North-Easterly Blast

Optimus Prime; I am not sure that I agree with you about a cold block not being able to sustain itself over the UK due to it not being able to provide the cold it used to be able to do. Look at the late February 2005 easterly. That northern blocking was able to sustain itself for a reasonable period of time even though there was no really cold air over Europe to tap into to make that easterly particularly cold. In late January 2006 our cold sources actually did became bitterly cold and yet a cold northern block never developed to get the cold air to the UK even though conditions were much colder over Europe at that time than in late Feb 2005. Only in Feb of this year Scandinavia became bitterly cold from a southward moving Arctic High but the synoptics couldn't allow this cold to reach the UK. The same is also true of the "Kettley High" scenario of Feb 2001; northern Europe turned bitterly cold and the right synoptics still couldn't develop for cold in the UK. The above just goes to show the fickleness of getting cold synoptics for the UK whether our cold sources are really cold or not.

Stratos Ferric; August 2006 was not exceptional? It was only close to average in terms of the CET at 16.1*C. You forgot to say that November and December 2006 were not exceptionally warm overall either at 1.2 and 1.4 above average respectively. Yes, now the record April CET will almost certainly be 11*C+ by the end of the month. 15.8 for the final eight days is pushing it I think. I would make a guess and say somewhere around the 11.2 mark is the likely final April CET. Which now makes it that five of the last twelve months have been exceptionally above average (2*C or more above the 71-00 average), and June and February well above also, at over 1.5 above the long term mean. Since March 2006 only August has seen a CET close to average, and although global temperatures have been half a degree warmer since 1998, including last year which was still only around 0.5 above the cooler 1961-90 average, the UK has been almost 2*C above the warmer 1971-2000 average over the last twelve months. So it is all down to synoptics. I will explain each month's synoptics below. May 2006: First half dominated by a southerly or south-easterly airflow with low pressure over the UK at times, and very warm. Second half around average dominated by low pressure and very wet conditions with mainly west to south-west winds, and a northerly in the closing days. June 2006: Very anticyclonic, with high pressure often situated over the UK or over Central Europe. Very warm first half, but second half nearer average as high pressure moved further west allowing a north-westerly flow to develop at times. July 2006: Extremely hot, with slow moving anticyclones often centered over Scandinavia or Central Europe and exceptionally hot through the second half with slow moving lows to the west of Ireland also, although a close to average spell did occur from about the 7th to 14th as a westerly flow developed. August 2006: Dominated by a northerly flow, although not from a long way north and often from Scandinavia and the month still managed a CET close to average and also the winds did become more westerly after the 20th. September 2006: Dominated by high pressure over Europe for the first half and then by low pressure to the west of the UK in the second half with a cyclonic southerly flow. Very warm throughout. October 2006: A similar pattern coninued, frequent slow moving low pressures to the west of the UK resulting in a prolonged southerly flow all month. A Greenland High built in the second half but it did not succeed in influencing the UK with cold northerlies. November 2006: An anticyclone from Greenland developed across the UK for the first ten days bringing colder frostier weather and then from the 10th onwards persistent south-westerlies associated with mild zonality brought mild weather. December 2006: The zonal Bartlett type dominated the first half but the second half saw a displaced Azores High sat over the UK and the jet well to the north of the UK with no high latitude blocking. January 2007: The mild zonal Bartlett type lasted until the 20th with SW-NE tracking depressions, but a northerly developed from the 21st to 25th followed by high pressure over the UK which sank further south allowing milder weather again. February 2007: High pressure over the UK moved west allowing a brief northerly from the 4th then an easterly as low pressure was to the south of the UK. Mild SW'lies returned from the 11th and lasted the rest of the month. March 2007: Mild south-westerlies until the 17th, then a northerly from the 18th to 21st followed by an anticyclonic south-easterly spell. April 2007: High pressure sat over the UK almost all month and at times to the east in Central Europe resulting in a mainly anticyclonic southerly type. You will note from the above that northerlies have been unusually rare during the past year and so have easterlies and winds from a southerly quarter have been the predominant pattern either due to a zonal Bartlett type, or persistent low pressure to the west of Ireland, or slow moving anticylcones over Central Europe.

