Forecasters say tornadoes and 5cm hail are a possibility from tonight’s storms

Thunderstorms are local, and the most severe impacts from them, such as large hail, strong winds and funnel clouds (tornadoes) are even more local. So only a very small fraction of the population will see these conditions, however they have the potential to produce power cuts, and travel disruption that could potentially affect a larger swathe of the population.

The Forecast: thunderstorms are forecast to break out across north western parts of England later this evening. Most computer models are forecasting large thunderstorms near Merseyside, Lancashire and moving north perhaps into Cumbria, with other parts of Northern England at risk. There is also a significant chance of storms affecting Central / Southern Scotland later in the evening / tonight. These storms look pretty severe, and fairly slow moving to, which contrasts with the fast moving storms of last Tuesday night. Forecasters at ESTOFEX (a European storm forecasting agency) are also suggesting there is a very isolated risk of tornadoes / hail 5cm in size. A second are of thunderstorms looks likely later in the night for eastern England, that can be seen below.

Thunderstorm Risk Zone 1: Earlier this evening / up to around 2am.

This means heavy rain is more of a risk. And in some places, there is the potential for some supercell thunderstorm risks. A supercell is a thunderstorm that holds enough energy / size to begin to rotate, and this rotation can increase mixing between air layers overhead, producing a risk of both hail and also very strong wind gusts. Some travel disruption is possible later on. Frequent lightning means some power cuts are also possible. As mentioned, not everywhere within the thunderstorm will see these most severe impacts (hail, strong winds).

RISK ZONE 2: Later in the night / early hours.

Later on in the night, increasingly from midnight and then into the early hours, there is the likelihood for a second batch of intense thunderstorms. This time, the focus is on more central, eastern and south eastern parts of England, from about midnight through to the early hours.

These storms might not be quite as severe as the ones further north west, however they could still produce some frequent lightning, hail and the risk of some surface water flooding. These storms could rumble well on into Friday across eastern parts of the country. This means there could well be a further risk of flooding in these areas on Friday.