Scotland storm: why so powerful?
A vigorous area of low pressure passed just to the north of Scotland last night, bringing hurricane-force winds, with a gust of 113mph recorded at Stornoway on the Western Isles.
Across a large part of Scotland, damaging gusts of wind in excess of 70mph were recorded, resulting in most rail services being suspended as a safety precaution.
Even though the storm was well forecast a few days in advance, inevitably such ferocious winds were going to cause disruption.
Why was the storm so powerful?
An extremely fast-moving jet stream has been speeding across the Atlantic ocean in the past 24 hours, travelling at around 280mph 30,000ft up in the atmosphere, according to weather charts issued by the Met Office.
Such a powerful jet stream is being driven by a much stronger than normal temperature contrast at the moment, between very cold arctic air and warm sub-tropical air off the east coast of the US.
This fast-moving ribbon of air high up in the atmosphere is sucking air upwards from the surface, faster than it can be replaced. This causes pressure to fall rapidly and a storm to form.
The jet stream is not only responsible for spawning these storms, it also acts as an atmospheric superhighway, catapulting them our way.
Top wind gusts
While some weather stations on the tops of mountains in Scotland recorded the strongest winds (140mph gusts at the top of Cairngorm summit), wind gusts at more representative low level locations were still exceptional;
Stornoway airport – 113mph
Loch Glascarnoch – 110mph
Altnaharra – 97mph
Wick airport – 93mph
Edinburgh Blackford Hill – 90mph
Kirkwall – 86mph
Damage and disruption
The stormy weather caused widespread transport disruption on road and rail, with most rail services in Scotland suspended.
The Aberdeen Sleeper hit a tree at Cupar this morning during #scotstorm. Tree was cleared & Sleeper slowly continuing pic.twitter.com/rDIGWiNyTX
— ScotRail (@ScotRail) January 9, 2015
There were also reports of tree being blown over, as well as damage to some buildings.
This is why the Forth Road Bridge is currently shut #scotstorm pic.twitter.com/xlKBVSLxLU
— Radio Clyde News (@RadioClydeNews) January 9, 2015
Is there more to come?
Another storm is going to pass a little further to the north of Scotland during Friday night, bringing more windy weather, although the peak wind gusts will generally be 50-70mph, with 90mph possible over Shetland.
While the peak wind gusts for this second storm will be notably less, they will occur over a wider area, with much of the UK seeing gusts of wind in the range of 50-70mph for a time – especially for coasts and hills.
It will also turn significantly colder for Scotland, Northern Ireland and northern England this weekend, with frequent snow showers, leading to more weather warnings being issued.
Snow could even accumulate to low levels for a time across Scotland and Northern Ireland, where there could be 2-4cm. However, in northern England, it should be confined to the hills.
Don’t forget, you can get the latest forecast on the Channel 4 Weather website. I’ll also be posting regular updates on Twitter – @liamdutton
Images: Eumetsat, Met Office, Wetterzentrale