December CET

[Nick L]

Looking very much like an ice day to end the month, should drop the average a further 0.2 and then it's on to the mandatory revisions, could end up mid 3s at that rate. Seems like a very dry month, was it?

I had 36.3mm so while it wasn't desperately dry it certainly wasn't wet either - thankfully we had a wet summer so drought problems are still a long way off yet!

Kentish Man - I don't think there has been much rainfall in the 2nd half of the month to be honest. Got most of mine at the start I think.

Edited December 31, 2008 by nick2702

[kold weather]

Just wondering what has the last 5 days averaged in terms of CET returns?

[Stu_London]

Just wondering what has the last 5 days averaged in terms of CET returns?

1.44C

[kold weather]

So cold but not quite exceptionally cold, though you've got to think the next 2 days will really drag the CET down towards the 0C mark.

[Stu_London]

the 30th and 31st December (if verifying) will be the only sub 0C days of 2008, CET wise, although the 19th February was exactly 0C.

I suspect we will beat that in the first week of 2009

Edited December 31, 2008 by Stu_London

[Optimus Prime]

Mean maxima looks set to be the lowest in December since 1996. Mean minima won't beat 2001 now, and so the lowest since 2001 (but only marginally lower then 2005)

[kold weather]

The 31st will certainly be an ice day now at least in terms of CET, indeed there is a high chance we are going to end up with a very cold day indeed wuith maxes having a hard time even reaching 0C, we shall see what the next 2hrs give us but I suspect we could average -2.5C.

[Guest North Sea Snow Convection]

I'm keeping the faith: 3.6C will be the final. Manley certainly so, and I think Hadley will go sharply lower on correction. May even be 3.5C.

I'm 44 and this has been a properly cold month, not merely based on memory or revisionism but empirically so with a final figure coming in 1C or more below average. Cold, no matter how even the most unscientific mild ramper attempts to deny facts.

A year (or less) ago the prospect of the number of average and now below average months wouldn't have been believed. The point here is not to suggest that we are seeing anything exceptional against the 30/40 yr means because obviously we are not. However this month is cold, against that mean, which ever way one might try to suggest it wasn't proper cold, it didn't come from the 'right sort of cold' etc etc

But it has also already illustrated that the bar is not as high as some emphatically have previously stated. And I think it would also be wise to keep a very open mind about the fact that we could readily see a month some way further below average than this one. The months CET has arrived without unduly cold synoptics. When a spell arrives with such as that, and it will come, then this illustration should be well made.

I would agree your 3.6 is a distinct possibilty now - which I had put at the lowest figure end of possibilities the other day. Good value when you take into account the very mild spell in the third week of the month .

[BLAST FROM THE PAST]

So it looks like the week to week variations being a big factor in this month. Two things happened this month for me for the CET to be lower than my 4.2c. The cold beginning of the month lasted longer than expected and the mild period not quite as mild as expected. On that point I think the signal is good that this current cold will last well into Jan and the mild slot 8-12 will be shortlived.

BFTP

[Optimus Prime]

 we shall see what the next 2hrs give us but I suspect we could average -2.5C.

If it was to average -2.5c, the CET would drop from 4.0c to 3.79c. 

-3.0c 3.77c

-3.8c 3.74c.

So -3.8c is really needed to get 3.5c from here, that's what requires a 0.3c drop. -3.5c is going to be far to low. -1.0c to -3.0c being the general idea. 1996 managed to take of 0.2c from the 30th-31st;

28th 3.3c

29th 3.2c

30th 3.1c

31st 2.9c

[West is Best]

If it was to average -2.5c, the CET would drop from 4.0c to 3.79c. 

-3.0c 3.77c

-3.8c 3.74c.

So -3.8c is really needed to get 3.5c from here, that's what requires a 0.3c drop. -3.5c is going to be far to low. -1.0c to -3.0c being the general idea. 1996 managed to take of 0.2c from the 30th-31st;

28th 3.3c

29th 3.2c

30th 3.1c

31st 2.9c

Sorry OP but all of that assumes the current Hadley mean is correct. So far they have removed 0.2C almost every month, and sometimes more.

It will finish on 3.6C Manley I think, but Hadley might yet be 3.5C

[kold weather]

Indeed if we do assume that there is going to be 0.2C knocked off then its highly likely we will end up at 3.6C after adjustments, which would be on par with December 2001 as the joint coldest since December 1996.

[nick sussex]

Indeed if we do assume that there is going to be 0.2C knocked off then its highly likely we will end up at 3.6C after adjustments, which would be on par with December 2001 as the joint coldest since December 1996.

Kold I've often wondered what do they do with this evening in terms of the CET, I thought the CET was the mean between 6pm to the following 6pm, so this evening we have 6 hours before the 1st January to be accounted for.

