20130329_R4

Source: BBC Radio 4: Today Programme

URL: N/A

Date: 29/03/2013

Event: Julia Slingo: On 65% of occasions "we do give indeed very helpful advice"

Attribution: BBC Radio 4

People:

Evan Davis: Presenter, BBC Radio 4 Today programme

Roger Harrabin: BBC's Environment Analyst
Sarah Montague: Presenter, BBC Radio 4 Today programme
Susan Rae: Announcer, BBC Radio 4
Professor Julia Slingo: Chief scientist, UK Met Office

Susan Rae: The Met Office has admitted giving the government unhelpful advice during the remarkable switch in weather patterns last spring. A Met Office memo, obtained under Freedom of Information laws, shows that forecasters thought it likely that April would be drier than usual. It was, in fact, the wettest in more than a hundred years. More details from our Environment Analyst, Roger Harrabin.

Roger Harrabin: The Met Office stopped publishing its seasonal forecasts after getting pilloried for promising barbecues in the damp summer of 2009. Since then, the Met Office have stressed that their forecasts are experimental, and shared them only with contingency planners. At the end of March, they projected: "The rainfall forecast slightly favours drier than average conditions for April-May-June, and slightly favours April being the driest of these three months." A soul-searching memo later confessed: "Given that April was the wettest since detailed records began in 1910, and the April-May-June quarter was also the wettest, this advice was not helpful."

* * *

Sarah Montague: Let's get more on that weather story we were just hearing about in the news, because we've been longing for the Met Office to tell us some good news - that when this freezing Easter is over, at least then we'll have some warm, sunny weather. But the Met Office are reluctant to give longer-term forecasts for a very good reason - they're not very good at it. They've admitted that the advice they gave government a year ago was "not helpful". They said April, May and June would be drier than usual - it turned out to be the wettest since records began, and that was back in 1910. Now we'll hear from the Met Office Chief Scientist in a minute - let's just get a word again from our Environment Analyst, Roger Harrabin. And Roger, they're always getting it in the neck - do they deserve to get it in the neck again?

Roger Harrabin: Well, in this case, I mean, I think we have to say that the Met Office didn't actually get it wrong. This is a probabilistic forecast, so they said it was more probable than not that the period would be dry, and in fact it turned out to be extremely wet, so you can't actually say it's wrong. And the Met Office also say that generally their long-term forecasts are helpful to the sort of people we have to turn to, to plan for droughts and floods.

But I think what's come out, interestingly in this - and more than particular interest to me, is that I've been trying for a while to get a system going where we can compare different forecasters and performances, called the Weather Test, that's still trundling along in the background, we're still negotiating on that, so I'm interested in that - but also another interesting thing is the science that has come out of this, and I'm sure Professor Slingo will talk to you about this in a moment. The Madden-Julian Oscillation has reared its head - you probably won't have heard that term on the programme before, but the Met Office are finding that there are new things that they really don't know enough about that are confounding their attempts to forecast long-term weather. This is a weather system that starts in the Indian Ocean, comes out and may eventually be influencing our own jet stream. It really shows how the world is tied together, and they need to know more about it. Reading University say the Met Office are not actually particularly good on that, but should be better soon, because their computer modelling will improve.

Sarah Montague: Okay. Well, Roger, thank you very much for that. As Roger says, the Met Office Chief Scientist, Professor Julia Slingo joins us now, on the line. Good morning.

Julia Slingo: Good morning.

Sarah Montague: Now, as Roger says, you didn't get it wrong, because with all these things, you say we've got a certain probability of having this weather. Do you know what your accuracy rate is?

Julia Slingo: Well, when we look - you have to, of course, with probabilistic forecasts, look over a large number of events, and we of course do that, on I think about 65% of occasions we do give indeed very helpful advice. I think it was quite right that we looked at this particular forecast last year, because listeners may remember that in March we were facing really very serious pressures on water resources, a major drought that had been going on for nearly a couple of years. And I felt, when I looked at the seasonal forecast at that time, that I would be not giving - being fair to the government if I didn't emphasise the fact that we did see a slightly enhanced risk of the drought continuing.

Likewise, I did also emphasise that there was also quite a chance that April would also be wetter than normal. But in the context of where we were, at that particular point, as a country, I felt it was right to emphasise the risk of dry conditions continuing, as a precautionary principle. Of course, that didn't happen, and I think it was quite right that I was honest about what the forecast had said and the advice that we had given to Defra, and so I wrote this report for the Defra Chief Scientist, which is what you're reporting on, this morning.

Sarah Montague: I mean, I guess your misfortune, with this case, was that it happened to be the wettest in almost a hundred years - well, in a hundred years... But that 65% accuracy rate would - sounds quite good, to me. I mean, surely it just needs to be better than 50-50.

Julia Slingo: Exactly. And so these forecasts, while still experimental, still at the very cutting edge of science, are proving to be useful.

Sarah Montague: Okay. Well, here's the one that we really care about. What is your forecast [they laugh] for now, looking ahead?

Julia Slingo: Well, we certainly see the cold weather continuing, at least for the next few days, and -

Sarah Montague: Yeah, we know that.

Julia Slingo: - and potentially into the middle of April.

Sarah Montague: No...

Julia Slingo: Our forecast, our monthly forecast, looking at April, favours - slightly favours cold conditions continuing. Beyond that, I think, as we go through the summer - into the summer, it's much more difficult to predict.

Sarah Montague: But go on - I know, we'll accept that this is not necessarily on the record!

Julia Slingo: Well, I think we're expecting a return to near-normal conditions into May and then June. But of course it's important to emphasise that this is only one of a whole sequence of forecasts we give, and as we get nearer in time to the date of the forecasts, the more accurate they become. So, for all of those who are listening to me this morning, please look at all our forecasts, and look at the three-month outlook, in the context of what we're saying, for the next week, for the next month, and so forth.

Sarah Montague: Okay. It doesn't - you haven't given me any reason to cheer, there. Professor Slingo, thank you very much.

Julia Slingo: You're welcome.

Evan Davis: Not unveiling the barbecue yet...