September CET!

[PersianPaladin]

A sub 14c September, after whats gone before, is going to be pretty darn amazing. The coldest September since 2001, and as it'll be within a couple of tenths of average, it'll be classed as an "average" September!

Another indication that since May, we seem to have entered a rather differant temperature set-up (for now)

I just see it as nature's way of balancing out the excessive anamolously above-average run of months we had from last year up to April.

Its not amazing. Its to be expected...more or less.

Edited September 29, 2007 by PersianPaladin

[Gavin P]

I was refering to amazing in context of whats gone before in Septembers 02-06.

This September has definatly been a trend-bucker.

Edited September 29, 2007 by Gavin P

[SP1986]

I was refering to amazing in context of whats gone before in Septembers 02-06.

This September has definatly been a trend-bucker.

To imply its a trend bucker suggests that future months following this September will not for a while produce another well above average month - not something I'd like to bet money on

It was bound to happen at some stage - it went so far up and had to come back down, before it will go back up, thats the way I see it anyway

[PersianPaladin]

To imply its a trend bucker suggests that future months following this September will not for a while produce another well above average month - not something I'd like to bet money on

It was bound to happen at some stage - it went so far up and had to come back down, before it will go back up, thats the way I see it anyway

Up, down, up, down. But the general trend is upwards.

[Gavin P]

I mean a trend bucker in the context of September, Stephen. I'm not making a point about whats going to happen in October, November, etc... Just making a point that we've had an incredible run of warm Septembers, and theres no getting away from the fact that this September has bucked that trend.

Edited September 29, 2007 by Gavin P

[Stratos Ferric]

That's fair enough SF - stringent indeed. But to be fair I wasn't asking for you to test whether the modern climate was a blip. That would be to deny the evidence of the last 50+ years. I'm certainly not going down that route, nor am I denying GW has been happening. What I was asking you was what it would take to make you begin to question whether the accelerated warming shows signs of slowing or even is beginning to go the other way i.e. reached its peak ? I've put that in bold not to shout, but to highlight the different issue.

p.s. The other below was that run from late 2005 to spring 2006.

Accelerated warming was never likely to last, and a short-term correction of some kind would be needed ASSUMING that there is no real variation in the long term trend. We keep saying it over and ovver but the message never seems to land, or at least isn't understood in some places: a warming climate does NOT require that each and every month be a warm month.

[SP1986]

I mean a trend bucker in the context of September, Stephen. I'm not making a point about whats going to happen in October, November, etc... Just making a point that we've had an incredible run of warm Septembers, and theres no getting away from the fact that this September has bucked that trend.

Sorry, I genuinely though you meant as a longer term solution. My apologies

[Glacier Point]

A sub 14c September, after whats gone before, is going to be pretty darn amazing. The coldest September since 2001, and as it'll be within a couple of tenths of average, it'll be classed as an "average" September!

Another indication that since May, we seem to have entered a rather differant temperature set-up (for now)

I think the interest here is that the warming trend of the 2000s has been most focused on Septembers and to a lesser extent Octobers. If there was a month you could gurantee warmth, September was IT. It shouldn't be a surprise that a coolish Summer relative to recent years has resulted in a coolish September.

[Nick F]

Thanks. I think the whole post was a bit out of line, but I'm not going to complain. I'd rather leave it up there - it doesn't refect very well on someone who is supposed to be senior on this forum

From West is Best.

WIB I hope you don't mean me dear boy, as your refer to Nick H as senior on the forum in regards to his comments? I'm Nick F not H? Nowt to do with me, get those specs on! :blush:

[West is Best]

I'm Nick F not H? Nowt to do with me, get those specs on!

Oops ! Sorry, but I'm also relieved.

Pretty chilly out there at the moment: single figures pretty much throughout the zone so this should clinch us going sub-14C!

[West is Best]

Manley 14.0C to 29th. After tonights minima it will certainly dip below 14C now. It's decidedly cold in the CET zone tonight with temps at 2 am ranging 4C to 9C. A further CET fall is therefore inevitable before the close, regardless of maxes getting well into the teens today. Manley should finish exactly on 13.9C.

