I'm actually slightly confused what locations are currently used for the Hadley CET. I thought it was Rothamsted, Pershore and Stonyhurst but the Met Office website also mentions Malvern and Squires Gate (is that the one up in Blackpool?). 

I live just a few miles from Rothamsted and I can vouch for the fact that it is significantly cooler than even St Albans. It is a semi-rural location on the outskirts of Harpenden. I regularly cycle past the location on my way to work and in the winter, the drop in temperature as I approach that location is often stark (especially in clear, calm mornings). Daytime maxima are typically 1C lower than here too. Stonyhurst appears to be surrounded by industrial freezer units as it is often the coolest location in that area, frequently cooler than other locations at a lower altitude. Pershore also tends to have very cool night minima. During July it had 4 nights with minima below 6C! 

Furthermore, in a westerly or north westerly regime, the western location bias comes into play too. Even more so if Squires Gate is being used.

So, I'm not really sure how representative it is of 'Central England' but it is a relatively consistent data set that can be used for data comparisons. 

I think Stonyhurst is pretty much Squires gate in the regional scale but the latter is pretty coastal- maybe it's an average of the coastal and slightly more inland and higher elevation sites, though I'm not sure what that's for. Pershore is pretty much Malvern (I think a little over 10km apart?). Whilst the triangle is representative of Central England, two of its stations (Pershore: contestable) are not in Central England. In fact, Stonyhurst is NW, Rothamsted SE. It's like the mean line in GEFS: equally polar opposites will make it average!

 

I think Stonyhurst is pretty much Squires gate in the regional scale but the latter is pretty coastal- maybe it's an average of the coastal and slightly more inland and higher elevation sites, though I'm not sure what that's for. Pershore is pretty much Malvern (I think a little over 10km apart?). Whilst the triangle is representative of Central England, two of its stations (Pershore: contestable) are not in Central England. In fact, Stonyhurst is NW, Rothamsted SE. It's like the mean line in GEFS: equally polar opposites will make it average!

I thought that was the whole point of the CET area, the statons around the perimeter, defining the perimeter aren't really in central England proper at all. The average of the 3 is meant to represent the area within the perimeter as defined.

 

I thought that was the whole point of the CET area, the stations around the perimeter, defining the perimeter aren't really in central England proper at all. The average of the 3 is meant to represent the area within the perimeter as defined.

I get that, but for 'Central' England, a smaller periphery would make more sense. The Lancashire coast can't be representative of C England- NW England is anomalously wet, for example, and whilst we're not talking about ppn here, the causal weather conditions will have an impact on temperatures.

An early definition of why CET was significant was related to places 'being remote from the influence of the sea'.

Manley's 1953 abstract talked about it being 'representative of the English Midlands.'

It is oft-quoted as being useful as 'the longest-running series...' but actually the locations used have changed so many times that this is questionable.

Locations were historically selected partly for their own individual longevity- understandable when you consider the sparsity of information available from the late 17th century.

I’m not going to get drawn into a debate on the merits of the CET series.

I will confirm that the stations currently used to calculate the CET are:

Stonyhurst

Rothamsted

Pershore College (not Pershore)

Met Office Hadley        16.1c         Anomaly   -0.0c. Provisional to 5th.

Metcheck                     16.85c       Anomaly   0.62c

Netweather                  17.14c       Anomaly   0.95c

Peasedown St John     16.12c      Anomaly    -0.26c.     

Met Office Hadley        16.1c         Anomaly   -0.0c. Provisional to 5th.

Metcheck                     16.85c       Anomaly   0.62c

Netweather                  17.14c       Anomaly   0.95c

Peasedown St John     16.12c      Anomaly    -0.26c.     

The long rise commences...

Hmm, okay, I'm getting a little concerned now!

A trend to prolong the heat and extend it further northwest during the middle part of next week is sending CET estimates soaring. Going by the GFS 06z, it could well be in touching distance of 20°C around 13th or 14th.

That particular run doesn't even cool off much after the heat departs - pleasantly warm, then warmer again to end. That last part is against teleconnection-based expectations but if it did happen, would probably lead to a final CET in the 18s °C.

Even if it does cool off markedly, a finish below the 17s is starting to look hard to come by. It's going to happen to me isn't it - too little heat by far last month, too much this month .

Down where I am, the outlook is even more sweat-inducing. GFS 06z has the local mean climbing through the 19s this weekend, 20s Mon-Wed, 21s Thu-Fri! It's the hottest run so far, so hopefully overdoing it... but trend of the past 24 hours is a bit scary!

