The UK Met Office has recently been much maligned for the poor quality of its long range weather forecasts in comparison to private forecasters who have a higher success rate. So much so that the bookies have banned Piers Corbyn at WeatherAction from betting on his own forecasts -v- the Met Office ones.
Now the Met Office has claimed that in October it did forecast this winter would be much colder than usual, but only in private to the UK government. At the same time, it was issuing this forecast of a warmer winter to the UK public:
The BBC's Roger Harrabin claims that
"The truth is it [The Met Office] did suspect we were in for an exceptionally cold early winter, and told the Cabinet Office so in October. But we weren’t let in on the secret. “The reason? The Met Office no longer publishes its seasonal forecasts because of the ridicule it suffered for predicting a barbecue summer in 2009 – the summer that campers floated around in their tents."Are we supposed to feel sorry for the Met Office for being scared to publish what it really believes while keeping the general public in the dark? Let alone misleading the local authorities that still believe its forecasts when preparing winter contingency plans. The Government's Winter Contingency Planners accepted what the Met Office told them, and acted accordingly i.e. didn't plan for a extra-bad winter. It still makes useful reading.
“We have discussed these issues in some depth with the Met Office and their climate research team at the Met Office Hadley Centre…we are advised to assume that the chance of a severe winter in 2010-11 is no greater (or less) than the current general probability of 1 in 20…The probability of the next winter being severe is virtually unrelated to the fact of just having experienced two severe winters, and is still about 1 in 20. The effect of climate change is to gradually but steadily reduce the probability of severe winters in the UK…we need to understand and accept that the chance of a severe winter is still relatively small…the probability of next winter being severe continues to be relatively small.”
So - if the odds each year are 1:20, and the probability of one severe winter is "virtually unrelated" to another severe winter, that makes the cumulative odds 1:400 for two years, and 1:8000 (or 0.0125%) for three years in a row.
We are always being reminded that weather is not climate. Fine. But when once-in-8000 year ‘weather’ events turn up you really do have to start asking questions. When the Met Office in their UKCP08 report were projecting much warmer summer and winter temperatures in UK to 70% and 90% confidence, that same year they would have put 99.9875% confidence on there not being three extreme winters on the trot.
On its own blog it now says
"We provided a long-range forecast to the Cabinet Office at the end of October highlighting the risk of a cold start to the winter. This forecast is used by government officials across the UK to support long-term planning."and
"We do not issue long-range forecasts to the public, as following research they have told us that they are of little use to them and they would prefer forecasts for shorter timescales. Therefore we offer forecasts for 6 to 15 days and 16 to 30 days ahead on our website."
We are now meant to believe the prediction of a warmer winter published in October was not a forecast we should have believed, because, err, it was a prediction, not a forecast. You might, like me, be wondering what the difference is between “forecast” and “prediction”. The Shorter Oxford English Dictionary (2007) gives the following definitions.
A conjectural estimate, based on present indications, of something in the future, esp. of coming weather; a prediction.
The action of predicting future events; an instance of this, a forecast, a prophecy.Hmmmm.
According to the BBC’s Environment Analyst Roger Harrabin
“I phoned the Met Office about this statement and the Met Office press office told me they’d given information to the Cabinet Office that we were facing an early cold winter. The Beeb now has an FoI request to Cabinet Office requesting verbatim info from the Met Office.”
Several others made FOI requests as well, and some have a response:
Met Office Initial Assessment of Risk for Winter 2010/11
This covers the months of November, December and January 2010/11, this will be updated monthly through the winter and so probabilities will change.
3 in 10 chance of a mild start
3 in 10 chance of an average start
4 in 10 chance of a cold start
3 in 10 chance of a wet start
3 in 10 chance of an average start
4 in 10 chance of a dry start
Summary: There is an increased risk for a cold and wintry start to the winter season.
Looking further ahead beyond this assessment there are some indications of an increased risk of a mild end to the winter season.
How does the "4 in 10 chance of a cold start" square with the claim we heard earlier from the BBC's own Roger Harrabin?
The truth is it [The Met Office] did suspect we were in for an exceptionally cold early winter, and told the Cabinet Office so in October.
Well, of course it doesn't, because "4 in 10 chance of a cold start" is the same as a "6 in 10 chance of a mild or average start" i.e. what the Mystic Met Office told the Cabinet Office is not the same as what Roger Harrabin claimed. If Harrabin had seen the evidence then he has deliberately lied to the public. Or if he had not seen the evidence, then he's incompetent and not believable. Either way, he's an embarrassment to the credibility of the BBC.
Posted by Keith MacDonald 7:23:16 PM