Tuesday, January 15, 2008

Corbynwatch

As P. Lewis has noted in the comments to this post, we are now half-way through the month of January, so it's time to check up on how Piers' forecast is coming along. His original prediction was for a rather cold month, with a mean temperature of "0.8C at best" (matching 1987), which would make it one of the coldest 6 Januaries in the past 100 years. Central England Temperature (the classic long time series) can be found here, and here (courtesy of P. Lewis again) is an interesting site which while unofficial, claims to track CET pretty well.

So far (at the time of writing) CET over the first half month is 5.92C, a full 1.72C above the 30-year mean (they use '71-'00). The historical data shows a standard deviation for January of about 1.8C, meaning that the temperature is running at 1sd above the mean, and poor Piers was forecasting it to be 2sd below.

You can't get much more wrong than that. Of course, we could be in for a couple of weeks of -6C (average) temperatures, which would save his prediction. But the 5-day forecast is for more mild weather, so I agree with my correspondent that +6C or higher over the month is looking like a rather more plausible outcome. That would put it in the top 10, rather than bottom 6, Januaries in the past 100 years.

Not to kick a man when he's down, but he was also predicting precipitation "well below normal", whereas in reality there is flooding across much of the country with the fear of worse to come...

7 comments:

AdamW said...

More on CET and the Hadley changes to it at Philip Eden's site:

http://www.climate-uk.com/

Henk L. said...

Piers admits there was something wrong: "We have uncovered a data procedure error ...", as can be read in the updated page for the Netherlands.

Perhaps later on in January, or in February, or in 2009 ....

san quintin said...

Yes, Corbyn also predicted enormous UK storms before Christmas 2006 which also didn't materialise. Not very impressive.

brian in the tamar valley said...

The update on the WeatherAction site dated 13 Jan just goes up to the end of the month. Piers is still going with a very cold snap - widesread heavy snow,strong winds and blizzards for pretty well all next week. At the moment it looks to me like the mild south westerly flow continuing over much of the UK. We shall see.

P. Lewis said...

End of month update.

The pseudo-CET came in at 7.03°C. The actual CET came in at 6.7°C I believe. The difference between the two was virtually constant during the month so far as I could gauge. Whether this difference is due to the slightly different monitoring locations or due to modification of the actual CET to account for UHI effects (or both) I don't know and is ultimately not important. PC was spectacularly wrong by either measure. Seems likely it's not just his web text that is overly red in nature "this month".

James Annan said...

Thanks, I'd checked the "pseudo CET" (and was about to blog it), but could you tell me where you got the real thing from?

P. Lewis said...

Hi James

I monitored the actual CET from the page at adamw's link above. Specifically, I used the data at http://www.climate-uk.com/page2.html for the average CET. It would be as well to double check when the actual CET data are finally archived.