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It seems the lessons of the limits of model reliability and the similar limits regarding the ensemble suites might need to be revisited.It might also be worth puncturing the myth that when the models show an extended mild period they’re invariably right; clearly they’re just as prone to error as any other long-range outlook.
It seems the lessons of the limits of model reliability and the similar limits regarding the ensemble suites might need to be revisited.
It might also be worth puncturing the myth that when the models show an extended mild period they’re invariably right; clearly they’re just as prone to error as any other long-range outlook.
Yes. Also it might be easy to argue that short term mild is a more stable prediction but that is probably because in winter it is less scrutinised and less critical. If this upcoming mild spell produces just 13C instead of 15C 24 hours before who cares? But the difference between 4C and rain and 2C and snow would cause uproar!
Good point well made: however, looking at the historic charts for the 60s, 70s and 80s, the one thing that has struck me is that these charts were less volatile than today. That is to say - weather systems seemed to me to move about more slowly. Toppler’s were 2-3 day affairs, and today a toppler seems to come and go in 1 to 1.5 days, just for example... To prove this, there would have to be an awful lot of sampling studies undertaken. It’s just a hypothesis from how it looks to the lay observer.Obviously, if this theory has any legs (or at least others have observed the same), then any such theory needs to consider the cause of any speeding up of passage of weather systems in our latitude and location. The obvious culprit is the increase of circa 1 degree in global temperature since the 60s. To my eyes - as a life-time weather observer, high pressure systems in winter just do not hang about for as long as they did in those (my formative) 3 decades. - and whilst this is true (to my eye) of Scandi’ highs, it seems true for where ever they are centred. May be this is the reason why ‘the winter easterly wind’ seems to have become such a rare phenomenon. Frosty blocking highs need to settle for the air to get cold enough to become a solid and immovable force - as it became in 1963 and many times in the 60s - up to 1970 and then again in the 80s too, but less so since.Anyone agree, disagree - or have a comment?
Good point well made: however, looking at the historic charts for the 60s, 70s and 80s, the one thing that has struck me is that these charts were less volatile than today. That is to say - weather systems seemed to me to move about more slowly. Toppler’s were 2-3 day affairs, and today a toppler seems to come and go in 1 to 1.5 days, just for example... To prove this, there would have to be an awful lot of sampling studies undertaken. It’s just a hypothesis from how it looks to the lay observer.
Obviously, if this theory has any legs (or at least others have observed the same), then any such theory needs to consider the cause of any speeding up of passage of weather systems in our latitude and location. The obvious culprit is the increase of circa 1 degree in global temperature since the 60s. To my eyes - as a life-time weather observer, high pressure systems in winter just do not hang about for as long as they did in those (my formative) 3 decades. - and whilst this is true (to my eye) of Scandi’ highs, it seems true for where ever they are centred. May be this is the reason why ‘the winter easterly wind’ seems to have become such a rare phenomenon. Frosty blocking highs need to settle for the air to get cold enough to become a solid and immovable force - as it became in 1963 and many times in the 60s - up to 1970 and then again in the 80s too, but less so since.
Anyone agree, disagree - or have a comment?
Absolutely agree from 60 years of observation.
Memory plays tricks in remembering only the more dramatic weather examples but I too would have said that through the 1950s to the 1970s a lasting frosty or foggy high was commonplace in Dec or Jan - not every year, perhaps 1 in 3, but common enough to be expected.However, there are examples of decade-long shifts in climate without the need to invoke global warming so caution is needed there. I'm thinking of the Dust Bowl in Oklahoma in the 1920s where farmers who had come to rely on regular rainfall were ruined by a decade of drought - and a recent programme on PBS suggested that decadal swings of this type in that area had occurred previously
Memory plays tricks in remembering only the more dramatic weather examples but I too would have said that through the 1950s to the 1970s a lasting frosty or foggy high was commonplace in Dec or Jan - not every year, perhaps 1 in 3, but common enough to be expected.
However, there are examples of decade-long shifts in climate without the need to invoke global warming so caution is needed there. I'm thinking of the Dust Bowl in Oklahoma in the 1920s where farmers who had come to rely on regular rainfall were ruined by a decade of drought - and a recent programme on PBS suggested that decadal swings of this type in that area had occurred previously
I wonder to what extent the reduction in air pollution has to play as well, particularly with fog. I haven't seen dense fog here for decades. Yet in the 50's and early 60's before the Clean Air Act it was widespread. It is hard for younger people to imagine not being able to find your home when just 100m away or walking into a lamp post and getting a bloody nose because you couldn't literally see your hand in front of your face due to fog(smog).
