Annual CET - 2008

[chionomaniac]

As I haven't really ever looked at this before can someone please help me with some data. When was the last year, last rolling monthly and last rolling daily sub 10ºC yearly CET recorded? I sincerely hope we get this this again in my lifetime as I rather hope I have a few years in me yet!!!!

[Stu_London]

The year end is also likely to be close to 10. If we don't manage it this year, then next year may be the last chance we have in our lifetimes of getting back under that mark on the reported annual basis.

I see the crystal ball is still in good working order - any chance of this saturday's lottery numbers?

[reef]

As I haven't really ever looked at this before can someone please help me with some data. When was the last year, last rolling monthly and last rolling daily sub 10ºC yearly CET recorded? I sincerely hope we get this this again in my lifetime as I rather hope I have a few years in me yet!!!!

Not sure on the daily figure, but the last rolling 12 month period to be sub-10C was back in December 2001 (9.93C).

We last came close in April 2006 with 10.03C.

Edited December 3, 2008 by reef

[Stu_London]

Not sure on the daily figure, but the last rolling 12 month period to be sub-10C was back in December 2001 (9.93C).

We last came close in April 2006 with 10.03C.

we will probably go sub 10C in running sometime between now and the 8th December 2008

[Stratos Ferric]

we will probably go sub 10C in running sometime between now and the 8th December 2008

6th is the first day that we're likely to dip under 10.00C.

[BLAST FROM THE PAST]

By my calculations (and I couldn't be bothered finding a calculator so I did it in my head so there could be errors), December needs to come in at 4.0c to give an annual CET of less than 10.0c. That is, of course, if there is no adjustment to November's figure.

The last time December had a CET that low was, coincidentally enough, 2001.

It'll be close IMO ....very close

BFTP

[chionomaniac]

Not sure on the daily figure, but the last rolling 12 month period to be sub-10C was back in December 2001 (9.93C).

We last came close in April 2006 with 10.03C.

Thanks Reef.

[Thundery wintry showers]

The year end is also likely to be close to 10. If we don't manage it this year, then next year may be the last chance we have in our lifetimes of getting back under that mark on the reported annual basis.

It may not be as bleak as that- the latest word from the scientists at the Hadley Centre of the Met Office is that, even if we work from the premise that the human contribution to climate change is as large as the current generation of climate models suggest, natural factors may offset the anthroppogenic warming for up to another decade. Which does mean, though, that we'd be likely to see a particularly abrupt warming during the 2020s and 2030s as the natural factors revert to warmer phase states.

[Stu_London]

CET 03/12/07-02/12/08 - 10.03C

Edited December 4, 2008 by Stu_London

[osmposm]

It may not be as bleak as that- the latest word from the scientists at the Hadley Centre of the Met Office is that, even if we work from the premise that the human contribution to climate change is as large as the current generation of climate models suggest, natural factors may offset the anthroppogenic warming for up to another decade. Which does mean, though, that we'd be likely to see a particularly abrupt warming during the 2020s and 2030s as the natural factors revert to warmer phase states.

Well, on a purely selfish note (and to hell with the kids), that would suit me fine. I'll be 70 in 2021 (assuming I haven't pegged it), so any reasonable chance of decent Southern England cold & snow may disappear just about the time I get too old to like it - and no longer have the dosh to pay the heating. Mind you, I don't suppose the summer heat will be much fun for a crumbly either, and air conditioning doesn't come cheap - for the individual or for the planet.

But back to the topic, I think we're still in with a significant chance of getting the 4.0 we need for sub 10.....though my impression is that the last week or so of December is commonly milder in England than what precedes it. Does anyone know if that's actually stastically true, or am I talking complete bull?

Ossie

[Stratos Ferric]

Well, on a purely selfish note (and to hell with the kids), that would suit me fine. I'll be 70 in 2021 (assuming I haven't pegged it), so any reasonable chance of decent Southern England cold & snow may disappear just about the time I get too old to like it - and no longer have the dosh to pay the heating. Mind you, I don't suppose the summer heat will be much fun for a crumbly either, and air conditioning doesn't come cheap - for the individual or for the planet.

But back to the topic, I think we're still in with a significant chance of getting the 4.0 we need for sub 10.....though my impression is that the last week or so of December is commonly milder in England than what precedes it. Does anyone know if that's actually stastically true, or am I talking complete bull?