I am not sure about the cold synoptics not being able to give us cold weather. March 2006 actually did give us some hope; up to the 23rd the CET was 3.2*C, and the first three days were dominated by northerly and easterly airflows, apart from the 7th-10th which had a westerly component to the flow, but as there was a south-westerly for the last seven days, it made the cold CET less outstanding and the CET for March 2006 ended up just over 1*C below the long term average at 4.9*C. November 2005 did also give hope, indeed after a very mild first half the second half saw a CET of 2.6*C, amazingly cold by November standards and was certainly cold even for the synoptics that occurred. Dec 2005, Jan and Feb 2006 produced CETs that were not bad for their synoptics, although none of those months saw an extended spell of zonal SW'lies, cold synoptics (N'lies/E'lies) were short lived during all the three months. The months I would say in recent years that should have produced colder CETs were February 2005, OK, winds with a south-westerly component were frequent in the first half, and northerlies at the start were from the top of a displaced Azores High, but the easterly spell from the 20th onwards should have been colder than it actually was, as there was no cold air over Europe to tap into to make that easterly especially cold. When I look at the synoptics of Feb 2005, I would expect it to have produced a below average CET probably nearer 3.5*C, but it didn't. Despite Feb 2005 not managing to achieve the negative anomalies that you would expect it to achieve, a positive side is that the period mid Feb 2005 to mid March 2005 still managed a CET of 3.2*C, 1.8*C below the 1971-2000 average and a larger negative anomaly than has occurred in any calendar month since 1997. August 2006 is another month where the synoptics should have produced a cooler month, as there were no spells of anticyclonic S'ly or SE'ly weather, but given that the northerlies that month were never from way up into the Arctic and they originated from Scandinavia or the Iceland area, I would have expected it to have produced a CET in the 15.0 to 15.5 region, around 1*C below average, but it didn't. In recent years the "close to average" months of Feb 2005 and Aug 2006 should have been up to around 1*C colder, but I think that the CETs of the colder months from Nov 2005 - Mar 2006 were reasonable for their synoptics. However, although last winter overall was very mild, the colder spells that occurred didn't do so bad though for the daily CETs that occurred; the anticyclonic spell in December did pretty well to get daily CETs around the 1.5 to 2.0*C mark. The cold spell in early February did pretty well for daily CETs for the synoptics, the 8th and 9th still managed daily CETs around or below the 0*C mark and the easterly on those dates was not from a particularly cold source and the source of the northerly earlier in the week was not especially cold either. The only spell that was not especially cold was the northerly from the 22nd-25th January, it only produced daily CETs down to around the 1.0 to 1.5 mark even though it had come from around the Arctic Circle border, possibly it didn't last long enough to allow enough cold air to dig in to the UK.

SF; I haven't exactly mentioned about re-baslining our definition re cold in the UK, I am just emphasising how far ahead British Warming is from Global Warming, and how the UK has warmed far more than logic suggests it should have done. I am also trying to raise that I can see no reason as to why we hardly ever see high latitude blocking even when this month has shown two attempts at a Greenland block and a northerly for the UK and neither have materialised and high pressure has just returned to its home sat over the UK, and these synoptics featured a good deal in the winter 2005-06, especially late Jan / early Feb when high pressure just remained over the UK and attempts at high latitude blocking failed, and even as to why most of last winter was dominated by the zonal Bartlett type and not the cold zonal polar NW'ly type. A record warm April is nailed now. The GFS progs temps into the low 20s widely by Thurs / Fri although admittedly this is on the warm side of the ensembles by late in the week, and an 11*C April CET looks highly likely now. Not sure about rainfall and sunshine though, there may be too much cloud and rain around earlier this week to break the driest / sunniest April record, and even the GFS is suggesting that there may still be some rain around even during the very warm weather its progging. We were stuck in this month's synoptics for the whole of June / July last year and it took two months to get out of the pattern of high pressure over, or to the east of the UK in Central Europe, and that was after a very cyclonic and wet May. Not sure about what May will bring, it is too early to tell how May will pan out, but given the pattern that has prevailed for this month it is difficult to see May being anything other than average to warm, and this spring is already challenging the possibility of the warmest spring on record.

