A relatively deep area of low pressure is tracking past the north of Scotland today and is then expected to head south into the North Sea tomorrow.
This will bring some strong winds to northern Scotland tonight, then to the east coast of England tomorrow – particularly through the afternoon.
These northerly winds are expected to gust up to 50-60mph, which is unlikely to cause any wind damage but could generate some big waves in the North Sea.
The Met Office has issued a warning this possibility as the big waves could combine with a storm surge to overtop sea walls and potentially flood some coastal roads.
A spokeswoman for the Environment Agency said: “Strong winds and large waves could cause minor disruption along the North Sea coast on Thursday from Yorkshire to Essex. Spray and waves may overtop sea walls and people are urged to stay safe and avoid coastal paths and promenades. The high winds and localised flooding on roads could make driving conditions difficult in coastal areas.”
But what is a storm surge?
Essentially this is a very localised rising of sea level – independent of tides – related to the track of an area of low pressure (storm) and its accompanying winds.
The storm causes this surge of water in two ways. Firstly, strong winds push water in their direction of travel, causing water to ‘pile up’ on coasts facing into the wind.
The second element of a storm surge relates to differences in air pressure. Areas of low pressure are always relative, meaning the air surrounding them must be at a higher pressure.
These areas of high pressure push down on the surface of the ocean, forcing water towards areas of lower pressure to create bulges in the sea level. For each 1 hPa drop in pressure, sea levels rise by up to 1 cm.
Bulges move with a low pressure as it tracks across the sea. North Sea areas are particularly prone to storm surges because water flowing south cannot escape through the narrow Dover Strait and the English Channel.
When storm surges combine with higher tides and big waves they can cause localised issues along coasts.