September CET!

[Stratos Ferric]

...Maybe with all the high tech recording equipment these days, it's time for a re-think on how the CET is calculated; it would give far more accurate results. Obviously running the current method as well, so fair comparisons with the previous CET records, just a thought.

Paul

More accurate does not necessarily equate to materially different. The argument you posit for 'artificially' elevated max temps might equally well be applied to minima, so it's 'swings and roundabouts' perhaps. Yes, it would be possible, theoretically, to run an integration to get the area beneath the curve and a more accurate derivation of the average; however, even if we did that there would not be consistent conversion of the integrated result to the simple calculation, and running in future with the more complicated version would then make historical comparison impossible.

[Optimus Prime]

GFS run, predicts 25th-30th will average out at 10.8c. Final figure should be around 13.8c.

[tesaro]

The argument you posit for 'artificially' elevated max temps might equally well be applied to minima, so it's 'swings and roundabouts' perhaps.

Fair point but surely less wild swings with the minima. Its amazing what a half hour burst of sunshine at 4.00pm can do for temps during an otherwise coolish day!

[Stratos Ferric]

The argument you posit for 'artificially' elevated max temps might equally well be applied to minima, so it's 'swings and roundabouts' perhaps.

Fair point but surely less wild swings with the minima. Its amazing what a half hour burst of sunshine at 4.00pm can do for temps during an otherwise coolish day!

Not much different to what the sudden appearance of cloud can do on a clear night. There is no reason whatsoever to suppose that the CET as currently calculated artificially inflates mean temperature.

GFS run, predicts 25th-30th will average out at 10.8c. Final figure should be around 13.8c.

13.8-13.9 is the landing strip I'd see at present: still very sensitive to o/n temps Wed + Thur, and also how warm we get at the w/e. Unfortunately for those looking for cold, CET-land does not fare best off a NE'ly.

[Polar Continental]

More accurate does not necessarily equate to materially different. The argument you posit for 'artificially' elevated max temps might equally well be applied to minima, so it's 'swings and roundabouts' perhaps. Yes, it would be possible, theoretically, to run an integration to get the area beneath the curve and a more accurate derivation of the average; however, even if we did that there would not be consistent conversion of the integrated result to the simple calculation, and running in future with the more complicated version would then make historical comparison impossible.

Hi SF,

Going back to my post, I was suggesting the current method was artificially inflating the mean under these current conditions; not really representative, yes it obviously work the opposite, as you say, swings and roundabouts.

But the present method of calculating temperature data is beginning to look out dated I think, with today’s modern equipment, data can be collected every second of a 24 hour period, to give very representative data. The current method is really only the equivalent to 1 reading in a 24-hour period, opposed to a possible 86,400 readings with today’s computers.

I agree a new modern method couldn't be used as a comparison with historical data, the old and new would have to be run side by side for many years, but eventually enough years of data would be collected from a new method to give a considerably more accurate feedback on climate behaviour.

Paul

[tesaro]

Not much different to what the sudden appearance of cloud can do on a clear night. There is no reason whatsoever to suppose that the CET as currently calculated artificially inflates mean temperature.

Surely your not telling me that temp fluctuations are as adverse during darkness as they are during daylight.

[Stratos Ferric]

Hi SF,

Going back to my post, I was suggesting the current method was artificially inflating the mean under these current conditions; not really representative, yes it obviously work the opposite, as you say, swings and roundabouts.

But the present method of calculating temperature data is beginning to look out dated I think, with today's modern equipment, data can be collected every second of a 24 hour period, to give very representative data. The current method is really only the equivalent to 1 reading in a 24-hour period, opposed to a possible 86,400 readings with today's computers.

I agree a new modern method couldn't be used as a comparison with historical data, the old and new would have to be run side by side for many years, but eventually enough years of data would be collected from a new method to give a considerably more accurate feedback on climate behaviour.

Paul

Agree with all of that. In practice, as a variable t doesn't change quickly enough, often enough, given the overall precision of measurement (0.1C), to necessitate much other than linear interpolation between hourly levels; in effect a strsight mean of 24 measurements rather than the average of the high-low. I agree it could be done be done more precisely, but it would be effecting the margins well into the decimals and is probably both more trouble than it's worth, and simultaneously slightly misleading re apparent precision.

[SP1986]

Not much different to what the sudden appearance of cloud can do on a clear night. There is no reason whatsoever to suppose that the CET as currently calculated artificially inflates mean temperature.

Surely your not telling me that temp fluctuations are as adverse during darkness as they are during daylight.

Probably just as adverse to be honest, but its a complicated subject. In broad daylight the sun coming out in my experience adds about 2-3C to temperatures, whereas frequently in winter of 2005, it would be 2-3C only for a cloud to come along and raise the temperature to 6-7C

[Stratos Ferric]

Not much different to what the sudden appearance of cloud can do on a clear night. There is no reason whatsoever to suppose that the CET as currently calculated artificially inflates mean temperature.