It is getting to the point now where we should begin to think if the winters of 2000-01 and 2005-06 are the modern versions of 1995-96, 1985, 1986, 1987 and even possibly 1978-79. The longer year on year goes on with month after month recording above average CETs, and the fact that we see chart on chart showing that we can hardly ever get a proper long lasting Greenland or Scandinavian block and a southerly tracking jet it just seems that, for the rest of our lifetimes anyway we will not ever likely even get a winter like 1995-96, or the mid 1980s winters let alone 1978-79 or 1962-63. With also the seemingly winter after winter zonality of the mild zonal Bartlett type, it just seems that even in any of our lifetimes we are never likely to get a cold polar maritime zonal setup like January 1984. What will ever trigger a trend or the mechanisms for proper Greenland / Scandinavian blocks to develop and a southerly tracking jet and proper long draw northerlies / easterlies to develop and an end to high pressure making its home slap bang over the UK like this month and also trigger Atlantic zonality to resemble the cold polar maritime type (NW-SE track) like January 1984? It should be noted that on two occasions this month (last week and the first week of the month) high pressure has made attempts to establish itself over Greenland but small areas of low pressure in the area have prevented this and so high pressure has returned to its home sat over the UK. This month's setup was also what prevented high latitude blocking to deliver a classic cold spell in late Jan / early Feb 2006 and much of the 2005-06 winter. Putting all the logic into place of Global Warming, the main facts of this are that the world overall has been half a degree warmer than the long term average since 1998, around half the margin of the warming seen in Britain as a whole since the mid 1990s! Logic here would suggest that Britain should have been half a degree warmer but it hasn't, it has been a full degree warmer, twice the Global Warming trends. The fact also is that British temperatures are only a very small proportion of temperature figures that are used to calculate the world overall average temperature, so none of this paragraph really makes out that it is impossible for a cold month to occur or a severe winter to occur in the UK, and logic says that it must even be possible for the UK to get a cold year like 1996, and still with global temps at the level they have been since 1998, when the UK is only a small proportion of overall global averages, so there must be far more to it than the world being overall half a degree warmer since 1998 that is causing us to hardly ever even be able to get the synoptics that would bring colder conditions to Britain let alone weather charts resembling those of the big freezes such as in 1978-79!

Reef; You are correct to say that prior to May 2006 we did have a six month period that was overall cold by recent year's standards at least, with six months in a row that were close to, or below the 1971-2000 average. That was on a par to another colder period in the winter of 2000-01 and the spring that followed. At least from the middle of December 2000 temps were overall below average until the start of May 2001; Jan 2001: 3.2*C (-1.0) Feb 2001: 4.4*C (+0.2) Mar 2001: 5.2*C (-1.1) April 2001: 7.7*C (-0.4) Another point of note is that Oct and Nov 2000 were also close to average overall. In fact extended spells of warmer than average temps were pretty rare from October 2000 to the end of April 2001. As you say, five years later, a similar pattern developed again from mid November 2005 which lasted for five months or so when extended spells of warmer than average temps were again pretty rare from mid Nov 2005 to around late April / early May 2006. The periods in 2000-01 and 2005-06 when extended spells of above average temps became rare for a few months are the only "cooler" periods of note since the start of 1997, when apart from these two periods temps have been consistently warm apart from the occasional cold month, although warm periods were rare in the summer of 1998, and this resulted in a cooler than average summer overall. Although at a plus, the rest of 2001 after the rather cold first third wasn't overly warm either apart from October and this at least did give a relatively cool year by recent standards.

