Met Office weather news: Freezing rain could fall tonight - what it is and the chaos it can bring

The Met Office has said that the below-average temperatures which have settled across the UK in the last week could produce an unusual phenomenon - which has the capacity to cause chaos.

While today is likely to stay mostly dry, and bright in a few places, winds will start to arrive in the south west, and are likely to bring rain with them.

Tonight the Met Office has predicted: “Mostly dry with clear spells and a frost. However, rain, with brisk winds, edging northeast into parts of Northern Ireland, Wales and southwest England. Patchy snow or freezing rain possible.”

Friday is likely to be chilly again, and cloudy and breezy across Northern Ireland, Wales and southwest England with rain and perhaps hill snow, and this weather front will reach western Scotland later. Forecasters say elsewhere frost will clear and it will be mostly fine.

And there is a loose warning for snow at the weekend, as the Met Office says: “Mostly dry, often cloudy and cold in the east and northeast. Weakening bands of rain and perhaps snow moving in from the west and southwest, where turning milder. Often breezy.”

The Met Office says freezing rain is “a rare type of liquid precipitation that strikes a cold surface, and freezes almost instantly”.

It adds: “The conditions needed for freezing rain are quite specific and we don’t see this phenomenon very often in the UK. It can produce striking effects, as the rain drop spreads out momentarily across the surface before it freezes, encasing the surface in a layer of clear ice.”

However, while it may look pretty it can be treacherous. The Met Office warns: “The weight of the ice can sometimes be heavy enough to bring down trees and power lines, and the glaze of ice on the ground effectively turns roads and pathways into an ice rink. The freezing rain can also prove extremely hazardous for aircraft.”

Freezing rain is more common elsewhere in the world, which tend to see sustained cold weather more often. In America the weather phenomenon is called an ice storm.

The Met Office explains that freezing rain normally starts as snow, sleet or hail, but passes through a layer of air that’s above 0C on the way down to the ground, melting into a liquid water droplet. “If these droplets then fall through a zone of sub-zero air just above the ground, they become supercooled. When these supercooled droplets strike surfaces that are close to or below freezing, they freeze on impact forming a glaze of ice.”