Ossie

I've not checked the temperatures, but the tendency in met-wisdom is for December to be most unsettled mid-month, and hence probably milsdest about this time too. Recent years have, I think, tended to buck this; the period around the 20th has probably tended to be cool or cold more often than any other period in winter, perhaps barring late Feb / early March.

Sub 4 looks very likely at present unless the HP out to our W move significantly closer to our SW, or HP asserts itself over W Russia. The models continue to suggest a weak jet and in these situations the surface can get locked in phase, a potentially tantalising prospect for cold lovers as we have cold dominating at present.

Given what we had last year it's going to take a dramatic shift in pattern to land above 10.00C now - not to be ruled out with most of the month remaining - in which case the next question is how low might the rolling value get? Even just an average winter by recent standards would see us down to 9.80C. I might be tempted to run some numbers to see what the theoretical floor looks like.

On monthly rolling the last time we were sub 10 for an extended period it bottomed out at 9.76 in June 2001.

It may not be as bleak as that- the latest word from the scientists at the Hadley Centre of the Met Office is that, even if we work from the premise that the human contribution to climate change is as large as the current generation of climate models suggest, natural factors may offset the anthroppogenic warming for up to another decade. Which does mean, though, that we'd be likely to see a particularly abrupt warming during the 2020s and 2030s as the natural factors revert to warmer phase states.

I note the use of the conditional. What's the thinking behind any short-term cooling? To last a decade or so from here would be fairly impressive and would require no Nina.

Edited December 4, 2008 by Stratos Ferric

[Snowly does it]

Given what we had last year it's going to take a dramatic shift in pattern to land above 10.00C now - not to be ruled out with most of the month remaining - in which case the next question is how low might the rolling value get? Even just an average winter by recent standards would see us down to 9.80C. I might be tempted to run some numbers to see what the theoretical floor looks like.

On monthly rolling the last time we were sub 10 for an extended period it bottomed out at 9.76 in June 2001.

Hi SF, its good to see you back.

If we were to come in at 9.99 for the year, then we could in fact allow ourselves 0.6 degrees above average for Jan/Feb - lets say 4.5 and 4.5 and come in at just below the June 2001 Nadir and the 71-00 average at 9.74

Thereafter an average Spring might get us to 9.5 which is my theoretical low point - it woul take something extraordinary to get us under 1996s 9.2 in running so I would say 9.5 is the 'Holy Grail' of this cooler period.

to get to 9.2 from here...... Dec 3.9 Jan 3, Feb 4, Mar 6, Apr 7, May 9.8...... not looking easy that mountain...

[osmposm]

I've not checked the temperatures, but the tendency in met-wisdom is for December to be most unsettled mid-month, and hence probably milsdest about this time too. Recent years have, I think, tended to buck this; the period around the 20th has probably tended to be cool or cold more often than any other period in winter, perhaps barring late Feb / early March.

The current 30-year av line on the GFS Ensemble 850 hPa temp graph for London & Manchester doesn't seem to show mildness mid-month, certainly - and for Aberdeen it shows a distinct dip for a few days from around the 13th.

I have a 1980 booklet called "Weatherwise" I found in a jumble sale years ago - it was published by Reader's Digest which didn't augur well, but in many ways it's actually rather good. There it is suggested that it is the first ten days of December that often show mild storminess, and goes on to say that temps tend to drop sharply around the middle of the month!! It also states - and this may be where I got my idea from - that "the period immediately after Christmas is one of the most predictable weather spells of the year. It is called the 'post Christmas storm', with high winds, snow in the north and the risk of floods in the south." I probably inferred from that that most of England tended not to be particularly cold then, even if it had been earlier in the month. The Scottish meteorologist Alexander Buchan's once-famous "Buchan's Spells" (of warm and cold hiccups), too, included a warm spell that finished around December 14th (starting about the 3rd) - but his research was done in the 1860s, a very different era.

Edited December 5, 2008 by osmposm

[Stu_London]

2007 started mild - had a cold inversion mid month and warmed up towards the end of the month.

