Thunderstorms, lightning and flood risk to continue
Whilst the past week has seen some warmth and sunshine across much of the UK, there’s also been plenty of thunderstorms, giving frequent lightning and intense downpours of rain.
The slow-moving nature of the heavy showers and thunderstorms has meant that some places have been inundated with a lot of rain in a short space of time, causing flash flooding.
With the potential for more thunderstorms and localised flash flooding during the next few days, I thought I’d explain what’s going on.
What’s causing the thunderstorms?
In the world of weather, to get clouds to form and rain to fall, air needs to rise upwards in the atmosphere. The more readily air rises, the bigger the clouds and the heavier the rain.
At the moment, and for the rest of the week, a very slow-moving area of low pressure will be over the UK, which means air can readily rise upwards through the atmosphere.
Also, there is some warm, moist, humid air across us at the moment. Moist, humid air acts as a source of energy in the atmosphere – in the form of latent heat – providing fuel on which thunderstorms can thrive.
Where is most at risk?
During the next few days, England and Wales are most at risk from thunderstorms and intense downpours of rain.
The Met Office has issued a yellow “be aware” warning, highlighting the places most at risk, where 15-25mm could fall in just an hour.
Such intense rain will bring a risk of localised flash flooding – especially in urban areas where there is a lot of man-made surfaces, such as tarmac and concrete.
The Environment Agency’s three-day flood risk forecast also emphasises the risk in the coming days, mentioning the risk of travel disruption and isolated property flooding.
Scotland and Northern Ireland will see some showers, but thunderstorms look less likely here, so the risk is lower.
Hit and miss
Once place might have a deluge of rain with flash flooding, whereas another location just 5-10 miles away will stay dry and have nothing at all.
So the main message is that whilst a few places will get a lot of rain in a short space of time, most places will avoid the worst of the downpours.