One has to remember that the later you get in any month, the warmer any day has to be to rise the CET by the same amount, as the devisory is greater. So, the very warm spell in mid April this year rose the CET from 9.5 at the 13th to 10.3 by the 16th, an 0.8*C rise in three days. However, if a similar equal warm spell occurred in the final three days of the month, then the CET would rise only by 0.4*C.

We all know that the CET will be well over 10*C after this weekend, but with Philip's site registering 0.5mm so far this month, I wonder what the odds are of this month being the driest April ever recorded in England & Wales, and even more so the driest month ever recorded in the England & Wales Rainfall Series which began in 1766. The record for the driest ever month is currently February 1891 which produced a rainfall average across E & W of just 3.6mm. It's a long shot I know but with runs showing very little low pressure activity near the UK for the forseeable future then the possibility cannot be ruled out. With the CET well over 10*C at the start of next week then a 10+ April CET must be quite likely now this year. The warmest April in recent years was in 1987 with a CET of 10.3*C. With little sign of anything cooler for much of next week it will even take a pattern change for the April 1987 CET of 10.3 to remain in tact.

I have noticed that when a winter is cold, dominated by north and or / east winds, it increases the chances that these patterns will be repetitive and cold spring months often follow: Winter 1916-17: CET 1.5 March 3.2 April 5.4 Winter 1928-29: CET 1.7 April 6.8 Winter 1935-36: CET 3.0 April 6.3 Winter 1940-41: CET 2.6 April 6.4 May 9.4 Winter 1941-42: CET 2.2 March 5.2 Winter 1946-47: CET 1.1 March 3.6 Winter 1950-51: CET 2.9 March 4.1 April 6.8 May 10.1 Winter 1952-53: CET 3.5 March 5.6 April 7.3 Winter 1954-55: CET 3.5 March 3.2 May 9.7 Winter 1955-56: CET 2.9 April 6.9 Winter 1961-62: CET 3.5 March 2.8 April 7.7 May 10.5 Winter 1963-64: CET 3.5 March 4.3 Winter 1964-65: CET 3.3 March 5.2 Winter 1968-69: CET 3.2 March 3.3 April 7.4 Winter 1969-70: CET 3.3 March 3.7 April 6.7 Winter 1976-77: CET 3.4 April 7.2 May 10.5 Winter 1978-79: CET 1.6 March 4.7 April 7.8 May 10.0 Winter 1984-85: CET 2.7 March 4.7 Winter 1985-86: CET 2.9 March 4.9 April 5.8 Winter 1990-91: CET 3.0 May 10.8 Winter 1995-96: CET 3.0 March 4.5 May 9.1 So, from the above, it shows that a cold / colder winter certainly increases the chances of below average CETs during the spring months, and that most colder than average winters lead to one or two cold spring months. Even many near average winters still often lead to colder spring months too: Winter 1957-58: CET 4.2 March 3.7 April 7.4 Winter 1965-66: CET 4.4 April 7.2 Winter 1970-71: CET 4.4 March 4.9 Winter 1977-78: CET 4.1 April 6.5 Winter 1982-83: CET 4.3 April 6.8 May 10.3 Winter 1983-84: CET 4.2 March 4.7 May 9.9 Winter 2000-01: CET 4.4 March 5.2 April 7.7 Winter 2005-06: CET 4.2 March 4.9 It seems that most mild / milder winters rarely lead to colder spring months, the only examples I can think of were in the mid 1970s: Winter 1974-75: CET 6.4 March 4.8 May 9.9 Winter 1975-76: CET 5.2 March 4.8 Also 1988-89: CET 6.5 April 6.6, but this was masked as this spring featured a cold April in between a mild March and a warm May, both of which were quite a bit above average. Winter 1997-98: CET 6.1 April 7.7, although this was again masked as it was a rather cold April in between a mild March and warm May, both of which were well above average. So my conclusion is that there is a correlation between average to cold winters and cold spring months, showing that once the winter weather patterns have become established, they often are repetitive during the spring months, so a colder winter is definitely the key to getting a lower annual CET and below 10*C. Without a cold winter it is very difficult to get the sort of yearly CET figures that we saw in years like 1996 and colder. Again, there is certainly some truth