Britain forecast horror 938-mile-long storm with 18mm of rain to fall in just 3 hours

This incredible weather map shows the UK is braced for a brutal 938-mile-long storm - with nearly 20mm of rain expected to batter some areas in just three hours.

The majority of the UK is covered in either a red, orange, green or blue hue in the map issued by forecasters at Ventusky, which claimed the storm would see wind gusts top 50mph. The band of low pressure, expected on Tuesday September 24, is huge - as it runs from around the Faroe Islands in the north to Brest in France in the south - approximately 938 miles.

It'll be wet everywhere, other than East Anglia and a slither of Southeast England. North Wales, notably across Eryi National Park (Snowdonia), will see the heaviest rainfall, with around 18 to 19mm feared to lash down in just a few hours. Around 15mm of rain will fall in the same timeframe across Perth and Kinross and Aberdeenshire, say forecasters.

And fog and mist will combine with the rain to leave dangerous conditions across northern England, particularly hazardous for motorists during morning rush hour. The maps indicate the thickest of the fog will be across Cumbria, including the Lake District, where again around 15mm of rain will fall.

READ MORE: Dunelm's thermal curtains are perfect for the colder months and they 'hang beautifully'

Winds will be southerly, and strongest across the northeast coast of Scotland. Gusts of around 50mph are expected along the coastlines of Aberdeen, Fraserburgh and John O'Groats among other areas. Winds will also be fierce along the Irish Sea coast, from Merseyside to Cumbria, and some southern areas.

The Met Office, on its long-range forecast which covers Wednesday September 18 to Friday September 27, writes: "Daytime temperatures will likely be above average for many regions, although some cool nights are possible with mist or fog patches developing overnight. Fairly strong winds could affect the south at times."

Temperatures this week have plunged significantly. The Met Office said the mercury dropped to -2.7C in Topcliffe, North Yorkshire, on Friday. It was also below freezing in Llysdinam, Powys, and in South Newington, Oxfordshire.

Snow fell across the Scottish mountains in the week, but the Met Office told us this "isn't unusual" - even in September. Although it will remain cold today and tomorrow across the Scottish Highlands, no further wintry showers are expected, the meteorologists said.