Wednesday, July 29, 2009

By popular demand...

My reader seems to think it's time I said something about our friend Piers:


(pic from my hit counter).

The context is obviously the embarassing bust of the UKMO forecast for a hot summer. My sympathy for them is in rather short supply, given the ridiculous way in which they have over-hyped the "danger" posed by the possibility of some tolerably pleasant weather over recent years. As I said at the time, even if it did turn out warm, the impact on human health was hardly going to come close to their hyperbolic suggestions (yeah yeah, you can try to pretend it's all the fault of the press if you like, but I don't see anyone trying to correct them).

I can't blame Corbyn for crowing about it, not that I actually think his opinion is worth anything. However, it does highlight the difficulty that numerical models have with handling the subtle shifts in weather patterns that can have a strong influence on the UK's climate. Coming hot on the heels of some thoughtful (and thoughtless :-) ) criticism of the recent UKCP predictions I suspect there may be some rather long faces in Exeter...

6 comments:

ac said...

Do the met office use a statistical model, or a GCM ensemble for their seasonal forecasts?

Certainly sounds like their expectation management has been a bit off - 65% doesn't seem especially certain.

James Annan said...

I'm pretty certain that this forecast would have been basically from a numerical model, though there will probably have been a bit of statistical processing in the interpretation of the output.

I agree that the hype was more of an issue than the forecast itself, which (AIUI) was basically for a warmer than average summer, and which might well be vindicated even if the "barbecue summer" and heatwave predictions are not.

Chuck said...

Did any of the forecasts predict that the Australians would be praying for rain?

ac said...

We're always praying for rain. Unless we're being flooded ...

Neither the official Oz outlooks (a statistical scheme based on sea surface temperatures - http://www.bom.gov.au/climate/ahead/archive/rainfall/index.shtml), nor more experimental outlooks based on GCMs (http://www2.apcc21.net/climate/climate01_02.php) predicted a break to the drought.

Some of the dynamical models were predicting a slightly wetter than average May and June in the southeast, but the signal was pretty weak. In the absence of a strong ENSO we're more or less limited to weather prediction timescales.

Chuck said...

I meant rain in England. Specifically, Edgebastion (or however they mis-spell their own language).

James Annan said...

I suspect the Aussies have had such little practice at that that it will not have had a significant effect.

But from now on, will they be praying for rain to save further embarrassment, or for fine weather so they have a chance of a result? I believe the forecast for the next test is decidedly mixed...

I like the sound of the Edgebastion of English cricket, but the locals generally omit the i (and I don't mean crcket).