in the warm September / mild winter correlation as well. Below are Septembers with CETs of 1*C or greater above average over recent decades and the winter that followed: Sep 2006: 16.8 Winter 6.4 Sep 2005: 15.2 Winter 4.2 Sep 2004: 14.9 Winter 5.2 Sep 2000: 14.7 Winter 4.4 Sep 1999: 15.6 Winter 5.4 Sep 1998: 14.9 Winter 5.4 Sep 1991: 14.7 Winter 4.6 Sep 1989: 14.7 Winter 6.2 Sep 1985: 14.6 Winter 2.9 Sep 1980: 14.7 Winter 4.5 Sep 1961: 15.2 Winter 3.5 Sep 1959: 14.9 Winter 4.6 Sep 1958: 15.1 Winter 3.5 Sep 1949: 16.3 Winter 5.1 Sep 1947: 14.9 Winter 5.1 Sep 1934: 14.6 Winter 6.1 Sep 1933: 14.9 Winter 3.2 Sep 1929: 15.3 Winter 4.6 I have quoted Septembers 14.6 or above as the 61-90 average is only 0.1 below the 71-00 average and is also the average for the entire 20th Century, so little difference by 71-00. You can clearly see from the above that in the last 100 years there has only on two occasions been a particularly cold winter (less than 3.5*C) that has followed a warm September (at least 1*C above average), in 1985-86, and that autumn also featured a very dry anticyclonic and rather warm October, and in 1933-34, although even that winter after a cold December, January and February were close to average. The only other two occasions that any winter was even anything below average after warm Septembers were in 1961-62 and 1958-59, although in 61-62 Dec was cold but Jan and Feb were average, and in 58-59 Jan was cold but Dec and Feb were average. So, the above paragraph holds that it was a well known fact in the British Climate that even for the entire 20th Century a warm September meant that it would not be a brilliant winter for cold weather, and the vast majority of winters in the 20th century that followed a warm September turned out to be milder than average, and it is certainly true for recent years. My conclusion to all the above is as cold winters often lead to cold spring months and that winter is rarely cold after a warm September, we certainly need to see a cool or at least average September before there will be much prospect or hope of a change of the weather patterns of recent years during the winter and spring, and even as long as the warm Septembers continue there will be little prospect of us getting away from the sort of yearly CET figures of the last ten years or so. Another point to mention is that, the winter of 1991-92 was also characterised by a zonal pattern almost throughout with strong depressions running through the GIN corridor, but a mild winter like 88-89 was denied as a displaced Azores High became sat over the UK much of the time especially in Dec and Jan and temperature inversions developed at times and also cold dry continental air was able to cover the UK at times, preventing mild weather in the UK although there was still a strong zonal pattern in the GIN corridor, and the pattern that was observed in Dec 1991 / Jan 1992 was very similar to the pattern seen in the second half of December 2006.

That makes winter 2006-07 the joint 4th warmest winter on record with 1974-75.

So what does all this mean for next winter 2007-08? Are any of the factors that wrecked winter 2006-07 likely to wreck next winter as well? Will last November's stratospheric cooling event affect the weather through the rest of this year and into next winter?

Glacier Point; how is La Nina likely to influence our summer weather? So, what wrecked winter 2006-07 for cold in the UK? My view was partly the very warm September and the prolonged mild SW'lies throughout the autumn that sent very mild air even as far north as northern Scandinavia and western Russia and prevented a build up of a cold pool there until much later in the winter, and the SST anomaly in the Pacific also wrecked winter 2006-07. A SST anomaly of an El Nino together with cold anomalies in the north Pacific just enhances the northern arm of the jet and is curtains for a cold winter in the UK. I do not know what the correlation is between a La Nina and summer weather in the UK.

