12 months of above average CET?

[damianslaw]

Can anyone confirm that we have just endured 12 months of above average CET? I recall the last below CET month being March 2006.

If so is this a record?

It appears that even getting an average CET month seems nigh impossible at present. I don't see April bucking the trend, however we are long overdue a below average CET month (law of averages and everything), I am rooting for September to do this..

[Nick H]

No Aug 2006 was slightly below the long-term mean. I believe some period in the mid-1950s holds the record for longest period above the 30 year mean (Kevin??!)

[damianslaw]

No Aug 2006 was slightly below the long-term mean. I believe some period in the mid-1950s holds the record for longest period above the 30 year mean (Kevin??!)

Thanks for that, I thought that August was just above the average.

If it was in the 1950's I will take some comfort as that decade did record some notable months with below average CET, so all may not be lost for the rest of this decade.

[Gavin P]

The highest CET spanning a 12 month period was from November 1st to November 1st 1995, where I think I'm right in saying every single month was above average (not sure about March 1995?) and the CET for that 12 month period was +11c - The only time an 11c CET has ever been achieved in this country in a 12 month period (though I think that the period June 2006 to June 2007 may just beat it, depending on what happens in the next couple of months)

[Stratos Ferric]

Against a ROLLING 30 year mean (see footnote) we had a 20 month run from Dec 1705 - Sep 1707 without a sub par month (though Sep 1706 came it at bang on average). June 1736-July 1737 delivered 14 months above par. May 1834 -April 1835 brough 12 months of unbroken above par outcomes. April 1947 - April 1948 gave 13 on the run, with the following May coming in bang on average. Feb 1959 - June 1960 gave 17 warm months. INterestingly, despite recent marked warming in the climate, this latter is the only warm run longer than the current series of 7, a figure whach has been matched several times since 1960, but not beaten. I'd have to say that sitting where we are now it looks probable that April will come ion above par and a new recent mark will be set. IN the past, more oftne than not, cold months used to cluster. Nowadays, although we have far fewer cold months, they do not cluster: hence, whilst the decline in cold months MIGHT lead one to expect longer sequence of monthly warmth, we are not yet seeing that: my hunch, unfortunatley, is that we are, however, on the cusp of starting to do so. The coming year will go a long way to proving that hypothesis, or not. The saving grace MIGHT be what looks like it might be a notable La Nina.

A further point: the recent run of warmth though not particularly long is exceptional in terms of NET warmth. The 1706 series averaged 1.1C per month, the 1960 series an anomaly of 1.0 per month. The current sequence is delivering an anomaly of 1.8C per month on average. The Standard Dev for the whole series of individual anomalies is only 1.3, and for longer series it would be less than this. Such a long run of significant warmth is bordering being exceptional. If it continues it will be genuione cause for raising of eyebrows, particularly as background forcing factors (El Nino) have now disappeared.

FOOTNOTE: this overcomes the problem that stepping the baseline only every ten years introduces a skew toewards the end of each ten year period IF temperatures are trending one way or another; a run of relatively warm / cold months becomes more likely because the CET no longer really reflects the period average. It's a bit like only buying clothes for a growing child once a year: at the start of the year all the clothes are too large, by the end they're all too small. The odds, therefore, of selecting clothes on any given day that are too large / small are not constant throughtout the year because the baseline being used is artifically and incorrectly fixed.

[Stratos Ferric]

The highest CET spanning a 12 month period was from November 1st to November 1st 1995, where I think I'm right in saying every single month was above average (not sure about March 1995?) and the CET for that 12 month period was +11c - The only time an 11c CET has ever been achieved in this country in a 12 month period (though I think that the period June 2006 to June 2007 may just beat it, depending on what happens in the next couple of months)

Srictly speaking Nov 1 - October 31st, when the running mean was 11.1C. March and September both came in BELOW the 30 year running mean; March alone crept in 0.1C below the then baseline of 1961-90. The warmth in that period was largely driven by a hot combination of July - August.

