WILTSHIRE should be spared the winter 'weather bomb' set to hit the north of England, Ireland, Scotland and Wales this evening.

But the Met Office has issued a severe weather warning for Friday when a second storm is predicted to hit more southerly areas.

Stormy weather has already caused disruption across parts of the UK today with power cuts, ferry and train cancellations and difficult driving conditions.

The process behind the storm - rapid cyclogenesis - is known colloquially as a weather bomb.

The Met Office has issued an amber warning for the west coast of Scotland, the Highlands and Islands, Orkney, Shetland and Northern Ireland.

Steve Willington, chief forecaster, said: "A period of severe gales is likely over northern and central Britain, as well as the potential for storm force winds over north-western coastal areas of Scotland."

He said of later in the week: "An area of low pressure has the potential to develop in the mid-Atlantic and then run quickly east northeast across the northern half of the UK during the first half of Friday.

"To the south of this low pressure centre, gales, or severe gales are likely to develop, with gusts in excess of 50mph quite widely in the warning area.

"Gusts of 60-70mph may develop in exposure, especially along Irish Sea and English Channel coasts.

"A period of heavy rain may also make for tricky driving conditions at times, especially across south Wales and southern England.

"This is a complex development and details may yet change. Therefore this alert is likely to be updated in the coming days as confidence grows in track and timing of this system."

Weather bomb fact file:

What causes one?

Warm sub-tropical air over the mid-Atlantic is colliding with cold Arctic air, which is causing a huge temperature contrast.

The bigger the contrast, the faster the jet stream moves and when it moves as fast as it is now the jet stream sucks up air, causing pressure to fall and a storm to form.

Why is it called a weather bomb?

The term relates to how rapidly a deep area of low pressure forms. When pressure falls more than 24 millibars in 24 hours, it can be called explosive cyclogenesis or a weather bomb.

Will more storms follow?

Further areas of low pressure in the next week will increase the risk of UK gales, heavy rain and snow, but that is expected to fall mainly over northern hills and mountains.