February CET

[West is Best]

My apologies John, you are quite correct and its a bad habit I need to get out of.

And recalculating it would be 7.9 and 8.0 respectively (I had erroneously used 4.75 and 4.85 as the base)

Is that entirely true Charlotte? John are you not right on the grand scale but not quite right with the detail of the question here? (With respect and all that.)

Charlotte was asked what figure was required to produce such-and-such a final figure. The answer to that can quite legitimately and correctly be to 1/100ths 1/1000ths 1/10000ths from any given point. If what she was giving was a mathematical calculation rather than a measure of temperature then it's quite legitimate to give the actual figure required. Where John is right is to point out that the final figure should then properly be rounded up or rounded down to the nearest 1/10th from whatever figure comes in on the slate. But we shouldn't confuse the difference between temperature measurements and mathematical calculations ... no?

Where I might have a little sympathy for Philip is where several independent data sets are being averaged; this, of course, is what happens with the CET. What you have then is a correct calculation of an arithmetic mean. Say the site averages were 10.8, 11.2, 11.2, and 11.5. The total is 44.7 and the arithmetic mean is 11.175 = 11.18 (depending on rounding convention). Each of the individual averages is correct to +/- 0.05 ( a range equal to the interval of measurement, which in this case is 0.1). This average of averages is subject to the same error (though it is less likely to fall at the margins, it is still possible). Strictly speaking, were you to round this average properly, to 11.2, then apply the margin, the range for the average would be 11.15-11.25. However, we have already demonstrated that the maximum possible value is actually 11.225, or 11.23. IN this instance rerounding for error would in one instance round to 11.3, and in the other to 11.2. Ultimately, we are arguing at the margins, and there won't be many occasions when rounding makes a difference, but in taking an average of independent averages it MIGHT be acceptable to show the absolute value, though if doing so I would always also show the margin of error, otherwise precision is implied that really is not present; what we're really showing is the precise mid point of a wider range.

I've just got to this point and it's exactly what I was getting it, only better phrased.

You are right on this SF. As an arithmetic calculation it's entirely valid. As a temperature measurement (John's point), he's probably correct for now. Mind you, presumably the more accurate the measuring techniques are the more valid it becomes to use them. No point remaining in the stone age if the technology is there - providing of course, as John says, one doesn't then use this to prove something against a previous mean which was only measuring to 1/10ths.

[Snowly does it]

Is that entirely true Charlotte? John are you not right on the grand scale but not quite right with the detail of the question here? (With respect and all that.)

Well, I bow to John's position here, the final figure is to one place so I will restrict to one place too.

Yes it is a mathematical calculation but in essence you can't achieve 4.xx or whatever because the final temperature output will be 4.x

So I was wrong.

[Stratos Ferric]

Is that entirely true Charlotte? John are you not right on the grand scale but not quite right with the detail of the question here? (With respect and all that.)

Charlotte was asked what figure was required to produce such-and-such a final figure. The answer to that can quite legitimately and correctly be to 1/100ths 1/1000ths 1/10000ths from any given point. If what she was giving was a mathematical calculation rather than a measure of temperature then it's quite legitimate to give the actual figure required. Where John is right is to point out that the final figure should then properly be rounded up or rounded down to the nearest 1/10th from whatever figure comes in on the slate. But we shouldn't confuse the difference between temperature measurements and mathematical calculations ... no?

I've just got to this point and it's exactly what I was getting it, only better phrased.

You are right on this SF. As an arithmetic calculation it's entirely valid. As a temperature measurement (John's point), he's probably correct for now. Mind you, presumably the more accurate the measuring techniques are the more valid it becomes to use them. No point remaining in the stone age if the technology is there - providing of course, as John says, one doesn't then use this to prove something against a previous mean which was only measuring to 1/10ths.