The current 12 months run is at about 11.4C pending March's final figure. This is an all time record that is likely to continue to rise until July, at which point last year's record warmth fall out of the cycle. If we get a warm July + August it might climb again by the end of August but I'd be surprised if we rematched last year's extensive mild autumn, so I'd expect the 12 month rollin value to drop away slightly by the end of the year, but as we sit there's around an evens chance of actually tipping the 11.00C value for the calendar year for the first time.

[Gavin P]

I think we're really being hit hard by a number of differant issues at the moment.

1. Interdecadal warming of the Atlantic Ocean. Theres no doubt in my mind this is what caused that initial switch from a cold climate to a generally mild clmiate in the late 80's. The switch happened way to quickly for it to have been anything else, IMO. I believe even now, nearly 20 years on, this warm phase of the Northern Atlantic, is having an impact on the climate across much of northern Europe.

2. Increased solar activity. I think there is good evidence that solar activity has been at histroically quite high levels. Quite how this works isn't clear to me, but there does seem to be some sort of link between sunspot activity and the weather on Earth, IMO.

3. Increased and stronger El Nino Activity. 1983, 1991 and 1997, all very strong or record breaking El Nino events, with weaker events in 1987, 1992-1995 (that period of weak El Nino activity spanning YEARS, was truely exceptional, IMO) 2002 and 2006/2007. That a LOT of El Nino's in a relatively short space of time, IMO.

4. Last but not least let us not forget Global Warming. Whether its man-made or natural, whether its being driven by the other factors or something in its own right (I personally favour AGW, rather than natural warming being the only driver behind current warming) Theres no question the Earth is going through a very pronounced, gradual warming trend. And this must also be having an impact.

Now, which of these is more important than the others and which is a driver and which is an effect, I'll leave it for others to decide, because I'm not quallified to draw any conclussions. What I will say is that with 4 scenario's really coming together to put us in the situation we currently find ourseleves in, I believe there IS still hope that if we can get a couple of factors to weaken, like the Interdecadal Warming and a decrease in solar activity, then we may enter something of a temporary cooler phase for a decade or two, before AGW eventually takes away the effect of those other mitigating factors. By a cooler phase, I'm talking back to the sort of climate we had in the early and mid 90's, where although many months were above average, below average months and even seasons, were possible on an occasional basis. Somehow I don't see us ever going back to an early or mid 80's climate, short of conveyor belt shut off, anyway.

I'm probably talking complete rubbish though.

Edited March 31, 2007 by Gavin P

[Nick H]

Last but not least let us not forget Global Warming. Whether its man-made or natural, whether its being driven by the other factors or something in its own right (I personally favour AGW, rather than Man-Made GW)

Eh? The two are interchangeable are they not?

[Gavin P]

Sorry, I meant AGW/Man Made GW over some other natural cycle. I believe there are natural cycles at play as well, but AGW is also at work and will eventually swamp all other cycles, probably.

Edited March 31, 2007 by Gavin P

[Stratos Ferric]

...(I personally favour AGW, rather than natural warming being the only driver behind current warming) ...

A(nthropogenic)GW IS man-made GW.

[Gavin P]

I understand this. What I'm saying is I think AGW(man-made) warming is a big and growing cause of warming, but that there are natural (not man-made) warming cycles at play as well and that ultimately, whilst these natural cycles that are causing European Warming may weaken to some degree and allow us to enter somewhat of a less hot phase, the man-made warming is of course (unless CO2 is reduced in significant amounts, which I don't think it will be) going to over-ride any natural cooling signal we might begin to see emerging over the next 10-20 years. .

Edited March 31, 2007 by Gavin P

[Weather-history]

. Feb 1959 - June 1960 gave 17 warm months.

Well I wouldn't call January 1960 warm, it had a CET of 3.8 and that was below the 1921-50 January average.

