North-Easterly Blast

In July 2021 rainfall was just above average, but not as wet as August 2020. July 2021's warm CET of 17.7 was largely due to a hot spell from the 16th to 23rd (which was the main hot spell of summer 2021), but apart from this spell the rest of the month was not far from average.

Summer 2010 had a fairly warm June and July, but August was a generally cool month. In that year June was a mostly dry month, July was near average for rainfall, and August fairly wet. That said an August that was warm overall in 2020 was slightly wetter than a generally cool one in 2010, so in each month you would notice that one was much warmer than the other but rainfall not much different in either of them.

The exact track of that low will be crucial, as 100 or so miles either way north / south, will dictate what parts of the country are in colder polar maritime air and thus see snow falling, and the parts of the country in milder tropical maritime air and see rain.

What is your winter index for 2021-22 so far by the way? Obviously it could change subject to what the weather is like up until the end of the month. Although not part of the meterological winter, March can also still deliver colder conditions at times that would be respectable for the other winter months.

Another similar example that I can think of is after the whole winter of 1988-89 was completely devoid of anything remotely cold, it actually did get more "wintry" during the second half of February 1989, just slightly below average temps and a little snow for a few parts of the country, but that was basically the 1988-89 winter, although in that year it did get cold in April, which for many areas brought colder weather at times than any part of the 1988-89 winter did. Also as you quote 1998, after the very mild 1997-98 winter which was almost as devoid of anything remotely cold as 1988-89 was; April 1998 did actually also got cold just before mid-month, and Easter that year was colder than most if not all of winter 1997-98, and there was snowfall in some parts of the country.

It appears from what you say that there were some examples, mostly way back in the 1700s, of warm Septembers (mainly similarly warm to those of 2005, 2011 and 2014 in recent times) that did lead to some colder winter spells in the following winter, but there are very few examples in recent times, at least since the earlier part of the 1800s. It appears that the theory of warm Septembers reducing the chance of colder winter weather in the following winter has largely developed in recent times, mainly in recent decades and to some extent since back in the 1800s. I will also point out that only one of those six examples that you quote had a September CET that was one of the top ten warmest on record to this day, thus implying that the bad news for cold conditions in the following winter gets worse the warmer that the September CET is.

September 1961 actually had a CET of 15.2, not 15.4, so it was as warm for the CET as September 2005 was. That winter was actually colder than most winters in the records that have followed warm Septembers, with a pretty cold December which lasted into early January, and although in that winter the rest of January and the first two thirds of February were not that cold, the cold did return later in February which set up the pattern for March 1962 being very cold. So in actual fact winter 1961-62 was one of the few exceptions to the warm September = mild winter theory in that it did go on to produce two significant cold spells, one earlier on and another one late in the winter. September 1958 is a bit of another exception, in that after having a CET of 15.1 (the same as that for 2011 and 2014) in that it did go on to produce a winter that did have a cold January in between a fairly average December and February, so that winter was actually colder than most winters have been after a warm September. After a September CET of 15.3, winter 1929-30 started off being largely mild but later on it did get much colder in February 1930 and the March that year wasn't that warm either. Although the main point that can be seen with high to very high September CETs, is that they do not bode well for cold conditions in the following winter, with the above three examples being the only real exceptions to this in the last century and even longer, and I certainly cannot think of any examples where the following winter as a whole has been cold after a high September CET. I will point out that Septembers 1929, 1958 and 1961 (similarly warm to those of 2005, 2011 and 2014) were just into the top 20 warmest September CETs on record from 1659 but not in the top ten warmest. That said I think when September 2021 was one of the top ten warmest on record for the CET from 1659 (along with 1999, 2006 and 2016 in recent times as well) I think that winter 2021-22 was already "dead in the water" before it even started, at the end of last September, and that after any high to very high September CET I am convinced that you can safely write off the following winter from bringing much in the way of cold weather.

