February 2013 CET (2012/13 Competition)

[North-Easterly Blast]

Since and including April 2012 and up to January 2013, 6 of those months were below the 1961-90 average. Remember the debates that raged of that we will struggle trying to get below average months? Getting excited over months that were only 0.1 or 0.2 C below the 1971-2000 average because it seemed such a struggle to achieve? And here we are now and we have returned 6 within a 12 month period that were below the 1961-90 average let alone 1971-2000 and 1981-2010. Could February 2013 be the 7th such month?

I reckon since and including January 2010, we have returned 17 below 1961-90 average months, that's out of 37.

To reach the 17th below 1961-90 average month in the previous 10 years ie January 2000 to December 2009, it took to the 79th month of that decadal period.

Something has definitely happened in the last 6 years, a shift away from constantly returning above average months dotted with the odd below average month, to an increase in frequency of below average months.

Rather than in the last six years, I would say more so that since winter 2008-09 and in particular winter 2009-10 the number of below average months has increased significantly. After July / Aug 2007 we had to wait until Dec 2008 / Jan 2009 to find a month that was anything more than fractionally below average. Then after Jan 2009 we had to wait until Dec 2009.

[Summer Sun]

3.4c to the 23rd

[reef]

The reason for the much warmer 1971-2000 winter average is that the 1990s were exceptionally warm, and also there were some mild winters in the early to mid 1970s too.

A winter with a CET of 3.8*C is hardly a cold winter. It is basically just a close to average to slightly below winter. The 1961-90 winter average is 4.1*C. In my books, to say that a winter is truly cold then it needs a CET of around 3.0 or below. 2009-10 was definitely a cold winter, 2008-09 was slightly below average though not a particularly cold winter. With a CET of 5.1*C, then 2011-12 was a mild winter overall.

Winter 2012-13 will go down clearly as a colder winter than most winters in the last 25 years although it wasn't particularly cold and temperatures overall were not far from average. In most periods of pre 1988 standards historically, winter 2012-13 wouldn't be seen as anything other than a typical average winter, it is just that by the standards of the last 25 years it is seen as cold.

To be frank, as Ive said before Im not too bothered about the 1961-1990 average because its 2013 and quoting a 23 year old average which has been superceded twice is irrelevent now. The weather in the last 30 years is more relevent now than back in the 60s. I said this winter will be respectably below average and compared to 1981-2010 it is.

[BornFromTheVoid]

I don't think the fact that this winter, or recent winters, will be/have been below average warrants the term "amazing." We're always going to record cold seasons easily as long as our threshold for what is considered cold continually increases.

[Harve]

I don't think the fact that this winter, or recent winters, will be/have been below average warrants the term "amazing." We're always going to record cold seasons easily as long as our threshold for what is considered cold continually increases.

A very good point. Nevertheless, for the four coldest winters of the last 15 years to have also been in the five most recent is still something.

[BornFromTheVoid]

A very good point. Nevertheless, for the four coldest winters of the last 15 years to have also been in the five most recent is still something.

I agree, we have seen a change from the 90s to early 2000s which were dominated by mainly zonal conditions, to a much more blocked, meridional pattern. It's interesting to see things change and the effect they have on the CET trend, with the 10 year mean showing the first signs of a decline.

(I think only of 3 of the last 5 winter are in the top 5 coldest of the last 15. Coldest 5 are 2009/10, 2010/11, 2008/09 then 2005/06, 2000/01?)

[Tamara]

As we see ever deeper solar minimum then this trend of a return to colder winters should gather pace and the period from the late eighties up to recent years will be seen in the cyclical context which it belongs.

February CET looks quite pleasant and the dessicating cold of recent days has been most refreshing I must say

Edited February 24, 2013 by Tamara Road

[Cleeve Hill]

Hi tamara.

Take a look into the artic sea ice thread. You solar activity idea is consistent with one of the thoughts about cooler N.W Europe winters.

Cheers

[Methuselah]

And the recent upward lurch in the amount of open water is also a contender...

[Tamara]

Hi tamara.

Take a look into the artic sea ice thread. You solar activity idea is consistent with one of the thoughts about cooler N.W Europe winters.