Agree with both your points there WiB. Re measuring to 100ths, the technology clearly does exist. I think, thoughm, that before we go there I would prefer a reassessment of how we calculate the daily mean. It is starneg to measure to 100ths (even tenths) yet derive the daily mean from the arithmetic mean of daily max and daily min. With continuous monitoring it should be possible to integrate the curve for the day and produce a weighted average, otherwise the error introduced by poor sampling is far greater than the precision with which we can apparently measure. It would be like investing in the finest micrometer screwgauge to measure the thickness of hand thrown plates; what's the point?

Well, I bow to John's position here, the final figure is to one place so I will restrict to one place too.

Yes it is a mathematical calculation but in essence you can't achieve 4.xx or whatever because the final temperature output will be 4.x

So I was wrong.

No, WiB's point is well made, the argument varies according to whether we're reporting data measured to a certain degree of accuracy, or whether we're reporting some different calculation derived from that data. Say we needed 31.5C over ten days to make a desired mark; the fact is that that averages 3.15C per day; to say that, therefore, CET would HAVE to be 3.2C every day to meet that mark is factually, as well as mathematically, incorrect. There are infinite permutations; one of which is 5 days at 3.1C and 5 at 3.2C; the average if these is still 3.15 but it's not the same as suggesting that 3.15C is required every day.

[Joneseye]

Morning all,

CET: (Feb 1-18): 4.8°C (+0.8 degC) © Philip Eden (If you wish to use or copy these figures, please acknowledge the source)

The current N-W UK tracker figure for February 2007 is: 4.74°C

(difference from average February CET is 0.54°C)

I am not going to enter into the mathmatical debate, but feel that I stand a good chance of being quite close with my punt (6.1) this month.

[Stratos Ferric]

Morning all,

CET: (Feb 1-18): 4.8°C (+0.8 degC) © Philip Eden (If you wish to use or copy these figures, please acknowledge the source)

The current N-W UK tracker figure for February 2007 is: 4.74°C

(difference from average February CET is 0.54°C)

I am not going to enter into the mathmatical debate, but feel that I stand a good chance of being quite close with my punt (6.1) this month.

You stand a very good chance. High 5s still look like the landing zone to me, and the error is morelikely upwards than downwards of this point as things look right now. Of course, as Matty points out elsewhere, the models might be being blind to BFTP's big event arriving from the E, albeit a week or so behind schedule; or maybe not...

[Thundery wintry showers]

I will have to stand up and admit that with this easterly not coming off, my 4.4C is too low; never mind, we all get it wrong sometimes. A landing zone of 5.5-6C is quite likely from what I can see.

I will have to stand up and admit that with this easterly not coming off, my 4.4C is too low; never mind, we all get it wrong sometimes. A landing zone of 5.5-6C is quite likely from what I can see.

Not sure about Philip Eden's calculating figures to 2dp myself; again, I can only really see SF's argument as a possible justification. In the meantime, I will continue to give predictions to 1 decimal place.

[kold weather]

Much depends on how mild these nights get, if anythign the GFS has upper the temps since last night and so given the latest 12z something above 6C is looking possible now according to that run, several days with maxes of 13-14C in the CEt zone will really hurt, esp given mins are not likely to get much below 6C on these days.

Last nights 12z came out around 5.8C (roughly), but having a quick nose i'd guess something very close indeed to Joneseye figure of 6.1C, my CEt is going to be a little too high unless those very mild days really do have really mild nights as well.

I think it may well end up being the case that actually somewhere between 5.8-6.4C is the range now given latest progs and likely more on the upper side of that.

This is a rare time that I egg on very mild temps!

Edited February 19, 2007 by kold weather

[Optimus Prime]

I'd say my 7.15c isn't completely out of the question.

[kold weather]

Be a very big ask tohugh OP, even the very mild 12z GFs is still quite a bit short of that figure, I suspect that my figure is too high as well but between 5.8-6.4C has a good cance of being on the money, hopefully for my predicition it'll end up on the higher side of my range!