I never said that many really cold winters followed on from a cool September, and whilst I still believe that a cool or average September CET does not appear to have any bearing on the winter that follows, I mean to say that a high September CET is more likely to be followed by milder conditions during the winter, and probably diminishes any reasonable chance of cold outbreaks during the winter to follow. It is worth mentioning that September 1962 was actually cool for its overall CET at 12.6, so a warm start must have only been for the first few days with cool weather dominating the rest of the month. September 1985 although warm for the CET was nowhere near as warm as last year was. The CET of 14.6 for September 1985 is actually the warmest that I can think of for a September CET that has led to a good winter for cold. September 1955's CET was 14.2, so the same as for 2009 and 1978. The 1961-90 average September CET is 13.6, for 1971-2000 13.7, for 1981-2010 14.0 and for 1991-2020 14.2. There is some mention of September 2020 having a warm summery spell in it - it did around mid-month although it was diluted by some cooler weather in the early part of the month and more so late on, and its overall CET was 13.9, so it was in between the older and most recent averages, so not especially warm. For recent times I am thinking what the coldest winters have been after warm Septembers. September 2014 had a pretty warm CET of 15.1 and the following winter's CET was 4.53, and it did have a fair amount of colder polar maritime zonality in it and some colder conditions at times, but overall it wasn't a particularly cold winter, about average for recent times but still a bit milder than the 1961-90 average, so despite a negative QBO of -26.9 it still did not manage to be below average, which shows that the previous warm September may have reduced the chance of a more prolonged and more intense cold outbreak that winter. September 2005 also had a warm CET of 15.2 and the following winter ended up close to average - although there was a fair amount of blocking to the north-east of the UK that winter and Europe saw cold weather at times, but in 2005-06 the really cold air never really quite made it to the UK, and classic cold looking charts never quite came together, and charts with high pressure staying over the UK were never too far away that winter, though the pattern did get more interesting late on in that winter, in late February and March was actually quite cold that year. In actual fact for the synoptics, and background signals being supportive of a colder winter that year, a weak La Nina, good SST anomalies in the May method used back then, and a negative QBO (-18.37), winter 2005-06 was actually disappointing in that regard in that it turned out to be more like a "failed cold winter," which gives evidence that the previous warm September could have reduced the chance of a classic cold pattern coming together in 2005-06. A warm September (CET 15.1 in 2011), was also followed by a winter in 2011-12 that was not cold overall but did see a fortnight's cold spell in the early part of February, but the rest of that winter wasn't up to much, and that winter was a negative QBO (-15.61) and a decaying La Nina winter that ought to have had a decent chance of being a colder winter but overall it wasn't so, so more evidence of a previous warm September reducing the chance of colder weather in that winter. A similar winter to this could be 2004-05 - September 2004 had a relatively warm CET of 14.9, and winter 2004-05 wasn't cold overall but did see a prolonged cold pattern in late February that lasted into early March, and a few short lived cold snaps earlier, so a winter with a fairly neutral QBO that was a bit like 2011-12, milder than average overall but not without its colder moments. All the above said, for the four Septembers that we have had since 1999 that were all four of the top ten warmest on record for the CET (1999, 2006, 2016 and 2021); all of them were followed by milder to very mild winters with very little in the way of cold outbreaks in them at least from proper cold synoptics. All of the above suggests to me that a much warmer than average September CET is bad news for cold prospects in the following winter, getting worse the warmer that September's CET is, but that it is still possible to have just a slightly above average September CET (say 14.0 to 14.6) and get a reasonable amount of cold outbreaks in the following winter, although September CETs in that range still appear to lead to a fairly equal mix of colder, average or milder winters to follow when looking back, but for high to very high September CETs it appears that the link is strong and it really does nail the coffin for any reasonable chance of cold outbreaks in the following winter.