With frequent talk that August 2006 should have been cooler than it actually was, I have another month in question when looking through the archives, April 1995. When looking through the archived charts, April 1995 featured mostly high pressure sat over the UK during the first half, (very similar to the setup progged for this coming Easter Weekend in 2007), and even a brief Bartlett around the 2nd, with low pressure frequently passing through the GIN corridor. The second half featured a Greenland High from the 18th -22nd and northerlies covering the UK, and looking at the bigger picture these northerlies were from way up into the Arctic, and then lower pressure to the south of the UK turned the winds easterly for the final week of the month, and admittedly, these easterlies from the 24th-29th April 1995 were from central and northern Scandinavia, so certainly still a cold source even at this time of the year. Despite the fact that there were true cold synoptics throughout the second half of April 1995, and even for much of the first half high pressure was rarely in a position where it could pull up extremely warm air from Africa, (such as in mid April 2003); the month still ended up being a full degree above average for the CET at 9.1*C. In my view the synoptics of April 1995 should at least have produced a CET close to average, and the synoptics of the second half should have given a much colder than average second half, but the month still managed a positive anomaly of 1*C, how did this come about looking through the synoptics? Plus more specifically, the 1988-1996 era was only in a Stage One modest warming for the UK compared to the Stage Two consistently warm period of the post 1997 era.

Thundery wintry showers; It should be noted that we have not even had a cold month at least 3*C below the 1971-2000 average let alone the 61-90 average since January 1987. It should be noted that in some months of the year there has never been a month that has recorded a CET 3*C or more below average or at the very most one or two. In the 348 year CET record, there has in fact never been a May or a June 3*C below average, and only one July and August 3*C below the average, and only about two Septembers. I do not think that there has been more than one or two Aprils 3*C or more below the mean. Whereas it is often winter months that are the colder than average by the largest amount. Months like Jan 1985 and 1987, Feb 1979, Feb 1969, Feb 1955 etc all recorded CETs at least 3*C below the 71-00 mean, and months like Jan & Feb 1963, Feb 1947, Feb 1956, Jan 1979, Feb 1986 all recorded CETs 4*C or more below the average.

I am not sure that I entirely agree with you re the Hadley CET coming out lower than Manley in cyclonic months, and higher than Manley in inversion months. Feb 2006 was 3.9 (Manley) and 3.7 (Hadley) and there was an inversion at the start of that month. Jan 2007 was a cyclonic month and Hadley's CET is 0.1 above Manley's 6.9. July 1983 was also a very hot anticyclonic month and Hadley's 19.5 is a full 0.4 below Manley's 19.9. In July 2006 Hadley is 0.15 below Manley.

It goes to say that whilst it is true that in the UK since 1997 we have not had the cold months of yesteryear, few months below the seasonal average, no cold seasons or notably cold months 2*C or more below average, but yesteryear it is certainly true that we did get sort of notably warm months of recent years; Winter 1868-69: CET 6.8*C Januarys 1916 & 1921: 7.5 & 7.3*C. Februarys 1903 & 1945: 7.1*C January 1796: 7.3*C February 1779: 7.9*C September 1729: 16.6*C Mid Dec 1974-mid Jan 1975: 8.3*C Also in a decade of generally cold winters, we still managed a CET of 19.5 for July 1983. All the above facts go to say that whilst we struggle to get cold synoptics to hold for sufficient time in any month to get the CET much below average, the warm synoptics of today do not really produce much higher temperatures than they have done for almost 300 years. Seeing this morning's runs; the record CET for April would be under threat. It shows high pressure sitting either slap bang over the UK or frequently pulling up warm southerlies to the UK - very much similar to the synoptics that featured during the very warm April of 1987, and that didn't even start until mid month! So goodness knows what sort of a CET we are in for if this morningt's runs come off. Judging by ECM the exceptional 80*F warmth of mid April 2003 could also be repeated in around ten days. The charts continue to show horrendous warmth for the time of the year with full ensemble backup. It makes you now begin to think if the UK warming has moved up yet another stage from what it did in 1997, and if the occasional below average months we have had since 1997 are no longer likely, and getting months with even near average temperatures will now be a struggle.