Any ideas on this.

Edited December 31, 2008 by nick sussex

[Kentish Man]

Here are the month end stats from Climate UK (Manley):-

CET: (Dec 1-31): 3.6°C (-1.5 degC)

E&W Rain: (Dec 1-31): 63.5mm ( 63 per cent)

E&W Sun: (Dec 1-31): 74.8hr (157 per cent)

© Philip Eden

[BARRY]

Here are the month end stats from Climate UK (Manley):-

CET: (Dec 1-31): 3.6°C (-1.5 degC)

E&W Rain: (Dec 1-31): 63.5mm ( 63 per cent)

E&W Sun: (Dec 1-31): 74.8hr (157 per cent)

© Philip Eden

wow happy with that as i predicted 3.7

[Snowly does it]

Some thoughts on the Hadley outturn before it is confirmed

3.8 looks like the unadjusted figure as Manley dropped 0.25 on the last day (it was a rounded down 3.8 to the 30th) - so if there is an adjustment to say 3.6, it will be only the second month to come in 1.5 degrees below the 71-00 mean since that mean came into being, the other being December 2001, also 3.6

Were it to squeak 3.5 on a big adjustment which is just about possible given the early month discrepancies it would be the coldest month against relevant 30 year mean since May 1996 which was 2.1 below the 61-90 mean and then December 1995 at 2.3 below the 61-90 mean

[stormchaser1]

Phillip eden has December 2008 as 3.6c which is the same as december 2001 , so this december was the coldest since 2001

December

2008= 3.6c

2007= 4.9c

2006= 6.5c

2005= 4.4c

2004= 5.4c

2003= 4.8c

2002= 5.7c

2001= 3.6c

Nigel

[West is Best]

Kold I've often wondered what do they do with this evening in terms of the CET, I thought the CET was the mean between 6pm to the following 6pm, so this evening we have 6 hours before the 1st January to be accounted for.

Any ideas on this.

The final minimum of every month is the first of the new month. That's my understanding.

Anyone know where we'll catch the official CET apart from here: http://www.metoffice.gov.uk/research/hadle.../HadCET_act.txt

or here:

http://hadobs.metoffice.com/hadcet/cet_info_mean.html

?

[Weather-history]

Here are the month end stats from Climate UK (Manley):-

CET: (Dec 1-31): 3.6°C (-1.5 degC)

E&W Rain: (Dec 1-31): 63.5mm ( 63 per cent)

E&W Sun: (Dec 1-31): 74.8hr (157 per cent)

© Philip Eden

Talking about Manley, it was the 6th consecutive month that the CET monthly maximum has been below the 1971-2000 average.

July: -0.8

August: -1.2

September: -0.7

October: -0.9

November: -0.3

December: -1.6

Edited January 1, 2009 by Mr_Data

[Cymro]

wel my gess at 3.7may have been a bit high then :L

[SNOWPLOUGH]

well without the month end adjustments i would have got it right,i guessed 3.8c

SP

[reef]

Its looking like Hadley are in the process of adjusting. The figures are up on the site but the final value isnt confirmed yet as 6 days are missing:

It will however be a large drop. The 25 days that have been published so far when (if it is assumed the remaining 6 days didnt change) would give a 0.3C drop and therefore a CET of 3.5C. Heres a look at the new adjusted figures and the difference from the provisonal values:

	Prov	Actual		Diff
1st	6	7		0.1
2nd	15	6		-0.9
3rd	24	18		-0.6
4th	34	32		-0.2
5th	43	39		-0.4
6th	40	34		-0.6
7th	18	14		-0.4
8th	29	18		-1.1
9th	38	25		-1.3
10th	22	17		-0.5
11th	17	14		-0.3
12th	38	31		-0.7
13th	42	34		-0.8
14th	28	27		-0.1
15th	17	25		0.8
16th	40	41		0.1
17th	57	54		-0.3
18th	71	71		N/A
19th	68	68		N/A
20th	72	72		N/A
21st	98	98		N/A
22nd	102	102		N/A
23rd	76	76		N/A
24th	74	62		-1.2
25th	61	57		-0.4
26th	35	34		-0.1
27th	16	13		-0.3
28th	24	19		-0.5
29th	8	10		0.2
30th	-5	-3		0.2
31st	-28	-25		0.3

	38.1	35.2		-0.29

[derby4life]

when was the last time the cet was 3.6 or below other than 2001 ?

[reef]

when was the last time the cet was 3.6 or below other than 2001 ?

The last coldest is 1996 which came in at 2.9C.

If we finish on 3.5C then it'll be the 4th coldest in the last 30 years.

[derby4life]

thanks reef much appreciated