It has just basically been the warm September = mild winter theory this year. Records show that a warm September in the UK does not favour cold patterns to develop during the following winter. I think that being shortly after solar minimum and an easterly QBO up until the end of last summer looked promising for a reasonable chance of cold outbreaks this winter, but then the winter killer pattern of a warm September reared its head and really nailed the coffin for any decent cold outbreaks for us this winter. Winter 2021-22 was written off in September 2021 and was already dead in the water after that. There is clearly a strong link in the UK's weather patterns that warm Septembers ruin the chance of cold during the following winter almost whatever other background signals may suggest.

Although when March 2016 followed the all time warmest December since 1659 which was warmer than any other March had ever been, it was not difficult at all for it to be colder than the previous December.

March 2016 was 3.9*C colder than the previous December, and in 2018 March was colder than the previous January. In 2013 March was colder than all three previous winter months. In 2008 March was colder than January, and in 2001 March was colder than the previous December, so it is certainly not uncommon for March to be colder than any of the previous three months, although it happens on average less than half the time.

Yes for a very mild winter - in fact one of the mildest on record - Winter 2006-07 did bring occasional colder and short wintry moments, compared to winter 2013-14 which was equally rubbish was devoid of anything remotely cold for most of the country, and brought less than 2006-07 served up. 2006-07 was one of, if not the most extreme example of the warm September = mild winter theory, as one of the mildest winters on record followed the all time warmest September CET on record since 1659, of which September 2006 was. Ten years later, September 2016 was a very warm one - the joint 5th warmest on record for the CET from 1659 and winter 2016-17 was just as devoid of anything interesting from a cold perspective as this winter; another five years later, we get the seventh warmest September on record from 1659 in 2021, and we face another winter with next to nothing. The warm September theory really nailing the coffin for colder winter weather in the following winter is clearly a well known fact of the UK's weather patterns.

In recent decades at least the warm September theory of being followed by a milder winter has certainly existed and shown up. That said it has still been shown that it is still possible to have a September CET that is around the 1991-2020 average but slightly above average and get a cold winter after it, like in 2009 and 1978. In recent decades the warmest September CET that I can think of was 1985s 14.6 that was followed by a colder winter. After a high September CET like last year's was, the trend is clear that they are mostly followed by a milder winter or at least a winter with little in the way of cold outbreaks in it. Although no-one can accurately forecast the UKs weather years into the future, if I was making a forecast, I would say that it is highly unlikely that there will ever be a cold winter in any given year following a warm September in terms of overall CET. I do not know what went wrong with past winters that have delivered next to nothing in terms of cold in the UK, but I have a pretty good idea that in 2015-16 it was ENSO Strong El Nino forcing, and in 2019-20 strong IOD forcing, and in 2021-22 and 2016-17 it was the very warm September before it.

I am not sure when all SSWs have taken place in the past, but I know that they can lead to notably cold outbreaks in the UK as the examples from Jan 2013 and Feb 2018 show, but I am not sure that a SSW guarantees a significant cold spell for the UK, as the dice has to still land as to if the blocking sets up favourably to get the UK cold. I am also of the opinion and I question if a SSW can bump the UK out of a cold spell, as I believe there was some stratospheric warming prior to the cold spell in February 2021 but after a week it disappeared abruptly and the UK went very mild. I also think that there was an SSW prior to the cold spell in Feb 2009, but that disappeared abruptly in mid-month and the UK again went very mild.

August 2020 was actually a pretty wet month as well as being warm overall, a bit like August 2004, so not all warm summer months are dry as these two examples show.

The run of mild Februarys in the mid-Victorian era really is notable. That said has a similar notable period for a long run of often mild Decembers, Januarys, or even Marches ever occurred similar to the 40 year run of mostly mild Februarys in that mid-Victorian era? That said I have calculated the February long term averages in that period. For the 1851-80 average I get 4.2, and for the 1861-90 average I get 4.5. So I would think that those 30 year February CET averages are warmer than most if not all other 30 year averages in the CET record. Having said that, judging by my calculated averages of that time period, the run of mild Februarys of the mid Victorian era is not as poor a showing as the period we have had since 1988, when you consider that the 1991-2020 average February CET is 4.9, (4.89 to 2 d.p). So the 1991-2020 average February CET tells us that the run of mostly mild Februarys in the most recent 30 odd years has exceeded the mid Victorian era of mild Februarys by almost half a degree!

