I’m old enough to remember when Berne was seen by at least one TWO member as the Gold Standard for UK cold weather predictions. Is it now Toronto's turn to seize the moment and become the benchmark?

For me reading the arcane, obscure and Runic models such as “When Thor's Ice Hammer melts in Iceland, Freya’s frigid white mantle cometh to Southern England”, is as good as any indicator for cold here. The reason being a winter easterly in Southern England almost always means a long fetch mild southerly for Iceland. The winter up there has been quite snowy and cold in recent weeks. And for now I can’t see much change. But who knows?

My Dad was a professional weather forecaster but could never pin down what in his opinion would lead to long lasting cold weather in the UK. He had a theory though that somewhere in a lava lamp lay part of the answer. The lava lamp was developed from a design for an egg timer using two liquids spotted in a Dorset pub for anyone who still wonders. He would have loved to see how much more accurate medium length weather predictions have become. But he always said it would be a shame if we could predict a year or more in advance as that would take away the daily magic of our lives if we knew exactly how a week, month or year will turn out.

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The fact that this is what you take as the key message from my post shows you don’t understand what I wrote.

Ok, I can guess the next two months will have above average temperatures and summer will be warmer than the LTA. None of this is model output analysis. 

As we are in the model output thread, what is your take on the last couple of GFS op runs for late January, especially in terms of the jet stream profile over N America and consequently N Europe? It would be helpful to see your analysis in this particular point especially given the meridional nature of the last two consecutive runs.

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Well put. 

Moomin (and some others) frequently fire out these zonal forecasts. Given that 8/10 winters will have prolonged unsettled spells (not always from a genuine zonal pattern, but that's another discussion) they're going to be right a lot of the time. 

As you say, it's not based on model output - so really should be in the Winter General Discussion thread - and is just firing out a forecast based on what is statistically likely. 

When they're wrong, they stress that they 'hold my hands up, I was wrong' but anyone with an ounce of understanding would ignore any forecast they make, whether right or wrong, because it's based on nothing more, like I say, than statistical probability. 

 

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Well he made a forecast before Christmas which looks like being spot on. For that he surely deserves some credit, after all, members are quick to attack him when he is proved wrong. 

This wet zonal dross is not what many (any?) of us want to see, but one has to say he looks to have called it correctly. 

Actually, not wishing to be pedantic here but there is a difference:  he made a prediction not a forecast.  A forecast is based on the available evidence. A forecast is based on data; a prediction is rooted in subjective judgements.

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This is an interesting discussion today 😊 I suppose there are merits to both sides and you could argue there is a significant overlap between the terms 'forecast' and 'prediction' given one can inform the other.

Reading moomin's previous posts it would seem they have turned a forecast into a prediction: a prediction based around the commonality of a zonal pattern in winter for the UK. If you look at the charts for evidence at the time (say, around the early festive period) you could confidently forecast a mild, zonal flow for a week, perhaps two and link to jet stream charts, ensemble data, etc.

Where the prediction then comes in is when you look beyond the model output (> 10 to 14 days in this case) and predict that the zonal pattern would continue. I would assume moomin did this because it is common for a w-e zonal flow to maintain beyond a week or two. The further out you call it, the less live data you have to evidence and IMO the less right you have to call it a forecast. It becomes an educated guess or prediction based on historical evidence and probabilities, rather than explicitly evidencing current model output 🤯



 

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This is an interesting discussion today 😊 I suppose there are merits to both sides and you could argue there is a significant overlap between the terms 'forecast' and 'prediction' given one can inform the other.

Reading moomin's previous posts it would seem they have turned a forecast into a prediction: a prediction based around the commonality of a zonal pattern in winter for the UK. If you look at the charts for evidence at the time (say, around the early festive period) you could confidently forecast a mild, zonal flow for a week, perhaps two and link to jet stream charts, ensemble data, etc.

Where the prediction then comes in is when you look beyond the model output (> 10 to 14 days in this case) and predict that the zonal pattern would continue. I would assume moomin did this because it is common for a w-e zonal flow to maintain beyond a week or two. The further out you call it, the less live data you have to evidence and IMO the less right you have to call it a forecast. It becomes an educated guess or prediction based on historical evidence and probabilities, rather than explicitly evidencing current model output 🤯

 

A very good and well put post. That's what the evidence was from around Dec 21st (disputed by a few) and sadly the predictive element based on experience and history that it might take some time to shift has also come to fruition.