Hmm, okay, I'm getting a little concerned now!

I'm far from worried.

A slip up in the competition is a very small price to pay for having a very unusual taste of the Mediterranean for one full week. 

The 6z suggests hot sunny days followed by thunderstorms every evening and night for 4 consecutive days. 

Love it !

Always good to have such blazing bright silver linings eh Gusty? 

Interesting to contemplate the effect of the layout of the CET stations on the response to this heatwave - I seem to recall that there's a bit of a western skew, while the Lancashire station is a fair way northward. So, the CET is likely to see relatively little impact. Still a fair bit, but not nearly as much as it would be if the heat was reaching all the way up to the northwest of England.

Latest August CET tracker.

CET estimate of 18.87C by 21 August having risen above 19C before that.

Could be looking at the warmest August since at least 2003 and possibly 1997.

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Met Office Hadley          16.7c       Anomaly        0.7cc Provisional to 6th.

Metcheck                       17.38c     Anomaly        1.16c

Netweather                    17.72c     Anomaly        1.53c

Peasedown St John      16.35c      Anomaly        -0.03c.

Latest August CET tracker.

CET estimate of 18.87C by 21 August having risen above 19C before that.

Could be looking at the warmest August since at least 2003 and possibly 1997.

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Chart1

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Chart2

Thanks GW. A nice, solid 18.0 and the hottest August since 2003 would be perfect for my summer forecast! 

Well, that is concerning. Going to take an impressive contrast for the final third of the month to bring the CET back into the 16s! 

Not that I'm ruling such a thing out. There is a La Nina out there, after all. I think we'll see our weather change markedly in tandem with the beginning of a ferocious period of Atlantic tropical cyclone activity, as a strong tropical wave (MJO) propagates across the tropical Atlantic starting about a dozen days from now.

Well, that is concerning. Going to take an impressive contrast for the final third of the month to bring the CET back into the 16s! 

Not that I'm ruling such a thing out. There is a La Nina out there, after all. I think we'll see our weather change markedly in tandem with the beginning of a ferocious period of Atlantic tropical cyclone activity, as a strong tropical wave (MJO) propagates across the tropical Atlantic starting about a dozen days from now.

Plenty of time for a low 16's finish. 

Get an area of high pressure to the west of Ireland, close enough to give clear cool light NW'ly nights but far enough away to allow daytime convective infill to inhibit max temperatures, combine this with the natural decline after 22nd August and bingo...there you have it !

That's the theory anyway 

 

Plenty of time for a low 16's finish. 

Get an area of high pressure to the west of Ireland, close enough to give clear cool light NW'ly nights but far enough away to allow daytime convective infill to inhibit max temperatures, combine this with the natural decline after 22nd August and bingo...there you have it !

That's the theory anyway 

You mean like a rerun of July then? 

Looking forward to today's CET reading.

The all time record of 25.2 has been hit twice including July last year- 25.2C.

But the August record from 1995 is a tad lower at 24.9. Might there be some challenge to this, this week?

Looking forward to today's CET reading.

The all time record of 25.2 has been hit twice including July last year- 25.2C.

But the August record from 1995 is a tad lower at 24.9. Might there be some challenge to this, this week?

Unfortunately I think the SE focused nature of this heatwave means the CET won’t get close to troubling the record books. Nothing special in Worcestershire, and bog standard in Lancashire. Even Rothamsted park is on the wrong side of the Chilterns for the hot stuff. Hoping we’ll at least see some impressive daily increases though.

Met Office Hadley         17.5c        Anomaly        1.5c. Provisional to 7th.

Metcheck                      18.20c      Anomaly        1.98c

Netweather                   18.48c      Anomaly        2.29c

Peasedown St John      16.97c      Anomaly        0.59c.    

GFS 12z shows the transition to an 'early autumn' that I've been anticipating to occur by the final third of the month.

Doesn't hammer the CET though - it drifts gently down from the mid-19s as of 17th to the low 18s as of 23rd, going by my rough estimation. If the rest of the month was then average, the finish would be in the mid-17s.

16s still technically in play, though it will take a lot to get the CET there. Something like Gusty described earlier.

Met Office Hadley        17.9c       Anomaly      2.0c Provisional to 8th.

Metcheck                     18.39c     Anomaly      2.16c

Netweather                  18.85c     Anomaly      2.66c

Peasedown St John     17.6c      Anomaly      1.22c.