It'll be interesting to see how the real Hadley figure relates to the Hadobs this month.

[West is Best]

Although 13.9C is the likeliest final Manley CET figure, the minima were so low last night that it is just possible it can fall to 13.8C. It depends on the maxima today but by my calculations if the CET maxima are around 14C or 15C (average) it will just about send the CET to 13.8C rather than the more likely 13.9C.

Either way the month is definitely sub-14C, and I'll post some thoughts on that 'ere long!

Edited September 30, 2007 by West is Best

[SP1986]

I may have to accept that the 14.0 bar that I suggested is about to fall, but I geneuinely didnt see last nights temps being as low as they were. By the way, whats the official stance on the average CET, its 13.4C isnt it I think? In which case the CET will end up around 0.1 to 0.2 above average. In that case we have a cool September, and I would have expected a below average so Im a bit surprised at the figure.

[West is Best]

Stephen it's 13.7C. But for those who use the old cold mean (61-90) it's 13.6C.

Yes the minima in the CET last night were 3C to 6C. Nippy!

[Weather-history]

0.3C below the 1961-1990 average over a 3 month period is substantial relative to recent performance would you not agree Kevin?

Has it been notably cooler compared to recent such periods? Yes

Is it substantially below the 1961-90 average? No

[West is Best]

Hi Kevin - fair enough, always a problem using qualitative words for quantitative date. How does this second half of September compare to recent and past Septembers?

[Weather-history]

. How does this second half of September compare to recent and past Septembers?

Probably, the coolest second half since 1994. Depends on yesterday and todays' value

[Roger J Smith]

I was looking through the daily CET figures from 1772 to present, and the coldest September day I could find was 6.8 which occurred on the 29th in 1829. But on 2-3 October 1817 it was 3.6 and 4.7, so that would seem to be the absolute coldest it can be at this time of year.

On the other hand, in 1908 they were enjoying quite a heat wave, the daily CET values were near 20 for several days.

And before I forget, there was an interesting almost-month of cold in 1991, from 23 January to 19 February, which is the same length as February, the mean for that 28-day period was -0.1 C, so months aren't everything I guess you could say.

[Weather-history]

I was looking through the daily CET figures from 1772 to present, and the coldest September day I could find was 6.8 which occurred on the 29th in 1829.

4.9C on the 28th September 1824.

[West is Best]

With sub-14C for Manley now pretty likely, I had a look back through this thread and it seems to me to provide salient warnings about the dangers of 1. being too assertive in LRFing and 2. trying to guess what will happen more than a week away. I'll add a third more debatable point down below.

I'm not going to paste in comments here, afterall I've been staggeringly inaccurate this past 'summer'. But the fact that Manley is about to come in below 14C when this was widely derided (even described as nonsense, little or no chance, absolute dross etc.) ought to caution us in future.

The third point I want to add is to caution those who assume GW will be the main warm driver in a given month. Sometimes you'll come a cropper. I did in winter 2005/6 and another warm protagonist has come a cropper this month if you look at the comments made by that person through this thread. Regardless of whether you believe the world is getting warmer and driving the CET ever upwards, failing to see the synoptic possibilities for much cooler interludes is a trap that it's only too easy to fall into.

A good learning month for us all!

[Stu_London]

With sub-14C for Manley now pretty likely, I had a look back through this thread and it seems to me to provide salient warnings about the dangers of 1. being too assertive in LRFing and 2. trying to guess what will happen more than a week away. I'll add a third more debatable point down below.

I'm not going to paste in comments here, afterall I've been staggeringly inaccurate this past 'summer'. But the fact that Manley is about to come in below 14C when this was widely derided (even described as nonsense, little or no chance, absolute dross etc.) ought to caution us in future.

The third point I want to add is to caution those who assume GW will be the main warm driver in a given month. Sometimes you'll come a cropper. I did in winter 2005/6 and another warm protagonist has come a cropper this month if you look at the comments made by that person through this thread. Regardless of whether you believe the world is getting warmer and driving the CET ever upwards, failing to see the synoptic possibilities for much cooler interludes is a trap that it's only too easy to fall into.