It is not entirely true to say that March 2006 had cold synoptics all month. It did have predominatly winds from a northerly or easterly quarter until the 24th, but the final week actually saw much milder synoptics with south-westerlies, and from a long way to the south-west around the 26th, so the March 2006 CET of 4.9 is fairly close to what one would expect with the south-westerlies of the final week partly offsetting the persistent cold weather for the first three weeks. To say that about August 2006, the northerlies that month only originated from around the south of Scandinavia or the south of Iceland, not way up into the Arctic, and winds from a westerly quarter prevailed from the 20th onwards. It is fair to say, had August 2006 not come on the back of such a hot July, when SSTs were so high, I personally think that those synoptics would have produced a CET nearer 15.5, rather than the 16.1 that was the actual result. One could never say that August 2006 synoptics could have produced the sort of CET that August 1986 did, as the northerlies that month were frequently from well up into the Arctic.

With it not looking like we will see much else other than high pressure close to or slap bang over the UK until possibly mid-month, it will offer warm days but rather cool by night, and there seems little prospect of high pressure retrogressing to a position where it can drive colder air across the UK out to the middle of April at least, so even at this stage, it is already difficult to see April developing into a cooler than average month.

Philip's CET for Feb 2007 was actually 6.05*C. I certainly think that Hadley are wrong that Feb 2007 had a CET of 5.8, it was definitely warmer than that, and it definitely felt as at least as warm as Feb 1989 did. Hadley are often slightly cooler than Manley, so I think that it should be 6.0 or possibly 5.9 at the lowest. I also do think that Hadley's 7.0 for Jan 2007 could possibly be a little too high, as Philip's is 6.9. I do not think that March 2007 had a CET of 7.2, I think that it should be more like 7.1. Going back to January, although it was so mild overall it still managed a 4-5 day colder spell with frosts and day maxima close to 2-4*C, and slight snowfalls in some places. The very mild Januarys of 1989 and 1990 couldn't even achieve this and during both those Januarys hardly anywhere even recorded maxima lower than 5*C during the month and they saw little frost and were snowless practically everywhere. Hadley have definitely underestimated the February 2007 CET at 5.8, and I do think they have slightly overestimated the March 2007 CET at 7.2, and possibly the January one as well. Another point that was made official, was that last year, the Met Office declared July 2006 as the hottest month since records began. This is only true on one scale but not the other. Since the adoption of the Manley series in 1974, there are two methods of computing the averages. July 2006 is 19.7 on Hadley's CET, and 19.85 on Manley's CET. Philip has July 1983 as 19.9 on his Manley scale, and Hadley have July 1983 at 19.5. So, according to the Hadley series, July 2006 was the hottest month on record, but according to Philip Eden's Manley series, July 2006 was fractionally below July 1983 by 0.05*C. Before anyone in the future mentions July 2006, they should quote the above.

Studying long term trends, until 1988 there was no sign of any warming trend in the British Climate very much above what was experienced over the past three centuries. The warming process kicked in abruptly in January, February and March in the late 1980s, and a notable warming process kicked in for September around 1997. November joined the bandwagon of the warming trend around 1994, although there was a run of mild Novs in the early 1980s. May also joined the warming bandwagon around 1998. It does now look possible and quite likely that June also joined the bandwagon in 2003. July and August are less easy to pin down as to when they joined the warming trend, but there has been a general easing up since the late 1980s. All the above mentioned months have joined the warming bandwagon around 1988 or more recently, but December joined the warming trend earlier, around the early 1970s. After the unusually cold December decade of the 1960s had passed, there began a run of mild Decembers around the start of the 70s and this generally persisted through the 1970s and 1980s followed by a slight easing back since then. But you are right Kevin B, and I can certainly identify that October was the first month to ever join the warming trend, and this happened as early as the late 1950s. Before then sub 10*C Octobers occurred more often than half the time, and even 11+ Octobers were relatively rare; ever since the end of the 1950s sub 10*C Octobers have been the exception and not the norm like they were in the pre 1950 era.