Cheers

Hi - yes I read a lot on this topic In terms of the monthly CET thread the discussion about trends has been, and will continue to be a recurring one in the context of what we have seen in recent decades

And the recent upward lurch in the amount of open water is also a contender...

There are many contenders Pete

[Eugene]

Yes its been a pretty good winter overall with cold snaps/spells in each winter month even December had a cold first half and January offered many their best snow cover in a long time, February has seen less snow cover than January but has offered more consistent cold spells, lots of model disagreement this winter but most of the time whilst not verifying megacold have verified cold instead of mild, i think the last week of February was looking mild and SW'ly just ten days ago which isn't the case now.

Shows you not to always back the mild formhorse like so many still do, one or two more surprises with winter before mid April i feel.

[Thundery wintry showers]

I don't think the posts relating to 1961-90 averages were unreasonable- during the 1990s and early 2000s most months were compared with the 1961-90 average and we rarely got below average months by that measure, so to have 17 out of the past 37 is very noteworthy.

I tend to agree that when comparing recent months with the modern-day "average", using an out-of-date average like 1961-90 is misleading, and thus for that sort of analysis I have actively embraced the use of 1981-2010 averages. But on the other hand, I think that when putting recent months into a longer-term context (e.g. "was this winter notably cold relative to the winters we got during the twentieth century?") then comparing with 1981-2010 is similarly misleading as it is far from representative of the twentieth-century average.

Hence some prefer to use 1961-90 because it is more representative of the twentieth-century average, and it is also the World Meteorological Organisation's default period with comprehensive data available from a range of climatological stations through the period. That said, if it was up to me, I'd choose a longer reference period.

The overall point is, though, this winter has been notably cold by recent standards, and even when you take a much longer-term perspective, it still comes out a little colder than average- the CET has been fractionally short of the averages for 1901-2000 and 1951-2000 as well as 1961-90.

Edited February 24, 2013 by Thundery wintry showers

[Stu_London]

to add

there has been a real shortage of low minima on offer considering the uppers that we have had

If they hadn't held up quite so much, Jan and Feb could have very easily been well below 3C

[hillbilly]

i think that those of us that wish for the cold have been disappointed that feb hasnt been just as cold as they would have liked and spoilt by the recent colder winters and 2010/2011 inparticular yet if this month came 5 years ago we would be pleased that colder months still exist

[Thundery wintry showers]

to add

there has been a real shortage of low minima on offer considering the uppers that we have had

If they hadn't held up quite so much, Jan and Feb could have very easily been well below 3C

I think the main reason for this has been the way the coldest spells have generally been cloudy, associated with easterly and south-easterly winds and stratocumulus from the North Sea- this has helped to hold the minima up somewhat.

[Summer Sun]

3.3 to the 24th

[Dave Kightley]

3.2 to the 25th.. Below average month looking a cert?

[Don]

3.2 to the 25th.. Below average month looking a cert?

Yes, I think we can safely say now that February 2013 will be below average. I think the CET will stabilise for the next few days, so 3.0C after adjustments most likely?

Edited February 26, 2013 by Don

[damianslaw]

My prediction wont be far off just slightly under. Will we squeeze a sub 3 finish?

[Guest pjl20101]

I still reckon Global Warming of TWO is pretty much dead on with what the CET is most likely to finish due to his helpful graph.

[Summer Sun]

3.3c to the 26th

[Summer Sun]

3.3c to the 27th

[Nigerian Prince]

This thread is as dead as a Dodo today, maybe end of winter fatigue, the final CET for February looks like ending between 2.7-,3.2 making my prediction of 2.5, looking quite a respectable guess. Gender male, Location Battersea, South London.

[chionomaniac]

This may have been asked before, but does anyone know why there is such a downward correction every month between the estimated CET and finalised value? Looking at the previous data it is over 1ºC out on some days - a remarkable difference considering that my own weather station is calibrated to 0.055ºC and that we live in a day and age where the 100m can be run and official time is known almost instantly.

[summer blizzard]

This may have been asked before, but does anyone know why there is such a downward correction every month between the estimated CET and finalised value? Looking at the previous data it is over 1ºC out on some days - a remarkable difference considering that my own weather station is calibrated to 0.055ºC and that we live in a day and age where the 100m can be run and official time is known almost instantly.

Hadley also adjusts to stay in line with Manley.