[Optimus Prime]

Possibly but not that much too high.

The latest GFS run for the 20th-25th comes out at a huge 8.9c. Some 5c above average.

By the 25th the CET will be around 5.5c. With only 3 days to go it would need some very high temperatures to get it into the 6s.

I reckon the final outcome will be comfortably 5.9c now. Still a margin of 1.25c isn't bad considering we had that cold spell earlier on.

[Don]

4C was not such a good CET prediction from me for February, especially as I was pretty close with January's. Although having said that we were pretty close to having a cold end to the month which would have made a close to average February CET a close call. Still nevermind, plenty more (warm!) months ahead to have a stab at!

Hats off to those who predicted a mild February.

[WBSH]

Oh dear, looks like the CET is going in only one direction! and thats towards the sky!

Oh well my prediction of 5.5c may have held some truths, although it will probably get higher, but I think it should just about be lower than January's CET.

[kold weather]

Hi OP, well just a rough estimate based on the 12z GFS came out at around 5.7C by the 25th, though the next 3 days have a CET average of over 11C which pushes it over 6C (about 6.3C, as i said this is rough given the resolution the GFS runs at past the 26th.)

tommorow should see it rise another 0.1C, though my rough calculations I made based on the temps recorded today came out at a rise of about 0.14C so it may get high enough to be rounded up to 0.2C rise.

[Snowly does it]

Hi OP, well just a rough estimate based on the 12z GFS came out at around 5.7C by the 25th, though the next 3 days have a CET average of over 11C which pushes it over 6C (about 6.3C, as i said this is rough given the resolution the GFS runs at past the 26th.)

tommorow should see it rise another 0.1C, though my rough calculations I made based on the temps recorded today came out at a rise of about 0.14C so it may get high enough to be rounded up to 0.2C rise.

Last 3 days are somewhat on the mild side of the ensembles however.

OK, lets see whre we are.... assuming Hadley is still 0.1 ahead of Phillip we require as follows.... (Manley 1st, Hadley second)

7 - 11, 10.8

6.5 - 9.6, 9.4

6 - 8.2, 8

5.5 - 6.8, 6.6

[Stratos Ferric]

...

This is a rare time that I egg on very mild temps!

I have to admit that my competitive belt ratehr leads me to wish temps on in the direction of wherever my punt happens to be; alas it tends to be mild.

what you really mean is

7.8C

or

7.9C

there is no such thing as 2 decimal places as I constantly harp on about.

You cannot pretend to be accurate to 2 decimal places when the original readings are to 1 decimal place.

Scientific fact.

John

John,

I am resolutely siding with SM on this one. The average required for the remainder of the month is an arithmetic calculation, so to quote to 2dps is fair enough; of course, that's not the same as each day's reported outcome.

Say we needed 87 cumulative degrees over 20 days, it would be perfectly correct to say that the average required would be 4.35C per day; the fact that the daily report is, and should be, to one d.p. is a quite different matter.

[johnholmes]

nuff said by me

[West is Best]

Unless I'm much mistaken, Philip will be on 5C when he releases shortly, with Hadley on 5.1C at the moment.

It's going to be interesting indeed to see how far it now climbs over the remaining 8.5 days (8 x 24 hours + only the maxima for 28th not the minima)

(Edit: just confirmed: Philip is on exactly 5C now, and we think Hadley is at 5.1C http://www.climate-uk.com/ )

Edited February 20, 2007 by West is Best

[Stratos Ferric]

Unless I'm much mistaken, Philip will be on 5C when he releases shortly, with Hadley on 5.1C at the moment.