Particularly bad in city areas. A clear HP just 20 miles from London would inevitably lead to dense smog once reaching the outskirts of the built up areas.
Indeed so, Peter.Much as GFS FI often cannot be taken that seriously for obvious reasons, there have been a couple of occasions this month when it has been correct in picking up on a trend well in advance:It began to pick up in the rise in pressure over Iberia & North Africa in FI about 10 days ago and then stuck fairly solidly with this thems for days afterwards. 2. Back in early December, it spotted the trend for pressure to build from the south northwards over the UK just after mid-month with the possibility of it moving towards Greenland/Iceland. This also took place and was responsible for the frenzy of excitement there was in this thread for a time a couple of weeks ago.It was in trying to pin down what was likely to happen from Christmas Day onwards where it seemed to struggle big time, but there again I think all the models struggled in that respect last week.
Indeed so, Peter.
Much as GFS FI often cannot be taken that seriously for obvious reasons, there have been a couple of occasions this month when it has been correct in picking up on a trend well in advance:
2. Back in early December, it spotted the trend for pressure to build from the south northwards over the UK just after mid-month with the possibility of it moving towards Greenland/Iceland. This also took place and was responsible for the frenzy of excitement there was in this thread for a time a couple of weeks ago.
It was in trying to pin down what was likely to happen from Christmas Day onwards where it seemed to struggle big time, but there again I think all the models struggled in that respect last week.
My view of FI (i.e from 7-10 days out) is still one of random noise. It shows what trends are possible but it is rare indeed to be consistent for one trend. On that basis it will always get one of the "spots" right from time to time. It must do because almost all possibilities are covered by at least one pert.
Well, my formative years were around the same time but my take away is systems either seem to move faster or things grind to a halt. We simply never see the classical Norwegian sequence of cold air before a low, a warm sector and then cold NWlies - it just never happens anymore. What are cold NWlies anyway....Wrt cold easterlies, well often there is no cold air to our east, and even though it is cold over Scandinavia this year sea ice there is barely at normal. We get cold winters from the east when its a cold winter to the east - that hardly ever happens now.I also see synoptics as a symptom not a cause - because they are being driven by that reality highlighted.
Well, my formative years were around the same time but my take away is systems either seem to move faster or things grind to a halt. We simply never see the classical Norwegian sequence of cold air before a low, a warm sector and then cold NWlies - it just never happens anymore. What are cold NWlies anyway....
Wrt cold easterlies, well often there is no cold air to our east, and even though it is cold over Scandinavia this year sea ice there is barely at normal. We get cold winters from the east when its a cold winter to the east - that hardly ever happens now.
I also see synoptics as a symptom not a cause - because they are being driven by that reality highlighted.
This is an accurate appraisal. Cold NWlies were the ones that in late winter and early Spring used to bring blustery spells of snow, sleet and hail to low levels in the South
Good post - never really thought about a comparison of a toppler's longevity or a stagnant high pressure but seems a fair comment . I remember HP sat over us trapping the fog for days and increasing the frost .
Sighs
They still sometimes deliver here
And here as the PPN runs through the Cheshire gap
We don’t care about there 😂😉
Much different feel to the weather in a weeks time
That seems to be the opposite of what many people seem to complain about on here: the weather getting “stuck in a rut” for weeks on end with little change.
Toppler’s were 2-3 day affairs, and today a toppler seems to come and go in 1 to 1.5 days, just for example... To prove this, there would have to be an awful lot of sampling studies undertaken. It’s just a hypothesis from how it looks to the lay observer.Anyone agree, disagree - or have a comment?
Toppler’s were 2-3 day affairs, and today a toppler seems to come and go in 1 to 1.5 days, just for example... To prove this, there would have to be an awful lot of sampling studies undertaken. It’s just a hypothesis from how it looks to the lay observer.
I agree re toppler's but also northerlies too - they don't last nearly as long compared to when use to get them in the 90's and 00's. Northerlies only last a day before backing north westerly/westerly etc.
Some nice WAA on the 12z https://www.wetterzentrale.de/maps/GFSOPEU12_135_2.png
better if it was straighter up into Greenland- but could change or Atlantic will just fire up
Something like this you mean ? ;)https://modeles16.meteociel.fr/modeles/gens/run/gensnh-27-1-174.png?12
now that pert is a lot better !