July CET

[Spirit of 1740]

Hi Kold. :o

I am one of those philistines still using the 1961-90 averages as I believe that they represent a good benchmark for the pre-recent warming climate, whereas I think the 1971-2000 are a bit of a half-way house between the last 10 years' climate and that before the warming set-in. Anyway, that debate can run and run.

Therefore, by the 61-90 averages, July 2007 was colder than March 2006. However, I accept your point on December 2001, so just 3rd coldest since Jan 97 then. The one thing on that, though, is that the cold of that month was focussed on the CET area (the METO areal series were not as cold) whereas with this month I expect the CET value to be fully reflected in the more extensive series.

Edited August 1, 2007 by Spirit of 1740

[SP1986]

I think what we've seen this month is a reverse extremity of what happened in 2003/2006 but in the cooler bracket. I don't think we are going to see too many of these below average figures - especially not more than 1C below average again for a while.

So I think we will soon return to normality. However if it didnt, then I'd be questioning our patterns of weather, and potentially would certainly be a case for challenging global warming if a string of moderately/significantly below average months did occur.

[Weather-history]

If it is confirmed as 15.2, its the joint 84th coolest July on record.

Its been a while since we had a month in the top 100 coolest in the rankings, March 2006 wasn't, neither was October 2003. I think December 1996 was the last one to be in the top 100 coolest for its month. (joint 77th)

[Spirit of 1740]

The patterns weren't especially cold this month, I believe, particularly in terms of circulation and the amount of sunshine. Therefore, I believe that a July CET of 14c, as recorded in 1965, could still be possible today.

[Duncan McAlister]

If it is confirmed as 15.2, its the joint 84th coolest July on record.

Its been a while since we had a month in the top 100 coolest in the rankings, March 2006 wasn't, neither was October 2003. I think December 1996 was the last one to be in the top 100 coolest for its month. (joint 77th)

Although this wouldn't have been unusual in the past, it certainly is incredible given the trend since last July, and I'd never have expected July of all months to have been so anomalously cold.

Also, have a look at the Januarys of a similar rank

http://hadobs.metoffice.com/hadcet/mly_cet_mean_sort.txt

Edited August 1, 2007 by Duncan McAlister

[Stu_London]

Although this wouldn't have been unusual in the past, it certainly is incredible given the trend since last July, and I'd never have expected July of all months to have been so anomalously cold.

Also, have a look at the Januarys of a similar rank

http://hadobs.metoffice.com/hadcet/mly_cet_mean_sort.txt

A run of tp 100 cool months through the winter would have this place going bananas! :o

[kold weather]

Maybe Spirit but we shouldn't underestimate the effect of having a compeltely saturated soil, lest us forget that May-July has easily been the wettest such period since the rainfall racords started and therefore had the soil not been so wet I think we'd have recorded a CEt probably a little higher, say 15.7C or something like that, because you right the synoptics weren't amazingly cold though it should be noted that it was a month dominated by low pressure, the mean max was way below normal backs this up and we did have quite a lot of NW airflows in the first 15 days of the month.

The most impressive thing is this very below average month has come on the back of the warmest 12 month period ever---that is the more re-assuring thing IMO.

[Duncan McAlister]

Saturated soil, LP and still managed below average minima, Kold

Edited August 1, 2007 by Duncan McAlister

[Spirit of 1740]

Kold - I'd go along with you to the extent that I believe that June did the groundwork for July by hauling down the SSTs. Soil moisture may also have played a role too, I admit, though remember that wet soils hold up night time minima. :o

If SSTs were lower at the outset of a hypothetical future summer, then I believe it wouldn't require May and June to be so wet in order to deliver a similar or even cooler July.

Edited August 1, 2007 by Spirit of 1740

[karyo]

The most impressive thing is this very below average month has come on the back of the warmest 12 month period ever---that is the more re-assuring thing IMO.

I am delighted to see a below average July. From April 2006 till April 2007, it felt like a significant event to get a below average day never mind month!

Let's just hope that it won't take us another year to achieve a below average month.

Karyo

Edited August 1, 2007 by karyo

[Weather-history]

The most impressive thing is this very below average month has come on the back of the warmest 12 month period ever---that is the more re-assuring thing IMO.

I said a while back that there could be some sort of crash. November 1994-October 1995 was the warmest 12 month period until now and that then was followed by a crash with December 1995 being well below average, infact there were notable cool periods right through until January 1997.

Might not happen again this time to that extent but a crash has happened in a way with this July.

Edited August 1, 2007 by Mr_Data

[Eugene]

I too am delighted about the negative CET figure for July. I said much earlier in the summer of hoping for a 1968 re-run (albeit expecting a significantly warmer version). It hasn't in the end actually been too far off the mark from the original The flooding has not been a good factor though by any means.

The best aspect of the July CET figure though is that perspective on what is still achievable in terms of cold anamoly has finally been illustrated - despite many proclamations of doubt.

August still to play for - the form card would suggest an immediate bounce back to above average. But just maybe not!...

