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Manchester, United Kingdom
Tyson is a beer hound and cheese addict living in the beery metropolis paradise known as Manchester
If the people are buying tears, I'll be rich someday, Ma

Wednesday, 29 July 2009

Here Comes The Sun Rain

The Met Office finally owned up today to the worst kept secret in Britain: they’re officially rubbish. They’ve apologised for saying, back in April, that we were in for a scorcher of a summer. They had people rushing to buy BBQs and the Sun was all set to splash “Phew! What A Scorcher” across its front page. But strangely this hasn’t materialised and people have started suspecting the MO of telling porkies. Hence today’s attempt to get out from the damage. Apparently they only said there was a 65% chance of a good summer and anyway, don’t blame them, it’s the jet stream’s fault-it’s just too unpredictable.

Questions are now being asked about the MO’s accuracy rate-they claim around 85% but some experts put it as low as 38%-and the wisdom of having long range forecasts at all. And this is all despite the MO using a £30M super computer. It’s been pointed out before on this blog that anything other than short term forecasts have proved very iffy indeed. Now why is that?

Well if, like me, you’re interested in the answer, you could do worse than read some of the works of Professor Jeffrey S.Rosenthal. Jeff’s something of a clever clogs-he had his PHD by age 25 and is now one of the world’s leading experts on probability. Annoyingly he’s also a pretty good writer. His 2003 Probability and Statistics: The Science of Uncertainty; now a standard text across the pond, is a good place to start.

Basically, detailed weather forecasts are good for 2-3 days only. A week’s forecast is playing the long odds and anything beyond that is pure happenchance. There are simply too many variables that increase exponentially with the length of time. These are simply impossible to predict. Think the Butterfly Effect. You may as well flip a coin. And if you get it wrong, you can always blame the jet stream.

6 comments:

Woolpack Dave said...

Actually, flipping a coin will effect the jet stream more than a butterfly's wings, surely, so by flipping the coin you've already changed the probability.......

Anyway, stop depressing me, it's now raining here, and has been for a while, puts a dampener on trade and no mistake.

It's going to get nice again soon, I just tossed a coin.

Curmudgeon said...

And this is the third year in a row they have made the same mistake.

Where's that global warming when you need it, eh?

Brewers Union Local 180 said...

Global warming is 8 time zones away, where the dog days of August are getting a head start: 41 yesterday and 43 predicated for today. As the rain puts a dampener on trade for Woolpack Dave, the heat is doing the same here. I was to be in Portland for a whisky and beer pairing with some of my own firkins today, but it was canceled due to the heat.

Curmudgeon said...

The UK often gets US weather a few weeks later - let's hope for a heatwave towards the end of August.

Tandleman said...

No. I'm in Germany then. The week after next would be best for me if that's OK.

Penny said...

But surely Global Warming is about warmer winters and wetter summers? So by that definition, we're still on course for it.