Storm Doris has rapidly deepened over the last 24 hours as it has under gone what the Met Office call Explosive Cyclogenisis making it a Weather Bomb.
In certain circumstances the central pressure inside a frontal depression can fall at a very rapid rate forcing violent winds from the system known as ‘bombs’.
What is a weather bomb?
A ‘weather bomb’ is not a perfect meteorological term but is defined as an intense low pressure system with a central pressure that falls 24 millibars in a 24-hour period.
A better description can be more directly linked to the meteorological phenomena known as rapid or explosive cyclogenesis. This is where dry air from the stratosphere flows into an area of low pressure. This causes air within the depression to rise very quickly and increases its rotation, which in turn deepens the pressure and creates a more vigorous storm.
How Storm Doris is affecting the UK
Dozens of flights into and out of Heathrow Airport are expected to be cancelled, with other passengers likely to experience delays.
A Heathrow spokesman said: “Strong winds and poor weather across the UK have resulted in approximately a 10% reduction to Heathrow’s flight schedule. With Heathrow operating at more than 99% capacity, there are no gaps in the schedule that can be used for delayed flights and as a result, some passengers may experience disruption to their journeys today.”
Aer Lingus cancelled 12 flights between the UK and the Republic of Ireland in anticipation of the winds.
Network Rail also warned of delays and cancellations after imposing speed restrictions for safety reasons. Limits of 50mph would be observed on some services run by Southeastern, Arriva Trains Wales, Chiltern Railways, Grand Central, TransPennine Express and Virgin Trains East Coast.
Highways England has issued a weather alert on major roads. Particularly at risk are high-sided vehicles, caravans and motorbikes and drivers are “strongly advised” to avoid travelling on some stretches of road in Yorkshire, the Midlands, and the East and North West.
Richard Leonard, head of road safety at Highways England, said: “(We) are urging drivers to consider changing their plans if necessary and to slow down in stormy weather.”
Meanwhile, up to 15cm of snow could fall across parts of Scotland and north-east England in treacherous, blizzard-like conditions. Weather warnings have been upgraded to amber across Scotland’s central belt, the Borders, Dumfries and Galloway, Tayside and Fife.
Amber warnings predict strong winds and heavy rain in parts of north Wales, the Midlands, and the East and North West, while winds as fast as 60mph are also expected to batter southern England.
Storm Doris is expected to move on quickly, with the worst of the weather gone by Thursday evening. While further Atlantic gusts will bring more rain and wind through the weekend and into next week, they are not expected to reach the heights of Doris.