A tornado may hit parts of the UK during Storm Isha, with danger-to-life wind warnings in place ahead of 90mph gusts, forecasters warn.
Multiple weather warnings, including two amber wind alerts, were put in place by the Met Office across the country for Sunday, when the storm will swoop in.
And a “tornado watch” zone was issued for Northern Ireland, as well as parts of Scotland and northern England by the Tornado and Storm Research Organisation (Torro) on Sunday afternoon.
It means a “strong tornado” is possible in those regions.
Meanwhile, Met Office forecaster Marco Petagna told the PA news agency: “There is a potential that we could see the odd isolated tornado largely tied in with the squally cold front mainly in western parts of the UK on Sunday evening.
“They can cause some significant damage but often on a very localised scale, they often don’t tend to last very long.”
Rail, sea and air travellers were hit with disruption on Sunday, with closures, cancellations and delays expected across a number of services.
Damage to homes and buildings, falling trees, power cuts, flying debris, large waves and even some flooding in places should also be expected, forecasters warn.
The Met Office said 90mph winds hit Capel Curig in north Wales during the afternoon.
Meanwhile, 76mph gusts were recorded in Loftus, North Yorkshire and 75mph winds blasted Brizlee Wood, near Alnwick in Northumberland, and Emley in Huddersfield.
Agencies across Cumbria have declared themselves on standby for a major incident, while elsewhere a person was hit by debris in Belfast.
Sellafield nuclear site in Cumbria said it closed as a precaution.
Met Office meteorologist Tom Morgan said: “We’re expecting widespread gales to affect the UK, amber warnings are in place for large parts of the country.
“There’s the potential for danger-to-life and damaging winds potentially leading to some power cuts in places, some large waves around coastal regions could bring some debris onto roads and trees could come down.”
He added: “We have a wind warning in place across the whole of the UK, it’s pretty unusual for the whole of the country to be under a blanket wind warning.”
The Met Office has said “everybody” will be affected by the storm.
Two different amber warnings are in place across most of the UK from 6pm to Monday morning, saying 70mph winds should be expected inland, with gusts of 80mph on coastal regions.
In parts of Scotland, northern England and Northern Ireland winds could reach 90mph.
A yellow wind warning also covers the UK, including parts of London and the south-east, while four rain alerts were in place around the country.
Nearly four inches of rain could fall over a few hours in some regions and cause localised flooding, with 23 flood warnings already in place across England.
Network Rail said 50mph speed restrictions have been imposed across most routes to keep passengers and trains safe from falling trees and debris blown onto tracks, with disruption likely to continue into Monday morning.
Scotland’s railway operator cancelled all of its services after 7pm and there will also be no Monday morning rush-hour services.
One train struck a tree at Crosshill, near Glasgow, while Network Rail teams responded to reports of a fallen tree on the overhead wires at Gartcosh, near Cumbernauld.
A number of rail services across the country warned against travel, while air traffic control restrictions were in place, leading to some flight cancellations.
National Air Traffic Services (Nats) told PA: “Due to adverse weather conditions across the UK, temporary air traffic restrictions are in place. Restrictions of this sort are only every applied to maintain safety.
“Our teams are working closely with airports and airlines to minimise disruption. Passengers should check the status of their flight with their airline.”
British Airways said: “Like other airlines, we have had to make schedule adjustments due to the adverse weather conditions across the UK and Europe caused by Storm Isha.
“We’ve apologised to our customers for the disruption to their travel plans and our teams are working hard to get them on their way as quickly as possible.”
Ferry company Wightlink also warned of potential disruption, while the RAC warned drivers to lower their speeds and even consider delaying journeys.
Storm Isha is the ninth named storm to hit the UK since the season began in September.
Each storm is named when it poses a risk to people and they are given names beginning with consecutive letters of the alphabet.
The record number of named storms in one year is when the Met Office began the practice in 2015/16, with Storm Katie being the 11th and final storm of the season.
If there are three more named storms between next week and August, this year will mark a new record.
Cold Arctic air pushing south into North America is making the jet stream more active, the Met Office said, and because it flows from west to east, it is bringing stormier weather to the UK.