Weather explained: What are weather fronts?

With all the talk of cold fronts lately, we thought it might be useful to dive a little deeper into what weather fronts actually are.

Weather conditions across the UK and Ireland are often changeable, with this change mainly due to weather fronts, but do you know what they are?

There are three main weather fronts: a cold front, a warm front and an occluded front.

A cold front is the name given to the leading edge of a cold air mass when it is replacing a warmer air mass. As a cold front passes, conditions become windier with a drop in temperatures and heavy rain. The air behind the cold front is then cooler and drier.

As you may suspect, a warm front refers to the leading edge of a warm air mass. When this front reaches colder air it rises- as warm air is lighter than cool air - replacing the cool air and bringing an increase in temperatures.

You will often see high level clouds like cirrus ahead of an approaching warm front. However, as the front passes, the clouds can become lower and rain is possible with thunderstorms around the front if the air is unstable.

Finally, we have an occluded front. These occur when cold fronts catch up with a warm front meaning the warmer air is lifted from the surface. There is often some rain along an occluded front, but when the front passes, the air is usually drier and the sky is clearer.