Britons are warned to stay at home and ‘prepare for the unexpected’ as Storm Floris unleashes hurricane-force winds on a 165mph jet stream.
Almost the entire country is on alert for up to 90mph gales to drive torrential downpours and thunder.
Storm Floris – an unusually deep and unseasonable storm spawned in America – threatens disruption into the early hours of tomorrow.
Travel experts have warned Britons to postpone journeys or take extra care on roads and motorways.
Met Office Meteorologist Aidan McGivern said: “This is really quite unusual for August and really quite exceptional, even in a windy part of the country.
“In some spots, there will be more than 50mm of rain, but in some of the wettest spots, more than 70mm to 75mm [3ins] of rain.
“Winds start to pick up from the middle of the afternoon, and by evening, we have widely 50mph to 60mph gusts across parts of Scotland, Northern Ireland and northern England, and in places, the risk of 70mph.
“There is a risk on Monday night that it will tighten even further, and there is a risk that winds will touch 80mph or slightly more in northern Scotland on Monday night.”
MET OFFICE
|Storm Floris arrives on the Jet Stream
Floris’ assault is made more unusual by the path it has taken into the UK, spawned in the United States and dragged in by the jet stream.
The storm will cross an unusually powerful jet, gathering strength as it does, before whacking into the UK west coast.
McGivern said: “It comes out of north America as a fairly shallow area of low pressure, but the important thing is that it is interacting with the jet stream, and the speed of the jet stream picks up strength.
“The area of low pressure is running into that strong jet stream, 165mph, and that is what helps to deepen it rapidly and when we can experience the biggest problems from these lows.
“On Monday, it moves onto the cold side of the jet stream in a zone that is particularly favourable for deepening that area of low pressure.”
WX CHARTS
|80mph plus wind gusts are expected
The first impacts across northern Scotland will be from torrential rain before winds pick up later in the afternoon, he added.
The AA has warned drivers to postpone journeys until the storm has passed amid warnings for widespread disruption.
Spokesman Shaun Jones said: “If you’re planning a journey – especially through exposed or rural areas – it’s worth checking the latest forecast, allowing extra time, and being prepared for the unexpected.
“If you can postpone your journey until the worst of the conditions pass, it might be advisable to do so.”
An amber 'danger to life' Met Office wind warning is in force this morning across Scotland and northern England.
While the worst of the weather will have passed by Tuesday morning, the north will stay wet and gloomy.
AccuWeather lead international forecaster Jason Nicholls said: “A storm will bring heavy and thundery rain across the UK on Monday.
“Showers will linger in the north on Tuesday, while the south remains dry and gets some sunshine before most enjoy sunshine and dry weather during the middle of the week.”
Jim Dale, meteorologist for British Weather Services and social commentator, added: “The storm will have cleared by Tuesday with a calmer picture for the rest of the week.”