The "new normals" for 1991-2020 (CET) now updated through December

[B87]

6 hours ago, DAVID SNOW said:

I think its worth pointing out that London is not in the CET area.

Is London not in the SE corner of the CET area?

[DAVID SNOW]

4 hours ago, B87 said:

Is London not in the SE corner of the CET area?

No.

[B87]

17 minutes ago, DAVID SNOW said:

No.

"These daily and monthly temperatures are representative of a roughly triangular area of the United Kingdom enclosed by Lancashire, London and Bristol."

Where is it, then?

[snowray]

3 minutes ago, B87 said:

"These daily and monthly temperatures are representative of a roughly triangular area of the United Kingdom enclosed by Lancashire, London and Bristol."

Where is it, then?

I think it goes as far east as the Heathrow area.

[DAVID SNOW]

9 minutes ago, B87 said:

"These daily and monthly temperatures are representative of a roughly triangular area of the United Kingdom enclosed by Lancashire, London and Bristol."

Where is it, then?

Hertfordshire is the closest to London, then as you say west and north west.

[Roger J Smith]

I haven't updated the Jan value because there is no official January CET yet, but looks likely to edge into the lower reaches of 4.7, whether that's how they calculate it from their method remains to be seen. (for 6.3 the average will be close to 4.66). 

[Roger J Smith]

So the 1991-2020 normal values (averages) are likely to be Jan 4.7, Feb 4.9 and Mar 6.7 now that the data are in for those three months. My disclaimer is that I calculate them from the average of listed means, whereas I think the Met Office calculate them from their averages of mean max and mean min. None of these are close enough to the rounding point that I feel they might end up lower (in the first two cases they aren't going to end up higher as they are 4.66, 4.89 and 6.74, March could conceivably be given out as 6.8, we shall see). 

If April were to finish at 10.5, then its new normal would be on the borderline of 8.9 and 9.0, could be either depending on their calculations. If it went higher then more likely to be 9.0. 

[Don]

2 hours ago, Roger J Smith said:

So the 1991-2020 normal values (averages) are likely to be Jan 4.7, Feb 4.9 and Mar 6.7 now that the data are in for those three months. My disclaimer is that I calculate them from the average of listed means, whereas I think the Met Office calculate them from their averages of mean max and mean min. None of these are close enough to the rounding point that I feel they might end up lower (in the first two cases they aren't going to end up higher as they are 4.66, 4.89 and 6.74, March could conceivably be given out as 6.8, we shall see). 

If April were to finish at 10.5, then its new normal would be on the borderline of 8.9 and 9.0, could be either depending on their calculations. If it went higher then more likely to be 9.0. 

So, the first four months of the 1991-2020 averages have warmed approximately 1C compared to the 1961-1990 average.

[Thundery wintry showers]

Yes, January +0.9, February +1.1, March +1.0, and April either +1.0 or +1.1 depending on which side of 10.5 we finish on.

[damianslaw]

I think better to now compare to 91-20 average than 61-90 especially given the 1 degree rise. Makes many warmer than average months not quite as special.. no 3 degrees above average, more likely 1.5-2 degrees above average.  We did well last October to have a month a few tenths degree below 61-90 average, both it and November appreciably below 91-20 average .

Edited April 19, 2020 by damianslaw

[Thundery wintry showers]

One sobering fact: after the predominantly cold Februarys of 1978 to 1987, February 1988 stuck out for many at the time as a mild month, with a CET of 4.9 and, as the RMetS Weather Log noted, a marked absence of easterly winds unlike many previous Februarys (there were northerlies in the last third of the month, but not particularly potent ones).  But compared with the 1991-2020 normals, February '88 was very average temperature wise...  Also that whole winter quarter of 1987/88 was only about 0.4C above the 1991-2020 average, taking the December 1991-2019 figure of 5.0C.

Edited April 20, 2020 by Thundery wintry showers

[Don]

1 hour ago, Thundery wintry showers said:

But compared with the 1991-2020 normals, February '88 was very average temperature wise...  Also that whole winter quarter of 1987/88 was only about 0.4C above the 1991-2020 average, taking the December 1991-2019 figure of 5.0C.