I think that February 1981 was quite cold overall with a cold spell in the second half, and some snow.

There is a difference in the sort of zonality in the months that you mention. January 1984 wasn't that mild, it was close to average for that time period, and it saw a lot of polar maritime zonality with frequent and at times heavy snowfalls in the northern half of the UK at least even to low levels at times; it was an impressive event when there was widespread snowfall from an Atlantic zonal flow, as it orientated on a NW - SE track and the air in its circulation was from the northern Atlantic ocean and at times Greenland. January 1986 was also often cold although I think it did get milder for a time around mid-month, so some cold outbreaks in that month as well. For January you could also add 1995 into that list as well, as that was generally quite mild, zonal and wet, although there were intervals of colder polar zonality that on one occasion did give a fairly localised heavy snowfall in the south Pennines and Yorkshire later in that month. December 1993 also featured cold polar maritime zonality at times that gave some snow at times in the northern part of the country (although the setup was less impressive than Jan 1984), so the zonal months that you mention were not all of the milder zonal variety.

Winter 2013-14 was just basically 6-10*C and raining all the time; it is just a pain if that's all the weather does all winter, and there was nothing cold at all in that winter, it was virtually snowless away from high ground in Scotland, and not much frost either in most of the country. Winter 2019-20 was not much different either. We certainly do not want to see either of those coming back for anyone who likes colder winter weather. Winter 2016-17 wasn't much better than this winter from a cold or weather enthusiast's perspective either - that winter never got its act together from a cold perspective and January that winter was equally benign and uneventful like last month, with high pressure often slap bang over the UK, and not much in the way of anything really cold or foggy, or frost persisting through the days. Winter 2016-17 also followed an equally very warm September like last year, and this winter and 2016-17 certainly put into perspective that warm Septembers do not bode well for colder conditions / weather patterns in the following winter, along with most other previous years that had warm Septembers.

Although Februarys 2009 and 2012 were cold right from the start up until the cold disappeared abruptly in mid-month and both went very mild for the rest of the month, whereas February 2021 wasn't that cold from the start, it only really saw a cold spell for about a week or so from the 7th to 14th, then like as you say, it disappeared abruptly in mid-month and went very mild, much like Feb 2009 and 2012.

From the archived charts, after the 4th, January 1962 to me really looks quite a zonal Atlantic driven month and often of the mild zonal variety rather than the polar maritime variety, though it did get colder near the end under a ridge of high pressure. January 2022 after the exceptionally mild first three days, was basically near average all the rest of the month and never that mild, even though there was never a significantly cold period during the month, as the northerly toppler after the 4th did not come to much, and the high pressure spell that followed just kept conditions benignly average with little in the way of "inverted cold" days and little in the way of significant fog. All this puts into perspective what a very uninteresting and uninspiring month January 2022 was from a weather enthusiast's perspective.

I really think that last year's very warm September has ruined this winter from a cold perspective, as it is a well known fact of the UK's weather patterns that it is very rare to get a cold winter after a really warm September. My view is, and looking at past records, it appears that a really warm September is more likely to be followed by milder conditions during the winter, and warm Septembers certainly do not bode well for cold patterns to develop in the following winter, and this winter the "warm September theory" has clearly struck again. Some years ago I believe that the Met Office used SSTs in May to forecast the following May's NAO state. I find that in some ways hard to believe that May SSTs affect the following winter's NAO; as the only reason that I can think of is that there must be a correlation between SSTs in May and similar SST anomalies occurring seven to ten months later. That said I believe that the warm September theory is more significant, as it appears that, whilst it is not clear that there is any trend between cool or average September CETs and the following winters weather patterns, it appears that if synoptic patterns occur that result in a high September CET, they do not favour cold patterns to develop for the UK during the following winter, three to six months later.