Tamara

Yes if it wasn't for all the rain and dull conditions even a cold CET in July can be pleasant, let's hope for the same kind of negative CET anamoly in a winter month in the near future

[cirrusstratus]

Surely you have have to look at average maxima and minima given the well above average rainfall which was always likely to raise the minima temperatures. Based on the Met office data the average maxima from 2004 to 2006 for June were 1.6, 1.7 and 2.6 above average, but just 0.6 this year. In terms of recent years that is a crash.

Edited August 1, 2007 by cirrusstratus

[Weather-history]

The second half of July was cooler than the first half of June and the last occasion that happened was 1982

[Optimus Prime]

June and July have a collective anomaly of 0.0c relative to the 1961-90 average.

The combined June/July period is actually 0.05c above the 61-90 average

But 0.15c below the 71-000 average.

[Spirit of 1740]

The combined June/July period is actually 0.05c above the 61-90 average

But 0.15c below the 71-000 average.

Not sure we are looking at the same data, but on Hadley the June figure is 15.1c, 0.9c above the 61-90 average of 14.2c whilst July was 15.2c, 0.9c below the 61-90 average of 16.1c.

http://hadobs.metoffice.com/hadcet/cetml1659on.dat

[Optimus Prime]

Yeah but you forgot the decimal place.

1961-1990 average is;

June; 14.2c

July; 16.0c

Average; 15.1c

June came in at 15.1c

July; 15.2c

Average; 15.15c

[North-Easterly Blast]

The July 2007 Hadley CET was actually 15.23*C, or 15.2 rounded down. July 1993 was exactly 15.20*C. So July 2007 is actually the coolest since 1993, not quite the joint coolest since 1988 with 1993.

[J10]

The cooler than average July caught out many of the entrants with no correct entry, closest were :-

Jim AFCB 15.5c (0.2c Out)

noggin 15.6c (0.3c Out) and

Snowyowl9 15.7c (0.4c Out)

In the Overall Competition Bottesford remains in the lead despite no entry in July, Cheeky Monkey rises from 13th to 2nd and John Acc finishes the top 3 (from 2nd).

In the seasonal competition, Snowyowl9 leads narrowly from Beng in 2nd with The underwriter in 3rd.

Overall Scores

JulyScores

July CET Spreadsheet

[Spirit of 1740]

Yeah but you forgot the decimal place.

1961-1990 average is;

June; 14.2c

July; 16.0c

Average; 15.1c

June came in at 15.1c

July; 15.2c

Average; 15.15c

Hi Optimus - the July average is 16.1c rather than 16.0c. You can check this using the data if you wish to do so. Therefore, the anomaly is 0.0c.

The July 2007 Hadley CET was actually 15.23*C, or 15.2 rounded down. July 1993 was exactly 15.20*C. So July 2007 is actually the coolest since 1993, not quite the joint coolest since 1988 with 1993.

North-Easterly - Not sure you are right there actually. Do you have the source? The reason I say this is that it is ranked above 1993 in the METO 'cold' month rankings:

http://hadobs.metoffice.com/hadcet/mly_cet_mean_sort.txt

84th place 2007, 95th place 1993. A higher ranking denotes a colder month.

[damianslaw]

Despite the attrocious wet conditions and persistant cloudy dull weather, I am overjoyed at the below average CET and not just below but comfortably below at that.

It has restored my faith in the hope that we can record some future below CET's in coming months and the upward trend of above average had not become set in stone.

It certainly makes for an interesting 5 year period of July's, 3 of which have been considerably above average and 2 comfortably below none very near average..

Extremity is the new word..

[Spirit of 1740]

One more stat on the Hadley figure - 11th coolest of the last 85 years. Only 1940, 1954, 1960, 1962, 1965, 1966, 1968, 1978, 1980 and 1988 were colder. Half of those were only 0.1-0.2c cooler.

Were a January to replicate that ranking, the associated CET would be 1.7-2.2c.

Edited August 1, 2007 by Spirit of 1740

[noggin]

The cooler than average July caught out many of the entrants with no correct entry, closest were :-

Jim AFCB 15.5c (0.2c Out)

noggin 15.6c (0.3c Out) and

Snowyowl9 15.7c (0.4c Out)

Well, I'm jolly pleased with my effort for July and congrats to Jim AFCB and Snowyowl.

[Don]

I'm very pleased that we've had a below average month of almost 1C below the 1961-90 average, let alone the 1971-2000 average. Lets have a few more of these come December, January and February!

[Stratos Ferric]

What an extraordinary stat Kevin.

I'm not a proper statitician, actually I'm not any kind of statitician, but doesn't that suggest that the July average is in some ways suspect? The implication is that it has a wider spread above and below of any other month proportionately, and that the average might be pulled by some rank hot outliers? Anyone able to tabulate that into a clever graph? Or is that nonsense? Mr Data? Stratos Ferric?

Just to test that, could we have the July average for the last 40 years without the 5 highest and 5 lowest months included? Just wondering ...

Applying chi squared suggests that in that set of data there is NO significant variation in the frequency of below average months. Had there been 7 cool Julys then there would be cause, at the 95% confidence level, to suggest something anomalous about this month of the year. The derived confidence level at which this data seems "suspicious" is around 82%. To the layman this might seem compelling, but in strict statistical terms this is just at the level of "noise".