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Not bad but probably a classic toppler
https://www.meteociel.fr/modeles/gfse_cartes.php?&ech=240&mode=0 

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GFS 12z op continues with the theme of a more amplified pattern in the mid to longer term, allowing colder shots from the North West or North - nothing particularly exciting I guess but brings snow chances for some and less warm rain for others 🤣

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I’m finding the day to day models are pretty much typical this time of year with a strong jet stream and a strong temperature gradient across our latitude.

What’s interesting me more is watching GEFS and a trend of general lowering of temperatures over time.

The jet stream will weaken and buckle as the temperature gradient begins to flatten, then model watching (hopefully) becomes exciting for wintery fans once again. Two or three weeks time?

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Not bad but probably a classic toppler
https://www.meteociel.fr/modeles/gfse_cartes.php?&ech=240&mode=0 

Should get direct heavy snowstorms like in the USA as there kinks on the isobars as it move south.  Cannot be bone dry set-up and topplers are my favourite weather as it bring lot of sunshine for few days afterward, that time I used to get frequent -6 to-10C temps at nights often from topplers back in the time I was living in the SE.  It been absent for several years now in winter and in summer months that started off cool with some sunny spells then warming up to hot and sunny weather as HP move east.

Nice to see lots of intersting discussion on here today, despite the relentless Atlantic onslaught (at least in the medium term).  Forgive me for being off topic, but I was doing a bit of TV schedule scrolling and noticed the the Channel 5 documentary 'The Big Snow of 82' at 9.30 this evening.  Something to feed the passions while we wait for this scrooge of a January to deliver something a little more interesting..... Maybe

Nice to see lots of intersting discussion on here today, despite the relentless Atlantic onslaught (at least in the medium term).  Forgive me for being off topic, but I was doing a bit of TV schedule scrolling and noticed the the Channel 5 documentary 'The Big Snow of 82' at 9.30 this evening.  Something to feed the passions while we wait for this scrooge of a January to deliver something a little more interesting..... Maybe

Off topic: Thanks for the reminder, I remember it well and is probably one of those events that sparked a lasting interest in snowy weather (and I didn’t even get a day off school as I could very easily walk there). It may just be because I was quite young but the snow seemed very deep in rural NI. It was also of course a record setting/equalling cold spell with -27.2°C being reached.
 

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GFS 12z op continues with the theme of a more amplified pattern in the mid to longer term, allowing colder shots from the North West or North - nothing particularly exciting I guess but brings snow chances for some and less warm rain for others 🤣

Yes, ECM 16 day ens now giving a definite cluster in the second half that is in the -4 to -6 range and that's the first time it has shown anything like this since the beginning of this zonal type spell.  Some support for an increased likelyhood of a period of Polar Maritime bias as suggested by recent GFS ops then. 
https://www.theweatheroutlook.com/charts2/ecmhrens/ecmwfens850london.png 

So something more below average or rather cold for a time?  Over the years its more often than not been a prerequisite to have this type of pattern if we are to see something more potent down the line.  However, more often than not, after a while it goes the other way again, but at least something for starters.

Polar Maritime would suit me and if cold enough NW would provide good snowshowers in my neck of the woods.  Actually been a long time since I can remember the repeated ominous dark clouds bring hefty snow showers

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I’m not seeing anything that suggests a change from the predominantly mobile westerly type weather for the next 10 days.
Brief fleeting wafts of Pm air are typical in this pattern, which in itself is typical of Januaries of recent years. 
Hoping for a change to dryer, cooler weather to get some outdoor jobs done and have a rest from this filthy mild gunk.

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Off topic: Thanks for the reminder, I remember it well and is probably one of those events that sparked a lasting interest in snowy weather (and I didn’t even get a day off school as I could very easily walk there). It may just be because I was quite young but the snow seemed very deep in rural NI. It was also of course a record setting/equalling cold spell with -27.2°C being reached.
 

I can't say what '82 was like in NI but I can tell you that it was pretty spectacular in the South East of ROI. The 2nd deepest snowfall of my lifetime, only beaten by February 2018.

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I can't say what '82 was like in NI but I can tell you that it was pretty spectacular in the South East of ROI. The 2nd deepest snowfall of my lifetime, only beaten by February 2018.

Also second place in Bristol, beaten only by December 29/30 1962.