FI Charts ( T120+ onwards) Winter 2023/2024 **READ MOD NOTE IN FIRST

Also March 2013 if my memory is correct. Northern Ireland got pasted and we got cold alright but not much else.

Lads, all your talk of historic busts may be jinxing things. The 0z GFS is not what we want to see..... Cold is less deep and very shortlived

I keep things very simple regarding cold & snow forecasts. MT Cranium. Latest forecast? Chilly next week and possibly mild the weekend of the 19th January. Nothing to see here, move along.....Those over on Netweather UK have worked themselves up into a frenzy, which I understand can be contagious.

D

Is this a downgrade? 😦

My very amateur take on this mornings output -

GFS is a sobering one this morning, the op only gives us a glancing blow of cold with the control not much better, both have Greenland heights flattering to deceive. Should be noted there is a lot of scatter in the ens beyond the 13th.

GFS Op

GFS Control

ECM looks good out to 240h, however the control which goes beyond this is not clear cut and bit too much diluting for my liking with the 850s not consistently in the -8c range.

ECM Op

ECM Control

Onto the UKMO and this one gives the best chance of light snow for the south on Tuesday with -8c uppers over us however I don't like the angle the bitter cold is taking after that as it appears to be heading south instead of west.........I can see Gonzo emigrating to Greece if that happens!!

Thats the spell I used to have the Northern Hemisphere SNowcover charts saved for. Lost them in a PC move. Basically the entire Northern Hemisphere down to Spanish Latitudes with SNow cover....except little old Ireland up at 53degN, an Oasis of Green in a Hemisphere of white.

Can't find the NOAA Snow and Ice charts for the days in question but found this Minimum Temperature chart instead which kind of does the same job. ie. Showing the Cold wall ended at Welsh Beaches! LOL.

The GFS is 4th in the verification stats. Still it could be right. Greenland highs are notoriously difficult to maintain because they either get sucked too far west or collapse due to a badly aligned Canadian Low. December 2010 being the most notable exception. We could still do well out of a mid latitude block. I am hopeful with the weak zonal winds we could get another attempt at high latitude blocking, perhaps to the North East next time.

An excellent post. @Gonzo, they could with you over on Netweather UK! 😊 Golden rule - if within 72hrs, then it's a near certainty that the cold will verify. Otherwise, it's just hopecasting/speculation. A major red flag for me is that MT does not appear to be on board at all - granted, that might change but he successfully predicted major cold periods in the past. At this point in time, I see nothing from him to indicate proper cold / snowfall.

D

I was weary after the 12z runs yesterday. There was clear evidence of the now familiar trend; a few runs show perfect clean evolution of heights building into Greenland, then the subsequent runs make it a messier and weaker affair but by bit. Hopefully it will go the other way this time.

Also the commentary on NW about only seeing this level of model consistency in 2010 and 2018 is rubbish. A couple of times every winter we get a day or two of cross model agreement of nirvana, but nearly always diluted quickly after 2 days or so. It seems like the models all pick up on an amplification signal and really run with it at first, then gradually make it more muted.

And don't get me started on the experts on Netweather. The teleconnections are always going to support the model output when the 'teleconnections' are also just the same model output.

I was looking back on the Boards thread for February 2018, and the models started signalling the 'Beast ' about 12 days in advance. There were wobbles and tears shed on here at around 10-8 days in advance as little shortwaves started causing issues, but the Beast was pretty much nailed on with 7 days to go. We are either in a wobble period or the trend of overnight continues. The ensembles are not too different to this time yesterday. I would think we would need a few members on all models to start showing much colder 850s though for a real prospect of a cold blast in 8-10 days time to materialise. By the way, I presently see no sign of a Beast from the East but a moderate (50%) risk of a cold northeasterly or northerly.

I disagree about the level of model consistency/support, I don’t recall seeing every single ensemble across all main models showing the same pattern except for 2010 and 2018, and even then this never stayed perfect without the odd wobble. Even the major fails ala 2012, while collapsing at a much shorter range, did not have every ensemble converging on the same pattern.

Caution advised but definitely the feeling that this time is different, we don’t normally have such strong background signals to back up the super charts. A long way to go still but EPS are still rock solid, if not better than 12z yesterday. UKMO also looks excellent as far out as it goes.

Maybe the GFS is picking up a new signal but as Gonzo pointed out, it could all fall back into line this evening with upgrades, or even get messier only to return to the original brilliant charts in the coming days… all to play for. I for one am already enjoying the more seasonal weather.

The ECMWF ensembles are anything but mild after mid month. As I said before, expectations of a colder blast mid month will rise for me if I start seeing some -10c 850 members appearing or growing in numbers.

I pop onto this thread twice a year, over the summer to see if we have a heat wave coming and at winter when we are given a hint of snow.

I know its complete madness but I ordered a snow sledge for the kids on Decathlon last night based on the last few days comments on here.

Dont let me down folks 😁😁