It's going to be interesting indeed to see how far it now climbs over the remaining 8.5 days (8 x 24 hours + only the maxima for 28th not the minima)

(Edit: just confirmed: Philip is on exactly 5C now, and we think Hadley is at 5.1C http://www.climate-uk.com/ )

My wet finger based on the general situation in the models would be for not more than +0.15C per day on average, giving an upper threshold of 6.2C (my original punt, why, oh why, oh why...), however, I still think this is pushing it - depending on overnight minima. 5.8-6.0 looks a good bet; certainly within +/- 0.2 either side of this unless something remarkable happens, and it would have to be up there on the scale or remarkableness with Mondy coming out in acceptance of a warming climate.

[VillagePlank]

So my 6C looks good, then? :wacko:

[Weather-history]

Warmest January/February combination is 1990 with a combined average of 6.9

It would need a February CET of 6.7 to equal it.

Could end up the 2nd warmest such pair on record, Feb would need a CET of 6.1 to beat the 1869 Jan/Feb pair

[West is Best]

My wet finger based on the general situation in the models would be for not more than +0.15C per day on average, giving an upper threshold of 6.2C (my original punt, why, oh why, oh why...), however, I still think this is pushing it - depending on overnight minima. 5.8-6.0 looks a good bet; certainly within +/- 0.2 either side of this unless something remarkable happens, and it would have to be up there on the scale or remarkableness with Mondy coming out in acceptance of a warming climate.

We're getting some pretty high temps today (12C's already at 12.30). The NW tracker has risen sharply again (0.1C in a handful of hours). It looks to me as if Hadley will make it to at least 5.5C by close of play tomorrow. You're absolutely right though the nightime minima are the real issue. In general it has been a bit chillier at night than I thought, Interestingly, and perhaps unsurprisingly, it's often been much milder from a westerly at night than a southerly this winter: mainly down to the wind/cloud effect I suspect. Looking at the charts though there is some serious potential for a fairly sharp rise. Although a way off the models do keep progging a real warm up for the last couple of days of the month too.

I actually cannot now see this being under 6C; I really can't. I don't think we'll get to 6.8C but especially when you consider that the final day's maxima could be comfortably at 12C or more (no minima on the 28th don't forget) then it looks really plausible that we could see something in the range 6.2C to 6.8C. My latest run came out at 6.6C for Hadley. On the other hand, I have had a tendency to go a small amount high this month.

[kold weather]

I agree richard, I can't see below 6C for the life of me now. The exacts will all depend on whether that weak NW flow over the weekend has any cooler air advected with it. If it has then its going to limit the CET by a couple tenths of a degree.

Saying that I still think somewhere between 5.8-6.4C is quite possible.

12z GFS suggested 6.3C yesterday while the day before went for 5.8C. todays will be lower due to that cooler NW flow we pick up for about 24hrs but in real terms as your post shows Richard temps are going to be higher by day at least then the GFS progged.

[North-Easterly Blast]

According to Philip Eden's graphs, the 30 day period ending on February 19th, was the coldest month of the winter 2006-07, with an average CET of 4.8*C.

Although CETs are generally looked at on the calendar months, you can also follow them through any monthly period straddling two calendar months. Mid Feb to mid March 2005 had a CET of 3.1; February 22nd - March 23rd 2005 was the coldest monthly (30 day) period of the 2005-06 winter with a CET of 3.2.

[parmenides3]

My punt appears to be missing from the 'list' for the February comp.! (page2, post 28)

Perhaps I should'nt say anything though... 6.3? That seems a little optimistic, now.

:)P

[West is Best]

My punt appears to be missing from the 'list' for the February comp.! (page2, post 28)

Perhaps I should'nt say anything though... 6.3? That seems a little optimistic, now.

:)P

No I think it could be spot on, or possibly under.

The CET rose 0.25C yesterday ... Philip is on 5.2 (corrected down from 5.25) and we think Hadley therefore is around 5.35C.

North-easterly blast. Moving goalposts is a pointless exercise. If you fiddle one set of figures you'd have to fiddle the others e.g. end up with the mildest 30 days ever recorded. Utterly pointless exercise in statistical fabrication

Edited February 21, 2007 by West is Best