope of things nothing severely cold or what you wouldn't expect somewhere in the Country to get every winter. The SSW was overplayed and under produced and I suspect the majority of us expected more. It certainly seemed that way if you read the late December to early January posts again! I think I can even more confidently say again that we are now relying on the last two weeks of February for anything notable although I can understand that for some parts, especially central South these last few days have been. Of course you can't discount March either at this stage although of course that isn't classified as winter.

Im not sure the ssw was overplayed i just think we were unlucky the pv split due to ssw but we didnt get the severe cold such as what parts of the US have just seen.

Goes to show a ssw doesnt guarantee cold for ua.

Do I detect a touch of sarcasm there. Mind you the composite anomaly chart at 100mb show quite strong gph from eastern Greenland over the pole into northern Russia,with low heights in our local. This could downwell by mid month if mjo baks off or stays around the cod.

I am sure in my mind that rather than the SSW working against the MJO it has been the other way around. If the MJO had stayed in low orbit the SSW would have downwelled faster. Had we been in a -qbo then the MJO would not have mattered.

My theory being the amped MJO trying to amplify westerly winds into a downward propagating reversed easterly airflow. Hence the stalling.

The 250 and 300mb composite anomaly for the end of Jan mirror what the ec46 has been showing but rather than praise the model I think it has been totally misleading yet poster on other forum who has rammed it down peoples throats for over two months still trying to justify its output.

Anyway to early just yet to give up on a cold, very cold spell developing mid month  or a little there after. Will be keeping a close eye on anomalies over coming week.

Quite a lot of areas of the UK away from those in the north had to wait until nearly the end of last winter before they saw anything really wintry, from what I remember reading on these threads at the time. So who knows? Stranger things have happened in the past.

From what I have seen of the GFS 12z and 18z ops, rather than a clear trend towards notably mild temperatures as we go further into February, what those runs appear to indicate is a return of the mostly cool/sold zonality that we have seen over the past fortnight at times. There are suggestions of a pressure rise to the S/SE, but these IMO are still too far away in time for us to have any real confidence in this coming to pass.

Zonality looks to be the form horse for the near future now, but whether it is of the cold or mild type is still open to question, IMO.

Exactly - So there was a tropospheric response to that SSW but just not over our parts of the world only in the USA ESP mid western states! 

I agree it happened and didn't work out for us this time but if you look back at many of the posts from late December onwards several people were pinning their hopes on it and reassuring everybody that it would have a big effect if they were patient!

Based on my checking of UKMO, ECMWF, ICON, GFS and GFS Para model Outputs in last 72 hours, it looks like there is going to be brief or a bit longer milder SW winds, but there is frost tonight and on Monday night for London hmm.

They are also predicting chilly Westerly winds as well quite often, unsettled and with spells of moderate to heavy rain is expected over the next 10 days or so.  By day 9-12 there looks like some more mild SW winds on offer.

Currently it is warmed up and mild to very mild in fact over South and SE Central USA right now, it is also less cold in Eastern Central Europe and SE Europe away from the far Eastern side at the moment, but NW, SW, North, West and NE Europe currently has the really cold weather it enjoys so much- the people ahem.

NW winds also expected but more shorter in length-duration in the next 7 days, as we progress towards the middle of 2nd week of February 2019, the current model output data shows deep areas of West to East moving PFJ Low pressure across Whole of North Atlantic UK and West to NW and North Europe in general, some mild sectors also are suggested as long fetch SW winds- but more chilly Westerly flows still going to push across the UK at times.

And patient we all were when the fact is we are not in February and we STILL have not seen any HLB to bring about a tropospheric response to this SSW.

What I can say is that it's be so wet ...-nice to see the sun today but really not looking forward to boring 2 weeks of milder and occasionally wet weather on offer and worse of all is that it will be overcast most days!