Infact February 1960 was below the 1921-50 average as well with a CET of 4.1

Edited March 31, 2007 by Mr_Data

[Thundery wintry showers]

Yes, and Jan/Feb 1960 also had some tantalising looking winter charts for snow lovers:

http://www.wetterzentrale.de/archive/ra/19...00119600114.gif

http://www.wetterzentrale.de/archive/ra/19...00119600212.gif

http://www.wetterzentrale.de/archive/ra/19...00119600215.gif

I'm guessing the 17-month record was judged relative to the 1961-90 average, consisting of months without a below average CET (since 3.8 is the 1961-90 average January CET)

[Stratos Ferric]

Well I wouldn't call January 1960 warm, it had a CET of 3.8 and that was below the 1921-50 January average.

Infact February 1960 was below the 1921-50 average as well with a CET of 4.1

As I said right at the start of my post, I was using a thirty year ROLLING mean. The 20s were a lot warmer than the 50s, and 1960 was right at the end of the period before the step change in baseline, hence the effect was exaggerated to the maximum extent possible. In fact, the point you make rather neatly exemplifies the argument I put forward in my footnote for not persisting with a ten year stepping baseline when drawing comparisons regarding anomalies.

[Thundery wintry showers]

That makes sense; thanks for the clarification.

[Weather-history]

As I said right at the start of my post, I was using a thirty year ROLLING mean. The 20s were a lot warmer than the 50s, and 1960 was right at the end of the period before the step change in baseline, hence the effect was exaggerated to the maximum extent possible. In fact, the point you make rather neatly exemplifies the argument I put forward in my footnote for not persisting with a ten year stepping baseline when drawing comparisons regarding anomalies.

Yes I can see that but my post was about you saying 17 warm months, a January with a CET of 3.8 I wouldn't call warm

[Stratos Ferric]

Yes I can see that but my post was about you saying 17 warm months, a January with a CET of 3.8 I wouldn't call warm

Well, let's not disappear down a pointless semantic dead-end. Substitute "warm" for "above average" and then, depending on which average you choose, you can argue whatever you like.

[Damien]

If Ian Currie is right (and be careful because he got last winter completely wrong at first) it will be 24 months.

http://www.frostedearth.pwp.blueyonder.co.uk/page9.html

[Gavin P]

If Ian's forecast comes off, an 11c+ CET for 2007 will be a certainty. A hot August. September to match last year. What sounds like a record breaking November. It just goes on and on, doesn't it?

[Nick H]

Not convinced by Mr Currie's March forecast of rainfall being twice the long term average and sunshine below long term norm.

In fact, it's one of the sunniest Marches on record and 15% drier than usual.

Edited April 1, 2007 by Nick H

[Weather-history]

If Ian's forecast comes off, an 11c+ CET for 2007 will be a certainty. A hot August. September to match last year. What sounds like a record breaking November. It just goes on and on, doesn't it?

Well his forecast for March was wrong, March was nowhere near as wet as he has forecast, nor as cool nor as dull. Doesn't inspire confidence for later months.

[Nick H]

Great minds think alike, Kevin

[Snowly does it]

Yes, not particularly accurate so far so not convinced at all!

Edited April 1, 2007 by snowmaiden

[Lettucing Gutted]

It could be 13 months above average now. I watched the Countryfile forcast and that useless-for-cold transitory Northeasterly isn't going to link up to the North Pole or Yakutsk, Siberia this April. Also the attending UK/Scandi Bartlett High just keeps swirling around the East Coast of Britain and will only let in the useless non-cold Atlantic westerlies again later this week so once yet again April 2007 will join the building list of warm Aprils and other warm months.

No Aug 2006 was slightly below the long-term mean.

At 16.1C August 2006 was below the 1970-2000 C.E.T August average of 16.2C however it was above the 1960-1990 C.E.T of 15.8C.

Edited April 1, 2007 by Craig Evans

[Snowly does it]

At 16.1C August 2006 was below the 1970-2000 C.E.T August average of 16.2C however it was above the 1960-1990 C.E.T of 15.8C.

True, but temperature is assessed against the current 30 year mean, so it was below average.

Otherwise we might as well just start cherry picking 30 year averages to suit our point.