UK Met Office: rainfall follies

Source:  Numbers  

And now for the weather aftcast

Time present and time past
Are both perhaps present in time future
And time future contained in time past.
Burnt Norton

Yes, it is rude to laugh, but sometimes it is irresistible. The new green Telegraph regales us with the headline ?

After deluge, expect more ‘extreme rain?

With due deference to the First Law of Journalism, it is all down to the famous Met Office. Suddenly, after a wet year, which naturally they failed to forecast, they have reversed their customary fiery slogans to ?Après nous le deluge?. Their antediluvian joy has given way to postdiluvian melancholy. As we noted just a year ago, they had been obliged to withdraw from issuing long term weather forecasts after their warming predictions became a national joke, with their ?barbecue summers? and ?milder than average winters?. These were all going to be the inevitable results of global warming, but now:

One likely cause is that a 1.26F (0.7C) increase in global air temperatures since pre-industrial times has led to a four per cent increase in moisture in the atmosphere, bringing with it a greater potential for heavy rain.

Another possibility is that a change in sea surface temperatures caused by decreasing Arctic sea ice has brought about changes in weather patterns.

There is no mention of that irrelevancy, the jet stream. As we noted last August the jet stream is the main factor that makes our long term forecasts so useless. But worry not; as we said back in 2009 (and, as it happens, mentioning the jet stream) one day they will be right. They appear to have difficulty with the concept of random sequences of events, such as the precise positioning of the jet stream, and the fact that they produce apparent patterns and records. It was primitive man?s inability to envisage an effect without human cause that gave rise to much of religion.

Of course it would have been most impressive if they had predicted all this a year ago, but they did not. Their predictions are as changeable as the weather and the only constant is the putative cause.