Storm Eunice could unleash a devastating sting jet, not seen in Britain for more than three decades, say forecasters.
The cyclone storm system is expected to bring hurricane winds of 100mph in parts of the UK as many Brits prepare to hunker down for the day.
The Met Office has issued two rare red warnings, only the 11th time this highest level has been implemented by the national weather agency.
Schools, business and transport have been locked down, with an array of other warnings to remain through the weekend, reports Wales Online.
The worst of the weather is forecast for South Wales and the south of England.
A sting jet is a rare system that sees an incredibly powerful, highly concentrated area of wind within a high-speed storm.
The worst of the damage caused in the Great Storm of October 1987 has been attributed to the phenomena - so named because its satellite photos resemble a scorpion's tail.
They are just 30 miles in width and last up to four hours in storms that pass across Europe.
The 100mph jets form when a stream of cold air is pulled down into a warmer system at the head of a storm, creating evaporation and accelerating air speeds.
Dr Ambrogio Volonté, of the University of Reading, described Eunice as a “bomb” cyclone, similar in structure to the 1987 storm.
According to The Telegraph, Eunice is a type of cyclone where the cold front does not catch up with the warm front, creating a gap which can pull strong winds towards the ground - creating the sting jet.
Dr Volonté added: “It was the sting jet that caused the catastrophic damage associated with the ‘87 storm."
Met Watch UK says Storm Eunice is “currently undergoing explosive cyclogenesis in the Atlantic and will likely have a Shapiro-Keyser cyclone structure as it arrives”, which means it has a greater chance of a sting jet.
Storm Eunice was forecast to last from 3am today, with strong winds then lasting through the weekend.
Major incidents have been declared across come cities and counties, with people advised not to travel unless essential.
Eunice comes on the back of Storm Dudley, which claimed one life and left thousands of people without power.
As well as warnings of high winds there are also warnings of snow for parts of the country.
