HadCET has 17.95C for the 1st 8 days of this month as provisional data

When I analysed my Access DB for daily CET Mean I got some higher ones for Sept1-8

2005 17.96

1999 17.98

1795 18.01

1898 18.35

1906 18.68

(Haven't desk checked them though !)

But this last week has been up there (but if you look at the September predictions you might see why I have not quite treated it like the pleasant surprise it is )

I think my maths, eyesight or ability to read have gone Martin (or more probably, all three!)

Edit: just looked at 1906 again and realised I was scanning down the August column in Hadley- it was a near but not quite! Need to go back now as I think I may have done that for the others. Double

Met Office Hadley       18.1c     Anomaly       3.6c provisional to 9th

Metcheck                    17.21c   Anomaly       3.49c

Netweather                 17.99c   Anomaly       4.3c

Peasedown St John    17.52c   Anomaly       3.24c.  

Looking like a 16c+ CET is pretty much nailed on now.

I believe you are right Caz- although the usual adjustment will no doubt knock half a degree off. Last night continued the run of warm nights- a 3rd consecutive with a min > 16C so we might still be around the 18C mark- I'll check Art's update later. But we're not at half month yet and after the model swing at month's start, I wouldn't be surprised at anything!

Gosh, CET actually went UP another 0.1C yesterday! 

I really am starting to wonder if a new record 17C CET September could be possible?

Would love an update from our guru GW soon! 

To do that would take some meaty hot days in the last week of the month. Don't forget that by the 21st we're in the autumn solstice and the days are drawing in at quite a rate.

Met Ofice Hadley        18.2c       Anomaly      3.7c  provisional to 10th

Metcheck                    17.32c     Anomaly      3.60c

Netweather                 18.05c     Anomaly      4.36c

Peasedown St John    17.53c     Anomaly      3.27c.       

Provisional CET for 1st-10th was right up against the record high for the period (1898): https://twitter.com/peacockreports/status/1436777893766569988

Actual is probably two or three tenths lower, mind.

Still, this is proving to be a staggeringly warm month. Far more so than the models were indicating as of August's end. Good of GW to apply penalties for entries after 1st. Even on 1st there was arguably some advantage so I wish I'd held on now!

Anyway, a curious feature of this month has been GFS periodically producing a batch of runs featuring extraordinary warm spells. The 06z of today went full late Sep 2011 on us, while the 12z is more laidback but, through sheer persistence of very warm days and mild nights, gives an even higher CET estimate to 27th (dashed line on the 2nd graph in the tweet).

Usually I'd toss them aside as crazed ravings, but here's the thing - GFS spotted the big plume of early this week ahead of all the other models. Not consistently, by any means, but then, it's not being consistent this time around either.

So maybe it's onto something.

There is one key difference, though. Before this week's hot spell, ECM was bringing changeable westerlies. Currently, it has an increasingly cool easterly (from a warm starting position in the middle of next week). So, if GFS' last success was bias-related, it might not enjoy such good fortune this time.

I have a bit of a conflict of mind on the matter. On the one hand, I could do with the CET coming right down to my prediction for obvious reasons. On the other, I enjoy exceptional warmth a great deal when it happens in spring or autumn, especially March-April or September-October. I'm also a big fan of impressive monthly stats. The warmest September for over 100 years, let alone on record, would be amazing to reflect on.

Just like to say that my prediction on 31st August was purely and totally based on nothing other than a funny feeling- it just got lucky, equal to the many unlucky ones previously!

Met Office Hadley        18.2c       Anomaly     3.7c provisional to 11th

Metcheck                     17.2c       Anomaly      3.48c

Netweather                  18.04c     Anomaly      4.35c

Peasedown St John     17.17c     Anomaly      2.59c.  

We do need to be cautious about assuming a 16C+ is nailed on for September. Even with this notable 18.2C to 11th, we still need 14.8 daily for the rest of the month to secure a 16. That is based on current HadCET reporting back, which of course is some way above what tends to happen. I do hope these regular, nay, constant downjustments are not just designed to cover up warming. Luckily GW is able to track closer to the truth as the month moves on.

How do you mean 'you hope these regular, nay, constant downjustments are not just designed to cover up warming'? Are you suggesting they are fiddling the data?

As for the 16c+ I agree that it is by no means are guarantee and I suspect the current 18.2c could be running at least 0.5c above the actual so far, but will see what GW says.

If I remember correctly there is a -0.2C adjustment made each month to allow for increasd urbanisation of the sites. Not a "cover up" but a way of getting consistency across the whole series going back into the Manley data from 1659

No- apologies to you and Taylor & anyone else- I should have posted a smiley; it was intended lightly. I certainly wasn't hijacking this brilliant thread with a climate agenda!

Soz.

Met Office Hadley       17.9c       Anomaly      3.5c provisional to 12th

Metcheck                    17.01c     Anomaly       3.28c

Netweather                 17.82c     Anomaly       4.13c

Peasedown St John     17.17c    Anomaly     2.89c.

Thanks ART! 

The decline has begun! Wonder where it will end up?

A Sepetmber CET in excess of 17C would be amazing. A September CET in excess of 18C would be truly amazing.

But look at December 2015 - A CET in excess of 9.0C Now that was incredible.

So these days anything is possible.

The next couple of weeks seem to look pretty stable in terms of max & min temps, with almost all days looking like having a CET of between 13c and 15c. If the rest of the month averaged about 14c, we'd be looking at a final figure of 15.5c - 16c (depending on downward adjustments).

I'm pretty confident this will be the case - barring any crazily anomalous spell not currently showing

This evening, the GFS Ens mean line is mostly > a degree above the black line, sometimes as high as +3 and only  reaching +0 on about two occasions.  This should give CETs at the higher end of your estimate.

I continue to be baffled by the black line- start and end of run just about the same, despite two weeks of autumnal onset. 

Met Office Hadley       17.7c     Anomaly      3.4c provisional to 13th

Metcheck                    16.89c   Anomaly      3.17c

Netweather                 17.67c   Anomaly      3.98c

Peasedown St John    17.92c   Anomaly     2.74c.