As for the annual CET in running - we will almost certainly go sub 10 in running by the end of today (We are about 10.00C or 10.01C up to the 4th). the 5th and 6th December 2007 were two of the mildest days of 2007, so assuming we are 2.5 after the 6th, that would leave us around 9.96C or 9.97C in running. Thereafter it becomes more difficult to push the rolling total down as it coincides with a colder spell last year.

As for the medium term prospects, my opinion is that we will be just over 10.00C for 2008, however given the relatively mild months of January and February 2008, there is the chance that we could at times dip significantly below 10C on a rolling basis during those months - perhaps as low as 9.75C might be achieveable, even without anything out of the ordinary occuring.

As for the real long term prospects, to effectively rule out sub 10C years after 2009 is a little bit ridiculous. You only have to look at the period 1995-1997 : -

1995 - 10.52

1996 - 9.20

1997 - 10.53

Even if warming does resume sometime soon then it isn't impossible to forsee a series that runs something like this, which is well within the year to year variances that the series has thrown up.

Year 1 - 10.90

Year 2 - 9.80

Year 3 - 10.50

Year 4 - 11.10

Hi SF, its good to see you back.

If we were to come in at 9.99 for the year, then we could in fact allow ourselves 0.6 degrees above average for Jan/Feb - lets say 4.5 and 4.5 and come in at just below the June 2001 Nadir and the 71-00 average at 9.74

Thereafter an average Spring might get us to 9.5 which is my theoretical low point - it woul take something extraordinary to get us under 1996s 9.2 in running so I would say 9.5 is the 'Holy Grail' of this cooler period.

to get to 9.2 from here...... Dec 3.9 Jan 3, Feb 4, Mar 6, Apr 7, May 9.8...... not looking easy that mountain...

01/02/1996 - 31/01/1997 - CET 9.05C

[Snowly does it]

01/02/1996 - 31/01/1997 - CET 9.05C

Now that's what I'm talking about!

Best chance for a sub-10 year we have had in a long time 2008, and best chance of a better than 1.5 below average month for some time - requires no sustained mild from here but so far so good.

[Duncan McAlister]

I probably haven't done this totally accurately, but the 12z gives a CET of 2.3 by the 20th.

If it's anywhere near right, the CET could still be in the 2's by the 20th - a real turn-up for the books and a welcome one for most on here I'm sure!

It's game on for a sub-10C year IMO

Edited December 7, 2008 by Duncan McAlister

[Nick L]

It's game on for a sub-10C year IMO

Agreed. Unless this month goes the shape of a very ugly pear, then we could be in with a shout of beating 2001 IMO.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Has the rolling year mean dipped under 10C yet?

[Stu_London]

Has the rolling year mean dipped under 10C yet?

Yes

Rolling CET - 07/12/07-06/12/08 - 9.975C

[Nick H]

The current 30-year av line on the GFS Ensemble 850 hPa temp graph for London & Manchester doesn't seem to show mildness mid-month, certainly - and for Aberdeen it shows a distinct dip for a few days from around the 13th.

The dashed line in Eden's graph shows the decline in temp as December progresses.

http://www.climate-uk.com/graphs/0812.htm

The decline is most rapid in the first third of the month.

I was very surprised looking at that graph how little the temperature declines in December. The minima hardly fall at all and the maxima by no more than 1.0C. I'm sure June, as the 1st month of summer, shows a much greater warmer trend than December does cooling.

[Stu_London]

Rolling CET - 08/12/07-07/12/08 - 9.96C

A couple of days more where falls are probable - thereafter it will probably rise again back over 10C - a coldish final third to the month would be needed for the year to come in sub 10C

[summer blizzard]

Do we have an update from yesterday??

[Stu_London]

Do we have an update from yesterday??

Rolling CET - 09/12/07-08/12/08 - 9.95C

[Stu_London]

Rolling CET 11/12/07-10/12/08 - 9.93C

Upward movement is likely from here until around the 23rd or 24th (back over 10C in all probability) with a good chance of another fall in the last week

[Stratos Ferric]

My rolling figures are running about 0.03C high, the cause of which is a mystery unless there's been a recent update to the daily figures. Anyway, allowing for that error the rolling looks like going back above 10.00C on about the 20th. The year end looks very close to 10.00C, though the trend in recent runs has been a warming one overall. Given no genuinely cold air in the offing, the best chance for sub 10.00C may well be HP slap bang overhead the UK from Christmas on, and prolonged radiative cooling.