Weather Watch: First thunderstorms spark lightning, rain and hail

During Sunday afternoon, some portions of the Aylesbury Vale, particularly towards the Chilterns, witnessed a spectacular display of nature’s fireworks with the first thunderstorms of the year.
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The towering thunderclouds gave a number of lightning strikes, torrential rain and even hailstones.

Lightning occurs within rapidly growing cumulonimbus clouds, whereby a separation of electrical charge takes place.

Positively charged particles gather near the top of the storm, and also in its lowest portions, while negatively charged particles often fill the middle regions of the storm cloud.

As soon as this charge-separation becomes too great, a bolt of lightning attempts to equalise this charge-difference, much as occurs when we give ourselves static shocks, but on a much larger scale.

It is estimated that about three quarters of all lightning strikes occur within the thunderstorm cloud itself, known as intra-cloud lighting.

Much of Sunday afternoon’s lightning did just this.

The remainder of lightning strikes snake between the cloud and the ground, known as cloud-to-ground lighting.

Lightning can be extremely powerful, reaching about 100 million volts, and direct strikes on people or animals will often prove fatal.

The sudden rise in temperature to over 30,000 degrees Celsius causes the air to explode around each lightning strike, and it is this that we hear as thunder.

Today will stand a good chance of scattered heavy showers with a risk of lightning, and it will be very windy for early May.

After a drier day tomorrow, showers will return on Friday and the weekend looks set to remain fairly unsettled.

Temperatures will be close to normal for the time of year but feeling cooler in the wind.