Northern Ireland

Funnel cloud caught on film in County Antrim

Doagh tornado Image copyright APril Matchett
Image caption This suspected 'tornado' was spotted near Doagh in County Antrim

An unusual funnel cloud was spotted near Doagh, County Antrim, on Sunday.

These pictures, sent in by April Matchett, show the distinct appearance of the cone-shaped cloud.

The weather over the weekend was generally unsettled and some areas experienced very heavy downpours, with hail and thunder.

This weather led to the formation of a funnel cloud, These are often mistaken for a tornado.

But a funnel cloud can only be a tornado when it touches the ground.

These clouds rotate and extend downward from the base of a thunderstorm.

When it reaches the ground, it is called a tornado. If the cloud had formed over water, it would be called a water spout.

Image copyright APril Matchett
Image caption Tornadoes require a 'trigger' to lift moist air into the atmosphere

No two tornadoes are the same and most are formed out of thunderstorms, given certain conditions.

They require lots of low level moisture and a "trigger".

This could be a mountain range, a cold weather front or even a local convergence of winds, such as warm winds coming off the land clashing with sea breeze coming on shore.

This "trigger" is necessary to lift the moist air up into the atmosphere.

Once the air begins to rise and becomes saturated, it will continue rising to several thousand feet to produce a thunderstorm cloud.

This can only happen if the atmosphere is unstable, which means the temperature falls rapidly as height increases above the ground.

Finally, tornadoes usually form in areas where winds at all levels of the atmosphere are not only strong, but also turn with height in a clockwise direction.

Hence the spinning motion of the "twister".

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