‘There’s nothing random about this year’s heatwave’

Jim Bacon at the Weatherquest headquarters in Norwich. Photo: Steve Adams (Image: Archant 2011 0)

In 50 years as a meteorologist Jim Bacon, best known as Anglia TV weatherman in the 1980s and ‘90s, has seen everything from floods and freezes to hurricanes and, of course, heatwaves.

During the long, hot summer of 1976 the former Thetford Grammar School pupil was a twenty-something student at Reading University, forecasting during the holidays and just starting out on his career.

There have been hot summers since then - notably in 1995, 1997, 2001, 2003 and 2006 - but nothing to really rival 1976. Until now.

These days, Mr Bacon is managing director of the East Anglian-based weather forecasting and analysis company Weatherquest.

He may not be on our TV screens as much as he once was but he’s still fascinated by all things weather. This summer is giving him plenty to get his teeth into.

And, he says, there’s nothing ‘random’ about the heatwave we’re experiencing.

“No matter what the weather, it’s all interesting and fascinating when you look at what’s happening in the atmosphere and this summer’s no different,” he says.

“The dry spell of ‘76 was a very regional thing in the UK but this year a fair chunk of Europe is experiencing similar problems. Weather that lasts for a longer period of time like this can point to large-scale interferences in the upper atmosphere.

“At the beginning of this dry spell the jet stream (a core of strong winds around five to seven miles above the Earth’s surface, blowing from west to east) was contorted so that it became stuck in a pattern called an Omega Block. It’s called this because it’s contorted to form the shape of the Greek letter omega.”

In an Omega Block, an area of slow moving high pressure gets sandwiched between two lows. These ‘blocks’ can persist for months around mid-summer, disrupting more usual weather patterns.

“A lot of research is going on into these blocking events as to what some of the reasons might be for these to become more common, if they are,” says Mr Bacon. “Climate change effects are most strongly felt in the northern latitude around the Arctic. That could mean we are going to get a lot of extra cold water flowing into the north Atlantic from melting ice and that changes how the jet stream flows across the north Atlantic.

“Until we have enough examples we can’t say it is to do with one or the other but there is increasing evidence that climate change is playing a part in this. If so, what we are experiencing this year would be a typical summer in the future.”

And that brings us on to one of the key differences between the summers of 1976 and 2018: water.

The heatwave of ‘76 quickly became a drought because it followed a prolonged dry period.

“We had a dry 1975 and a dry winter of ‘75-76, when water stores would normally be replenished. The effect of this was that in 1976 you did not need much of a dry spell for water shortages to become a real issue,” says Mr Bacon. “That’s not the case this year. We can sustain supplies over a warm summer but if we went into a dry winter and had another dry summer next year it might be very different. Water management will be a key issue if events like this become more common, as well as looking at what happens when the countryside gets very dry, as we are seeing with fires in Greece and even in Scandinavia, where they don’t normally get hot weather on this scale.”

Other than the water issue, then, there seems to be little difference between these two landmark summers for us in the UK.

“In 1976 there were 15 days or so on the trot when temperatures exceeded 30C, I think,” says Mr Bacon. “You never had to wonder whether you’d be able to have a barbecue that evening; you just knew you would. The longer this current hot spell lasts the higher the chances that it continues to get hotter as the soil is now acting like a giant radiator.”

So, what does he think is the likelihood of rain in the coming weeks?

“The question is, to what extent will weak fronts that cross the Atlantic survive to bring rain,” he says. “You can’t rule out isolated thundery showers developing but apart from that I see nothing that suggests real change in the next two to three weeks.”

But, he points out, in August 1976 two things happened that were almost guaranteed to bring an end to the drought: the appointment of a drought minister and a Bank Holiday. History is unlikely to be repeated on the first but the second, well, that could be another story...