THERE is a one in three chance that unprecedented levels of rainfall will bring heavy flooding to at least one region of England every winter for the next decade, forecasters have warned.
The Met Office, which harnessed a “supercomputer” to measure the risk of extreme rainfall in the current climate, is now predicting weather events up to 30 per cent wetter than current records.
The computer was able to analyse data from 1,750 simulated winters, instead of the 35 for which actual records exist.
Lead researcher, Dr Vikki Thompson, said: “Some of the simulated weather states, which look plausible to our most experienced forecasters, show higher regional rainfall than has ever been observed.
“The computer models are telling us that these could happen - we just haven’t seen them yet.”
The new data comes on the tenth anniversary of devastating summer floods in large parts of Yorkshire. More than 7,000 homes and 1,300 businesses in Hull were damaged, and the River Don burst its banks, flooding Sheffield and Doncaster.
In June of 2007, 111mm of rainfall was recorded at Fylingdales in North Yorkshire and there were fears that the dam wall at the Ulley Reservoir near Rotherham would burst. Five people died that month.
The new analysis revealed an eight per cent risk of record monthly rainfall in south east England in any given winter.
When other regions of the country were also considered, the chances of at least one of them being hit by a record deluge rose to 33 per cent.
Four regions - the north east including Yorkshire, south-east, the Midlands and East Anglia - were said to have met the threshold set for a high risk of extreme rainfall.
Meteorologist Prof Richard Allan, from Reading University, said exceptional seasonal rainfall in the UK was the result of a “perfect storm” of atmospheric influences.
He said: “Using serious number crunching power, the new study plays back thousands of possible weather patterns that emerge from detailed computer simulations of recent decades, some of which produce more extreme rainfall events than have actually been experienced to date.
“As the planet continues to warm due to human-caused greenhouse gas emissions, extra moisture in the air will fuel increasingly intense rainfall causing a continued rise in the risk of damaging events into the future.”
His colleague, Prof Len Shaffrey, added: “Using weather and climate models to better understand the probability of extreme weather is an important method that is becoming more widely used to help inform those dealing with weather impacts about the risks of extreme events.”
Meanwhile, Yorkshire can expect an “unsettled regime” of rain and wind, mixed with bursts of sunshine, for at least the rest of July, the Met Office said.
There will be sunny spells today before rain sweeps in from the south west tomorrow. The heaviest showers and strongest winds are likely to be in the north west, but the forecast for the weekend is showery everywhere.
High pressure may bring more settled conditions and hotter temperatures from August 6.
But by the middle of August, signals “become mixed”, reducing confidence in accurate forecasting.