December 1991 did see a spell of "inverted cold" under a mid-latitude Rex block, with frost and cold conditions through the days and frequent fog from around the 7th to 15th, although the rest of that month was generally of the mild, dry and anticyclonic type, so anticyclonic conditions in Dec 1991 were not all of the cold type! The last third of January 1992 also saw a very similar surface cold Rex block type with frosty days and frequent fog. December 1992, after a relatively mild but unsettled first half, also saw a very similar spell for a fortnight from around the 20th which lasted until about 3rd January 1993, which again, under a mid-latitude Rex block, gave cold conditions at the surface with frost often persisting through the days and frequent fog, and in fact the relatively cold overall CET of 3.6 for December 1992 was largely due to a mid-latitude Rex block giving surface cold in the second half of that month and never deep cold Arctic air. The lack of fog on any widespread scale that persisted through the days was a very disappointing fact of the anticyclonic synoptics of last month (Jan 2022), and really showed how the weather that such winter synoptic patterns deliver in the UK has become far less wintry in recent times. From what I can think of from memory, the last hurrah for widespread foggy type winter anticyclonic spells was just after mid December 2006, from about the 19th to 23rd of that month, and although not especially great in terms of widespread fog, mid December 2007 had an inverted cold type anticyclonic spell, as did late December 2008 that lasted into early January 2009, and I recall a mainly surface cold type anticyclonic spell in the first half of February 2012.

Yes winter 1979-80 was certainly much milder than the previous severe winter, but certainly not as mild as many winters in recent years. I believe that winter 1979-80 started very mild at the start of December then it got colder later in the month, and for most of January 1980 it overall was cold (though obviously nowhere near as cold as the previous winter was) but it then turned milder, and I think that it had a pretty mild February of 1980, but I do believe that after that there was some colder weather in March 1980. Winter 1979-80 although not a particularly cold winter, did have some colder weather from late December through most of January and it did come back a bit in the March, though it was never anything like the previous winter was. Summer 1979 appears to have been a relatively cool summer overall, although the July appears to have been dry overall with near average temperatures, but it turned cool and more unsettled in the August.

Back to the point the final January 2022 CET was 4.58*C, or 4.6 rounded up. It was average by recent standards (1991-2020), and a little above 1981-2010 averages, but back to the 1961-90 and 1951-80 averages it would have been a mild month, which puts into perspective how the January weather in the UK has changed so much in the last 30 odd years. January 2022 was also a month where its CET does not tell you a great deal about the weather pattern and types of weather that the UK experienced during the month. After a very mild first three days, temperatures were basically just average all the time for the rest of the month with no significant cold spells, and bar a short northerly snap from about the 4th to 7th, the rest of the month was more or less high pressure slap bang over the UK, and the pattern simply never got itself together from the perspective of a proper cold spell or even a cold snap, as the UK High never moved to a favourable position for that. The weather also never really lived up to what its, in a sense "wintry potential" would have been in such a synoptic setup many years ago, in terms of widespread fog or really cold days through an "inverted cold". During the month there was hardly any snow for most places except for the favoured areas that saw short lived falls in the brief northerly episode in the first week. I do believe that 30-40 years ago and longer ago than that, January 2022s synoptics would have delivered widespread fog that lasted for many days and never cleared, and would have given the atmosphere a very white look and it would have felt very wintry, but hardly any fog in last month's anticyclonic spell was very disappointing from a wintry perspective. All in all, in my opinion, January 2022 was definitely a very disappointing month from a weather enthusiasts perspective, and model watching perspective, and about all in all as poor as the Januarys of 2007, 2008 and 2020 even though January 2022s overall CET was quite a bit colder than those three very mild ones. It puts into perspective of how a winter month with a similar CET may include a week's cold spell with also a mild period and a bit of an average period, and some winter months with higher overall CETs than last month have actually seen more in the way of proper cold synoptics and more cold days and more snow than January 2022 did.