Surely your not telling me that temp fluctuations are as adverse during darkness as they are during daylight.

Clearly radiant energy inbound exceeds re-radiated flux, otherwise we wouldn't warm and cool as we do, which is why I said 'not much' different. What you do have to remember though is that we measure ambient shade temperature. What we feel when the sun goes in and out is not what the mercury monitors. Yes, temperatures can go up or down by 1-2C quite readily as the sun comes and goes, perhaps more in cold air during spring, but the impact of the sudden appearance of cloud in a polar flow on a forst night can quite easily swing temperatures a couple of degrees as well. I remember last autumn running on a tartan track which under clear skies at 7pm was rather slippery, but under cloud half an hour later was completely frost free; for the same reason cloud serves to dissipate mist very often. I have seen larger swings during the day, but often there will be other factors at play in addition to sun / cloyd, most typically showers and associated downdraughts; these latter can swing temperatures very quickly by 5-6 degrees on occasion.

In summary, yes, we get larger swings during daylight, but the simple impact of cloud / clearance is not so markedly different between day and night.

[West is Best]

In fact the Beeb are going for around 16C in the CET zone today and 13C tomorrow. GFS are sticking with maxima of 11C tomorrow - surely a tad low.

Not sure which BBC section you looked at but that was only a temp given for London KM I think - at least on the main website.

It's bloomin cold today with maxes really pegged back. A few places look as if they've struggled up to 16C, but it looks to me as if one of the CET stations has barely managed 11C.

I also agree with Paul Carfoot. GFS progged 10C and 11C last night. The reality was widespread single figures in the countryside.

Stratos - I love the way you are gradually inching your way nearer and nearer to the magic average CET figure!

[SMU]

Not sure which BBC section you looked at but that was only a temp given for London KM I think - at least on the main website.

It's bloomin cold today with maxes really pegged back. A few places look as if they've struggled up to 16C, but it looks to me as if one of the CET stations has barely managed 11C.

I also agree with Paul Carfoot. GFS progged 10C and 11C last night. The reality was widespread single figures in the countryside.

Stratos - I love the way you are gradually inching your way nearer and nearer to the magic average CET figure!

yes I did notice that- 14.3 ..... 14.2 ...... 14.0 Now 13.9/13.8

S- Cold here 10C

[SP1986]

I still think that the CET will finish 14C, to get 13.8/9 relies n cold nights, and while there will be cold nights - 13.8/9 and 14.0 is going a very thin line to where it finishes.

[Snowyowl9]

That looks a little high to me was showing 4/5c.

http://85.214.49.20/pics/Rtavn1817.png

http://85.214.49.20/pics/Rtavn182.png

9.6c here now and breezy and more cloud cover than blue.

Tomorrow`s my interest see if I can beat my lowest temp for sept doubt it as they`ve gone up was showing 8c at one point. <_<

http://85.214.49.20/pics/Rtavn3017.png

[Optimus Prime]

S- Cold here 10C

10.4c here, easily the coldest so early on since April.

I should thinkj a ground frost shall be recorded in a few isolated places across Northern England and a frost more generally across Scotland.

Nw temp tracker is currently 14.89c. I should think 24 hours from now it'll be closer to 14.55c with mins around 6c and maxes 12. That's a daily CET of just 9c!

A dip of 0.3c is fairly likely. So down to 14.2c on Philips site once it's taken into account for todays dip and the eventual occurance of tomorrows coldness.

[The PIT]

Well the temps are falling off nicely here. Peaked at 15.6C according to the Davis VP2 now at 9.7C just need the wind to fall off and it may get to the coldest night so far.

[West is Best]

0.1C off Manley but not on the headline rate as rounded up rather than yesterday rounding down.

The real hit on the CET starts now. Tonight's temps are low, although not bone chillingly so just yet because of the breeze. At 4.00 we're looking at temps in the 5C to 7C range outside the cities, so likely to lose another couple of degrees in places before dawn. With low maxes we may well see the Manley headline 24 hrs from now down from 14.6C to 14.3C

Edited September 26, 2007 by West is Best

[Stratos Ferric]

0.1C off Manley but not on the headline rate as rounded up rather than yesterday rounding down.

The real hit on the CET starts now. Tonight's temps are low, although not bone chillingly so just yet because of the breeze. At 4.00 we're looking at temps in the 5C to 7C range outside the cities, so likely to lose another couple of degrees in places before dawn. With low maxes we may well see the Manley headline 24 hrs from now down from 14.6C to 14.3C

I think you're continuing to wish it down WiB! Philip's site now has us at 14.55, and my extrapolation forward continues to look, ever more tightly, like 14C. Last night wasn't quite as cold as expected, and it was one of the two 'big' nights on which a below average outturn was hinging. We're now at the point where daily means need to be around 9.5C to deliver below par; we might get one or two, but I don't see five in a row from here. The fat lady isn't singing yet, but I can hear her in the wings warming up!

