Storm Brian: WORSE than Ophelia - Derry bracing itself for 'WEATHER BOMB'

At present, Storm Brian is out over the Atlantic Ocean and is, what meteorologists describe as, a weather bomb.

A weather bomb is when the pressure inside a low pressure system falls very rapidly, creating violent winds.

In order for it to be categorised as a weather bomb the central pressure of the low pressure system must fall 24 millibars inside a 24 hour period.

It's linked to the meteorological phenomenon known as rapid or explosive cyclogenesis. That is where dry air from the stratosphere flows into an area of low pressure.

This air within the depression then rises very quickly and increases its rotation which in turns deepens the pressure and creates a more vigorous storm.

Storm Brian is expected to bash Ireland and parts of Britain on Saturday.

Whilst the winds are not expected to be as strong as those of Ophelia earlier in the week, it's predicted that many trees loosened by Opehlia could cause problems.