The 1961-90 average actually included a cooler period in the British Climate especially in the 1960s, so today it is a rather out of date set of averages to compare more recent periods with. Look how many Julys and Augusts in the 1960s were cooler than the 61-90 average let alone the 71-00. Even after 1965 there was no July that could reasonably be described as "well below average" on the 61-90 scale. Julys 1978, 1980, and 1988 were 1.4*C below the 61-90 but were well below average by the 71-00 scale. The same is true of the Decembers of the 1960s, and look how many Decembers in the 1960s were much below the 61-90 average. There is also this truth in the Marches of the 1960s. Marches 1962, 1969 and 1970 were all notably cold, and colder than any March we have had since. After 1970 the only Marches more than 1*C below the 1961-90 average were 1987 and 1996. The rise between the average July, August and December CET from 61-90 to 71-00 is largely due to the number of below average months in the 60s rather than the warmth of the 90s, and to some extent the average March CET. Although the rise in the average CET for January and February is more due to the number of mild months in the 90s, as the Jans and Febs of the 60s were not especially cold overall apart from 1963. Before anyone mentions Feb 1969 being very cold there was also a very mild Feb that decade - 1961.

It is unusual about October in that although since and including 2001 we have had three Octobers with CETs of 13.0 or greater, and even Oct 1995 recorded 12.9, there was a run of average Octobers from 1997-2000 and indeed a run of average to cool Octobers from 2002-2004. So, although there have been four exceptionally above average Octobers in the past 12 years, and also Oct 1996 was pretty warm (11.7), the other seven were certainly not what you would call warm Octobers. September is what strikes the biggest warming trend for me. Although Sep 2006 was the warmest on record, and Sept 1999 almost made the exceptionally above average category (15.6, +1.9), four other Septs in the last 10 years were certainly in the warm category (14.9, 14.7, 14.9, 15.2). Since 1996 apart from Sept 2001 which was average to even very slightly below (13.4) there has not been any other September which has recorded anything close to average for the CET. Also, we have not had a below average May since 1996, and the only average May in the last 11 years was in 2005. The last 12 months have also been truly exceptional. Four of the last 12 months have been exceptionally above average (July, Sep, Oct 2006, Jan 2007), also June 2006 and Feb 2007 were certainly well above average. It is sickening to see that we have not had a below average month since March 2006, and not even a close to average month since last August.

Another warm month looks highly likely with a CET of around 9*C. Judging by the models, even at this very early stage with the 1st two days away, it is already difficult to see April developing into a cooler than average month.

Assuming March returns a CET of 7.2*C, (7.1 may be still just about possible), then we will have had the warmest first quarter of a year since 1998: Jan-Mar 2007: 6.73*C Jan-Mar 1998: 6.80*C Although the first quarter of 2002 was only marginally less mild than 2007: Jan-Mar 2002: 6.70*C The warmest first quarter of a year in the entire CET record was in 1990, with the Jan-Mar period averaging 7.37*C. So, looking at the above, the first quarter of this year has already put us on target for another very warm year, and it would certainly take a brave man to bet on the annual CET for 2007 being below 10*C, unless a number of cool months occurred during the rest of 2007, which by recent year's standards, looks highly unlikely. We may get one or maybe at the most two cooler than average months this year if we are lucky, but it is difficult to see it not being above average in most months again this year, and it is even already difficult at this stage to see the annual CET for 2007 not being around the 10.50 mark or above.