Makes it even more of an eye opener really doesn’t it?!

[reef]

6 hours ago, Thundery wintry showers said:

One sobering fact: after the predominantly cold Februarys of 1978 to 1987, February 1988 stuck out for many at the time as a mild month, with a CET of 4.9 and, as the RMetS Weather Log noted, a marked absence of easterly winds unlike many previous Februarys (there were northerlies in the last third of the month, but not particularly potent ones).  But compared with the 1991-2020 normals, February '88 was very average temperature wise...  Also that whole winter quarter of 1987/88 was only about 0.4C above the 1991-2020 average, taking the December 1991-2019 figure of 5.0C.

I've always had the marker in my mind of a 'stinker' of a winter being anything above 6C. Its quite possible in 30 years or so that that sort of winter could be 'average', assuming the 2021-2050 mean increases by a similar amount.

How grim is that? We'd need a winter some 3.5C below average just to match 2009/10, never mind anything like 1962/63.

[Don]

1 hour ago, reef said:

I've always had the marker in my mind of a 'stinker' of a winter being anything above 6C. Its quite possible in 30 years or so that that sort of winter could be 'average', assuming the 2021-2050 mean increases by a similar amount

Horrible thought indeed but probably likely given the ongoing mean warming?

[cheeky_monkey]

strange that the UK cant buy a below average month these days..whilst here we cant get any above...only 2 in last 24 months have achieved it.

[B87]

4 minutes ago, cheeky_monkey said:

strange that the UK cant buy a below average month these days..whilst here we cant get any above...only 2 in last 24 months have achieved it.

October and November 2019 were the last below average months.

[cheeky_monkey]

Just now, B87 said:

October and November 2019 were the last below average months.

Jan 2019 and May 2018 were our last above average months here.

[Roger J Smith]

Where I am located, about 500 km southwest of CM, we have probably been above or below average in equal measures over the past two years. Feb 2019 was a particularly cold month in this region and may have been coldest February on record in some locations. We also had a very unusual cold spell at the end of September 2019 where it snowed in this area about a month ahead of the normal schedule. But this past winter was not that cold here, we seemed to get into the shallow outer layers of the prairie cold a few times but otherwise were in a transitional zone most of the time. The Pacific mild air mass generator has not been raging in recent years, just quietly pulsating. 

It has been notably warmer than average over most of the past two years in eastern North America with the conspicuous exception of Nov 2019 which was a very cold month, after UHI adjustment it was in the lowest 10% for Toronto going back into the generally colder 19th century data. That cold didn't last into December and the last four months have gone into the books around 10th to 30th warmest after adjustments. April so far has been rather cool in the eastern regions, especially this past week.

[cheeky_monkey]

15 hours ago, Roger J Smith said:

Where I am located, about 500 km southwest of CM, we have probably been above or below average in equal measures over the past two years. Feb 2019 was a particularly cold month in this region and may have been coldest February on record in some locations. We also had a very unusual cold spell at the end of September 2019 where it snowed in this area about a month ahead of the normal schedule. But this past winter was not that cold here, we seemed to get into the shallow outer layers of the prairie cold a few times but otherwise were in a transitional zone most of the time. The Pacific mild air mass generator has not been raging in recent years, just quietly pulsating. 

It has been notably warmer than average over most of the past two years in eastern North America with the conspicuous exception of Nov 2019 which was a very cold month, after UHI adjustment it was in the lowest 10% for Toronto going back into the generally colder 19th century data. That cold didn't last into December and the last four months have gone into the books around 10th to 30th warmest after adjustments. April so far has been rather cool in the eastern regions, especially this past week.

February 2019 was the third coldest on record here and the coldest since 1939..September 2019 wasn't too bad but Sept 2018 was the coldest on record with quite a lot of snow that fell between the 12th and the end of the month...summer 2019 was the worst for cold and rain i have seen on the prairies..hoping for a better summer this year.

[Roger J Smith]

The outcome for April 2020 (10.4) places my calculation just under the dividing line between 8.9 and 9.0 for the new April normal so I will say it's likely to be 8.9 but they might calculate it differently and arrive at 9.0. But the mean of means method gives 8.947. 