A good learning month for us all!

Congratuations on sticking to your guns on this one. It has coincided with the model output doing the same (i.e. no downgrading, backtracking etc), something that is notable. Not sure how they will verify overall, but the trends and themes have proved correct. Maybe there is hope for improved performance through the winter, when they struggle most.

[West is Best]

Congratuations on sticking to your guns on this one. It has coincided with the model output doing the same (i.e. no downgrading, backtracking etc), something that is notable. Not sure how they will verify overall, but the trends and themes have proved correct. Maybe there is hope for improved performance through the winter, when they struggle most.

Thanks Stu. You've been notably modest about your own achievement: you called 14.2C before the month began and you're going to be very close to that.

It's not yet done and dusted that Hadley won't nip below 14C. Hadobs has updated to 14.1C as of yesterday and with last night's mins and the fact that Hadobs has been higher than the official Hadley figure the past two months it's a real possibility it might also nip below 14C.

[Optimus Prime]

My review for September;

A fairly sunny and very dry month overall and quite similar to August in being, minima was generally fairly low while maxima was comparatively warmer to the averages. The first half was very warm, sunny and very dry (no rain recorded at all) The warmest spell was from the 1st-7th with temperatures around or above 20c. The highest being 24.6c on the 7th and sunny which was the highest temperature of the month and followed an exceptionally high Minima of 16.2c giving a remarkably high daily temperature of 20.4c (and was the highest 24 hour temperature of either July or August!) and so easily the best day of the extended "summer". From the 8th it turned progressively cooler with cold nights but days remained well above normal.

From the 15th it was almost always cool with maxima never rising to 20c or above and minima generally into single figures. It was also a wetter period with rain falling on 5 days compared to 0 before the 15th. The 27th was very cold with Minima dropping to 5.5c and Maxima of 13.3c. The remaining last few days were slightly warmer but duller. Temperatures were overall, very slightly colder than normal. Mean maxima almost exactly equal to the 61-90 average while minima well below.

First half;

Max; 21.4c (+2.4c)

Min; 10.82c (-0.18c)

Mean; 16.1c (+1.1c)

Second Half;

Max; 16.6c (-2.4c)

Min; 9.73c (-1.27c)

Mean; 13.16c (-1.84c)

Mean temperature (61-90 average);

Max; 19.0c (+-0.0c)

Minimum; 10.27c (-0.73c)

14.63c (-0.37c)

Graph (The anomolay throughout the month);

[The PIT]

Well last night the skies did clear and we got our first ground frost. Still won't stop us getting an above average month.

Anyway back to CET zone and it looks like I'll just miss out on my 14.1C guess earlier on this month. Boo Boo.

[Mammatus]

With sub-14C for Manley now pretty likely, I had a look back through this thread and it seems to me to provide salient warnings about the dangers of 1. being too assertive in LRFing and 2. trying to guess what will happen more than a week away. I'll add a third more debatable point down below.

I'm not going to paste in comments here, afterall I've been staggeringly inaccurate this past 'summer'. But the fact that Manley is about to come in below 14C when this was widely derided (even described as nonsense, little or no chance, absolute dross etc.) ought to caution us in future.

The third point I want to add is to caution those who assume GW will be the main warm driver in a given month. Sometimes you'll come a cropper. I did in winter 2005/6 and another warm protagonist has come a cropper this month if you look at the comments made by that person through this thread. Regardless of whether you believe the world is getting warmer and driving the CET ever upwards, failing to see the synoptic possibilities for much cooler interludes is a trap that it's only too easy to fall into.

A good learning month for us all!

I'd also like to congratulate you Richard. Two weeks ago you said sub 14C was possible which I completely disagreed with at the time. Well looks like your very near the mark on this one.

Well last night the skies did clear and we got our first ground frost. Still won't stop us getting an above average month.

Anyway back to CET zone and it looks like I'll just miss out on my 14.1C guess earlier on this month. Boo Boo.

You won't be far away The PIT, very good guess. My guestimate was far to warm.

Mammatus