Well the temps are falling off nicely here. Peaked at 15.6C according to the Davis VP2 now at 9.7C just need the wind to fall off and it may get to the coldest night so far.

I think you hit the nail on the head there PIT. Too much breeze and just enough mixing to hold things up.

yes I did notice that- 14.3 ..... 14.2 ...... 14.0 Now 13.9/13.8

S- Cold here 10C

I don't think so Steve: I think I've pinned the tail on 14C for pretty much the last week; though before that I was, admittedly, expecting a warmer end to the month. What I have absolutely maintained is that we wouldn't go sub par, and I still can't see it. If anything, at present, we're running right at the top of the forward projection I produced on the 22nd.

Edited September 26, 2007 by Stratos Ferric

[SP1986]

I'm in full support of SF here, largely because its such a difficult task to try to pinpoint where a CET might finish when relying on night mins, which can themselves mean the difference between 0.1 or 0.2 difference so to speak. I do think that 14.0 is the finishing line that we should expect. I think its a difficult one though, and everyone predicting from 13.9 to 14.0 is going to be very close and its going to be down to a puff of wind to decide whether it gets reached or not - really interesting month

[West is Best]

I think you're continuing to wish it down WiB! Philip's site now has us at 14.55,

I had today down for mins 6C and maxes 12C.

Right on the money I reckon ...

Quietly confident SF.

[Stratos Ferric]

I had today down for mins 6C and maxes 12C.

Right on the money I reckon ...

Quietly confident SF.

Not that flippin quiet! You obviously haven't seen Sunday's chart. My fine tuning now has us in 13.9-14.0. Since the weekend the main changes have been slightly warmer days Monday / Tuesday, and the removal of some of the edge off overnights, particularly Fri-Sat. It really needs six sixes off the final over, but the bowler looks like banging in a couple of yorkers I'm afraid. Still, on the one hand another cooler than recent par month. On the other, the cool trend is upwards. Whither October?

[The PIT]

Well Yesterdays figures made 0.05C difference to our average. The Max temps for Sept are still higher than June or July. Won't stay that way though. We're still 0.9C above average. Down from 1.5C but looks like an average to above average month for us.

[Optimus Prime]

Well Yesterdays figures made 0.05C difference to our average. The Max temps for Sept are still higher than June or July. Won't stay that way though. We're still 0.9C above average. Down from 1.5C but looks like an average to above average month for us.

What's your mean Minima?

Mine is currently 19.6c. 1.7c below that of Augusts.

Mean minima is 10.5c. Only 1.4c below Augusts Minima.

I'd say my Maxima will finish around 19.1c and minima 9.7c.

Could be the third consecutive month with minima at least 1.0c below normal.

Cettainly going to be below the 61-90 normal for me.

Edited September 26, 2007 by Optimus Prime

[The PIT]

What's your mean Minima?

Mine is currently 19.6c. 1.7c below that of Augusts.

Mean minima is 10.5c. Only 1.4c below Augusts Minima.

I'd say my Maxima will finish around 19.1c and minima 9.7c.

Could be the third consecutive month with minima at least 1.0c below normal.

Cettainly going to be below the 61-90 normal for me.

Bang on average at 9.6C at the moment. Max at 19C Warmer than June or July :)

The average Max for us 17.1C for us 1970 -00.

Both will go down in the next few days though.

[reef]

Bang on average at 9.6C at the moment. Max at 19C Warmer than June or July :huh:

The average Max for us 17.1C for us 1970 -00.

Both will go down in the next few days though.

Amazing the difference that 70 miles makes. Here the average maxima is close to average at 18.8°C (+0.6°C) but the minima is way up at 11.7°C (+1.3°C). We've really struggled to get single figure minima though. Today is only the 5th day of the month to manage it. Like yourself however, September will be an above average month here. We're still a degree over and once the wind changes north-easterly it wont budge much in this location.

[West is Best]

Not that flippin quiet! You obviously haven't seen Sunday's chart. My fine tuning now has us in 13.9-14.0. Since the weekend the main changes have been slightly warmer days Monday / Tuesday, and the removal of some of the edge off overnights, particularly Fri-Sat. It really needs six sixes off the final over, but the bowler looks like banging in a couple of yorkers I'm afraid. Still, on the one hand another cooler than recent par month. On the other, the cool trend is upwards. Whither October?

I had mins 5C and maxes 15C for Sunday SF. Again, I'm happy with that. The really cold night banker is tonight. I've got mins of 4C and maxes 12C tomorrow. Again, fairly happy about that. It's going to be very cold tonight. In fact, in computring to 13.8C these were my figures:

Tues 9 15

Wed 6 12

Thur 4 12

Fr 7 13

Sa 5 14

Sun 5 15

Remember these are the averages of the CET stations themselves, and not the city centre figures ...

On which point, we're in with an outside chance I think of the September min record going (in Scotland). Probably won't but something around -4C a real possibility there.

I assume that elevated stations don't count? Or how does it work?