[reef]

5 hours ago, Roger J Smith said:

The outcome for April 2020 (10.4) places my calculation just under the dividing line between 8.9 and 9.0 for the new April normal so I will say it's likely to be 8.9 but they might calculate it differently and arrive at 9.0. But the mean of means method gives 8.947. 

The Metoffice tend to just use the average from the rounded monthly figures (e.g 10.4C for April 2020 rather than 10.42C) so the figure will be 8.95C rounded up to 9.0C.

[Don]

There we are.  The first four months of the 1991-2020 average are consistently 1C above the 1961-1990 average.

[Thundery wintry showers]

Aye, scary stuff, although looking at Roger J Smith's figures for 1991-2019, it would seem that the first four months of the year, along with November, have warmed the most relative to 1961-1990 (November 1991-2019 was 0.9C warmer).  None of the other months were more than 0.7C warmer than 1961-1990 over the period 1991-2019, and October and December were just 0.3C warmer.  May was 0.7C warmer, so we'd need an exceptionally warm, possibly record breaking, May to continue the sequence of months that have been warmer by 1C plus or minus 0.1C.

Edited May 3, 2020 by Thundery wintry showers

[Roger J Smith]

It would appear that July and August 1991-2020 means will be 0.1 higher than 1981-2010 (16.8 and 16.5). 

June went up 0.3 (to 14.7) as the 1980s were considerably cooler than the Junes of the 2011-20 decade. Despite that, June has been fractionally warmer in the past, although never rounding to anything higher than 14.7 (1822 to 1851 is actually the warmest in two decimals at 14.72). 

As explained in edited post number one where the data are being presented as they develop, my method is slightly different from the Met Office, who take mean max and mean min for the thirty years and average those to get a 30-year mean. My method is simply to average the thirty months in the period from the CET stats, which can lead to 0.1 deg differentials if my average is close to a dividing line. March and April were close to those dividers, but from May to August the months have come in fairly close to middle of the 0.1 range, so I have more confidence in these being the same values as we will hear when an official announcement is made. For March and April the lower of the two possible values is probably more likely (since my method will more often than not catch rounded up averages of max and min). 

August was going to need to finish almost 19.0 to get into the range of 16.6 as the new normal. July with any sort of warm performance would have finished 16.9 rather than 16.8. 

[North-Easterly Blast]

1 hour ago, Roger J Smith said:

It would appear that July and August 1991-2020 means will be 0.1 higher than 1981-2010 (16.8 and 16.5). 

June went up 0.3 (to 14.7) as the 1980s were considerably cooler than the Junes of the 2011-20 decade. Despite that, June has been fractionally warmer in the past, although never rounding to anything higher than 14.7 (1822 to 1851 is actually the warmest in two decimals at 14.72). 

As explained in edited post number one where the data are being presented as they develop, my method is slightly different from the Met Office, who take mean max and mean min for the thirty years and average those to get a 30-year mean. My method is simply to average the thirty months in the period from the CET stats, which can lead to 0.1 deg differentials if my average is close to a dividing line. March and April were close to those dividers, but from May to August the months have come in fairly close to middle of the 0.1 range, so I have more confidence in these being the same values as we will hear when an official announcement is made. For March and April the lower of the two possible values is probably more likely (since my method will more often than not catch rounded up averages of max and min). 

August was going to need to finish almost 19.0 to get into the range of 16.6 as the new normal. July with any sort of warm performance would have finished 16.9 rather than 16.8. 

I believe that the 1991-2020 July average is 16.79, and August 16.51.  1981-2010 July average is 16.71, and 1981-2010 August average is 16.41.  The cool August of 1986 alone dropping out of the recent 30 year dataset is responsible for most of the 0.1 increase for August.  July has generally been warm in the 2010s, although in the 1980s, 1983 saw a very warm July and 1989 was also pretty warm.  The only really cool July that has now dropped out of the recent 30 year dataset was 1988, although actually if you take July 1988 out of the 1981-2020 equation you have got 16.78.

Edited September 1, 2020 by North-Easterly Blast