Why good weather is hard to predict

A A A

Forecasters warned today of the pitfalls of predicting the weather a long way in advance after the British summer has so far failed to live up to expectations.

The warning came as the Met Office was set to issue a revised forecast following its claim in April that the UK was "odds-on for a barbecue summer".

Since a hot spell at the end of June and beginning of July, rainy conditions have been dominant and are set to continue.

Tom Tobler, forecaster at the MeteoGroup, the weather division of the Press Association, said it was difficult to forecast more than around two weeks ahead.

"The further you go into that period the more uncertain it is," he said. "We are usually confident about the general weather system for a number of days.

"As far as seasonal forecasting is concerned, it's only a very vague, general forecast."

The Met Office's summer predictions were based on percentage chances of it being warmer than average, although it did state Britain was unlikely to escape some downpours.

Mr Tobler said: "They will only say there is a certain percentage chance of it being warmer than average.

"If it was a 65 per cent chance it doesn't really tell you a lot as there is a 35 per cent chance that it could go the other way.

"It's a chaotic system. You are looking at the UK which is a fairly small area and it only takes a small change in the atmosphere to affect the weather.

"A small change one day leads to a bigger change the following day.

"Part of the problem with long-range forecasts is communicating with the public the uncertainty.

"When there is that much uncertainty it's not that useful to the general public but people are looking for the headlines like 'barbecue summer' and don't necessarily read on."

Revising forecasts is normal, Mr Tobler said.

"Whenever you do a long-range forecast you would update it at intervals because you are getting more information all the time," he said.

Mr Tobler said technology was being developed but long-term forecasting was likely to remain limited.

"It's something that is being worked on all the time," he said. "It's still in its infancy. Over time things will improve but there is that much unpredictability in the atmosphere that there will always be a limit to how far we will be able to predict with any accuracy other than a general trend."

The forecaster said temperatures should rise next week although there would still be rain around.

Ewen McCallum, chief meteorologist at the Met Office, said in April: "After two disappointingly wet summers, the signs are much more promising this year.

"We can expect times when temperatures will be above 30C, something we hardly saw at all last year."

But Mr McCallum warned that while there was a two in three chance the forecast would be right, there was a one in three chance it would be wrong.

He urged caution over seasonal forecasts and said the forecast was based on probabilities which showed there was a 50 per cent chance of the temperatures in June, July and August being above average, a 30 per cent chance they would be average and a 20 per cent chance they would be below average.



Philip Eden, vice president of the Royal Meteorological Society, criticised the Met Office for using the "barbecue summer" phrase.

He told BBC Radio 4's Today programme: "The key is that these are experimental forecasts. That's fine by me - it's exactly what they should be doing.

"They should be doing research into long-range forecasts.

"The problem is that we don't actually know very much about the forcing factors, the outside influences which affect the weather during a period of, say, a month or three months ahead.

"The big problem with these forecasts was the spin that was put on it by the Met Office's press office - the 'barbecue summer' bit."

He pointed out the wording of the forecast was "unambitious" and had a "very wide target".

"They simply predicted that temperatures for the summer quarter would be above average," he said.

  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: Senior Digital Marketing Consultant

£28000 - £45000 per annum: Recruitment Genius: A Senior Digital Marketing Cons...

Recruitment Genius: Assistant Stores Keeper

£16640 - £18500 per annum: Recruitment Genius: An Assistant Stores Keeper is r...

Recruitment Genius: Claims Administrator

£16000 - £18500 per annum: Recruitment Genius: This is an excellent opportunit...

Recruitment Genius: Software Developer - C# / ASP.NET / SQL

£17000 - £30000 per annum: Recruitment Genius: Developer required to join a bu...

Day In a Page

'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power
Rare and exclusive video shows the horrific price paid by activists for challenging the rule of jihadist extremists in Syria

The price to be paid for challenging the rule of extremists

A revolution now 'consuming its own children'
Welcome to the world of Megagames

Welcome to the world of Megagames

300 players take part in Watch the Skies! board game in London
'Nymphomaniac' actress reveals what it was really like to star in one of the most explicit films ever

Charlotte Gainsbourg on 'Nymphomaniac'

Starring in one of the most explicit films ever
Robert Fisk in Abu Dhabi: The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers

Robert Fisk in Abu Dhabi

The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers
Vince Cable interview: Charging fees for employment tribunals was 'a very bad move'

Vince Cable exclusive interview

Charging fees for employment tribunals was 'a very bad move'
Iwan Rheon interview: Game of Thrones star returns to his Welsh roots to record debut album

Iwan Rheon is returning to his Welsh roots

Rheon is best known for his role as the Bastard of Bolton. It's gruelling playing a sadistic torturer, he tells Craig McLean, but it hasn't stopped him recording an album of Welsh psychedelia
Russell Brand's interview with Ed Miliband has got everyone talking about The Trews

Everyone is talking about The Trews

Russell Brand's 'true news' videos attract millions of viewers. But today's 'Milibrand' interview introduced his resolutely amateurish style to a whole new crowd
Morne Hardenberg interview: Cameraman for BBC's upcoming show Shark on filming the ocean's most dangerous predator

It's time for my close-up

Meet the man who films great whites for a living
Increasing numbers of homeless people in America keep their mobile phones on the streets

Homeless people keep mobile phones

A homeless person with a smartphone is a common sight in the US. And that's creating a network where the 'hobo' community can share information - and fight stigma - like never before
'Queer saint' Peter Watson left his mark on British culture by bankrolling artworld giants

'Queer saint' who bankrolled artworld giants

British culture owes a huge debt to Peter Watson, says Michael Prodger
Pushkin Prizes: Unusual exchange programme aims to bring countries together through culture

Pushkin Prizes brings countries together

Ten Scottish schoolchildren and their Russian peers attended a creative writing workshop in the Highlands this week
14 best kids' hoodies

14 best kids' hoodies

Don't get caught out by that wind on the beach. Zip them up in a lightweight top to see them through summer to autumn
Robert Fisk in Abu Dhabi: The acceptable face of the Emirates

The acceptable face of the Emirates

Has Abu Dhabi found a way to blend petrodollars with principles, asks Robert Fisk