8:02PM, Thu Jun 28, 2012

Chaos In Tyneside Caused By Dangerous Super Cell Thunderstorm

By Hugh Macknight Location: Newcastle

Forecasters said the storm which hit Newcastle was part of a band of rare super cell thunderstorms that swept across the country today.

Super cell thunderstorms were common in areas like the plains of the US Midwest but made up just 1% of storms in the UK, according to Paul Knightly, senior forecaster with Meteogroup, the weather arm of the Press Association.

They can do "disproportionate damage" by bringing with them large hailstones, tornados, heavy rain and and high winds, he said.

Three of them had been caused by a "Spanish plume", a warm weather front heading north from Iberia which has risen over cooler Atlantic air as they meet over the British Isles, leading to powerful thunderstorms, he added.

"They (the plumes) happen from time to time and we get some massive thunderstorms and large hailstones," he said.

"But today had the added factor of high wind-shear (sideways movements). What that does is cause the thunderstorms to become more prolonged, and when that happens they can get more intense.

"Today they were rotating; it is called a super cell thunderstorm.

"To get one is pretty rare, to get three is very unusual indeed."