Let’s All Blame The Atlantic For Our Poor Summers

Even the most steadfast supporter of the British holiday industry would admit that the recent summers have been less than helpful over the last few years. True, we have had spells of fine weather - who can forget the wonderful second half of March that we had last year, or the splendid June of a couple of years ago.

But anyone with any knowledge of the industry will tell you that the “summer” months, namely those that cover the school holiday months of July and August hold the key to a successful season, year in and year out. “Indian” summers put the icing on the cake only if the preceding months have been the real deal.

It’s true that out of season breaks are flourishing, to cope with the peculiar times of year that decent weather can arrive (often unexpectedly), but  fine weather at these times cannot always guarantee the level of daytime temperature that many holidaymakers require, and that romantic “after dinner” stroll along the beach will most likely be taken in pitch darkness, as the bright summer evenings have yet to arrive.

Well, apparently recent research suggests that the problem is somewhere out in the Atlantic, with a cyclical warming of that contentious stretch of water taking the blame. Scientists and meteorologists say that this 10 to 20 year pattern of Atlantic warming was shifting the jet stream, leading to washouts in six of the last seven summers. They gathered at the Met Office in Exeter, obviously not trusting themselves to find somewhere warmer!

But there was hope that the pattern would change at some point in the next decade, with the location of the fast moving winds of the jet stream being central to the UK's weather. When it becomes fixed in position south of the British Isles, low pressure systems find themselves stuck in the peaks and troughs that form along the edge of the stream, giving us the seemingly endless rainy days that have been part of our summers in recent years.

Prof Stephen Belcher from the Met Office Hadley Centre, who lead the discussions said that changes in the Atlantice Multidecadal Oscillation (AMO), as the ocean current is called, was one of the prime factors.

"It's the pattern of warm and cold water, it's the contrast of the warm and the cold, when that sits in the right place beneath the jet stream, it can kind of steer the jet stream and influence where it goes," he said. "I'm excited about this work, it's a new thing that we didn't really know about."
Explaining the cold winters of 2010/11 and this past spring were more of a challenge, said the scientists. Dr James Screen from the University of Exeter said that a more complicated basket of factors was involved.

"The cycle we've been talking about in the north Atlantic seems to be more important for controlling summer weather in the UK, our current understanding of the role of Arctic sea ice is that it is more important in controlling winter weather."

The researchers say that the glimmer of good news is that the AMO might change in five to 10 years, and warmer summers might return. However the winter was more difficult to predict said Prof Belcher. "There are hints we are coming to the end of the cycle. With the cold winter weather, the loadings of the dice don't seem to follow cycles," he said.

Well that’s all well and good, even if you do understand what they are on about! But what are our chances for this year?  According to Dr Adam Scaife from the Hadley Centre, you'd be wise to keep an umbrella handy.

"In 2012, like the previous few summers, we've had conditions in the northernmost Atlantic that were much warmer than normal.  So that pre-conditioning was there this year and that shifts the odds slightly in favour of this summer being wetter than the historical average.”